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THEORETICALLY POSSIBLE HAMMOND FACTORY TONEWHEEL GENERATOR OUTPUT LEVELS FOR THE HAMMOND ORGANS OF THE VARIOUS ERAS OF PRODUCTION.

By Kon Zissis

I have never seen any Hammond factory chart that shows the official correct factory TG output levels measured directly from the TG terminal strip in millivolts Peak to Peak ( mVpp ) or in millivolts RMS ( mV RMS ) . However there is an Alan Young factory report from 1969 which has some information . Mike Fulk posted this to Hamtech in 1998 and it says the following:

Report by Alan C Young, Senior Product Analysis Engineer:

"Part 1 Recognizing The Hammond Sound. Levels.

The output voltage of each tone source (tone wheel coils) follows a prescribed "pre-emphasis" schedule varying from 3.2 to 8 mV. The upper portion and lower portion rise at about 2 db per octave from the mean low level at about 250 Hz. This contour has been modified only once, in 1956, for the convenience of our test equipment procedure."

250 Hz is between the TG notes 36 and 37. 3.2 mV RMS is 9.05 millivolts peak to peak ( mVpp ) and 8 mV RMS is 22.62 mVpp. To convert sine wave frequencies in mV RMS into mVpp , you multiply the mV RMS level by 2.828 to get the mVpp level. To convert the complex waveform mV RMS level of the bass pedal TG notes 1 to 12 into mVpp , you multiply the mV RMS level by 4.7. For example ,a sine wave at 3.2 mV RMS multiplied by 2.828 equals 9.05 mVpp and a complex waveform bass pedal note at 14.89 mV RMS multiplied by 4.7 equals 69.83 mVpp

According to most of the measured TG output curves that l have , Alan Young's quoted 9.05 mVpp seems weaker than the more common 10 to 11 mVpp for the TG note 36 and 22.62 mVpp for the TG note 91 seems too strong compared to the more common 15 to 20 mVpp levels of the measured TG’s in my TG spreadsheet. I do not know how accurately these Alan Young quoted mV levels compared to the actual Hammond factory TG output curve specs used by the Hammond employees who calibrated the TG's, but l have made up a theoretical output curve by drawing a straight upward line starting with 9.05 mVpp for the TG note 36 and then going all the way up to 22.62 mVpp for the TG note 91 and l have printed out these output levels for the TG notes 36 to 91 further down below.

I have the measured TG output levels of over sixty organs in my amassed collection of TG output levels data in my TG data spreadsheet including pre 1964 TG's with wax capacitors , pre 1964 TG's that have been recapped with new capacitors and post 1964 TG's with red mylar capacitors .

By looking at the all the measured TG data in the TG spreadsheet l can see a definite trend in the TG output levels. Although each TG has slight differences with individual notes sticking out or being weaker than others , there is a definite similar overall pattern with most of the output curves.

There is the measured TG output curve of a recapped 1937 BC but all of the output levels seem a little weaker than all that of all the other TG’s in my TG spreadsheet but apart from the levels of the sine wave ‘’bass all the way down ‘’ TG notes 1 to 12 , the rest of the TG notes 13 to 91 have an approximately similar looking output curve shape to that of the 1940’s CV’s and early 1950's B2 and C2 TG's and a 1956 B3 TG.

I have measured the TG output levels of a wax capped 1937 BC and the TG notes 1 to 48 were similar to that of the output levels of the same TG notes of the other recapped 1937 BC. The levels of the wax capped TG notes 49 to 91 had the predictable weakened output level characteristics of TG's with aged deteriorated wax capacitors.

The earlier Model A organs and the BC organs with serial numbers between 4000 and 5075 did not have the manual tapering scheme but instead the manual key contact resistance wires all had 16 ohms resistance wires although I have read about the possibility that the key contact resistance wires for the folded back treble TG notes on the upper octaves of the manuals might have been 23 or 24 ohms instead of 16 ohms. Because the manuals of the earlier Model A and the earlier BC organs had the untapered manuals with the 16 ohms key contact resistance wires, this would have sent very strong TG signal levels to the input of the organ preamps so therefore it is possible that the TG's of these early Model A and BC organs might have been calibrated with slightly weaker output levels and then when the Hammond factory introduced the manual tapering scheme sometime in 1937 they might also have changed the factory TG calibration curve by slightly increasing the output levels of all the TG notes.

The TG output levels of the early era organs such as the 1940’s CV's ,the B2, the C2 and a 1956 B3 have noticeably stronger complex waveform bass pedal TG notes 1 to 12 output levels and slightly stronger bass and lower midrange TG notes 13 to 36 output levels compared to the TG's from 1959 up to the 1970’s.

Many of the recapped or mylar capped TG’s from 1959 onwards also have a similar overall output curve. By studying all of these similar output curves , l have made up a few ‘’theoretically possible factory output levels ‘’ output curves which might possibly be very close to the factory intended TG output curve. These are shown further down below.

