Circuit Analysis

The research folders: please contribute whatever little piece of information you might have on stompbox circuits new or old. Discussion should be civil and to the point.

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Vintage Stompbox Corner ( ... - 1975)
Discussion regarding early stompbox technology: 1960-1975 Please keep discussion focused and contribute what info you have...
Topics: 656

656 Topics

15031 Posts

Last post Re: Bell Electrolabs - Flanger
Dirk_Hendrik
30 nov 2023, 18:46
Modern Stompbox Effects (1975 - ...)
All about modern commercial stompbox circuits from Electro Harmonix over MXR, Boss and Ibanez into the nineties.
Topics: 1647

1647 Topics

24262 Posts

Last post Re: Question about the old EH…
lornaroa3
30 nov 2023, 13:27
Boutique Stompboxes dissected...
General documentation, gut shot, schematic links, ongoing circuit tracing, deep thoughts ... all about boutique stompboxes.
Topics: 1838

1838 Topics

58249 Posts

Last post Re: Xotic - SL Drive
mauman
yesterday, 00:02
DIY Projects
Original effects with schematics, layouts and instructions, freely contributed by members or found in publications. Cannot be used for commercial purposes without the consent of the owners of the copyright.
Subforums: Printed/Published Online Designs, Original Tracer Layouts
Topics: 1571

1571 Topics

28333 Posts

Last post Re: Ammo Can Reactive Load
Vitallka
03 dec 2023, 05:02
Electric Guitar/Bass Wiring
Pickups, wiring schemes, switch techniques and onboard active electronics for guitars and basses
Topics: 281

281 Topics

2494 Posts

Last post Re: 9V Low Battery Indicator …
george giblet
12 nov 2023, 21:20
Analysis Requests Folder
Before you launch a request, please a) search the forum; b) search the web and c) share whatever you did find and where you searched.
Topics: 1202

1202 Topics

4439 Posts

Last post thomasbe86
16 nov 2023, 22:28

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Last post

Original tracer layouts for classic pedals

Last post by andregarcia57 « 30 May 2023, 14:03
Replies: 61
by peps1 » 26 Apr 2010, 18:16
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Rating: 2.2%

(Hope this is in the right place, as it n0ot really a technical question and didn't want to post a request in the vintage section)

Hi Guys,

Trying to gather a collection of Original tracer layouts for classic pedals like the Tycobrahe Octavia, Dallas Rangemaster, ToneBender, Muffs & so on.

Got a couple so far....but would love more!
61 Replies

43645 Views

View the latest post Re: Original tracer layouts …
Last post andregarcia57
30 May 2023, 14:03
The BOSS Book (pdf & mp3's)

Last post by The G « 15 Dec 2020, 15:28
Replies: 3
by The G » 15 Dec 2020, 15:02

Rating: 3.9%

Discussion is here

--------
Did a compressed version. Didn't noticed visual differences compared to the original.

The Boss Book.pdf

And the audio files:

01-AudioTrack 01.mp3
02-AudioTrack 02.mp3
03-AudioTrack 03.mp3
04-AudioTrack 04.mp3
05-AudioTrack 05.mp3
06-AudioTrack 06.mp3
07-AudioTrack 07.mp3
08-AudioTrack 08.mp3
09-AudioTrack 09.mp3
10-AudioTrack 10.mp3
11-AudioTrack 11.mp3
12-AudioTrack 12.mp3
13-AudioTrack 13.mp3
14-AudioTrack 14.mp3
15-AudioTrack...

3 Replies

15734 Views

View the latest post Re: The BOSS Book
Last post The G
15 Dec 2020, 15:28
Tim Escobedo's "Folkurban" circuits. Zipped.

