Search found 22 matches

by jsaily
27 Jan 2020, 07:56
Forum: Boutique Stompboxes dissected...
Topic: Mad Professor - Snow White Auto Wah [traced]
Replies: 304
Views: 103312

Re: Mad Professor - Snow White Auto Wah [traced]

I have modified the filter sweep range from the standard 250-2500 Hz to 100-1300 Hz by changing the capacitors C5 and C6 to 47nF (were 22nF). This is confirmed by audio network analyzer and also with 5-string bass! It now quacks like a duck and feels very responsive & funky with bass. My idea is to ...
by jsaily
23 Jan 2020, 12:54
Forum: Boutique Stompboxes dissected...
Topic: Mad Professor - Snow White Auto Wah [traced]
Replies: 304
Views: 103312

Re: Mad Professor - Snow White Auto Wah [traced]

An old thread for sure, but has anyone managed to extract the changes needed for the Bass-version of this pedal?
by jsaily
04 Dec 2015, 14:28
Forum: Boutique Stompboxes dissected...
Topic: Mad Professor Forest Green Compressor [traced]
Replies: 149
Views: 62294

Re: Mad Professor Forest Green Compressor [traced]

Here is the whole directory containing all Eagle and layout files.

Jussi
by jsaily
31 Jan 2015, 16:32
Forum: Boutique Stompboxes dissected...
Topic: Diamond Bass Comp
Replies: 59
Views: 33704

Re: Diamond Bass Comp

lohstah wrote:great ! did you use a dual red/green led ? what value did you use for R37 ?
I had a tri-colour led (red, green, blue) and wired up the correct cathodes ;-) R37 was 10k. The red led is quite bright but I guess it's designed that way. Green lights up when its compressing.
by jsaily
30 Jan 2015, 12:18
Forum: Boutique Stompboxes dissected...
Topic: Diamond Bass Comp
Replies: 59
Views: 33704

Re: Diamond Bass Comp

My unit is now completed and works nicely! I used an NSL-32 optocoupler, OPA2134, LM358, all 2N3904 BJTs, polyester and ceramic caps, 1% metal film resistors. The Sabrotone Diamond Compressor vero layout was easily modified for the bass compressor because there is enough space. Thanks a lot for trac...
by jsaily
23 Jan 2015, 18:15
Forum: Boutique Stompboxes dissected...
Topic: Tech21 SansAmp PSA-1 PCB traces and schematics [traced]
Replies: 38
Views: 20306

Re: Tech21 SansAmp PSA-1 PCB traces and schematics [traced]

The 27C64 chip is a 64k (8k x 8-bit) EPROM which is not too hard to dump and clone since it cannot be write protected like modern microcontroller internal memories. It's truly old school device (I'd imagine early 90's) with a 68HC processor ;-)
by jsaily
19 Jan 2015, 20:06
Forum: Boutique Stompboxes dissected...
Topic: Diamond Bass Comp
Replies: 59
Views: 33704

Re: Diamond Bass Comp

I'll build one of these as well. I'm quite happy with the Forest Green Compressor clone but you can never have too many ;-) I have some NSL-32 optos and a few roll-your-own LED+LDRs I tried in the FGC before the NSL-32. It seems that the original VTL5C3 vactrols are almost obsolete or very highly pr...
by jsaily
17 Jan 2015, 19:27
Forum: Boutique Stompboxes dissected...
Topic: Hermida Audio - Zendrive [ goop-alarm ] [traced]
Replies: 342
Views: 150217

Re: Hermida Audio - Zendrive [ goop-alarm ] [traced]

Thanks Jsaily but I seem to behaving trouble oping the pho files . I downloaded freeopener but it can't open those files. Do you use another programme ? You need some program which can show gerber files to view the pho-files. I know there are some freeware programs for that also. However, you can j...
by jsaily
17 Jan 2015, 09:34
Forum: Boutique Stompboxes dissected...
Topic: Hermida Audio - Zendrive [ goop-alarm ] [traced]
Replies: 342
Views: 150217

Re: Hermida Audio - Zendrive [ goop-alarm ] [traced]

Here's the PCB layout I drew based on frequencycentral's layout and schematic. I had to redraw because I need the gerber files for printing etching masks and I've built a couple of pedals with this and it works well. The rar-file has PDFs + gerber, silk, soldermask and drill files so you can even se...
by jsaily
23 Dec 2014, 09:44
Forum: Boutique Stompboxes dissected...
Topic: Mad Professor Forest Green Compressor [traced]
Replies: 149
Views: 62294

Re: Mad Professor Forest Green Compressor [traced]

I found out that Q3 (lower BC550 transistor in LED driver circuit) is flipped in the schematic and in layout too. Emitter should point towards 110R + ground and not the LED. Funnily, it works quite nicely both ways ;-) If it's the wrong way around, only positive spikes are compressed. When building ...
by jsaily
14 Oct 2014, 08:51
Forum: Boutique Stompboxes dissected...
Topic: Mad Professor Forest Green Compressor [traced]
Replies: 149
Views: 62294