There is a very old output curve graph called ‘’ Approximate output voltage readings of organ generator frequencies 1 to 91 ‘’. This graph has two output curves, the first output curve is a stronger curve with a significantly stronger bass for the Model B organs with serial numbers between 4000 and 5075 that had the untapered manuals. The second output curve shows a noticeably weaker output curve with a significantly weaker bass response for the Model B organs with serial numbers above 5075 and the Model E organs with serial numbers above 8000. These organs had the manual tapering scheme.

This output curve graph gets it’s readings from the preamp GG output terminals with the expression pedal at full volume and the tone control being ‘’as set at the factory’’ , and the chorus controls switched off.

With the stronger output curve graph for the earlier Model B organs , the TG notes 1 to 49 are measured with the 16 ft drawbar pulled all the way out and the appropriate keyboard keys played. The TG notes 49 to 91 are measured with the 1 ft drawbar pulled all the way out and the appropriate keyboard keys played.

With the weaker output curve for the later Model B and E organs , the TG notes 1 to 36 are measured with the 16 ft drawbar pulled out and the appropriate keyboard keys played . The TG notes 37 to 48 are measured with the 5 2/3 ft drawbar and the appropriate keys played and the TG notes 49 to 91 are measured with the 1 ft drawbar pulled out and the appropriate keyboard keys played. Because of the sudden drop off in the bass response and the fact that the 5 2/3 ft drawbar is used for the TG notes 37 to 48 , it appears that this output curve is for the organs built after the manual tapering scheme and the bass fold back wiring was introduced.

Both the stronger and the weaker output curve levels of this graph are shown further down below.

The B3 / C3 service manuals has a chart of what seems to be the actual measurements of an existing B3 or C3 organ. These measurements were made by connecting each TG notes 1 to 91 to the preset panel bus bar # 4 ( fifth from the bottom ) whilst the voltage meter was connected the GG outputs of the AO28 preamp. The expression pedal must be at the full volume position and the chorus / vibrato controls should be turned off. Although the B3 / C3 manual does not mention this , the 1940’s Model G service manual does instruct that the tone control should be set to full brightness.

These output levels seem to be of dubious worth because they depend on the setting of the gain trimmer capacitor and the condition of the preamp and the actual TG calibration of the test organ. When experimenting I discovered that the organs with aged wax capacitors actually produce noticeably stronger output level readings for the TG notes 49 to 91 than the organs with the capacitors at the correct mfd values. I think that this has something to do with the fact that the TG notes are severely loaded down when they are connected to the busbars which have a very low impedance and this some how causes the TG notes 49 to 91 whose wax capacitors have gone off spec to produce a higher output reading.

As such these particular output levels are not reliable to be used as an authoritative guide to TG calibration and although the service manual states that you should connect the TG notes to the busbar #4 , I have noticed that with the gain trimmer capacitor set at the approximate factory setting of one and a half turns anti clockwise from zero , the output levels produced with the TG notes connected to the Busbar 4 seem too weak compared to the levels shown on the service manual chart. Connecting the TG notes to the Busbar 5 ( sixth from the bottom ) produces output levels closer to those shown on the chart. A number of other people who have tried out this method have also noticed that when they connected the TG notes to the the busbar 4 , the resulting output levels were too weak compared to the levels shown on the chart. This suggests to me that the test organ used for this chart may have had the gain trimmer capacitor set to a higher than normal level thus resulting in a hotter output from the preamp. The B3 / C3 service manual output levels are shown on a table further down below.

Here below are the actual output levels tables.

Here below is my own assumptive 'straight upwardly increasing line' output levels curve based on the minimal information mentioned on the 1969 Alan Young report specs for the TG notes 36 to 91.

9.05 mVpp for the TG note 36 seems too low compared to the more common 10 mVpp to 11 mVpp levels of the TG note 36 on most TG’s that are in my TG spreadsheet.

22.62 mVpp for the TG note 91 seems too high compared to the more common 15 mVpp to 20 mVpp levels of the TG note 91 on most recapped or red mylar capped TG’s that are in my TG spreadsheet.

The following measurements would be taken directly from the TG terminal strip.

TG             Alan Young     Alan Young
Note            mVpp            mV RMS
36              9.05            3.20

37              9.25            3.27
38              9.5             3.36
39              9.75            3.45
40              10              3.54
41              10.2            3.61
42              10.4            3.68
43              10.7            3.78
44              11              3.89
45              11.2            3.96
46              11.4            4.03
47              11.7            4.14
48              12              4.24

49              12.2            4.31
50              12.4            4.38
51              12.7            4.49
52              13              4.60
53              13.2            4.67
54              13.4            4.74
55              13.7            4.84
56              13.9            4.92
57              14.2            5.02
58              14.4            5.09
59              14.7            5.20
60              15              5.30

61              15.2            5.37
62              15.4            5.45
63              15.7            5.55
64              15.9            5.62
65              16.2            5.73
66              16.4            5.80
67              16.7            5.91
68              16.9            5.98
69              17.2            6.08
70              17.4            6.15
71              17.7            6.26
72              17.9            6.33

73              18.2            6.44
74              18.4            6.51
75              18.7            6.61
76              18.9            6.68
77              19.2            6.79
78              19.4            6.86
79              19.6            6.93
80              19.9            7.04
81              20.1            7.11
82              20.3            7.18
83              20.6            7.28
84              20.8            7.36

85              21.1            7.46
86              21.3            7.53
87              21.5            7.60
88              21.8            7.71
89              22.1            7.81
90              22.4            7.92
91              22.62           8.00

The TG output levels tables below are the output levels of the theoretically possible factory output levels that l have worked out by comparing the similarities of many of the TG curves in my TG spreadsheet.

