Search found 507 matches

by grrrunge
10 Mar 2024, 20:18
Forum: Parts & Tools Sourcing & Trading
Topic: Ordering from Tayda? Customs & taxes in the EU
Replies: 5
Views: 576

Re: Ordering from Tayda? Customs & taxes in the EU

DDP from Tayda would be nice, however - I haven't been able to find the option on the site 🙄
by grrrunge
06 Dec 2023, 13:52
Forum: Pedal Debugging & Troubleshooting Support
Topic: PedalPCB sproing [SOLVED]
Replies: 4
Views: 4316

Re: PedalPCB sproing [SOLVED]

Sounds odd. Could you measure the voltages on all 8 pins of IC2 and list them here.
by grrrunge
22 Aug 2023, 19:19
Forum: DIY Projects
Topic: Dual output buffer/splitter design
Replies: 16
Views: 1860

Re: Dual output buffer/splitter design

I whipped up a simulation of a single buffer, to see what's going on. Admittedly, I got the BE-bypass cap all wrong. My intuition told me that C1 would begin conducting at the break frequency of the high-pass filter created by C1 and R1, and short out the BE junction - effectively bypassing the tran...
by grrrunge
22 Aug 2023, 04:43
Forum: DIY Projects
Topic: Dual output buffer/splitter design
Replies: 16
Views: 1860

Re: Dual output buffer/splitter design

I am sure the Cornish buffer is well thought out. My intention was to bash the PCB I did way before I had any idea about proper layout techniques. Perhaps that didn't come across properly. My bad :) My concern was with the configuration presented here: https://www.freestompboxes.org/viewtopic.php?p=...
by grrrunge
21 Aug 2023, 19:50
Forum: DIY Projects
Topic: Dual output buffer/splitter design
Replies: 16
Views: 1860

Re: Dual output buffer/splitter design

I know I did a layout for the Cornish buffer. That was a long time ago. I wouldn't put too much faith into that one these days ;) I never really got the idea about the base-emitter bypass cap. It effectively disables the transistor gain af high frequencies. I would most definitely get rid of that! :...
by grrrunge
21 Aug 2023, 13:33
Forum: DIY Projects
Topic: Dual output buffer/splitter design
Replies: 16
Views: 1860

Re: Dual output buffer/splitter design

Both will function just fine.
For the discrete solution, I would go for BJT's instead of JFET's, since they are more robust against ESD and way more available.
by grrrunge
27 Jul 2023, 21:22
Forum: Pedal Debugging & Troubleshooting Support
Topic: Morning Glory problem with 2N5457
Replies: 19
Views: 1897

Re: Morning Glory problem with 2N5457

Assuming the aionFX version has been tested ok, maybe it's an idea to compare the two schematics for differences:
https://aionfx.com/app/files/docs/cerul ... ion_v1.pdf
by grrrunge
27 Jul 2023, 21:08
Forum: Vintage Stompbox Corner ( ... - 1975)
Topic: Mirano - EF-1 - Exciting Fuzz [schematic]
Replies: 21
Views: 13184

Re: Mirano - EF-1 - Exciting Fuzz [schematic]

You've got it :thumbsup It's listed in the schematic as well:
Screenshot_2023-07-27-23-05-28-05_40deb401b9ffe8e1df2f1cc5ba480b12.jpg
by grrrunge
27 Jul 2023, 17:14
Forum: Pedal Debugging & Troubleshooting Support
Topic: Morning Glory problem with 2N5457
Replies: 19
Views: 1897

Re: Morning Glory problem with 2N5457

I have had issues with 2Nxxxx JFET's from different manufacturers having mirrored pinouts. Check the specific datasheet from the manufacturer of your transistor and verify that it is mounted correctly.
by grrrunge
13 Jun 2023, 08:34
Forum: Modern Stompbox Effects (1975 - ...)
Topic: Diezel VH4 Pedal [schematic]
Replies: 284
Views: 168220

Re: Diezel VH4 Pedal help [schematic]

