Search found 77 matches

by idy
26 Jun 2020, 21:36
Forum: Pedal Debugging & Troubleshooting Support
Topic: Buffer adding hisssssssss
Replies: 10
Views: 284

Re: Buffer adding hisssssssss

Why a charge pump for a buffer? If you wanted lots of clean boost I would understand, but buffering means gain around 1, so unless you are buffering a signal already close to 30v(!) that is wasted headroom and parts and power and... an invitation for trouble... Maybe it's part of something bigger?
by idy
07 Mar 2020, 19:20
Forum: Pedal Debugging & Troubleshooting Support
Topic: RC Booster dark low volume sound with controls at noon
Replies: 7
Views: 223

Re: RC Booster dark low volume sound with controls at noon

Always good to try different tapers. I have built a number of these. I like to change the clipping diodes for MOSFETs plus diodes, or even a single mosfet for assymetry... or really any single clipper for assymetry. Also playing with the value (and taper) of the gain pot can give you a different ran...
by idy
04 Mar 2020, 19:44
Forum: Pedal Debugging & Troubleshooting Support
Topic: RC Booster dark low volume sound with controls at noon
Replies: 7
Views: 223

Re: RC Booster dark low volume sound with controls at noon

Sorry I didn''t notice you worked from the smaller layout. Still the questions are why is the base less than .6v above the emitter... and check the off board wiring...and can you audio probe it....
by idy
03 Mar 2020, 17:40
Forum: Pedal Debugging & Troubleshooting Support
Topic: RC Booster dark low volume sound with controls at noon
Replies: 7
Views: 223

Re: RC Booster dark low volume sound with controls at noon

So I see you took two rows off the layout, and that should be okay, the top two rows just made a nice arrangement for the diodes, and it looks like you adjusted things. I think I see a missing cut: it should be in your second from the to row, fourth column...maybe part of your "adjustments?" I think...
by idy
03 Mar 2020, 17:21
Forum: Pedal Debugging & Troubleshooting Support
Topic: RC Booster dark low volume sound with controls at noon
Replies: 7
Views: 223

Re: RC Booster dark low volume sound with controls at noon

The B and E of the transistors should be "one diode drop" apart, about .6v. Audio probe might help find where things are going wrong.
by idy
22 Feb 2020, 19:02
Forum: Modern Stompbox Effects (1975 - ...)
Topic: All Test Devices ATD - PB-1 Transducer Pre-Amp/Booster [schematic]
Replies: 10
Views: 1286

Re: All Test Devices ATD - PB-1 Transducer Pre-Amp/Booster [schematic]

Any insight into the feedback(?) between the two transistors, R9 and C2?
by idy
17 Nov 2019, 19:16
Forum: Vintage Stompbox Corner ( ... - 1975)
Topic: Pédale de Vibrato et de Super-Aigues [schematic]
Replies: 6
Views: 2610

Re: Odd 2 transistor treble booster? [schematic]

The first transistor is a booster. Then there is a "T" filter that cuts bass. The second transistor is a gain recovery stage. So your signal is super hot and super aigue.
by idy
24 Oct 2019, 01:35
Forum: Pimp-My-Cheap-Pedal
Topic: TC Tube Pilot Dry/Mix Mod
Replies: 6
Views: 1333

Re: TC Tube Pilot Dry/Mix Mod

Spltter/Blender is one very useful thing you will find many uses for. You can find them on the strip board layout sites. The simple one shown above should do the trick. Some have two "send/return" loops so you can also pan between two effects.
by idy
20 May 2019, 18:10
Forum: Vintage Stompbox Corner ( ... - 1975)
Topic: Eko - Multitone [schematic]
Replies: 8
Views: 4100

Re: Eko - Multitone [schematic]

Is that booster schematic right? very unusual...?
by idy
28 Dec 2018, 17:58
Forum: Vintage Stompbox Corner ( ... - 1975)
Topic: Univibe repair advice needed
Replies: 24
Views: 4047

Re: Univibe repair advice needed

If it sound right it is right. The bulb isn't to read by, so as long as you like the sound, no need to go trying to brighten it. Though there are ways to do that . Your unit seems to be missing the light shield, the little (shiny) metal box that encloses the bulb+LDRs. That will deepen the sound a b...
by idy
27 Dec 2018, 04:00
Forum: Vintage Stompbox Corner ( ... - 1975)
Topic: Univibe repair advice needed
Replies: 24
Views: 4047