I have no way of verifying how 100 percent accurate any of these output levels shown below are to the actual correct Hammond factory TG output curve but judging by the similarities of many of the measured TG output curves in the TG data spreadsheet , I believe that these output curves shown below do in fact represent a realistic example of a "typical" stock TG calibration and that these TG output curves do produce a very acceptable sounding organ so therefore I believe that these TG curves can be used as a realistic and reliable guide for someone who has a messed up TG calibration or if they have recapped the TG and the output levels of TG notes 49 to 91 are now all over the place and they want to get back to a more stock TG calibration with a smooth output curve.

The two columns shown here below are the theoretically possible output levels of the earlier Model A and BC organs built before the manual tapering scheme was introduced sometime in 1937.

The following measurements would be taken directly from the TG terminal strip.

TG            Early A & BC    Early A & BC
Note            mVpp           mV RMS
1               22              7.78
2               19.2            6.79
3               17.6            6.22
4               15.8            5.59
5               14.9            5.27
6               13.9            4.92
7               12.5            4.42
8               11.8            4.17
9               11              3.89
10              10.5            3.71
11              10.3            3.64
12              10.1            3.57

13              10              3.54
14              10              3.54
15              10              3.54
16              10              3.54
17              10              3.54
18              10              3.54
19              10              3.54
20              10              3.54
21              10              3.54
22              10              3.54
23              10              3.54
24              10              3.54

25              9.9             3.50
26              9.8             3.47
27              9.7             3.43
28              9.6             3.39
29              9.5             3.36
30              9.4             3.32
31              9.3             3.29
32              9.2             3.25
33              9.1             3.22
34              9               3.18
35              9               3.18
36              9               3.18

37              9               3.18
38              9               3.18
39              9               3.18
40              9.1             3.22
41              9.2             3.25
42              9.3             3.29
43              9.4             3.32
44              9.5             3.36
45              9.6             3.39
46              9.7             3.43
47              9.8             3.47
48              9.9             3.50

49              10              3.54
50              10.1            3.57
51              10.2            3.61
52              10.3            3.64
53              10.4            3.68
54              10.5            3.71
55              10.6            3.75
56              10.7            3.78
57              10.8            3.82
58              11              3.89
59              11.2            3.96
60              11.5            4.07

61              11.7            4.14
62              11.9            4.21
63              12.1            4.28
64              12.3            4.35
65              12.5            4.42
66              12.7            4.49
67              12.9            4.56
68              13.1            4.63
69              13.3            4.70
70              13.6            4.81
71              13.7            4.84
72              13.8            4.88

73              14              4.95
74              14              4.95
75              14              4.95
76              14              4.95
77              14              4.95
78              14              4.95
79              14              4.95
80              14              4.95
81              14              4.95
82              14              4.95
83              14              4.95
84              14              4.95

85              13.9            4.92
86              13.8            4.88
87              13.7            4.84
88              13.6            4.81
89              13.5            4.77
90              13.4            4.74
91              13.3            4.70

The two columns shown here below titled as Later BC are purely own assumption of what the TG output levels might possibly have been for the post 1937 Model A, BC, C , D and the Concert Model E organs built after the manual tapering scheme was introduced in 1937 but before the sine wave bass TG notes 1 to 9 were discontinued during the era of the 82 note TG's. The folowing TG output levels assume that the TG output curve was changed to accomodate the manual tapering scheme but thus far ( Sep 2007 ) I have not yet seen the measured TG output curves of a post 1937 Model A , BC ,C, D , and E organ with the 91 note TG and with the sine wave bass TG notes 1 to 12 so therefore I do not know how accurate the following TG output curve id.

The following measurements would be taken directly from the TG terminal strip.

            91 note TG     91 note TG
TG           Later BC        Later BC
Note          mVpp            mV RMS

1               25              8.84
2               23.5            8.31
3               22.5            7.96
4               21              7.43
5               20              7.07
6               19              6.72
7               18.5            6.54
8               17.5            6.19
9               17              6.01
10              16.5            5.83
11              16              5.66
12              15.5            5.48

13              15.3            5.41
14              15              5.30
15              14.9            5.27
16              14.8            5.23
17              14.7            5.20
18              14.6            5.16
19              14.5            5.13
20              14.4            5.09
21              14.3            5.06
22              14.2            5.02
23              14.1            4.99
24              14              4.95

25              13.9            4.92
26              13.7            4.84
27              13.5            4.77
28              13.3            4.70
29              13.1            4.63
30              13              4.60
31              12.8            4.53
32              12.7            4.49
33              12.5            4.42
34              12.3            4.35
35              12.2            4.31
36              12.1            4.28

37              12              4.24
38              12.1            4.28
39              12.2            4.31
40              12.3            4.35
41              12.4            4.38
42              12.5            4.42
43              12.6            4.46
44              12.8            4.53
45              13              4.60
46              13.1            4.63
47              13.2            4.67
48              13.3            4.70

