Search found 5 matches

by Bachmanm
Mon Nov 19, 2012 2:09 pm
Forum: PAiA Jabber
Topic: FATMAN notes dither
Replies: 5
Views: 19787

Re: FATMAN notes dither

Scott.. Glad to see the end of jumpers! There was a day when a 2 layer was a significant increase in cost (though plateing etc) back in 1978, I was etching my own boards, and the single layer boards were much easier to make. On the Vleoity mod idea. I tested several different varients before decidin...
by Bachmanm
Tue Nov 06, 2012 4:17 pm
Forum: PAiA Jabber
Topic: FATMAN notes dither
Replies: 5
Views: 19787

Re: FATMAN notes dither

Steve Thank you!!. I should have closed out this post.. but for the record, you are right.. After I made my last post, I couldn't sleep until it was fixed. I looked at the bit lines to the DAC and data lines to the latch. One of the DAC bit lines was wavering.. it should have had a steady waveforem ...
by Bachmanm
Tue Oct 30, 2012 11:20 am
Forum: PAiA Jabber
Topic: FATMAN notes dither
Replies: 5
Views: 19787

Re: FATMAN notes dither

If I just touch IC4, the data latch for the DAC, with my finger, I can get the dithering to start or stop. It seems not to be pressure (indicating a bad solder joint) but seems to be the noise casued by my body (we are all coursing wi th 60Hz hum and such from all the RF around us). If i look at the...
by Bachmanm
Mon Oct 29, 2012 11:59 am
Forum: PAiA Jabber
Topic: Fatman help
Replies: 6
Views: 19156

Re: Fatman help

Since you say "digital noises", I suspect tha the software is not running correctly. Since SW doesn't normally go bad (PROMs can go bad every once in awhile), I would suspect the connections to these chips or power. Looking at the circuit, the MIDI red LED only needs +5 and the opto to work properly...
by Bachmanm
Mon Oct 29, 2012 11:36 am
Forum: PAiA Jabber
Topic: FATMAN notes dither
Replies: 5
Views: 19787

FATMAN notes dither

On certian notes, at random times, my Fatman'd notes "dither". By this I mean the pitch trilss between the actula note and some other descrete step. Sometimes fast (5 hz or so),, sometimes slow (1hz). Only certian keys do this, like B4. It is not pitchbend (none on my keyboard) and it is not softwar...