Search found 243 matches

by Groovenut
30 Mar 2020, 00:43
Forum: Parts Sourcing & Trading
Topic: Need help finding JMP-1 transformer
Replies: 8
Views: 1196

Re: Need help finding JMP-1 transformer

Given that the caps in the HT power supply are rated at 350V, I would guess they are running the filtered DC to the plate resistors at around 300 volts. Most Marshall preamps run this voltage between 245 and 350 volts, so it seems in the ball park.
by Groovenut
17 Oct 2019, 15:29
Forum: Pedal Debugging & Troubleshooting Support
Topic: How to remove the popping noise when switching the reverb po
Replies: 4
Views: 360

Re: How to remove the popping noise when switching the rever

You might try bypassing each side of the switch with a 1M-2M2 resistor. So from common to each pot wiper connection. That should maintain the DC bias across the switch but limit the signal when disconnected.

Just a shot
by Groovenut
07 Aug 2019, 17:30
Forum: Modern Stompbox Effects (1975 - ...)
Topic: Rat - Little Bear R.ATTACK chinese
Replies: 5
Views: 3544

Re: little bear r.attack - RAT copy

It's an on-off-on switch The LEDs are always connected and active when in the center switch position. The center lug of the switch is connected to ground. The other sets of diodes are connected to the respective outside lugs. The lower Vf diodes will take over from the LEDs when they are activated. ...
by Groovenut
16 May 2018, 20:14
Forum: Ready-To-Build Effect Projects
Topic: BAJA MDR overdrive pedal 9v 060218
Replies: 44
Views: 4313

Re: BAJA MDR overdrive pedal 9v 060218

Baja,

Maybe a silly question, but how are you accounting for the asymmetric clipping in early gain stages of the real amp?

Thanks!
by Groovenut
30 Apr 2018, 14:35
Forum: Pedal Debugging & Troubleshooting Support
Topic: True-bypass popping issue with a booster
Replies: 2
Views: 215

Re: True-bypass popping issue with a booster

Sounds like the fet might be leaky and need replaced. damaged gate junction or something the like.
by Groovenut
30 Mar 2018, 16:18
Forum: Ready-To-Build Effect Projects
Topic: BAJA Orange AD200B MkII bass amplifier in a 9v pedal 270318 [verified]
Replies: 24
Views: 2768

Re: BAJA Orange AD200B MkII bass amplifier in a 9v pedal 270 [verified]

BlueMeany wrote:Hi Baja, cool stuff! What is going on with the tl062 stage? Looks interesting.
I believe it is modeling the output stage behavior
by Groovenut
16 Dec 2017, 14:35
Forum: Boutique Stompboxes dissected...
Topic: JHS - AT (Andy Timmons) Signature Drive [traced]
Replies: 22
Views: 8227

Re: JHS - AT (Andy Timmons) Signature Drive [traced]

The toggle is a on/off/on, so no clipping diodes in middle position? I do believe that is correct. This should correspond to the 100W mode, described as "cleaner, loud". I was under the impression that the louder setting were the LEDs , the lowest setting were the Schotky's and the middle...
by Groovenut
16 Dec 2017, 03:43
Forum: Boutique Stompboxes dissected...
Topic: JHS - AT (Andy Timmons) Signature Drive [traced]
Replies: 22
Views: 8227

Re: JHS - AT (Andy Timmons) Signature Drive [traced]

The toggle is a on/off/on, so no clipping diodes in middle position? I do believe that is correct. This should correspond to the 100W mode, described as "cleaner, loud". I was under the impression that the louder setting were the LEDs , the lowest setting were the Schotky's and the middle...
by Groovenut
05 Sep 2017, 14:41
Forum: Boutique Stompboxes dissected...
Topic: Fulltone - OCD [traced]
Replies: 570
Views: 197169

Re: Fulltone - OCD [traced]

Schematic.png Here ya go, I'll upload a pinout for the 3PDT shortly. I have PCBs ready to go for this if anyone wants em. I'm aware that Q5 appears to be upside down, I reconfirmed this multiple times, it is correct. Since these are 2N5457 the Drain/Source is interchangeable. thank you very much in...
by Groovenut
01 Sep 2017, 19:04
Forum: Boutique Stompboxes dissected...
Topic: Friedman BE-OD Pedal [traced]
Replies: 663
Views: 210159

Re: Friedman BE-OD Pedal [traced]

