1)
Introduction
Jürgen Haible
and I were having a discussion about playing distorted sounds on the Korg CX-3
(see also the beginnings of "Crunching
Korg CX-3").
JH came up with a problem of the CX-3 having different output levels at different
keys and stops which has an impact on the external distortion effect since it
is driven differently.
I wanted to know more about that and sat down and did some measurements.
2) The Measurement
The output volume was set to maximum, everything else to 0, tuning and tone
controls were in middle position.
Of course no overdrive, rotary effect and percussion (sigh, I love percussions
;-) and key click was involved.
The oscilloscope was hooked up to the high level output of the organ.
I wrote down the cursor readout of the respective drawbar at full position
and each key starting from left to right.
I did not measure the high stops because the level was low and the noisefloor
quite heavy (at least I'd need a better probe) but a tendency can well be seen
(and it started to get boring although I was listening to some pretty good synthmusic
;-).
3)
The Questions
Aside from all the not so common effects one can do with a tube-preamp or other
fuzz-box I still love the distinct sound of an overdriven Hammond like the '70s
rock organ sounds (e.g. Jon Lord and Ken Hensley) as well
as the timbres played by people like Jimmy Smith.
* I have a vague memory that a Hammond as well has changing output levels but I can't recall how that looked like. Any idea?
* Would it make sense - if possible - to modify the Korg CX-3 in a way that equalises the output levels of each stop? Or does it look quite ok to you as it is?
4) The Comparision
In regard to the first question Glen
Berry from the Synth-DIY List
kindly provided a scan
of a chart of the original Hammond B-3 service manual showing the correct
output levels of the Hammond generator. He explains the number sequence as follows:
"As for mapping frequency numbers to musical notes, frequency #1 is
a C note. Frequency #2 is a C-sharp, etc."
Thanks a lot Glen!
I compiled a diagram from that chart which is shown
below.
To answer my first question above - yes, the Hammond has uneven output levels
as well, but those are quite different than the Korg CX-3, as one can see.
| SDIY Notes |
© 2003, Michael Zacherl, last revised 03/09/03 10:51 PM |
| Stop | Outputlevel
in mVpp per Stop |
|||||
| Key | No. | 16' |
5/3' |
8' |
4' |
2' |
| C1 | 1 |
190,0 |
157,0 |
140,0 |
109,6 |
118,8 |
| # | 2 |
190,0 |
170,0 |
138,0 |
112,8 |
122,8 |
| D | 3 |
191,0 |
166,0 |
143,0 |
108,4 |
126,8 |
| # | 4 |
199,0 |
170,0 |
137,0 |
111,6 |
131,6 |
| E | 5 |
199,0 |
168,0 |
144,0 |
119,6 |
131,6 |
| F | 6 |
206,0 |
179,0 |
141,0 |
119,6 |
131,6 |
| # | 7 |
203,0 |
177,0 |
146,0 |
117,6 |
