Search found 264 matches

by POTL
07 Jul 2020, 12:16
Forum: Boutique Stompboxes dissected...
Topic: Walrus Audio - Deep Six Compressor [traced]
Replies: 31
Views: 18792

Re: Walrus Audio - Deep Six Compressor [traced]

I agree.
Nearby stands u1 looks like 78l05, strange.
by POTL
07 Jul 2020, 11:23
Forum: Boutique Stompboxes dissected...
Topic: Walrus Audio - Deep Six Compressor [traced]
Replies: 31
Views: 18792

Re: Walrus Audio - Deep Six Compressor [traced]

IC 1 - what is it?
Looks like a p-channel mosfet, for reverse polarity protection.
But i can`t see the markings.
by POTL
04 Jul 2020, 22:40
Forum: Boutique Stompboxes dissected...
Topic: Analogman - Chorus [traced]
Replies: 25
Views: 5131

Re: Analogman - Chorus [traced]

Right, I get that but did we ever figure out what the changes and values were? Not There is no reliable scheme anywhere. These photos were not taken by me, they are from the local local forum. i re-drawed schematic of analog man chorus (s/n ~3000), it's almost 99.9% Tonepad Small Clone , including ...
by POTL
17 Apr 2020, 13:36
Forum: DIY Stompbox designs
Topic: Stupid and easy question
Replies: 3
Views: 518

Stupid and easy question

Greetings The question is really simple, I played many times with the equalizers of various amplifiers, but only recently drew attention to the fact that the mid-frequency and high-frequency controls of different amplifiers have different characteristics. Mesa boogie (mark) VOX Fender black / silver...
by POTL
08 Sep 2019, 23:33
Forum: Modern Stompbox Effects (1975 - ...)
Topic: PAL Fx JCM 800 Emulator
Replies: 41
Views: 17513

Re: PAL Fx JCM 800 Emulator

You will need to make some changes to the circuit. MOSFets in schemes of a similar style. 1) Zvex Box Of Rock, Distortron, etc http://i40.tinypic.com/kejina.png 2) Catalinbread RAH. http://www.madbeanpedals.com/EP/schematics/Ankh.gif But you should understand that MOSFets sounds completely different...
by POTL
02 May 2019, 20:04
Forum: Parts Sourcing & Trading
Topic: j201 substitute
Replies: 28
Views: 7952

Re: j201 substitute

I wondered, some transistors are listed as amplifiers, some only as switches. Could this somehow affect the sound?
by POTL
02 May 2019, 01:00
Forum: Parts Sourcing & Trading
Topic: j201 substitute
Replies: 28
Views: 7952

Re: j201 substitute

Yes, I ordered them in China. Pinout does not play any role for me, since I use solderless development boards.
by POTL
01 May 2019, 20:11
Forum: Parts Sourcing & Trading
Topic: j201 substitute
Replies: 28
Views: 7952

Re: j201 substitute

I ordered adapter cards from to-92 to sot23 and wait for them. I looked at the digikey and mouser sites that most of the popular jfet are no longer produced, but the following are still available: J113 MMBF4393 2SK208-R 2SK209-Y MMBFJ270 MMBFJ177 MMBFJ309 2SK3666-2 Most likely, closer to the summer ...
by POTL
28 Apr 2019, 11:18
Forum: Parts Sourcing & Trading
Topic: j201 substitute
Replies: 28
Views: 7952

Re: j201 substitute

In order to show you the differences I have done a small experiment and ran a simualtion with a substitution of the J201 by the MMBF4393LT1G JFet. I loan the circuit from the Peppermill Overdrive which is designed as a clipper circuit. The Rd set up so that a symmetrisch clipping were achieved. Aft...
by POTL
24 Apr 2019, 12:58
Forum: Parts Sourcing & Trading
Topic: j201 substitute
Replies: 28
Views: 7952

Re: j201 substitute

I had a look at the datasheets of the JFETs form the list. IMO there is no direct replacement possible in each case the circuitry must be adapted, because there is no match with the forward transconductance ranges. If you believe the site ROG, then only VGSoff and IDSS are important. Are you talkin...
by POTL
24 Apr 2019, 12:55
Forum: Parts Sourcing & Trading
Topic: j201 substitute
Replies: 28
Views: 7952

