Doepfer

> Hi M.
> 
>> I've been trying to use my A-114 to double the frequency of a
>> waveform (as
>> suggested by some articles about modular synthesis), but
>> couldn't get it to
>> work.
>> (After all, a ring modulator gives the sum and the difference
>> of its inputs,
>> so having the same signal at both inputs would give only the
>> sum, the same
>> waveform one octave higher, yes?)
>> It seems that the sound doesn't change much at all if I send
>> the same sine
>> wave trough both its inputs.
> 
> From a quick look-see I did last night I'd say your 114 is probably working
> fine - I think the reason you are apparently not *hearing* a doubling of
> frequency is due to the rather approximate sine shape output from the 110. The
> 110 sine output is actually a kind of logarithmic approx to a sine wave, and
> it gets less accurate as the frequency is increased. On one of my 110's, if I
> feed the sine into both 114 inputs, at lower frequencies it clearly is being
> doubled, and switching between the two is easy to tell the difference by
> listening. However as the frequency is increased, because the 110 output gets
> more distorted, the doubled output from the 114 actually looks more like a
> full-wave rectified version of a sine wave (all the positive humps appear
> flipped to negative): whilst measuring it on the scope it does have half the
> period (i.e. double the frequency), listening to it I can hear very little
> difference between the doubled 114 output and the original from the 110 - this
> doesn't seem too unreasonable since all the frequencies arising from the sharp
> changes in direction of this 'rectified' wave are probably beyond hearing
> range. (In the 110's defence, this is working at about twice the 'as
> advertised' range of the module.) The output from a 122 or 123 filter in
> self-oscillation is a pretty good sine wave, and feeding this into the 114
> does give a fairly nice sine wave at double the frequency out, and switching
> between the two, the difference in sound is much more noticeable. (This may
> not help you if you don't have either of these though - I didn't try the 121
> multimode because the sine wave from this can be quite distorted.) I also
> tried the triangle wave from the 110 into the 114 - even though this also
> loses it shape at high frequencies, the output from the 114 is actually quite
> rounded, and to my ears sounded like there is a greater difference between the
> input and the doubled output, when compared to the sine wave.
> 
> Tim

Thanks Tim.
Well, I tried every signal source I have, A-110, various LFO's, A-121 and
A-123, and ran them through an oscilloscope and a frequency counter but the
frequencies stay roughly the same.
I don't get it. My A-114 seems to work fine when used "as a ring modulator",
but seemingly it won't do anything to the signal if I feed it the same
inputs. I've tried the trick on a Putney and that worked.
Maybe there's two different versions with different electrical behavior?