Search found 272 matches

by POTL
04 Sep 2020, 15:00
Forum: Pimp-My-Cheap-Pedal
Topic: Behringer VM1 Vintage Time Machine
Replies: 109
Views: 60627

Re: Behringer VM1 Vintage Time Machine

Hello. This circuit looks like an attempt to take the best of both worlds (I think Chase Bliss Tonal Recall was able to achieve this). We all know that DMM has excellent replay quality and built-in modulation. But reps can get overwhelmed. The boss has a high input impedance, which allows him to wor...
by POTL
23 Aug 2020, 10:42
Forum: Pedal Debugging & Troubleshooting Support
Topic: 3 Band Baxandall Calculator
Replies: 2
Views: 238

Re: 3 Band Baxandall Calculator

I built it several times and simulated it several times.
3 bands are too many for this equalizer, the controls become dependent on each other (not very much, but noticeably).
I would consider other schemes.
by POTL
06 Aug 2020, 10:38
Forum: DIY Stompbox designs
Topic: Tap Tempo for BBD
Replies: 2
Views: 278

Re: Tap Tempo for BBD

Another addition. I tested the LFOs of most flangers and noticed that they have a wider range than other effects. At least those that don't use the original watch. Interestingly, there are some interesting exceptions among deep-sounding flangers. 1) The Electric Mistress uses a non-inverting amplifi...
by POTL
06 Aug 2020, 08:37
Forum: DIY Stompbox designs
Topic: Tap Tempo for BBD
Replies: 2
Views: 278

Re: Tap Tempo for BBD

OK I modulated the standard LFOs Most circuits have a range of no more than 4V between maximum and minimum values, which means that we can simulate normal LFOs well. The only exceptions are Flangers, which work without original watches. Perhaps this is the reason for the lack of commercial flangers ...
by POTL
05 Aug 2020, 21:23
Forum: DIY Stompbox designs
Topic: Tap Tempo for BBD
Replies: 2
Views: 278

Tap Tempo for BBD

Hello. The idea behind Tap Tempo in analog modulation and delay pedals is not new, but still hasn't been covered in detail at the DIY level. I looked through a lot of commercial products such as JHS, Chase Bliss and noticed that they all use BBD 3007/5, 3207/5 with a clock as a module (do not give u...
by POTL
23 Jul 2020, 08:46
Forum: Amplifiers
Topic: Dr. Z - Z-Wreck [schematic]
Replies: 8
Views: 5180

Re: Dr. Z - Z-Wreck [schematic]

220 kΩ gives more gain. Much more interesting is another point, in the original VOX circuit, the 2 halves of the triode in the first stage have a common cathode resistor and capacitor, in this circuit, the second half of the triode is turned off (how wasteful), which means Dr. Z should have changed ...
by POTL
18 Jul 2020, 20:48
Forum: Amplifiers
Topic: Dr. Z - Z-Wreck [schematic]
Replies: 8
Views: 5180

Re: Dr. Z - Z-Wreck [schematic]

Almost 100% VOX AC30.
When I look at the schematics of boutique replica classic amps, I wonder, "Hey guys why can't you add master volume?"
R13 + R14 is almost equal to a 500kΩ potentiometer.
Why not give the opportunity for more flexible sound settings?
by POTL
12 Jul 2020, 08:48
Forum: Pedal Debugging & Troubleshooting Support
Topic: Rangemaster weird voltages
Replies: 4
Views: 208

Re: Rangemaster weird voltages

Hi, I suspect that the error may be in the most commonplace. You are using a circuit with a pnp transistor that requires a negative voltage. Power supply and LED connection for positive voltage. Tell me, do you only use battery power or are you using a power supply? Do you have other pedals? Do you ...
by POTL
07 Jul 2020, 11:16
Forum: Boutique Stompboxes dissected...
Topic: Walrus Audio - Deep Six Compressor [traced]
Replies: 32
Views: 19970

Re: Walrus Audio - Deep Six Compressor [traced]

I agree.
Nearby stands u1 looks like 78l05, strange.
by POTL
07 Jul 2020, 10:23
Forum: Boutique Stompboxes dissected...
Topic: Walrus Audio - Deep Six Compressor [traced]
Replies: 32
Views: 19970

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, 21:40
Forum: Boutique Stompboxes dissected...
Topic: Analogman - Chorus [traced]
Replies: 25
Views: 5949

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, 12:36
Forum: DIY Stompbox designs
Topic: Stupid and easy question
Replies: 3
Views: 685

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, 22:33
Forum: Modern Stompbox Effects (1975 - ...)
Topic: PAL Fx JCM 800 Emulator
Replies: 41
Views: 18455

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, 19:04
Forum: Parts Sourcing & Trading
Topic: j201 substitute
Replies: 28
Views: 8935

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, 00:00
Forum: Parts Sourcing & Trading
Topic: j201 substitute
Replies: 28
Views: 8935

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, 19:11
Forum: Parts Sourcing & Trading
Topic: j201 substitute
Replies: 28
Views: 8935

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, 10:18
Forum: Parts Sourcing & Trading
Topic: j201 substitute
Replies: 28
Views: 8935

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, 11:58
Forum: Parts Sourcing & Trading
Topic: j201 substitute
Replies: 28
Views: 8935

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, 11:55
Forum: Parts Sourcing & Trading
Topic: j201 substitute
Replies: 28
Views: 8935

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,...