Help!!!!!! I’m building a PCB Mania Benzin Vh4. I have signal passing however is quiet and has very little gain. Sounds more like a light overdrive. There is a lot of noise and whining specifically when I touch the gain pot with it maxed. I swapped out the pot for a spare I had laying around with t...
by grrrunge
13 Jun 2023, 07:58
Forum: Modern Stompbox Effects (1975 - ...)
Topic: Diezel VH4 Pedal [schematic]
Replies: 284
Views: 168220

Re: Diezel VH4 Pedal [schematic]

I did some simulations of this circuit in LTspice and I was actually quite puzzled at the behaviour of the zener diodes in the feedback loop of the 2nd gain stage. All plots taken just after the gain stage w/5.6V zeners: - In blue, no diodes. - In red, D815A diode model. - In turquoise, BZX384B dio...
by grrrunge
23 Mar 2023, 10:27
Forum: Modern Stompbox Effects (1975 - ...)
Topic: MXR M87 / 1176 Pics
Replies: 2
Views: 2352

Re: MXR M87 / 1176 Pics

High resolution gut shots from somewhere... :)
by grrrunge
07 Mar 2023, 04:47
Forum: Boutique Stompboxes dissected...
Topic: The Beatles Pedal
Replies: 32
Views: 4257

Re: The Beatles Pedal

It's a passive first-order low-pass filter with a corner frequency of 1/(2*pi*R*C)
Look up passive RC filters for more info 🥳
by grrrunge
17 Feb 2023, 23:07
Forum: Pedal Debugging & Troubleshooting Support
Topic: T-Rex Replica delay schematic
Replies: 2
Views: 579

Re: T-Rex Replica delay schematic

Take the pedal apart, and take high resolution pictures of both sides of the PCB and upload them here. Then we might be able to help you 👍
by grrrunge
13 Feb 2023, 21:43
Forum: Boutique Stompboxes dissected...
Topic: The Beatles Pedal
Replies: 32
Views: 4257

Re: The Beatles Pedal

deltafred wrote: 13 Feb 2023, 09:28
CheapPedalCollector wrote: 13 Feb 2023, 06:32 What is this pedal trying to achieve?
Sales! :lol:
Exactly. And maximum return of minimal investment 🤣
by grrrunge
09 Feb 2023, 07:08
Forum: Boutique Stompboxes dissected...
Topic: The Beatles Pedal
Replies: 32
Views: 4257

Re: The Beatles Pedal

Agreed, interwinding capacitance and cable capacitance won't improve the matter. However, interwinding capacitance is negligible as it is mostly series coupled. Cable capacitance on the other hand could very well be a contributing factor. At 150pF/m cables can't be longer than a few meters before ha...
by grrrunge
08 Feb 2023, 08:43
Forum: Boutique Stompboxes dissected...
Topic: The Beatles Pedal
Replies: 32
Views: 4257

Re: The Beatles Pedal

Manfred, I respectfully disagree on your comments on the significance of miller capacitance, when taking pickup inductance and winding resistance into account. Below is a simulation of the circuit where the gain setting is stepped. The top plot shows input impedance while the bottom plot shows overa...
by grrrunge
06 Feb 2023, 23:19
Forum: Boutique Stompboxes dissected...
Topic: The Beatles Pedal
Replies: 32
Views: 4257

Re: The Beatles Pedal

Except for a noise level reduction, a parallel connection of the transistors does not change anything. Each silicon small signal transistor can be replaced by any other in the low frequency range. The invidual internal capacitances of these only have an effect in the high frequency range. I ran som...
by grrrunge
05 Feb 2023, 20:57
Forum: Boutique Stompboxes dissected...
Topic: The Beatles Pedal
Replies: 32
Views: 4257

Re: The Beatles Pedal

IMG_20230205_214421.jpg This is probably a good starting point for experimentation. There are too many uncontrolled variables to my liking in this design. Output impedance is high, and input impedance is low. Input impedance varies with the gain setting, and output impedance varies with the output ...
by grrrunge
04 Feb 2023, 09:52
Forum: Boutique Stompboxes dissected...
Topic: The Beatles Pedal
Replies: 32
Views: 4257

Re: The Beatles Pedal

Agreed - 10K log taper for the gain control sounds like a sensible value.
Volume pots should be log taper as well. 500K log would be a good starting point. Lower values than that will start to impact the maximum available gain from the common emitter amplifier severely.