Re: Mad Professor Forest Green Compressor [traced]

Sorry for the delay, but here are the updated layout and placement files based on daimondamps files. Use the schematic and components values from there. The new layout with ground fills is a big large for the 1590B box, but can be cut to fit although you need to make a gnd jumper link. I've built tw...
by jsaily
21 Sep 2014, 09:59
Forum: Boutique Stompboxes dissected...
Topic: Mad Professor Forest Green Compressor [traced]
Replies: 149
Views: 62294

Re: Mad Professor Forest Green Compressor [traced]

I finally finished my latest FGC build based on daimondamps's PCB. Thanks for providing me with the Eagle files so I could generate gerber files. I made also some slight modifications like a ground fill around the board. The compressor effect is very low noise and works nicely now, much better than ...
by jsaily
02 Apr 2013, 10:18
Forum: Modern Stompbox Effects (1975 - ...)
Topic: EBS - Multicomp [schematic]
Replies: 56
Views: 43150

Re: EBS - Multicomp [schematic]

I'm repairing one Multicomp for my friend and it has exactly the same burned zener and resistor. The nice people at EBS immediately replied to my enquiry that the zener is indeed (BZV49C10) and the resistor 5.6 ohms 1W (0207). I haven't replaced them quite yet but it was a royal pain to remove the p...
by jsaily
15 Sep 2012, 16:24
Forum: Boutique Stompboxes dissected...
Topic: Mad Professor Forest Green Compressor [traced]
Replies: 149
Views: 62294

Re: Mad Professor Forest Green Compressor [traced]

Thanks. It sounds good to my ears. The only thing is after the compression knob is turned clockwise from fully CCW to about 9'o clock i hear a good amount of compression come on - then turning more clockwise from there, i don't here much more. I feel like it went from "zero" to "full compression" i...
by jsaily
06 Sep 2012, 06:29
Forum: Boutique Stompboxes dissected...
Topic: Mad Professor Forest Green Compressor [traced]
Replies: 149
Views: 62294

Re: Mad Professor Forest Green Compressor [traced]

Is that resistor/LED combo okay? It's hard to say, maybe your ears can tell ;-) I have built the FGC on ShortScaleMikes layout plus on my own surface mount PCB, but haven't gotten a good tone yet. Last night I assembled my final try on the other vero board layout, will try it on weekend. I'll insta...
by jsaily
05 Sep 2012, 11:28
Forum: Boutique Stompboxes dissected...
Topic: Mad Professor Forest Green Compressor [traced]
Replies: 149
Views: 62294

Re: Mad Professor Forest Green Compressor [traced]

Moonibopper wrote:Yep! That did the trick. Maybe the layout should be corrected.
You probably also had a bad solder joint in either end of the resistor. Low volume means that only the unity gain signal (sustain) from the JFET gets through to the output stage (BC560C).
by jsaily
05 Sep 2012, 11:25
Forum: Boutique Stompboxes dissected...
Topic: Mad Professor Forest Green Compressor [traced]
Replies: 149
Views: 62294

Re: Mad Professor Forest Green Compressor [traced]

With a multimeter hooked on to the two leads of the LDR, and guitar plugged in and compression knob dimed, I get around 12.5K when not playing the guitar and about 2K when strumming really hard. Is this right? What kind of LDR did you use? It seems that most people have been successful with about 2...
by jsaily
04 Sep 2012, 05:15
Forum: Boutique Stompboxes dissected...
Topic: Mad Professor Forest Green Compressor [traced]
Replies: 149
Views: 62294

Re: Mad Professor Forest Green Compressor [traced]

The output volume is controlled by the BC560C transistor output stage and the opamp. There should be plenty of volume ;-) When you get it working, I'm interested to hear if you hear any artefacts in the sustained sound (like I do).
by jsaily
03 Sep 2012, 20:43
Forum: Boutique Stompboxes dissected...
Topic: Diamond - Compressor [new gut shots added] [traced]
Replies: 142
Views: 44179

Re: Diamond - Compressor [new gut shots added] [traced]

Anyone opened up a Diamond Bass Compressor yet? It should have a switch to drop the EQ center frequency from 900 to 250 Hz for bass use. I bought myself a cheap Moen Uni-Comp (Diamond clone) and am wondering whether it could be pimped up more for bass. Such a switch would be optimal. I also bought a...
by jsaily
29 Aug 2012, 12:22
Forum: Boutique Stompboxes dissected...
Topic: Mad Professor Forest Green Compressor [traced]
Replies: 149
Views: 62294

Re: Mad Professor Forest Green Compressor [traced]

My unit is still not behaving satisfactorily. I made a Multisim simulation model of the LED driver circuitry, and it is evident that we can get wider LDR modulation range simply by lowering the capacitor C13 value (and/or lowering the resistors R16 & R167). C13 values of 15uF or 10uF give a much str...