Re: j201 substitute

What about the MMBFJ201? https://nz.mouser.com/ProductDetail/ON-Semiconductor-Fairchild/MMBFJ201?qs=sGAEpiMZZMv4z0HnGdrLjpo3FY8YkyPvx%252BQykc9k8ic%3D Or j201? https://nz.mouser.com/ProductDetail/InterFET/J201?qs=sGAEpiMZZMv4z0HnGdrLjo0W1AxRZQdlr4Y9S0sHX3DXCATSkEoEcg%3D%3D Mouser is not convenient,...
by POTL
24 Apr 2019, 00:41
Forum: Parts Sourcing & Trading
Topic: j201 substitute
Replies: 28
Views: 7952

j201 substitute

Hello everyone, I recently encountered a j201 deficit in my country, having studied the forums I found several models that other manufacturers use (mmbf4393 Catalibread and 2SK208 AMT) or recommend stores (PF5102 Smallbear). I also found some more options in stores. If someone used them, then tell u...
by POTL
17 Mar 2019, 20:16
Forum: Boutique Stompboxes dissected...
Topic: Friedman BE50 schematic needed
Replies: 9
Views: 1856

Re: Friedman BE50 schematic needed

Are these exactly current schemes? I am confused by the voltage divider after the first cascade 68K / 10M This gives a voltage drop of 24dB, the first stage is something like a treble booster with a gain of about 12dB, more like a lightweight heater and tone corrector. I did not play friedman - doe...
by POTL
15 Mar 2019, 22:19
Forum: Boutique Stompboxes dissected...
Topic: Friedman BE50 schematic needed
Replies: 9
Views: 1856

Re: Friedman BE50 schematic needed

plush wrote:Year 2019, yet still no input protection...
Are you talking about this?
To be honest, I saw a lot of schemes for new models of amplifiers and pedals, and nowhere did I encounter protection at the input.
Perhaps this is overengineering.
opamp-input-Fig-01.png
by POTL
15 Mar 2019, 16:20
Forum: Boutique Stompboxes dissected...
Topic: Friedman BE50 schematic needed
Replies: 9
Views: 1856

Re: Friedman BE50 schematic needed

Are these exactly current schemes? I am confused by the voltage divider after the first cascade 68K / 10M This gives a voltage drop of 24dB, the first stage is something like a treble booster with a gain of about 12dB, more like a lightweight heater and tone corrector. I did not play friedman - does...
by POTL
25 Feb 2019, 22:00
Forum: Modern Stompbox Effects (1975 - ...)
Topic: Op Amp Theory
Replies: 5
Views: 975

Re: Op Amp Theory

Hey. I conducted an experiment a couple of years ago, I called my two friends, one musician who is a little keen on the effects, the second radio amateur, who sometimes plays music: LOL We collected several mockups of popular pedals, like OCD and Screamer and JHS Angry Charlie (it was a long time ag...
by POTL
23 Feb 2019, 19:46
Forum: DIY Stompbox designs
Topic: Some theoretical questions about tubes
Replies: 1
Views: 960

Some theoretical questions about tubes

Hello I had a few trivial questions about tube preamps. I understand that the forum is dedicated to stompboxes, but I am sure that competent people will help me. I looked at the scheme of the preamp EVH 5150 III, which is a modernized version of the Peavey 5150/6505. I have a few questions 1) In mos...
by POTL
13 Feb 2019, 22:35
Forum: Boutique Stompboxes dissected...
Topic: Friedman BE50 schematic needed
Replies: 9
Views: 1856

Friedman BE50 schematic needed

Anybody have?
by POTL
02 Feb 2019, 21:45
Forum: Boutique Stompboxes dissected...
Topic: Supro 1304 Fuzz Schematic
Replies: 1
Views: 996

Supro 1304 Fuzz Schematic

Снимок экрана 2019-02-02 в 23.45.46.png
Thansk for schematic pedalPCB.com
Links here
https://www.pedalpcb.com/docs/ReproFuzz.pdf