Last post by modman « 26 Jan 2020, 03:10
Replies: 24
by culturejam » 17 Mar 2012, 15:41
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Rating: 11.2%

I've recently noticed that Tim's great site at is coming up as a virus, trojan horse, or other bad things in my browser. So I thought I'd grab all the circuit images and zip them up for safe keeping. I have emailed him in the recent past, but there has been no reply. :hmmm:

Attached is a zip file of ALL of the effects circuits from his site.

Rock on, and may the creative spirit of the Great Escobedo be with you always. :thumbsup
24 Replies

27382 Views

View the latest post Re: Tim Escobedo's "Fol …
Last post modman
26 Jan 2020, 03:10
THE ENGINEER'S THUMB... At last, a better compressor!

Last post by jhergonz « 20 May 2018, 18:09
Replies: 101
by merlinb » 21 Apr 2012, 14:23
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Rating: 14.3%

For a long time I've felt guilty that my pedal board didn't include a compressor. Finally, after about a year of breadboarding, I have produced a circuit that can take on a Dynacomp and win , boasting:

Up to five times more headroom than a Dynacomp
Less noise than a Dynacomp
Same available sustain as a Dynacomp
Fewer parts than a Dynacomp
Cheaper than a Dynacomp
Feedforward side chain
Possibility for all five controls
Fits in 1590B
Millennium bypass

Despite its final simplicity, I went though...
101 Replies

54687 Views

View the latest post Re: THE ENGINEER'S THUMB... …
Last post jhergonz
20 May 2018, 18:09
READ THIS before posting!!

Last post by modman « 11 Sep 2011, 13:52

by modman » 11 Sep 2011, 13:52

Rating: 1.7%

This section is devoted to circuit analysis . This means...

requests for schematics or layouts will be moved the the Request section
messages about your sick puppy or your new Android powered phone should go into the FSB Café
debugging questions will be moved to the Workbench
useless post (containing no extra information) may get deleted to preserve the readability of the thread.
you should check whether a thread exists about the unit in question, and add your info in that thread.
you...

0 Replies

51684 Views

View the latest post READ THIS before posting!!
Last post modman
11 Sep 2011, 13:52
DO NOT post requests in this forum. Pretty please.

Last post by modman « 19 Mar 2010, 09:41
Replies: 2
by culturejam » 22 Nov 2009, 21:18

Pretty please, with sugar on top.

Don't post in this forum asking is there is a schematic or layout or info on XXX pedal.

There is a subforum setup for requests already. It is located here:
REQUESTS FORUM

Any requests posted here will be moved to proper sub forum, and I'll also make nasty remarks about your mother. :mrgreen:

2 Replies

51781 Views

View the latest post Re: DO NOT post requests in …
Last post modman
19 Mar 2010, 09:41
DO NOT post requests in this forum. Pretty please.

Last post by lolbou « 22 Nov 2009, 21:23
Replies: 1
by culturejam » 22 Nov 2009, 21:18

Pretty please, with sugar on top.

Don't post in this forum asking is there is a schematic or layout or info on XXX pedal.

There is a subforum setup for requests already. It is located here:
REQUESTS FORUM

Any requests posted here will be moved to proper sub forum, and I'll also make nasty remarks about your mother. :mrgreen:

1 Replies

48615 Views

View the latest post Re: DO NOT post requests in …
Last post lolbou
22 Nov 2009, 21:23
The Goose, the Middleman, the Idolmaker and Gomer Pyle

Last post by noelgrassy « 01 Feb 2008, 19:42
Replies: 91
by CS Jones » 07 Dec 2007, 21:41
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Clay, I would really love to hear the full story on this one. It seems like you have lots to tell!

Thanks LPD. How much do you want to hear? The Reader's Digest version or the pull up a chair, get comfortable because it'll be a while version ?

I'll try to finish something up this weekend. Long and short versions, if you're still interested. :)
91 Replies

210656 Views

View the latest post
Last post noelgrassy
01 Feb 2008, 19:42
Xotic - SL Drive

Last post by mauman « Yesterday, 00:02
Replies: 14
by aion » 24 Nov 2023, 16:45

Rating: 3%

A semi-original from Xotic... some RAT similarities, but plenty of differences compared to your average RAT clone.

