DS-1 to True Bypass (3PDT)

Started by s.r.v., August 14, 2007, 05:26:05 PM

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s.r.v.

on the pcb, is 12 positive or is 14 positive? either way, would i connect the battery snap and the positive of the LED to this hole, but with a resistor going to the LED? thanks!
also, is the unmarked hole at the top the ground? should i connect it to something? I'm almost done, just awaiting some LED's in the mail, then i have to drill 3 holes for the jacks and footswitch. I'm not sure if it will fit in the new enclosure

s.r.v.


moro

Did you ever finish this, s.r.v.?

I was just looking at the schematic that Brian posted and I'm not sure what to do with the power. If you take the electronic switching out, don't you have to jumper the +9V to somewhere so the effect is always on?

wampcat1

Quote from: moro on September 01, 2007, 12:08:59 PM
Did you ever finish this, s.r.v.?

I was just looking at the schematic that Brian posted and I'm not sure what to do with the power. If you take the electronic switching out, don't you have to jumper the +9V to somewhere so the effect is always on?

the 9v is always connected to the IC and transistors... see that arrow pointing up next to D7? Then see how Q2, pin 7 of the ic, etc have arrows that point up where they connect to power?
By connecting it like I have it, the circuit is always on. I personally don't like leaving in the jfets and the buffers (unless necessary for impedance purposes) in the signal path. The less "stuff" in the way of the circuit, the more I like it. Just a personal preference, and there are probably some who disagree with me.

Hope that helps! :)
bw

moro

Quote from: wampcat1 on September 01, 2007, 12:57:01 PM
the 9v is always connected to the IC and transistors... see that arrow pointing up next to D7? Then see how Q2, pin 7 of the ic, etc have arrows that point up where they connect to power?
By connecting it like I have it, the circuit is always on. I personally don't like leaving in the jfets and the buffers (unless necessary for impedance purposes) in the signal path. The less "stuff" in the way of the circuit, the more I like it. Just a personal preference, and there are probably some who disagree with me.

Hope that helps! :)
bw

Yes, that's great. Thank you! I'm going to go try this out now. :icon_biggrin:

moro

#25
I'm kind of stumped here. Has anyone tried this on a newer DS-1? Mine doesn't match the schematic, which is making debugging a real PITA.

I removed Q6 and Q7, and wired R5 and R18 to the 3PDT. I removed the LED, momentary switch, and battery clip. (I never use batteries.) The + terminal of the DC jack is connected to PIN 8 on the opamp (M5223), which I believe is the + voltage pin. So it seems like it should work. But it doesn't.

The bypass is working, so that part of it seems to be wired correctly, but I get a signal for a split second when I step on the 3PDT. I get the same thing when I leave the 3PDT in the on position, then disconnect / connect the DC jack. When I plug it back in, I get signal for a split second. It seems like the electronic switching is still in there and working in some mutant backward way? :icon_confused:

Voltages on the opamp and Q2 pretty much match the readings on my stock DS-1:

opamp
1: 4.7 V
2: 4.7 V
3: 4.7 V
4: 0 V
5: 4.7 V
6: 4.7 V
7: 4.7 V
8: 9.4 V

Q2
E: 0.11 V
C: 4.4 V
B: 0.602 V


moro

Ok, so forget everything I just wrote. :icon_eek: I just built an audio probe and the pedal actually seems to be working. If I unplug / plug in the output jack, I get a signal for a split second, like before. If I put the audio probe on the same cable and touch the ground to the the output jack ground and the tip (0.1uF cap) to the jack tip, the signal is fine!

I tried this with two different cables with the same results. What in the world is going on?

moro

Yes, I realize I'm talking to myself.

I tried 0.56uF and 330pF (the smallest I had) caps as well, and the pedal works fine. So, if I plug the cable directly into the output jack, the signal cuts out after a split second. If I put a capacitor between the jack tip and plug tip, everything is fine.

I'm guessing I'm triggering the electronic switching somehow. Can I safely remove Q4, Q5, and Q8?

wampcat1

sure, go ahead and remove them. Personally, I'd remove everything except for Q2 which is a gain stage. Then, I'd just route the signal as shown in that drawing I posted, ignoring all the buffers.
bw

moro

Quote from: wampcat1 on September 05, 2007, 03:13:03 PM
sure, go ahead and remove them. Personally, I'd remove everything except for Q2 which is a gain stage. Then, I'd just route the signal as shown in that drawing I posted, ignoring all the buffers.

Thanks! I'll try this tonight. I'm so tantalizingly close to getting this working. It's driving me nuts.

*fingers crossed*

mars_bringer_of_war

Quote from: thebattleofmidway on August 15, 2007, 11:06:00 AM
why? it sounds fine bypassed...

C'mon, don't you know that true bypassing is the path to greatness? Why, think of all the notable pedal users with great tone who had complete true bypass chains:
Hendrix...no, wait....Van Hal...no, wait...The Edge...um, no...SRV...
Ah, forget it.
I will quietly resist.

moro

I give up. I pretty much removed every component that wasn't between the two inner Xs in the schematic and I was still having the same problem. So I tried wiring it with a cap before the output, and that works, but it sounds like crap. :icon_cry:

I'm going to put it aside and re-populate the board some rainy day.

rarebuzzer

I hate to revive a dead thread, but I am looking to do the same. I have taken a look at the schematics for the Boss DS-1 as it sits, and I think I have a solution:

1) Remove Q6, Q7, Q8. On Q6 and Q7, jumper across. This basically cuts out the entire JFET switching circuit.

2) Remove D2. This cuts out the LED circuit, but provides an easy +9V point.

2) From the 3PDT switch (I use a PCB): W1 - Input; W11 - Output; D2 (cathode) - +9V; W12 - Ground. LED is switched from the 3PDT.

Thoughts?