Search found 33 matches

by Guilherme
13 Dec 2012, 13:20
Forum: Pimp-My-Cheap-Pedal
Topic: BYOC Comp Threshold Control + Vbias question
Replies: 5
Views: 2594

Re: BYOC Comp Threshold Control + Vbias question

Well, the Emma is a Dynacomp with mods. http://www.freestompboxes.org/viewtopic.php?f=7&t=4340&hilit=emma And the Dynacomp is actually a limiter, not a compressor. The pot changes threshold. There's a plot of the limiting curve of a Dynacomp with the pot on max and min on the trhead about merlin's "...
by Guilherme
12 Dec 2012, 11:20
Forum: Pimp-My-Cheap-Pedal
Topic: BYOC Comp Threshold Control + Vbias question
Replies: 5
Views: 2594

Re: BYOC Comp Threshold Control + Vbias question

Well, the "sustain" pot is already a threshold control. (and btw the "attack" pot is actually a release control - see the emma transmogrifier for proper attack/release controls)

You may want to investigate how to add a "ratio" control to this circuit, this is a mod I've never seen.
by Guilherme
30 Oct 2012, 00:04
Forum: Ready-To-Build Effect Projects
Topic: THE ENGINEER'S THUMB... At last, a better compressor! [verified]
Replies: 101
Views: 10249

Re: THE ENGINEER'S THUMB... At last, a better compresso [verified]

Please forgive if I insist on the matter, I'm not looking for "deffects" on your design or something like that, I just want to understand the circuit and know the best ways to use it. Looking at the blue curve, if I set the threshold for 100mV for example, to plot the new curve I Imagine I'd have to...
by Guilherme
29 Oct 2012, 18:58
Forum: Ready-To-Build Effect Projects
Topic: THE ENGINEER'S THUMB... At last, a better compressor! [verified]
Replies: 101
Views: 10249

Re: THE ENGINEER'S THUMB... At last, a better compresso [verified]

Merlin, The blue line in your graph shows what happens with a high ratio (limiting), low threshold. So it works like a sustainer, like we are used to with guitar "compressors". If I wanted to use it with as a limiter, with the high ratio, but with a high threshold, so that I was just taming the peak...
by Guilherme
27 Oct 2012, 14:51
Forum: Ready-To-Build Effect Projects
Topic: THE ENGINEER'S THUMB... At last, a better compressor! [verified]
Replies: 101
Views: 10249

Re: THE ENGINEER'S THUMB... At last, a better compresso [verified]

I guess they feel interactive because the ratio control changes how much gain for signals below the trheshold. If you have a compression curve like this: http://www.radialeng.com/whbeta/images/komit-dev-flexknee-1.jpg A non-interative ratio control would be able change the slope of the curve after t...
by Guilherme
27 Apr 2012, 21:44
Forum: Modern Stompbox Effects (1975 - ...)
Topic: AMT Electronics - S1 Legend series [schematic]
Replies: 633
Views: 242136

Re: AMT S1 Legend series [gut shots] [schematic]

can you post the voltages at each node?
by Guilherme
27 Apr 2012, 16:28
Forum: Ready-To-Build Effect Projects
Topic: THE ENGINEER'S THUMB... At last, a better compressor! [verified]
Replies: 101
Views: 10249

Re: THE ENGINEER'S THUMB... At last, a better compresso [verified]

Thats for the article! :D Here some more joyful reading on this fascinating subject (at least for a nerd like me): "Audio Dynamic Range Compression for Minimum Perceived Distortion" Barry A. Blesser IEEE Transactions on Audio and Electroacoustics, vol. AU-17, No. 1, March 1969 "On Transient Distort...
by Guilherme
27 Apr 2012, 16:23
Forum: Modern Stompbox Effects (1975 - ...)
Topic: AMT Electronics - S1 Legend series [schematic]
Replies: 633
Views: 242136

Re: AMT S1 Legend series [gut shots] [schematic]

The cab simulation is driving me nuts! Looks like all the Legend series have the same cab sim circuit.. :scratch: I have bread boarded it about 3 or 4 different times trying all sorts of crazy crap but still get nothing? I think the schematic is missing something...? Can anybody flex their brain mu...
by Guilherme
26 Apr 2012, 16:10
Forum: Ready-To-Build Effect Projects
Topic: THE ENGINEER'S THUMB... At last, a better compressor! [verified]
Replies: 101
Views: 10249

Re: THE ENGINEER'S THUMB... At last, a better compresso [verified]

A lot of people complain about digital fx, recording interfaces or guitar synths that have latencies around 8-10 ms, or even less. Studio gear, if you're not doing "software monitoring", can have a much longer latency with no problem. For a guitar compressor, no latency is way more important than an...
by Guilherme
26 Apr 2012, 15:48
Forum: Amplifiers
Topic: Solid state Amp discussion allowed (of course!)
Replies: 39
Views: 52519

Re: Solid state Amp discussion allowed (of course!)

rocklander wrote:is that seriously a 2 component amplifier? just seems too simple :shock:
Check this:
http://www.ssguitar.com/index.php?topic=1630.0