Schematic:
xotic-sl-drive-trace-schematic.png

Full tracing journal here:

PCB available here:

14 Replies

1931 Views

View the latest post Re: Xotic - SL Drive
Last post mauman
Yesterday, 00:02
Ammo Can Reactive Load

Last post by Vitallka « 03 Dec 2023, 05:02
Replies: 20
by soulsonic » 10 Apr 2023, 03:36
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Rating: 6.9%

I finally got around to designing my DIY version of the Suhr Reactive Load. I was able to simplify the circuit with off-the-shelf parts and retain nearly identical frequency characteristics. I haven't formally measured the AC impedance yet, but spice said it should be nearly the same.
AmmoCanLoad01.JPG
Sine wave sweep of the circuit produced a frequency response almost identical to the Suhr, with the major peaks and dips at the same frequencies. One thing I noted was my design had a steeper...
20 Replies

2769 Views

View the latest post Re: Ammo Can Reactive Load
Last post Vitallka
03 Dec 2023, 05:02
Origin Effects Cali76?

Last post by CHEEZOR « 02 Dec 2023, 21:53
Replies: 10
by smear » 03 Mar 2023, 20:34

Rating: 3%

anyone have one of these they can open up?

the original 1176 is crazy expensive these days. i thought it'd be pretty elaborate, but looking at the original 1176 schematic, seems like a couple JFETs and a some BJTs. presumably the pedal removed the 5532 differential input. and the marketing doesn't mention any transformers so i guess they skipped that too. runs on +30V and -10V, nothing too crazy.

they're charging $359 for a pedal clone, and i bet most of that price is just based on the...

10 Replies

2700 Views

View the latest post Re: Origin Effects Cali76?
Last post CHEEZOR
02 Dec 2023, 21:53
Tetrafuzz

Last post by Vitallka « 02 Dec 2023, 16:42
Replies: 5
by Vitallka » 29 Nov 2023, 21:42

Rating: 1.9%

Hi to all.
Maybe you, like me, have a lot of germanium pnp transistors that have a small beta (20-30)? And you don't know where to apply them? I have the same problems :)
And I thought that it is possible to apply them somewhere and found some solution. The essence of this solution is as follows: the first stage should be a silicon npn transistor to significantly amplify the signal and solve ground problems, then two stages on germanium pnp transistors, and then a silicon npn transistor...

5 Replies

617 Views

View the latest post Re: Tetrafuzz
Last post Vitallka
02 Dec 2023, 16:42
Bell Electrolabs - Flanger

Last post by Dirk_Hendrik « 30 Nov 2023, 18:46
Replies: 8
by contobruto » 01 Aug 2012, 10:49

Rating: 0.9%

Screen Shot 2023-10-29 at 16.13.37.png Screen Shot 2023-10-29 at 16.13.49.png Screen Shot 2023-10-29 at 16.13.56.png Screen Shot 2023-10-29 at 16.14.06.png Screen Shot 2023-10-29 at 16.14.16.png Screen Shot 2023-10-29 at 16.14.25.png Screen Shot 2023-10-29 at 16.14.35.png

seems to be rare, can't find much info about it...
I got this from a music shop cellar clean out, it's had a bit of schorching and smoke damage to the outer shell, although the plastic knobs and marshall type jacks are not...

8 Replies

3348 Views

View the latest post Re: Bell Electrolabs - Flang …
Last post Dirk_Hendrik
30 Nov 2023, 18:46
Question about the old EHX Doctor Q envelope follower.

