Search found 61 matches

by Billb3
Thu Dec 25, 2014 10:01 pm
Forum: PAiA Jabber
Topic: Fatman upgrade
Replies: 0
Views: 12701

Fatman upgrade

I upgraded the power block on my fatman, found a free supply with a Harmon Kardon computer speaker. https://www.flickr.com/photos/129435558@N05/15487071043/ https://www.flickr.com/photos/129435558@N05/16080997366/ Added a power supply connector for add on modules https://www.flickr.com/photos/129435...
by Billb3
Tue Dec 16, 2014 1:13 pm
Forum: PAiA Jabber
Topic: lfo - bipolar vs unipolar output
Replies: 2
Views: 13954

lfo - bipolar vs unipolar output

Is there an easy way to convert a bipolar signal to unipolar? I want to use the output of an lfo / s&h to drive an oscillators CV. having negative voltages really doesnt work well with my oscillators. :( my current thought is to change the power supply to be unipolar but am wondering if there are ot...
by Billb3
Mon Dec 15, 2014 9:54 am
Forum: PAiA Jabber
Topic: Tuning a Fatman with guitar pedal tuner
Replies: 2
Views: 13733

Re: Tuning a Fatman with guitar pedal tuner

the fatman has a much higher output level than a guitar. try setting the output level to a low level.

also, make sure the vco's are tuned together even though you will only be using one vco for tuning because the 2nd vco still influences the output somewhat.

Billb
by Billb3
Thu Dec 11, 2014 4:19 pm
Forum: PAiA Jabber
Topic: 556 dual 555 timer
Replies: 3
Views: 17281

Re: 556 dual 555 timer

I've found that my 3rd oscillator will NOT sync to the first pair no matter how hard I try. I used a regular 555 and an LED instead of the 10 ohm resistor. the power cable to this board is about 18" long and I suspect that is the reason for this. Cable capacitance? has anyone tried a smaller power c...
by Billb3
Wed Dec 03, 2014 12:41 pm
Forum: PAiA Jabber
Topic: Waves in and out of phase
Replies: 5
Views: 19233

Re: Waves in and out of phase

I need to break out my 4 channel scope and make a video of it. its actually kinda cool to watch it phase in and out. my sub octave is running off the reset pulses (i think) so if the flip flop misses a pulse the it will change its phase state. the -1 sub is either in or out, the -2 sub has 2 other s...
by Billb3
Tue Dec 02, 2014 10:47 am
Forum: PAiA Jabber
Topic: dead Korg DW8000
Replies: 4
Views: 16811

Re: dead Korg DW8000

only burns were right at the chips.

but no burned traces. p/s is fine after I replaced the 7805 #2.
no blown fuses
I'll check the diodes.

there was a hunk of metal loose in the case under the cpu board. I think if fell of the bottom of one of the keys.
by Billb3
Sat Nov 29, 2014 11:17 am
Forum: PAiA Jabber
Topic: dead Korg DW8000
Replies: 4
Views: 16811

dead Korg DW8000

recently acquired, the main CPU chip has its top blown off.

has anyone worked on one with extreme damage?

I am concerned that many chips my be fried.

Bill
by Billb3
Tue Nov 25, 2014 3:35 pm
Forum: PAiA Jabber
Topic: Fatman Rank select added
Replies: 2
Views: 14108

Re: Fatman Rank select added

Its a resistor network replacing the 10k tuning pot.

the switch selects the high and low resistor pair and puts them on either side of the new 1 k fine tune pot. each set of resistors also has a trimpot for setting it up.

bill
by Billb3
Fri Nov 21, 2014 10:26 am
Forum: PAiA Jabber
Topic: Fatman Rank select added
Replies: 2
Views: 14108

Fatman Rank select added

I finally added a rank selection switch to my fatman.

has 3 settings.

1 A4 = 220 hz
2 A4 = 440 hz
3 A4 = 880 hz

the Pitch pot now has a range of +/- 1 semi tone.

https://www.flickr.com/photos/29708075@N08/15225090613/

Bill
by Billb3
Wed Nov 19, 2014 3:09 pm
Forum: PAiA Jabber
Topic: Waves in and out of phase
Replies: 5
Views: 19233

Re: Waves in and out of phase

by "out of phase" I mean that when one oscillators wave is at its peak the others is in a valley. the result is no sound output as the waves cancel each other out. this is randomly happening with my sub oscilators. I can cause it by changing the pitch of vco1 slightly and then returning it to locked...