Image

Image

10W x2 (stereo!).
by Guilherme
26 Apr 2012, 12:09
Forum: Ready-To-Build Effect Projects
Topic: THE ENGINEER'S THUMB... At last, a better compressor! [verified]
Replies: 101
Views: 10249

Re: THE ENGINEER'S THUMB... At last, a better compresso [verified]

If I had to guess how ANY compressor with a fast attack and a relatively slow release would behave with a signal that has a short, large transient, a fast decay and then a much lower sustain level, such as aguitar note, I'd bet it would completely lack overshoot, like above, BUT it would have kind o...
by Guilherme
25 Apr 2012, 12:33
Forum: Ready-To-Build Effect Projects
Topic: THE ENGINEER'S THUMB... At last, a better compressor! [verified]
Replies: 101
Views: 10249

Re: THE ENGINEER'S THUMB... At last, a better compresso [verified]

Almost a nice idea, but unfortunately there's rather a lot of "prior art": Hey, that's mine :) It's from 1990. There's an error on the drawing, swap inputs +/- on U9A. I only tested it on bass, I liked it. BTW later I learned there was a (supposedly very nice) MXR studio limiter that used a switchi...
by Guilherme
20 Apr 2012, 23:12
Forum: Modern Stompbox Effects (1975 - ...)
Topic: AMT Electronics - S1 Legend series [schematic]
Replies: 633
Views: 242136

Re: AMT S1 Legend series [gut shots] [schematic]

I've simulated it (only the speaker simulation, not the whole pedal) in LTspice. Seems OK, but a bit dark. It may be difficult to bias, the only fet model I have that worked was a J201 (specially for the second fet, the common source at the stage which has the CRC "T" in the feedback - the simulatio...
by Guilherme
06 Apr 2012, 17:07
Forum: Modern Stompbox Effects (1975 - ...)
Topic: Vox - Cooltron Line of pedals
Replies: 22
Views: 15213

Re: Vox - Cooltron CT-01DS, CT-02OD and CT-03BT

Sorry to bump such an ancient thread. But I think we were looking at the wrong patent: http://www.google.com.br/patents/US7397303?printsec=abstract&dq=korg+tube&ei=khl_T7CQGYnDgAef3MSHCA#v=onepage&q=korg%20tube&f=false This one matches with the actual schematics. Look at fig. 2, very low plate and f...
by Guilherme
08 Mar 2010, 21:20
Forum: Modern Stompbox Effects (1975 - ...)
Topic: Giannini - FZ-110 Axcess Fuzz
Replies: 16
Views: 4864

Re: GIANNINI New AXCESS FUZZ FZ-110

At R$ 120 it may be cheaper than to import the switch and a hammond box...
by Guilherme
11 Dec 2008, 10:53
Forum: Boutique Stompboxes dissected...
Topic: Ayan - Smooth & Slim [traced]
Replies: 74
Views: 12167

Re: Ayan - Smooth & Slim [traced]

Some background. Gil Ayan used to post in Ampage and in the Boogie Talk mail list. I think a couple of the Mesa Boogie schematics that are on the net were contributed by him. From what I remember, the S&S was not a proper "business", it was more like someone at the boogie list would e-mail him and a...
by Guilherme
12 Nov 2008, 10:53
Forum: Vintage Stompbox Corner ( ... - 1975)
Topic: Sound ( by Malagoli ) - ES2 ( Fuzz-Wah-Vol)
Replies: 10
Views: 3001

Re: New EH OCTAVE MULTIPLEXER

As far as I know it's not the same Palmer. The brazilian Palmer used to make organs, amplifiers (they used to make some very, very good tube amps based on Marshall models, including a killing Major clone), PA stuff. I think they are out of business. http://picasaweb.google.com/edu.audiolist/Contribu...
by Guilherme
10 Nov 2008, 23:19
Forum: Vintage Stompbox Corner ( ... - 1975)
Topic: Sound ( by Malagoli ) - ES2 ( Fuzz-Wah-Vol)
Replies: 10
Views: 3001

Re: New EH OCTAVE MULTIPLEXER

Chorus Super OD schem: http://xs433.xs.to/xs433/08461/superod-chorus911.jpg.xs.jpg I like the way the gain control is wired, less gain, more bass, more gain, cuts bass. Sound ES-2 schematic, wha and fuzz http://xs433.xs.to/xs433/08461/es-2326.jpg.xs.jpg I have not included the switching. Some Sound ...
by Guilherme
10 Nov 2008, 11:10
Forum: Vintage Stompbox Corner ( ... - 1975)
Topic: Sound ( by Malagoli ) - ES2 ( Fuzz-Wah-Vol)
Replies: 10
Views: 3001

Re: New EH OCTAVE MULTIPLEXER

Yeah, this thread could be split. A note: the Sound ES-2 PCB pictures doesn't show the inductor, that I took off to use somewhere else. I'll try to locate the inductor and take a picture. Looking at your list, I think Palmer used to make pedals in the 70's too (they made amplifiers, organs and tape ...