Last post by lornaroa3 « 30 Nov 2023, 13:27
Replies: 6
by Rambozo96 » 09 Feb 2020, 05:15

Rating: 0.6%

Hello all just worked on a Doctor Q and got it running and ran into a rather weird deal with the circuit. I noticed when I use just the pedal by itself the “quack” doesn’t begin to occur until 10-11 o clock and even then you gotta attack the strings pretty hard. Seems as if the circuit wasn’t being driven hard enough for the range to do much as far as having a versatile range. Sure enough when I switch on the Alembic booster on my strat the effect seems to quack with ease at 10-11 o clock where...

6 Replies

2229 Views

View the latest post Re: Question about the old E …
Last post lornaroa3
30 Nov 2023, 13:27
Xotic EP-Booster

Last post by stolen « 30 Nov 2023, 10:35
Replies: 172
by Greg » 16 Nov 2009, 11:08
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Rating: 10.2%

Here's the new Xotic EP-Booster.

Inspired by the EP Pre-amp.. but it turns out the circuit is quite different to the Pre-amp portion of the EP..
it doesn't use the same values or voltages. :D .

Cute and compact little enclosure, but the build quality is pretty lousy IMO.

Why do they use the board mounted DC jacks with no relief when everyone knows how much trouble they can cause ?
Also, the only thing keeping the battery from the board tracks and DC jack is a cheapass piece of rubber and...
172 Replies

111305 Views

View the latest post Re: Xotic EP-Booster
Last post stolen
30 Nov 2023, 10:35
Rockett Allan Holdsworth Overdrive

Last post by Paul Marossy « 29 Nov 2023, 23:40
Replies: 9
by mirosol » 15 Apr 2014, 19:31

Rating: 0.6%

So. Anyone has any information on this one? It seems to be a nice sounding overdrive.

I stumbled on a blog post with a few photos, but there's not much that can be done with those. Anything more than guessing.

I'll throw in my 2c with speculating about the JRC4558 having 1N4148s and Schottkys in the feedback loop. Gain pot at A50K could point the gain setting to be closer to Marshall Bluesbreaker than a TS. 5 transistors in all, could be two AMZ mini-boosts or any other muamp...

9 Replies

4856 Views

View the latest post Re: Rockett Allan Holdsworth …
Last post Paul Marossy
29 Nov 2023, 23:40
Maxon - PH-350 Rotary Phaser

Last post by ppluis0 « 29 Nov 2023, 17:03
Replies: 22
by idy » 30 Jun 2015, 20:19
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Rating: 2.2%

This one has escaped the forums and layout sites. Switchable 4/6/10 stages, the feedback control is minimum at noon, one direction adds fb out of phase, the other in.
gut shot here:
22 Replies

13533 Views

View the latest post Re: Maxon - PH-350 Rotary Ph …
Last post ppluis0
29 Nov 2023, 17:03
MXR M-151 Doubleshot distortion [schematic]

Last post by JordanFontaine « 29 Nov 2023, 16:48
Replies: 1
by dylan159 » 01 Apr 2023, 14:43

Rating: 1.5%

Intro

Hi everyone! I had the chance to get my hands on the MXR Doubleshot for a little while, and found out there are no available schematics anywhere. It's nice to do some selfless circuit tracing once in a while, in the true spirit of FSB.
Starting from what was known already, the Doubleshot is usually described as the dual channel version of the Dime, and we'll see this is accurate. That circuit already has something interesting in its own right, but this one builds upon it with the...

1 Replies

875 Views

View the latest post Re: MXR M-151 Doubleshot dis …
Last post JordanFontaine
29 Nov 2023, 16:48
Caline CP-25 Highway Man (and CP-12 Pure Sky)

Last post by CheapPedalCollector « 27 Nov 2023, 18:17
Replies: 8
by mirosol » 17 Dec 2017, 17:48

Rating: 3%

Hmm. Caline catalog is becoming quite puzzling one. These two here. Same f*king circuit. Paul Cochrane Timmy. 4558D, no switch for clipping, just the four 4148s for both. Highway Man has linear and log pots for bass/treble and Pure Sky has them at C50K. Pure Sky has designation screen prints under the components, but just by looking at the boards, component values and topology, i can safely say the circuits are identical.

