Search found 27 matches

by Maxwell
06 Jan 2012, 19:43
Forum: Modern Stompbox Effects (1975 - ...)
Topic: Tech21 - Character Series. [schematic]
Replies: 435
Views: 235255

Re: Tech21 - Character Series. [schematic]

Found most of the answer on page 4, thanks... it seems mostly some weird drawing styles were adding to my confusion as well. This is a very educational thread!
by Maxwell
06 Jan 2012, 01:03
Forum: Modern Stompbox Effects (1975 - ...)
Topic: Tech21 - Character Series. [schematic]
Replies: 435
Views: 235255

Re: Tech21 - Character Series. [schematic]

I meant to add...it looks like the diodes in the feedback loop must perform some kind of clipping function after the first opamp add gain to the signal (I guess)?
by Maxwell
06 Jan 2012, 01:01
Forum: Modern Stompbox Effects (1975 - ...)
Topic: Tech21 - Character Series. [schematic]
Replies: 435
Views: 235255

Re: Tech21 - Character Series. [schematic]

To better communicate what I'm talking about, it is this part of the circuit (grabbed from an earlier posted schematic):
liverpool_drive.tiff
liverpool_drive.tiff (58.68 KiB) Viewed 948 times
I've not seen a circuit like this before.
by Maxwell
05 Jan 2012, 22:44
Forum: Modern Stompbox Effects (1975 - ...)
Topic: Tech21 - Character Series. [schematic]
Replies: 435
Views: 235255

Re: Tech21 - Character Series. [schematic]

I'm interested in building one of these but I'd like to understand the circuit a bit more before I jump in...could anyone offer an explanation as to what is happening in the "Drive" or distortion part of the circuit? Those two opamps, the second of which has the diodes in the feedback loop, look rea...
by Maxwell
08 Jun 2010, 17:48
Forum: Boutique Stompboxes dissected...
Topic: DBA - Soundwave Breakdown
Replies: 38
Views: 6189

Re: DBA - Soundwave Breakdown

null.fuzz wrote:I'm going to take some shots of mine and trace it, but my Soundwave Breakdown (#2) looks nothing like that circuit at all. It only has 2 transistors - it is significantly simpler than what you've posted!

Cool - looking forward to it. I wonder what circuit this pedal is from then?
by Maxwell
20 Nov 2009, 21:49
Forum: Boutique Stompboxes dissected...
Topic: DBA - Soundwave Breakdown
Replies: 38
Views: 6189

Re: DBA - Soundwave Breakdown

Alright, so I've done some more tweaking and gotten it to work so that it at least sounds similar to clips I've heard of the real pedal, but it seems more heavily gated than I thought it would be. Part of it could be that I haven't bothered to match my 3n5306 transistors. I've also used some slightl...
by Maxwell
18 Nov 2009, 05:56
Forum: Boutique Stompboxes dissected...
Topic: DBA - Soundwave Breakdown
Replies: 38
Views: 6189

Re: DBA - Soundwave Breakdown

Update: So I've gone and attempted a build based on the first schematic but no luck so far...I just get a lot of shrieks and splats. Reversing Q1 made it slightly more musical but not much...
by Maxwell
13 Nov 2009, 17:47
Forum: Boutique Stompboxes dissected...
Topic: Voodoo Lab Pedal Switcher
Replies: 8
Views: 2678

Re: Voodoo Lab Pedal Switcher

Pretty cool... I actually built my own MIDI switcher, but using an AVR microcontroller. I don't know assembly but I do know C and since there are C compilers for it the writing of the firmware (which I did from scratch) was at least possible to figure out how to do, though it took a lot of work. Mic...
by Maxwell
13 Nov 2009, 17:38
Forum: Boutique Stompboxes dissected...
Topic: DBA - Soundwave Breakdown
Replies: 38
Views: 6189

Re: DBA - Soundwave Breakdown

I'm really curious if anyone has built this based on the schematic...I thought I might try it. And what's with the 970k resistors? (That's such a non-typical value and is very close to 1M?)
by Maxwell
10 Nov 2009, 15:10
Forum: Boutique Stompboxes dissected...
Topic: Voodoo Lab Pedal Switcher
Replies: 8
Views: 2678