49              13.4            4.74
50              13.6            4.81
51              13.7            4.84
52              13.9            4.92
53              14              4.95
54              14.1            4.99
55              14.2            5.02
56              14.4            5.09
57              14.6            5.16
58              14.8            5.23
59              14.9            5.27
60              15.3            5.41

61              15.5            5.48
62              15.8            5.59
63              16              5.66
64              16.4            5.80
65              16.6            5.87
66              16.8            5.94
67              17              6.01
68              17.2            6.08
69              17.4            6.15
70              17.6            6.22
71              17.8            6.29
72              18              6.36

73              18              6.36
74              18              6.36
75              18              6.36
76              18              6.36
77              18              6.36
78              18              6.36
79              18              6.36
80              18              6.36
81              18              6.36
82              18              6.36
83              18              6.36
84              18              6.36

85              17.9            6.36
86              17.8            6.33
87              17.7            6.26
88              17.6            6.22
89              17.5            6.19
90              17.4            6.15
91              17.3            6.12

Here below are the theoretically possible factory output levels of the 91 note TG's built from around 1947 and up to around 1956 based on the similar output levels of the TG notes 1 to 91 of the output curves of the recapped 1940's CV's , the wax capped B2 and C2 and the recapped 1956 B3 and the TG notes 49 to 91 shown of a recapped 1950's B3. The 1969 Alan Young report says that the output curve was changed in 1956 and this seems to correspond with the heavier bass and the slightly mellower treble output curves of the TG's up to 1956 in my TG spreadsheet.

These following measurements would be taken directly from the TG terminal strip.

              91 note TG      91 note TG
TG            pre 1956 TG    pre 1956 TG
Note            mVpp            mV RMS
1               90              19.15
2               88              18.72
3               86              18.30
4               84              17.87
5               82              17.45
6               81              17.23
7               80              17.02
8               79              16.81
9               78              16.60
10              77              16.38
11              76              16.17
12              75              15.96

13              15.3            5.41
14              15              5.30
15              14.9            5.27
16              14.8            5.23
17              14.7            5.20
18              14.6            5.16
19              14.5            5.13
20              14.4            5.09
21              14.3            5.06
22              14.2            5.02
23              14.1            4.99
24              14              4.95

25              13.9            4.92
26              13.7            4.84
27              13.5            4.77
28              13.3            4.70
29              13.1            4.63
30              13              4.60
31              12.8            4.53
32              12.7            4.49
33              12.5            4.42
34              12.3            4.35
35              12.2            4.31
36              12.1            4.28

37              12              4.24
38              12.1            4.28
39              12.2            4.31
40              12.3            4.35
41              12.4            4.38
42              12.5            4.42
43              12.6            4.46
44              12.8            4.53
45              13              4.60
46              13.1            4.63
47              13.2            4.67
48              13.3            4.70

49              13.4            4.74
50              13.6            4.81
51              13.7            4.84
52              13.9            4.92
53              14              4.95
54              14.1            4.99
55              14.2            5.02
56              14.4            5.09
57              14.6            5.16
58              14.8            5.23
59              14.9            5.27
60              15.3            5.41

61              15.5            5.48
62              15.8            5.59
63              16              5.66
64              16.4            5.80
65              16.6            5.87
66              16.8            5.94
67              17              6.01
68              17.2            6.08
69              17.4            6.15
70              17.6            6.22
71              17.8            6.29
72              18              6.36

73              18              6.36
74              18              6.36
75              18              6.36
76              18              6.36
77              18              6.36
78              18              6.36
79              18              6.36
80              18              6.36
81              18              6.36
82              18              6.36
83              18              6.36
84              18              6.36

85              17.9            6.36
86              17.8            6.33
87              17.7            6.26
88              17.6            6.22
89              17.5            6.19
90              17.4            6.15
91              17.3            6.12

Here are the theoretically possible factory TG output levels of the TG's from 1956 up to the 1970's , based on the similar TG output curves of many of the TG's from this era in my TG spreadsheet.

The following measurements would be taken directly from the TG terminal strip.

TG          Post 1956 TG        Post 1956 TG
Note            mVpp            mV RMS
1               70              14.89
2               69.2            14.72
3               68.3            14.53
4               67.3            14.32
5               66.4            14.13
6               65.5            13.94
7               64.5            13.72
8               63.6            13.53
9               62.6            13.32
10              61.7            13.13
11              60.8            12.94
12              60              12.77

13              15              5.30
14              14.6            5.16
15              14.3            5.06
16              14              4.95
17              13.6            4.81
18              13.3            4.70
19              13              4.60
20              12.6            4.46
21              12.3            4.35
22              12              4.24
23              11.6            4.10
24              11.3            4.00

25              11              3.89
26              11              3.89
27              11              3.89
28              11              3.89
29              11              3.89
30              11              3.89
31              11              3.89
32              11              3.89
33              11              3.89
34              11              3.89
35              11              3.89
36              11              3.89