Re: Univibe repair advice needed

The resistor in series is a cautious thing. Maybe 100ohms? Just something in case. It will drop some voltage, your circuit won't get all the juice it should. The power supply voltage seems a bit low for a univibe, and yes that transformer looks modern... But you say it was working, so it's big enoug...
by idy
26 Dec 2018, 03:31
Forum: Vintage Stompbox Corner ( ... - 1975)
Topic: Univibe repair advice needed
Replies: 24
Views: 4047

Re: Univibe repair advice needed

You're new enough here that somebody has to say: be careful with that power transformer and the AC! You will get some people who have done this exact repair and will tell you what to be careful about when powering this up again. I've built clones but never messed with an original unit with an issue ...
by idy
25 Dec 2018, 17:02
Forum: Vintage Stompbox Corner ( ... - 1975)
Topic: Univibe repair advice needed
Replies: 24
Views: 4047

Re: Univibe repair advice needed

Diodes burn out if they carry too much current. So there could be a problem "down stream" causing the circuit to demand too much from the power supply. A short circuit or something. The diode just chops the AC wave in half, what they call a half wave rectifier, very crude way to get choppy DC. The d...
by idy
24 Dec 2018, 17:35
Forum: Vintage Stompbox Corner ( ... - 1975)
Topic: Univibe repair advice needed
Replies: 24
Views: 4047

Re: Univibe repair advice needed

Yes, a CD player or such (looper pedal) is a good signal source. The signal tracer cable doesn't go directly to a speaker but rather to a small, not-to-valuable amp then to the speaker. The other "simple" way to get started is to measure voltage at all the pins of all the transistors.... No signal a...
by idy
15 Dec 2018, 20:42
Forum: Vintage Stompbox Corner ( ... - 1975)
Topic: Univibe repair advice needed
Replies: 24
Views: 4047

Re: Univibe repair advice needed

If there is no sound at all I would not begin suspecting the LFO but start signal tracing. It could be something so simple even... you or I could fix. Maybe. Signal tracer... cable with a capacitor to block DC. Hook up a sound source to the vibe and find out where the sound stops. A bad LFO probably...
by idy
28 Oct 2018, 16:21
Forum: Pimp-My-Cheap-Pedal
Topic: Has anyone modded their MXR Distortion + ?
Replies: 7
Views: 2216

Re: Has anyone modded their MXR Distortion + ?

DIstortion+ is a good choice for first experiments. One of my first. I doubled the diodes. Friends were impressed. I couldn't duplicate the great sound. Finally discovered I'd broken one of the (glass) diodes. So I found I like asymetric clipping... Yes, the "best" path is to get a breadboard and a ...
by idy
30 Apr 2017, 04:52
Forum: Pedal Debugging & Troubleshooting Support
Topic: Axis Face - Can't get Q2 biased - Please Help!
Replies: 3
Views: 101

Re: Axis Face - Can't get Q2 biased - Please Help!

You should not get DC voltage at the volume pot: that's what that cap is for, to keep the DC "inside" the circuit. A voltage that the bias trimmer won't change on Q2 means something is up with that transistor; loose, bad connection, ruined transistor, something. You breadboarded it and it worked, yo...
by idy
29 Jun 2016, 22:44
Forum: Modern Stompbox Effects (1975 - ...)
Topic: Joyo - JF-02 Ultimate Drive "2010" MISTAKE [schematic]
Replies: 32
Views: 26015

Re: Joyo - JF-02 Ultimate Drive "2010" MISTAKE [schematic]

If you remove the diode the single remaining mosfet clips in one direction as a silicone diode (.6v), in the other as a mosfet, more like 1.8v. A good assymetric clip. Very nice sound. Which is probably what you get with the "fixed" version, since when you have two "clippers" in parallel the lower v...
by idy
06 May 2016, 02:32
Forum: Pedal Debugging & Troubleshooting Support
Topic: High Gain + Buffer = No Squeal. Why?
Replies: 0
Views: 90

High Gain + Buffer = No Squeal. Why?

This has happened several times. FET amp simulators (Black '65, this time DLS mkIII). High frequency oscillation, probably caused by too much wiring attached to strip board layouts. Only a problem at highest gain/highest treble settings. I put the guitar (lace sensor pickups) into a buffer first (an...
by idy
22 Mar 2016, 17:25
Forum: Pedal Debugging & Troubleshooting Support
Topic: MAESTRO Filter Sample Hold CLONE problem
Replies: 17
Views: 183

Re: MAESTRO Filter Sample Hold CLONE problem

GGG posted "original" and "modern improvements" versions, latest update may 2015.
Is this your first project?
Why do you think the original would be better?