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Farfisa Compact Duo low signal problem

Farfisa Compact Duo low signal problem

2003-10-02 by William J. Spiropoulos

Hey all

Just joined the group here. I have several old keyboards that might 
benefit from some advice from you all, but I'll start off with my 
Compact Duo. I finally received a replacement 7-pin Amphenol plug in 
the mail yesterday--my Duo has been sitting inert for some time 
because the old plug was shot--and after a little bit of fiddling was 
delighted to hear that it still worked. It actually worked a bit 
better than it used to because the old plug had a crappy and 
incomplete wiring job. The pinout I'd figured out was as follows, for 
those interested:

pin#  color             function
1     braided shields   ground
2     black             ground?
3     pink (shielded)   main audio
4     red               9VDC for organ
5     black (shielded)  switched audio out to reverb unit
6     nc                nc
7     9VAC              red keyboard-split indicator lamps

At first I'd hooked up the reverb and main backwards...in addition to 
funky interaction between the organ and the accessory FA/R box, the 
signal was way, way down. Reversing them made everything work 
correctly. It was great to have most if not all the tabs more or less 
doing what they were supposed to do.

Except for the fact that the overall volume level of the organ is 
still WAY below what I would expect it to be. The inherent noise from 
the FA/R is quite prominent compared to the organ signal, and I have 
to turn it (and the noise) way up for it to generate an marginally 
acceptable signal. Either something in the organ is blocking much of 
the signal from getting to the FA/R or there is something funky in 
the FA/R itself. I doubt the latter because running other stuff 
through the external input isn't nearly as bad.

To make matters even worse, certain combinations of tabs seem to 
affect the overall volume level of the organ. The yellow main tabs 
for the upper manual seem to make the quietest signal, even when all 
are on; the green "boost" tab section make for a somewhat louder 
sound (although I doubt this is what they meant by "boost" in this 
case!). What's goofy is that activating the Tremolo/Repeat/Percussion 
section makes the overall signal considerably louder, even when only 
the Tremolo tab is depressed and thus doesn't actually apply any 
tremolo. Even so, it isn't enough to bring the signal up where it 
should be.

I know this is an old old organ, but I wouldn't expect it to sound 
like it was coming over a shortwave radio, and certainly not to crank 
the FA/R--well as the input gain on my multitrack--up all the way in 
order to get an acceptable signal level. I can't believe that Farfisa 
would intentionally design an organ with such poor audio specs; 
people still use them on pop records in the digital age, for 
chrissakes, so I can imagine that a properly functioning Duo would 
sound reasonably loud, crisp and clear. I assume that there IS in 
fact a problem somewhere in the organ or the FA/R. And hopefully it's 
one that can be fixed reasonably easy (and hopefully cheap!).

In a nutshell: The actual audio producing circuitry seems to buzzing 
along just fine. But something seems to be getting in the way of it 
and pushes it down in level far enough to mingle with the FA/R's 
inherent noise. Also, volume levels change depending on which tab 
sections are in use.

Any advice from the pros or better-informed amateurs would be 
appreciated, devoured, and put to good use instantly.

That's where I'm at at the moment. However I'm still ecstatic to have 
the Duo making ANY kind of noise right now! Zowie! So I'm not letting 
this little tech problem get in MY way. :-)

thx

Billy S.

Re: Farfisa Compact Duo low signal problem

2003-10-05 by William J. Spiropoulos

--- In vintagesynthrepair@yahoogroups.com, "Mike Walters" 
<mike@m...> wrote:
> Hey Billy, you'd probably benefit to join this group as well:
> http://groups.yahoo.com/group/ComboOrgan/
> -Mike

I did rejoin and posted my message there, but now as before, 
people over there don't seem to be particularly interested in 
replying as yet. Maybe it's just because it's a weekend...I'm 
hoping the folks over here might be a little more helpful.

regards,

Billy S.

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