37              11.1            3.93
38              11.2            3.96
39              11.3            4.00
40              11.4            4.03
41              11.5            4.07
42              11.7            4.14
43              11.8            4.17
44              12              4.24
45              12.2            4.31
46              12.5            4.42
47              12.8            4.53
48              13              4.60

49              13.2            4.67
50              13.4            4.74
51              13.6            4.81
52              14.0            4.95
53              14.2            5.02
54              14.5            5.13
55              14.7            5.20
56              15.1            5.34
57              15.2            5.37
58              15.6            5.52
59              15.8            5.59
60              16.0            5.66

61              16.3            5.76
62              16.6            5.87
63              17.0            6.01
64              17.3            6.12
65              17.7            6.26
66              18.0            6.36
67              18.5            6.54
68              18.8            6.65
69              19.2            6.79
70              19.4            6.86
71              19.6            6.93
72              19.8            7.00

73              20.0            7.07
74              20.0            7.07
75              20.0            7.07
76              20.0            7.07
77              20.0            7.07
78              20.0            7.07
79              20.0            7.07
80              20.0            7.07
81              20.0            7.07
82              20.0            7.07
83              20.0            7.07
84              20.0            7.07

85              20.0            7.07
86              19.7            6.97
87              19.3            6.82
88              19.0            6.72
89              18.7            6.61
90              18.3            6.47
91              18.0            6.36

The TG's from the spinet organs such as the M3 , M-100 series ,and the L-100 series organs had much higher output levels for the complex waveform bass pedal TG notes 1 to 13 and the reason for these very high output levels is because the pickup coils of the TG notes 1 to 13 were not shunted to ground with the 16 ohms resistance wires that were wrapped around the top of the phenolic part of the pickup coil bobbins of the console organs. Because of the shorter manuals there were no TG notes 14 to 17 and the TG notes 18 to 91 seem to have followed the similar trend as that of the post 1956 console organs.

The Porta B spinet organs had the same very high output levels for the pedal bass TG notes 1 to 13 and the TG notes 14 to 91 followed a similar pattern as the post 1956 console organs.

The following are the measured TG output levels of the complex tone wheel bass TG notes 1 to 13 of my 1963 L-102 organ. These following TG output levels are at a more or less similar level as that of my late era L-143 organ as well as a mid 60's L-111 organ and a 1971 Porta B organ that I have measured.

Although the output levels of the complex waveform pedal bass TG notes 1 to 13 might seem to be extremely high , in reality the actual audible volume levels of these bass pedal TG notes 1 to 13 when heard through the bass pedals are at similar volume levels as the rest of the sine wave TG notes heard when playing the organ keyboards . The bass TG notes 1 to 13 first pass through an inductor coil filter that rolls off the buzzy or 'farty' sounding higher harmonics that are a part of the complex waveforms and after this the bass TG notes go to the bass pedal drawbar and then in to the organ pre amplifier. The inductor coil filter causes the complex waveforms to sound much mellower and closer to a that of sine wave bass note and this inductor coil filter also reduces the overall volume level of the bass TG notes 1 to 13 so that they are better matched with the rest of the sine wave TG notes.

TG           1963 L-102      1963 L-102
Note            mVpp           mV RMS
1               404             85.96
2               414             88.09
3               430             91.49
4               430             91.49
5               427             90.85
6               427             90.85
7               433             92.13
8               430             91.49
9               449             95.53
10              430             91.49
11              440             93.62
12              440             93.62

13              329             70.00

The earlier era T-series organs seem to have had a very high treble calibration with the output levels of the TG notes 73 to 91 continuing upwards until the high treble TG notes 85 to 91 reached up to somewhere in the 30 to 35 mVpp region (10.61 to 12.32 mV RMS ).

I did some modification and repair work on a friend's 1970 T-300 organ with the high treble calibration and the sound was very thin and nasal sounding and I recalibrated the TG to have a similar output curve as that of the B3 , C3 , A100 etc organs and doing this significantly improved the sound of the 1970 T-300 organ.

It is possible that enough people might have complained about this nasal sound with the result that Hammond seem to have gone back to the more normal standard post 1956 type TG calibration for the later era T-series and the XTP organs. The T series and the XTP TG's only had the TG notes 18 to 91.

As an example of very thin and nasal sounding high treble calibration of the earlier era T-series organs , the following measurements were taken directly from the TG terminal strip of my friend's 1970 T-300 before I recalibrated the TG to have a much better sounding B3/C3 etc type TG output curve. Note that the TG of the T-series and the XTP series spinet organs do not have the tone wheels 1 to 17.