Re: Voodoo Lab Pedal Switcher

Here's an article that shows the basics of using a transistor to drive a relay:

http://www.jaycar.com.au/images_uploaded/relaydrv.pdf

Any relay-based switcher is doing something similar. The diode is important, because without it back EMF from the relay coils will fry the transistor.
by Maxwell
22 Oct 2009, 19:14
Forum: Boutique Stompboxes dissected...
Topic: Death By Audio - Harmonic Transformer - Guts [traced]
Replies: 105
Views: 21585

Re: Death By Audio - Harmonic Transformer [ugly guts] [traced]

Well personally I'd like to see the schematic/layout because I'm curious to try one out... the parts should easily be under $25.
by Maxwell
29 Aug 2009, 17:06
Forum: Boutique Stompboxes dissected...
Topic: TC Electronic PRE Integrated Preamplifier
Replies: 23
Views: 4010

Re: TC Electronic PRE Integrated Preamplifier

So this looks a little different from a typical circuit... Is this an inverting amplifier following a buffer (Q2) or is something else going on?
by Maxwell
24 Jun 2009, 16:47
Forum: Enclosure Finishing
Topic: Clearcoating enclosures
Replies: 6
Views: 5222

Re: Clearcoating enclosures

I was checking out the clearcoat at my local auto parts store, and I noticed Duplicolor makes at least two different types...one is an acrylic lacquer (I believe this is the "Truck, Van, and SUV" can), and the other is an acrylic enamel (this is the more ordinary labelled clearcoating). Any idea whi...
by Maxwell
16 Jun 2009, 04:46
Forum: Resistors
Topic: Those little potentiometer nibs (panel mount)
Replies: 6
Views: 3579

Those little potentiometer nibs (panel mount)

Question - So these little nibs that are made to sit in a tiny hole in the enclosure, next to the hole that the shaft goes through...What do you prefer do with them? Do you bother drilling a tiny hole (a pain to get just right) or do you just cut them off?
by Maxwell
26 May 2009, 21:18
Forum: Boutique Stompboxes dissected...
Topic: Voodoo Lab Pedal Switcher
Replies: 8
Views: 2678

Re: Voodoo Lab Pedal Switcher

Cool. The relay switching section looks very much the same as the GCX switcher. Basically the same setup I'd guess - relay, diode, and RC snubber circuit across the relay coil to reduce popping noises.
by Maxwell
19 May 2009, 18:44
Forum: DIY Stompbox designs
Topic: +/-15VDC from 9VDC!
Replies: 7
Views: 2110

Re: +/-15VDC from 9VDC!

Digikey has them for $4.96 a piece, so they're not too bad pricewise, but I wouldn't want to have to use too many.

I'm guessing the 80% efficiency means 20% of the incoming power is wasted as heat?
by Maxwell
19 May 2009, 17:54
Forum: DIY Stompbox designs
Topic: +/-15VDC from 9VDC!
Replies: 7
Views: 2110

+/-15VDC from 9VDC!

I learned about these DC to DC voltage converters recently: http://www.cui.com/pdffiles/VASD1-DIP%20Series.pdf So, I think you could run your op amps at +/- 15VDC this way, from a 9VDC input! Like this?: http://i39.tinypic.com/2qvtawh.jpg The catch is I guess you have to keep the current draw below ...
by Maxwell
19 May 2009, 06:42
Forum: DIY Stompbox designs
Topic: Getting 30VDC from 9VAC
Replies: 1
Views: 953

Getting 30VDC from 9VAC

I think this is one way to power op amps with +/- 15V (probably better for big enclosures). I traced this power supply from a mixer I have:

http://i42.tinypic.com/se6ipw.jpg

Image

I have not built it yet to check for mistakes. Does it look correct?
by Maxwell
19 May 2009, 04:35
Forum: Modern Stompbox Effects (1975 - ...)
Topic: DOD - FX10 BiFET Preamp [schematic]
Replies: 20
Views: 18106

Re: DOD FX10 BiFET Preamp (Booster Pedal) [schematic]

Yeah I was wondering a bit about that...I expected to see a discrete FET buffer or something like that.

I don't notice the controls having any effect when it's off. The bypass seems pretty good but I keep mine in a loop anyway.
by Maxwell
16 May 2009, 05:23
Forum: Modern Stompbox Effects (1975 - ...)
Topic: DOD - FX10 BiFET Preamp [schematic]
Replies: 20
Views: 18106

Re: DOD FX10 BiFET Preamp (Booster Pedal) [schematic]

Well as an experiment I changed out the op amp for a BB OPA2134. It has a fuller tone now I'd say which I like. More bass and clearer highs. I'm going to leave it in.