Xpantastic!

Hi Simon,
 
Yeah, the capacitors are easy to find and cheap. Ibought 200 for around $20.00 USD.
The part is a 2.2 uF @ 50VDC. Try to get the newest ones you can find.  
 
On your current question. I am a little unclear here. AFAIK The VCA2 is usually set to  0
and a modulator ( envelope or lfo ) is used to change it's setting. If you turn VCA2 up it will 
continuously sound. Is this whats going on, or something different?
 
Best Regards
 
- Karl
 

--- On Fri, 3/6/09, Simon G <playthefivetones@yahoo.com> wrote:

From: Simon G <playthefivetones@...>
Subject: Re: [xpantastic] Re: xpander dac
To: xpantastic@yahoogroups.com
Date: Friday, March 6, 2009, 7:52 AM










that was a lot of really great information, Karl, thank you. presumably those capacitors are easy to find?

do you think the problem below could be a capacitor issue?

does anybody else had/ have a problem where VCA 2 is 'stuck on' some old notes...almost like a midi note is stuck on.i've tried the boot reset, all midi notes off (i'm quite convinced it's not midi related at this point), still there. always get a  tuning pass across the board, except one time where VCF failed (still sounded fine). i have not been able to duplicate that. doesn't seem to be isolated to one voice.  plays fine, sounds great (amazing), just have to leave vca2 at 0 which in most patches seems to make little difference. 

also i've been using the stuck VCA2 to make easy drones which i quite like.

i searched for the problem everywhere and found someone else who had posted with it  and got a couple of responses... one saying it was common on Jupiters (iirc) but no real solutions. 

can it be tuned out with a good calibration? considering everything else works should i just leave it alone? could i be making it worse by using it like this?

thanks 
s



--- On Thu, 2/26/09, Karl <shire03@sbcglobal. net> wrote:


From: Karl <shire03@sbcglobal. net>
Subject: [xpantastic] Re: xpander dac
To: xpantastic@yahoogro ups.com
Date: Thursday, February 26, 2009, 4:43 AM





Hey Everyone,

I have been helping folks fix their Xpanders / Matrix 12s for awhile 
here. I can tell you that by far the most failed component is 
electrolytic capacitors. A 2.2 uF @ 50V coupling capacitor is used 
through out the analog voice boards. This capacitor will fail and 
cause numerous voice problems from failed auto-tune to no sound. The 
next part would be the encoders. Usually a good cleaning fixes this.
Next would be the VFD displays which are very hard to find. Steve 
Lanham is working on an upgrade for this one. 
see:
http://us.mc838. mail.yahoo. com/mc/compose? to=steve@ bendentech. co.uk

There have been a few cases of VCO ( 3374 ) and VCF filter chips ( 
3372 ) failing. Not impossible to find, but expensive.
The DAC issue from Takis is the first I've seen of that part failing. 
Many times things can be fixed by simply re seating ( pulling out and 
putting back in ) the chips. This is easy on the Xpander because 
every integrated circuit is in a socket. Finally, many problems are 
caused by cold solder joints. Simply re flowing the solder around the 
suspect part can fix this. I always recommend doing this first
before replacing parts.

I personally have fixed my matrix 12 (owned since 1987) several times 
This included cleaning the key contacts (typical of any keyboard) 
Several of the before mentioned capacitors. An analog switch chip 
which had it's pin folded under at the factory. And finally, several 
74HC14 Schmidt trigger chips which debounce the encoders. 

Soon ( when time permits ) I would like to make a better list along 
with part numbers etc. that we could all use to trouble shoot these 
wonderful machines. I have been collecting capacitors/ battary etc.
to recap mine. 

BTW If you have any software issues/questions Tony C. is the man to 
talk to, and PeWe is the best expert on sound design / functionality
( on nearly any synth ) I have ever talked to. Actually, all the 
folks in this group are sharp characters ( they own xpanders :-) 

Best Regards

Karl

--- In xpantastic@yahoogro ups.com, Tony Cappellini <cappy2112@. ..> 
wrote:
>
> Not really, but my gear is very under-used compared to most.
> One voice is a little squirrly (occasionally) . Karl was nice enough 
to
> point me to which cap typically goes bad that causes my symptoms. 
Karl
> is very knowledgable about the Xpander.
> 
> I've wanted to recap my voice circuits, but haven't found someone I
> will trust my Xpander with.
> 
> For a long time that voice failed auto-tune now & then, but I 
coulnd't
> hear anything bad. Now I can hear it ;-)
> I bought a bunch of spare parts a long time ago when they were easy 
to find.
> 
> 
> On 2/25/09, Simon G <playthefivetones@ ...> wrote:
> >
> >
> > thanks for the info. if you don't mind me asking, has anything 
failed on your xpander?
> >
>