TG            1970 T-300       1970 T-300
Note            mVpp            mV RMS
18              13              4.60
19              12.2            4.31
20              12              4.24
21              11.5            4.07
22              11.4            4.03
23              11              3.89
24              11.1            3.93

25              11              3.89
26              10.1            3.57
27              10.4            3.68
28              10              3.54
29              9.9             3.50
30              9.7             3.43
31              9.8             3.47
32              10.1            3.57
33              9.9             3.50
34              10              3.54
35              10.3            3.64
36              9.8             3.47

37              10              3.54
38              9.9             3.50
39              13.2            4.67
40              10.2            3.61
41              11              3.89
42              13.9            4.92
43              11.3            4.00
44              11              3.89
45              11.2            3.96
46              11.1            3.93
47              11.9            4.21
48              12.9            4.56

49              13.1            4.63
50              12.2            4.31
51              13              4.60
52              13              4.60
53              12.4            4.38
54              12.6            4.46
55              14              4.95
56              15              5.30
57              14.8            5.23
58              16.1            5.69
59              15.4            5.45
60              16.7            5.91

61              19.9            7.04
62              17.4            6.15
63              12.3            4.35
64              20.9            7.39
65              19.9            7.04
66              49              17.33
67              21.5            7.60
68              22              7.78
69              29.8            10.54
70              21.5            7.60
71              22.3            7.89

72              21.5            7.60
73              60              21.22
74              24.9            8.80
75              24.2            8.56
76              27.4            9.69
77              20.8            7.36
78              30.3            10.71
79              23              8.13
80              27.1            9.58
81              26.7            9.44
82              20.9            7.39
83              29.9            10.57
84              18.5            6.54

85              34.3            12.13
86              43.5            15.38
87              25.4            8.98
88              31.2            11.03
89              32.1            11.35
90              28              9.90
91              30.1            10.64

I have measured the TG output levels of an early 1970's R-124 organ and this organ had the sine wave bass TG notes 1 to 12 and the levels of these bass TG notes 1 to 12 were at similar levels as that of the sine wave bass TG notes 1 to 12 of the later BC organs. The TG notes 13 to 91 of this R-124 followed the similar pattern as that of the post 1956 console organs.

============================================

Here below are the output levels of the old Hammond output level graph called '‘Approximate output voltage readings of organ Generator frequencies 1 to 91’’. The ‘’Old Graph # 1 ‘’ is of the stronger output curve for the Model B organs with serial numbers between 4000 and 5075. These organs had the untapered manuals. I assume that this output curve also applies to the earlier Model A organs. The ‘’Old Graph # 2 is of the weaker output curve for the Model BC organs with serial numbers above 5075 and Model E organs with serial numbers above 8000.These organs had the manual tapering scheme.

The following measurements would be taken from the GG output terminals of the preamp whilst the appropriate drawbars are pulled out and the appropriate keys are played.

TG             Old Graph #1    Old Graph #2
Note            AC Volts        AC Volts
1               3.3             0.8
2               3.32            0.81
3               3.34            0.84
4               3.35            0.85
5               3.37            0.87
6               3.39            0.89
7               3.4             0.9
8               3.41            0.93
9               3.42            0.97
10              3.43            1
11              3.43            1.02
12              3.43            1.06

13              3.43            1.1
14              3.43            1.15
15              3.42            1.2
16              3.41            1.26
17              3.4             1.34
18              3.39            1.44
19              3.38            1.51
20              3.35            1.61
21              3.32            1.72
22              3.3             1.96
23              3.28            2.03
24              3.23            2.3

25              3.2             2.46
26              3.15            2.46
27              3.1             2.4
28              3.04            2.32
29              3               2.2
30              2.9             2.1
31              2.82            1.94
32              2.71            1.79
33              2.65            1.67
34              2.55            1.55
35              2.45            1.47
36              2.35            1.39

37              2.21            1.31
38              2.08            1.26
39              1.95            1.2
40              1.86            1.15
41              1.77            1.11
42              1.69            1.06
43              1.56            1.02
44              1.51            1
45              1.44            0.96
46              1.36            0.93
47              1.3             0.91
48              1.25            0.9

49              1.19            0.88
50              1.15            0.87
51              1.12            0.85
52              1.1             0.82
53              1.07            0.81
54              1.06            0.8
55              1.05            0.79
56              1.04            0.77
57              1.03            0.75
58              1               0.74
59              0.99            0.71
60              0.96            0.7

61              0.94            0.69
62              0.9             0.67
63              0.86            0.65
64              0.82            0.63
65              0.78            0.62
66              0.73            0.6
67              0.7             0.59
68              0.67            0.58
69              0.65            0.56
70              0.61            0.55
71              0.6             0.53
72              0.58            0.5

73              0.56            0.49
74              0.54            0.47
75              0.51            0.45
76              0.5             0.44
77              0.5             0.42
78              0.5             0.41
79              0.49            0.4
80              0.49            0.39
81              0.49            0.36
82              0.48            0.33
83              0.47            0.32
84              0.46            0.31

85              0.45            0.3
86              0.43            0.29
87              0.42            0.27
88              0.4             0.25
89              0.36            0.22
90              0.33            0.21
91              0.3             0.2

================================================

Here below are the output levels shown on the 1940’s Model G service manual and the B3 / C3 service manual . The Model G manual instructs to use a 4 K ohms per volt voltage meter and the B3 / C3 manual instructs to use a 1 K ohms per volt voltage meter.

The following measurements would be taken from the preamp GG output terminals whilst each TG note is connected to the preset panel busbar # 4 ( fifth from the bottom ).