131,6 |
| G | 8 |
211,0 |
179,0 |
146,0 |
112,4 |
120,0 |
| # | 9 |
211,0 |
179,0 |
144,0 |
106,8 |
105,2 |
| A | 10 |
211,0 |
179,0 |
150,0 |
93,2 |
95,2 |
| # | 11 |
211,0 |
181,0 |
140,0 |
80,8 |
79,6 |
| H | 12 |
195,0 |
186,0 |
136,0 |
62,0 |
66,4 |
| C2 | 13 |
220,0 |
186,0 |
150,0 |
136,8 |
151,2 |
| # | 14 |
212,0 |
189,0 |
143,0 |
135,6 |
151,2 |
| D | 15 |
208,0 |
189,0 |
147,0 |
135,6 |
151,2 |
| # | 16 |
207,0 |
180,0 |
143,0 |
136,4 |
151,2 |
| E | 17 |
205,0 |
171,0 |
148,0 |
143,2 |
158,4 |
| F | 18 |
205,0 |
199,0 |
145,0 |
140,8 |
154,8 |
| # | 19 |
202,0 |
194,0 |
148,0 |
130,0 |
145,6 |
| G | 20 |
211,0 |
194,0 |
148,0 |
117,2 |
127,2 |
| # | 21 |
204,0 |
199,0 |
148,0 |
109,2 |
110,8 |
| A | 22 |
214,0 |
202,0 |
148,0 |
88,4 |
96,8 |
| # | 23 |
206,0 |
207,0 |
143,0 |
70,0 |
79,6 |
| H | 24 |
206,0 |
210,0 |
136,0 |
57,6 |
63,2 |
| C3 | 25 |
206,0 |
215,0 |
156,0 |
142,0 |
141,2 |
| # | 26 |
208,0 |
207,0 |
156,0 |
151,2 |
136,0 |
| D | 27 |
207,0 |
207,0 |
156,0 |
153,6 |
136,0 |
| # | 28 |
211,0 |
197,0 |
159,0 |
152,8 |
136,0 |
| E | 29 |
211,0 |
177,0 |
160,0 |
150,8 |
136,0 |
| F | 30 |
208,0 |
227,0 |
154,0 |
146,4 |
130,8 |
| # | 31 |
218,0 |
229,0 |
158,0 |
146,4 |
128,0 |
| G | 32 |
215,0 |
229,0 |
156,0 |
132,0 |
130,8 |
| # | 33 |
223,0 |
231,0 |
157,2 |
112,4 |
98,4 |
| A | 34 |
215,0 |
231,0 |
150,4 |
93,2 |
81,6 |
| # | 35 |
213,0 |
235,0 |
142,4 |
80,8 |
67,2 |
| H | 36 |
195,0 |
233,0 |
124,8 |
67,2 |
56,4 |
| C4 | 37 |
280,0 |
227,0 |
212,0 |
144,0 |
98,8 |
| # | 38 |
274,0 |
223,0 |
212,0 |
144,0 |
101,2 |
| D | 39 |
280,0 |
217,0 |
216,0 |
142,0 |
94,8 |
| # | 40 |
275,0 |
188,0 |
216,0 |
142,0 |
94,8 |
| E | 41 |
276,0 |
168,0 |
216,0 |
138,0 |
85,6 |
| F | 42 |
289,0 |
247,0 |
220,0 |
135,2 |
80,8 |
| # | 43 |
292,0 |
230,0 |
220,0 |
128,8 |
79,6 |
| G | 44 |
298,0 |
227,0 |
220,0 |
114,0 |
66,4 |
| # | 45 |
300,0 |
213,0 |
215,0 |
103,2 |
64,4 |
| A | 46 |
291,0 |
197,0 |
200,0 |
91,2 |
52,0 |
| # | 47 |
280,0 |
192,0 |
190,0 |
70,8 |
43,6 |
| H | 48 |
248,0 |
181,0 |
163,0 |
59,6 |
37,2 |
| C5 | 49 |
358,0 |
175,0 |
221,0 |
102,0 |
63,2 |
| # | 50 |
364,0 |
172,0 |
221,0 |
98,8 |
57,2 |
| D | 51 |
367,0 |
162,0 |
213,0 |
95,2 |
56,0 |
| # | 52 |
372,0 |
159,0 |
213,0 |
88,4 |
52,2 |
| E | 53 |
374,0 |
150,0 |
213,0 |
86,8 |
49,6 |
| F | 54 |
372,0 |
146,0 |
207,0 |
83,2 |
45,0 |
| # | 55 |
383,0 |
136,0 |
213,0 |
79,6 |
40,6 |
| G | 56 |
365,0 |
126,0 |
205,0 |
72,0 |
36,0 |
| # | 57 |
365,0 |
123,0 |
205,0 |
66,0 |
34,2 |
| A | 58 |
342,0 |
113,0 |
191,0 |
56,4 |
30,0 |
| # | 59 |
319,0 |
96,4 |
180,0 |
47,2 |
28,8 |
| H | 60 |
274,0 |
80,8 |
161,0 |
37,6 |
26,2 |
| C6 | 61 |
238,0 |
68,8 |
141,0 |
29,6 |
25,6 |
| < SDIY Notes |
© 2003, Michael Zacherl, last modified 03/09/03 10:51 PM |