sorry I missed this , one pad is ground and there is another that you can see the traces on the pcb lead to it , so just two leads to solder
this is where to solder jumper wires to when using 3.5 mm jacks instead of 1/4 "
this is where to solder jumper wires to when using 3.5 mm jacks instead of 1/4 "
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So, I soldered 1K resistors in parallel with the 100Ks for the four LEDs. The time LED isnāt working at all, and I did test the LED separately. The other three are now in a good range. To match the bypass LED to them, I added an additional 900R in series. So, If I can just figure out why the time LED isnāt turning on, Iāll be set. Did the wet only mod as well.
hey, would this work as a guitar/bass pedal ? (most intrested for the bass pedal)
You would probably want something to boost the signal going in since synth signals are hotter, and then attenuate the signal coming out. Also it requires a Ā±12V power supply. If you can do the mods on a stripboard, feed it Ā±12V, and fit it all in a pedal enclosure, why not.
Maybe you could modify Ken Stoneās (synth-to-) Stomp Box Adapter:
http://www.synthpanel.com/modules/cgs46_sba.html
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Ahhh this is perfect, thanks!!
Has anyone tried to get the outputs from separate delay lines post-fader?
Iād love to do a mod with outputs of each delay line individually, and also mixing them to stereo with pan controls.
Anyone know what points would be the best place to get the delays?
Thank!
The output comes from an inverting amplifier with gain 100/15
whose input comes off the third PT2399ās pin 15 through a 1k resistor and a 10uF capacitor
On the first two PT2399s that resistor and capacitor are not present
so the obvious thing to try would be to add them and from there go into three attenuator pots, then sum those with 15k resistors at the input to the final op amp. However, my guess is that would affect the signals from the first two PT2399s going into the next ones. Maybe add voltage followers to each of the three outputs or at least the first two before going into the low impedance summing amplifier.
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iāve got this built and working for the most part but the input is either very low or clipping. the delay seems to have similar issues where itās either very quiet or feeding back like crazy. iāve checked over the input amplifier section (U4A) carefully but i donāt what to do next. the on/bypass switch thunks pretty hard as well, not sure if this is normal or a sign of something bad. any help would be appreciated!
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annoyingly. to save on component count I did not buffer the outputs of each of the delay outputs. however it doesnāt mean you cant experiment!
if I had put opamp buffers between each delay stage you could have tapped into each of the delays without any negligible effect, however at the same time! it may not effect it. depending what you plug it into. best bet is to wire a jack for output of delay 1 to pin 15 of the pt2399 chip. maybe via a 10uf capacitor, + on p[in 15 and minus going to the jack socket??? do the same to the second delay to get the output of that.
but Like I said I have no idea if this will effect the end of the output, it may very well not do!
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hey! that doesnāt sound like normal operation. it shouldnāt be clipping however I have had a similar problem with one of mine before and it turned out to be a dry joint, which I cannot for the life of me remember what. I think it was one of the capacitors going to ground. C23,24,25 ground pin?
I suggest turning up the heat and going over it again. maybe wiggle some components and see if there is any movement on the other side of the board, this would signal a loose connection.
your very close!!! itll just be a tiny error I recon
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Thanks! i think iāve got it all sorted now. i didnāt see the note about C22 and with that removed itās much more well behaved. seems like taking some care to limit the dynamic range at the input is also necessary. itās working well now, no more clipping and no more thunking! i think iāll look into a fine adjust for the delay time eventually.
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Hey guys just built my delay and it worked! All but number 3 for reasons unknown
I set about reflowing and plugged back in to get a puff of smoke and then it went dead
Noticed I had shorted C4 legs to each other so I replaced it assuming it had burnt out but still doesnt work
Certainly never had such an exciting failure but now dont know what to do, what else am I likely to have damaged do you reckon?
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Hey, do you have the .sch file for this mod? Doing my own mod and wanted to use yours as a starting point 
How does this look?
So basically adding two more TL074s, one for gain stages on each delay output which then would go to their own jacks (the del 3 is the same as your main output), then going to a volume mix pot then simple left/right pan for each, then another unity gain summing stage before the stereo output.
Any thoughts?
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The input impedence of your gain stage is 15k. I think thatās probably too low and itāll affect the signal going from one PT2399 to the next.
Also, whatās the rationale for having three inverting stages?
Also also, my inclination would be to just provide three outputs for the three PT2399s and do the mixing and panning in a separate module.
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What would you suggest for the input impedance? I just went with 15k since that was whatās one the output of out3 in the original circuit, but I see what you mean about it affecting things in the first two.
Re mixing/panning in another module, yeah thatād be straight forward, but Iām doing it this way because I donāt have space im my rack for anything else at the moment! Iām converting the panel to eurorack (basically just putting in on its side) so I have an extra inch or so to play with having these other controls all built in.
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Re 3 inverting stagesā¦ I donāt know haha! I guess that last bit of the circuit it just how I learnt summing mixers, but I guess since itās being inverted at the gain stage I could just leave out the second op amp inversion stage, maybe just use a TL082 instead.
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adding to this when i say it doesnt work i mean it jsut wont turn on
i dont wanna keep it plugged in for very long, but maybe its just the LEDās?
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Finally got back into the dungeon and inspected the module, found the culprit
Was one of the FB resistors had fried
What are they there for? I notice every module has them, is it for exactly this reason
All works a treat now other than the output seems noticeably lower than what goes in
Anyone else found this?
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What are they there for? I notice every module has them, is it for exactly this reason
Filtering and/or (not very great) fuses and/or āI saw it somewhereā, see here:
In this case they may actually have worked as fuses, but if they burn out odds are you have a problem elsewhere.
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