                Model G         B3 / C3
TG        Service Manual     Service Manual
Note            AC Volts        AC Volts
1                               9.8
2                               11
3                               11.5
4                               12
5                               13
6                               14
7                               15
8                               15
9                               16
10              1.7             15
11              1.8             16
12              1.8             13

13              4.1             14.5
14              4.2             15
15              4.7             14
16              5               15
17              4.7             14
18              6               15
19              6.2             15
20              6               16
21              6.2             15
22              6.1             13
23              6.1             15
24              5.8             14

25              5.1             11.5
26              5.1             12
27              4.9             10
28              5               11
29              4.9             10
30              5               10
31              4.5             11
32              4.5             8.5
33              4.5             10
34              4               9
35              4.5             10
36              4.5             8

37              4.5             9.5
38              4.3             10
39              4               9
40              4               10
41              4               8
42              4               9
43              1.9             9
44              1.7             2.5
45              1.7             2.7
46              1.7             2
47              1               2.5
48              0.9             2

49              1               2.25
50              0.9             3
51              0.9             1.5
52              0.9             2
53              0.9             1.8
54              0.9             1.8
55              0.9             1.8
56              0.9             1.8
57              1.1             2
58              0.9             1
59              0.85            1.8
60              0.9             1.5

61              1.9             3
62              1.7             3
63              1.4             2
64              1.5             2.5
65              1.4             2.2
66              1.4             3
67              1.5             1.2
68              1.7             1.6
69              1.4             2
70              1.2             1.6
71              1.3             2
72              1.4             1.4

73              1.1             1.4
74              1               1.2
75              1               1
76              1               1.2
77              0.8             1
78              0.6             1.2
79              0.75            0.8
80              0.75            0.6
81              0.75            0.7
82              0.55            0.4
83              0.6             0.6
84              0.75            0.5

85              0.6             0.7
86              1               0.5
87              0.6             0.3
88              0.75            0.4
89              0.8             0.2
90              0.75            0.5
91              0.6             0.25

=========================================================

CUSTOMIZED TG RECALIBRATION OF KON'S RECAPPED 1962 C3.

For many years I have been very interested in learning about how the TG calibration affects the sound of the Hammond organs and I know that some Hammond technicians do recalibrate the TG's of the organs of their professional customers. The late Bill Beer in particular was known to recalibrate the TG's to produce what he described as a "hot bitchin fat and ballsy sound" and he also recalibrated the TG's in order to complement his proprietary solid state preamps and high power solid state Leslies.

Out of curiosity I have recalibrated the whole TG of my 1962 C3 a few times in order to find out what kinds of TG output curves produce the best sound and currently I have a non stock customized louder and fatter than stock sounding recalibrated TG output curve. An advantage of the louder than stock TG output curve of my 1962 C3 is that there is a noticeably improved signal to noise ratio because the louder tone wheel signals now mask some of the background mechanical rumble and hum that is often audible under some of the TG notes especially when playing on the upper octaves of the keyboards.

Even though the pickups are now closer to the tone wheels , the sine wave quality of the tone wheels still sounds normal like that of a stock organ. However there is a limit as to how close you can bring the pickups to the tone wheels before the sine wave quality starts to sound dirtier and more warbly thus spoiling the organ sound and I think that the current recalibrationof my 1962 C3 is near the limit and if I try to bring the pickups closer to the tone wheels than what they are now, then the tone wheel sine wave quality will start to deteriorate and thus spoil the organ sound .

As well as the louder overall output levels of all the TG notes 1 to 91, I have recalibrated the TG output curve to be more like that of the pre 1956 TG output curves that had stronger bass and midrange levels thus producing a fatter organ sound.

I am aware of the potential dangers or the pickup rod hitting a tone wheel whilst recalibrating the TG and I have the proper voltage meters to do a proper TG recalibration

My 1962 C3 originally had the aged wax capacitors and soon after buying the C3 in 2002 I then replaced the aged wax capacitors with new correct mfd spec capacitors. However after reading all the information and the controversy about the correct way of recreating the proper factory capacitor matching procedure I decided to replace the recapped capacitors brass tray of my 1962 C3 with the red mylar capped brass tray from a 1970 T-300 organ. The reason for this was because the red mylar capacitors have not drifted off spec like the wax capacitors did so therefore the red mylar capacitors would still more or less be correctly matched with the corresponding inductor coil transformers.

Interestingly after I installed the red mylar capped tray of the 1970 T-300 into my 1962 C3, the output levels of the TG notes 49 to 91 then became noticeably louder than what they were with the original recapped capacitors tray of my 1962 C3. The inductor coils of the brass tray that was originally in my 1962 C3 have the dark brown enamelled wire around the bobbins whilst the inductor coils from the 1970 T-300 brass capacitors tray have the bright red enamelled wire around the bobbin. It would appear that the inductor coils with the bright red enamelled wire used in the late 60's or early 70's organs produced a higher Q or resonance levels than the inductor coils with the dark brown enamelled wire used in the early 1960's organs.

The stock complex waveform TG notes 1 to 12 of my 1962 C3 sounded mediocre to my ears so therefore after listening to the warmer fatter sounding characteristic of the pedal bass notes of the L-100 series organs, I decided to apply this approach to the complex waveform TG notes 1 to 12 of my 1962 C3. To do this, first I very carefully cut off the 16 ohms grounding shunt resistance wires that are wrapped around the top of the phenolic bobbins of the pickup coils of the TG notes 1 to 12 and this resulted in significantly louder output levels for the complex waveform bass TG notes 1 to 12. The TG notes 1 to 12 were now closer to the levels of the L-100 series TG notes 1 to 13.