Why on earth would anyone release two differently named pedals that have...

8 Replies

8559 Views

View the latest post Re: Caline CP-25 Highway Man …
Last post CheapPedalCollector
27 Nov 2023, 18:17
Stamps - DriveOmatic

Last post by aion « 27 Nov 2023, 14:25
Replies: 9
by analogguru » 18 Feb 2008, 09:19

Rating: 0.6%

Occasionally on ebay, now here the first time some guts:

analogguru

9 Replies

3727 Views

View the latest post Re: Stamps - DriveOmatic
Last post aion
27 Nov 2023, 14:25
Fred Briggs - Super OCD

Last post by Beedoola « 26 Nov 2023, 06:21
Replies: 65
by briggs » 28 Feb 2012, 16:39
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From my blog:

The Fulltone OCD has been an overdrive favourite for many years now. It's got a really nice tone when your amp is set right (I prefer it with Marshalls I must say). Well, I've always thought about modifiying the basic circuit (which itself is based around the old Voodoo Labs Overdrive) to give it a little more variety and use over a wider spectrum of tones.

As you can see the Super OCD has a few extra controls:

- Firstly the Bass control - it's nicked from Paul C's Timmy pedal...
65 Replies

20525 Views

View the latest post Re: Fred Briggs - Super OCD
Last post Beedoola
26 Nov 2023, 06:21
BJF - Honey Bee Overdrive degooped

Last post by aion « 25 Nov 2023, 19:51
Replies: 493
by modman » 05 Mar 2009, 22:47
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Rating: 4.3%

The Honey Bee....
hb1.jpg hb2.jpg
SDC10232.jpg SDC10231.jpg SDC10233.jpg
493 Replies

161292 Views

View the latest post Re: BJF - Honey Bee Overdriv …
Last post aion
25 Nov 2023, 19:51
Keeley - Compressor Plus

Last post by uncleboko « 25 Nov 2023, 11:50
Replies: 1
by aion » 24 Nov 2023, 16:35

Rating: 1.1%

It didn't seem like anyone had attempted this one aside from the photos in this thread , so here you go.

Schematic:
keeley-compressor-plus-trace-schematic.png

Full tracing journal here:

PCB available here:

1 Replies

795 Views

View the latest post Re: Keeley - Compressor Plus
Last post uncleboko
25 Nov 2023, 11:50
Germanium and Silicon diodes comparison

Last post by thomasbe86 « 25 Nov 2023, 11:24
Replies: 35
by thomasbe861 » 13 Oct 2023, 10:01
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Rating: 7.6%

Long story short, I ended up testing and measuring a good part of all odd diodes I have had accumulated over the decades of tinkering.
Some are modern, widely available, some are more rare and not produced anymore, germanium, silicon, including Schottky, silicon carbide, Zener, LEDs, IR, etc.
Here are the graphs, showing the forward voltage drop for a given current (I-V curve) for different types of diodes. Hope this is helpful to anyone. All were measured using a Peak Atlas DCA75 Pro.

The...
35 Replies

7559 Views

View the latest post Re: Germanium and Silicon di …
Last post thomasbe86
25 Nov 2023, 11:24
Digitech JamSync - How does it work?

Last post by Glin76 « 25 Nov 2023, 11:12
Replies: 85
by Sega_SVN » 09 May 2015, 23:00
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Hey, I need to synchronize my looper to perform a couple of our band's songs live but all production solutions are too exprensive and give me too many options I don't need (currently). We don't use computers or synths I only need to sync drummer's metronome and my looper. We tried with the drummer having me on headphones but my loops often don't have pronounced rhythm and I easily overwhelm them (and I could get very noisy :lol: ).

First idea is to send click from looper's rhythm machine to...
85 Replies

70548 Views

View the latest post Re: Digitech JamSync - How d …
Last post Glin76
25 Nov 2023, 11:12

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