Search found 13 matches

by mwelch55
21 Nov 2018, 16:11
Forum: DIY Stompbox designs
Topic: Tube Preamp/Pedal Switch
Replies: 3
Views: 1357

Re: Tube Preamp/Pedal Switch

Thanks for the reply. In one position, the output will be the full preamp signal, intended to be sent to a power amp. The other position will be attenuated for use as an effects pedal or amp emulation pedal. I would need to switch to the appropriate mode BEFORE using it. If I am going to use it as a...
by mwelch55
20 Nov 2018, 23:27
Forum: DIY Stompbox designs
Topic: Tube Preamp/Pedal Switch
Replies: 3
Views: 1357

Re: Tube Preamp/Pedal Switch

What is your opinion. Can anyone think of a better way?
by mwelch55
20 Nov 2018, 23:25
Forum: DIY Stompbox designs
Topic: Tube Preamp/Pedal Switch
Replies: 3
Views: 1357

Tube Preamp/Pedal Switch

I am building a stomp box that can be used as a preamp or as a pedal. This will be based on the preamp of a hot-rodded Marshall.

The output of a 4-stage tube preamp is too hot for the input of am amp, so I wanted to install a switch that will attenuate the output for use as a pedal.
by mwelch55
02 May 2018, 22:49
Forum: Amplifiers
Topic: Danelectro Honey Tone Amp Doesn't Work
Replies: 1
Views: 1426

Re: Danelectro Honey Tone Amp Doesn't Work

This is what I was talking about. Would the zeners on the input provide protection for the op amp? If so, what values would you recommend?
by mwelch55
02 May 2018, 17:06
Forum: Amplifiers
Topic: Danelectro Honey Tone Amp Doesn't Work
Replies: 1
Views: 1426

Danelectro Honey Tone Amp Doesn't Work

I was using my Danelectro Honey Tone amp with an audio signal probe I built to troubleshoot audio circuits. It worked great until I used it to probe a tube preamp circuit. Now there is no output. I think I blew the op amp (TL072) because the signal is too high in a tube preamp. I will replace the op...
by mwelch55
15 Sep 2017, 19:54
Forum: Boutique Stompboxes dissected...
Topic: Wampler Sovereign Distortion [traced]
Replies: 36
Views: 22154

Re: Wampler Sovereign Distortion [traced]

screenshot.676.png
Referring to the schematic posted last year, does anyone know the purpose of the MOSFET in the power section of the schematic? I have never seen that before.

Mike
by mwelch55
05 Sep 2017, 17:39
Forum: Boutique Stompboxes dissected...
Topic: Friedman BE-OD Pedal [traced]
Replies: 663
Views: 191003

Re: Friedman BE-OD Pedal [traced]

Thanks for the detailed response. I have been wondering about this for a while.
by mwelch55
01 Sep 2017, 18:26
Forum: Boutique Stompboxes dissected...
Topic: Friedman BE-OD Pedal [traced]
Replies: 663
Views: 191003

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
by mwelch55
30 Jan 2017, 21:25
Forum: Vintage Stompbox Corner ( ... - 1975)
Topic: Rangemaster; Trouble finding trannies that bias
Replies: 7
Views: 2411

Re: Rangemaster; Trouble finding trannies that bias

I bought the OC-44 Germanium Transistor from SmallBear. The price is $8.95, which is expensive, but it biased perfectly and has relatively low noise. I bought one off of eBay that was unusable.
by mwelch55
13 Jan 2017, 16:23
Forum: Announcements and Forum Rules
Topic: Madbean registration problem
Replies: 15
Views: 14810

Re: Madbean registration problem

I agree with everything peterc said. Also, the forum members and the admins are very respectful and don't make newbies feel like they are stupid.

Mike
by mwelch55
02 Dec 2016, 20:07
Forum: Boutique Stompboxes dissected...
Topic: Amptweaker - Tight Metal [traced]
Replies: 634
Views: 202416

Re: Amptweaker - Tight Metal [traced]

I have heard it mentioned in this forum that you can build the Tight Metal and Tight Rock from the same layout, but with different component values. Does anyone have the component values of the tight rock (or a schematic with values)?

Mike
by mwelch55
24 Nov 2015, 20:45
Forum: DIY Stompbox designs
Topic: GTFO - A true valve high-gain overdrive
Replies: 352
Views: 136246

Re: GTFO - A true valve high-gain overdrive

DarkRain,

What kind of inductor do you use in your SMPS? I am using a toroid inductor rated at 3 amps, but it takes a lot of space. I like how compact your power supply is.

Thank you for sharing your GTFO information. It has really been educational.

Mike
by mwelch55
14 Oct 2015, 19:21
Forum: Amplifiers
Topic: Roc Pro 1000 combo - volume and pop problems
Replies: 19
Views: 10303

Re: Roc Pro 1000 combo - volume and pop problems

I have a Fender Roc Pro 700 and it has the same problem. After looking at the schematic, I noticed that volume and gain pots are linear instead of Log. I think this was a design flaw. If the volume pot was changed to a log taper pot, it would prevent this sudden jump in volume. I haven't done that, ...