After some experimentation I decided to ground out each of the TG notes 1 to 12 with 100 uf resistors connected between the TG terminal strip and the TG chassis. Doing this has resulted in much mellower and fatter sounding bass TG notes 1 to 12 and these TG notes now do sound more like the filtered pedal bass TG notes 1 to 13 of the L-100 organs and this new sound is noticeably better sounding to my ears than the stock complex waveform TG notes 1 to 12.

After doing this refiltering modification I then connected a voltage meter to the AO28 GG output terminals and I set the expression pedal to the full volume position and then I pulled out the 16 ft bass pedal drawbar and I played the bass pedal note 13. I took notice of the output level voltage reading of the bass pedal note 13 and I then played each of the bass pedal notes 1 to 12 and I noticed that there were inconsistencies in the levels of the TG notes 1 to 12 and they were generally weaker in level than the rest of the pedal notes 13 to 25 so therefore I recalibrated the pickups of each of the bass pedal TG notes 1 to 12 by weighing down the corresponding bass pedals and I then brought the pickup rods slightly closer to the tone wheels until all the bass pedal notes 1 to 12 produced the same output voltage readings as the bass pedal TG note 13 when measured through the AO28 GG output terminals.

This refiltering and recalibration of the bass TG notes 1 to 12 has resulted in more beefy sounding bass pedals in my 1962 C3.

Here below are the measured TG output levels of the recalibrated TG of my 1962 C3. These output levels are current as of 2 September 2007.

The refiltered bass TG notes 1 to 12 with the 100 uf grounding shunt capacitors ( instead of the original stock 16 ohms grounding shunt resistance wires ) do sound more like sine waves but the waveforms are not as pure as real sine waves. Because the refiltered bass TG notes 1 to 12 now do sound closer to sinewaves , I have used the mVpp levels divided by 2.828 conversion formula to convert the mVpp levels of the re filtered bass TG notes 1 to 12 into mV RMS but I do not know if the calculated mV RMS levels of the filtered bass TG notes 1 to 12 are truly accurate.

Although the output levels of the refiltered bass TG notes 1 to 12 seem to be significantly higher than the TG notes 13 onwards , the actual audible levels of the bass TG notes 1 to 12 are not as noticeably different from the rest of the TG notes when playing the organ because the TG notes 1 to 12 are loaded down by the key circuits and the drawbar matching transformer.

The measurements are taken from the TG terminal strip and the TG notes 1 to 12 are refiltered with the 100 uf grounding shunt capacitors instead of the original stock 16 ohms grounding shunt resistance wires.

TG           Kon's 1962 C3          Kon's 1962 C3
Note            mVpp                    mV RMS
1               334                     118.1
2               277                     97.9
3               302                     106.8
4               186                     65.8
5               200                     70.7
6               183                     64.7
7               154                     54.5
8               159                     56.2
9               121                     42.8
10              119                     42.1
11              112                     39.6
12              106                     37.5

13              29                      10.3
14              28.6                    10.1
15              27.6                    9.8
16              27                      9.5
17              26.3                    9.3
18              26.2                    9.3
19              26.1                    9.2
20              25.5                    9.0
21              25.2                    8.9
22              25                      8.8
23              24.8                    8.8
24              24.3                    8.6

25              24                      8.5
26              24                      8.5
27              24                      8.5
28              24                      8.5
29              24                      8.5
30              24                      8.5
31              24                      8.5
32              24                      8.5
33              24                      8.5
34              24                      8.5
35              24                      8.5
36              24                      8.5

37              24                      8.5
38              24                      8.5
39              24                      8.5
40              24                      8.5
41              24                      8.5
42              24                      8.5
43              24                      8.5
44              24                      8.5
45              24                      8.5
46              24                      8.5
47              24                      8.5
48              24                      8.5

49              25                      8.8
50              25                      8.8
51              25                      8.8
52              25.1                    8.9
53              25                      8.8
54              25.7                    9.1
55              26                      9.2
56              26.2                    9.3
57              26.4                    9.3
58              25.9                    9.2
59              26.5                    9.4
60              27                      9.5

61              26.2                    9.3
62              27.2                    9.6
63              27.5                    9.7
64              27.8                    9.8
65              28                      9.9
66              28.5                    10.1
67              28.8                    10.2
68              28.9                    10.2
69              29                      10.3
70              29.1                    10.3
71              29.5                    10.4
72              29.8                    10.5

73              30                      10.6
74              30                      10.6
75              30                      10.6
76              30                      10.6
77              30                      10.6
78              30                      10.6
79              30                      10.6
80              30                      10.6
81              30                      10.6
82              30                      10.6
83              30                      10.6
84              30                      10.6

85              30                      10.6
86              29.1                    10.3
87              28                      9.9
88              27                      9.5
89              26                      9.2
90              25                      8.8
91              24.1                    8.5

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