I was wondering why Friedman and others have Vbias going through an op amp? Is there an advantage to this like less noise or is this just something you do with unused op amps? screenshot.642.png It provides a low impedance bias rail that is very stable. Plus it's something to do with that left over...
by Groovenut
21 Aug 2017, 19:09
Forum: Boutique Stompboxes dissected...
Topic: Friedman BE-OD Pedal [traced]
Replies: 663
Views: 210159

Re: Friedman BE-OD Pedal [traced]

C12 could be a 1n capacitor, as noted by Pakrat in his post: http://www.freestompboxes.org/viewtopic.php?f=7&t=27775&start=80#p264115 C12: 12pf MLCC? ( Marked "CDM 102 +/-5%") ...even if, in the following post he says: Correction, C12 is indeed 120pf silver mica. Sorry about that....
by Groovenut
09 Aug 2017, 14:55
Forum: Modern Stompbox Effects (1975 - ...)
Topic: E-WAVE Giant Distortion Schematic
Replies: 13
Views: 5334

Re: E-WAVE Giant Distortion Schematic

Yes wired in anti-parallel, like normal to ground clippers, it is just the body diode that does the clipping. If you want the internal zener clipping of the mosfet, you have to wire them like zeners.
by Groovenut
05 Aug 2017, 15:04
Forum: Boutique Stompboxes dissected...
Topic: Friedman BE-OD Pedal [traced]
Replies: 663
Views: 210159

Re: Friedman BE-OD Pedal [traced]

@rmroza - just in case you missed this earlier reply. Also, it may be the angle of the pic but to me LED3 and LED4 by IC3 look like they are facing the same direction. They should be facing opposing directions. One flat down, one flat up. Same with the 2 LEDs next to IC1. The cathodes should face op...
by Groovenut
05 Aug 2017, 14:50
Forum: Boutique Stompboxes dissected...
Topic: Friedman BE-OD Pedal [traced]
Replies: 663
Views: 210159

Re: Friedman BE-OD Pedal [traced]

Interesting, what difference does it make? It guarantees you a stiff 4.5v dc bias voltage - the op amp has a very low output impedance compared to the high impedance (5k in this case) from the 2 x 10k voltage divider. I think the fried man (or whoever laid the board out) made a stupid layout mistak...
by Groovenut
05 Aug 2017, 03:26
Forum: Boutique Stompboxes dissected...
Topic: Friedman BE-OD Pedal [traced]
Replies: 663
Views: 210159

Re: Friedman BE-OD Pedal [traced]

I do Tayda for pots however small bear and mammoth are great as well for hardware :applause: Biggest issue with Tayda and pots is they don't carry a wide variety of pcb mount right angle pots. Especially in anti-log. Which is why I suggested Mammoth. Steve at Small Bear carry just about everything ...
by Groovenut
05 Aug 2017, 02:30
Forum: Boutique Stompboxes dissected...
Topic: Friedman BE-OD Pedal [traced]
Replies: 663
Views: 210159

Re: Friedman BE-OD Pedal [traced]

rmroza wrote:Thanks. I was just about to it myself since I have the time....now

What about the PCB pots? I'm having a hard time locating all the necessary variations in the states from my sources!!!
Mammoth Electronics has them all
by Groovenut
05 Aug 2017, 00:36
Forum: Boutique Stompboxes dissected...
Topic: Friedman BE-OD Pedal [traced]
Replies: 663
Views: 210159

Re: Friedman BE-OD Pedal [traced]

@rmroza - it also looks like you may be reading your IC pins in the wrong order. That or your bias network is borked. Pins should be read as facing the top of the chip with the detent up. Pin 1 is upper left and then proceed 1-8 in a counter clockwise horse shoe 1 - - 8 2 - - 7 3 - - 6 4 - - 5 Also,...
by Groovenut
31 Jul 2017, 14:46
Forum: Boutique Stompboxes dissected...
Topic: Friedman BE-OD Pedal [traced]
Replies: 663
Views: 210159

Re: Friedman BE-OD Pedal [traced]

What is pin 1 voltage after the wire jumper is installed?
by Groovenut
30 Jul 2017, 18:26
Forum: Boutique Stompboxes dissected...
Topic: Friedman BE-OD Pedal [traced]
Replies: 663
Views: 210159

Re: Friedman BE-OD Pedal [traced]

Biggest thing that jumps out is the voltage on pin1 of U1. It should be ~4.5V I would check your paralleled 82k resistors as that is the main path for the bias voltage to get to pin1. If there is 4.5V on pin2 and conductivity on R4 and R5, then you should have 4.5V on pin1.