freestompboxes.org

Hi! Long time reader here...

A friend of my gave this pedal for weekend, I think this is great and pretty versatile booster.
Here's some pics, I will try to draw a schematic soon..

I'm not nuts about the wiring, but overall that looks like a pretty good setup on the inside.

Is it a machine-carved copper foil instead of an etched PCB?

lolbou wrote:Is it a machine-carved copper foil instead of an etched PCB?

Yes it is, at least it isn't etched.
Schematic is almost finished, I'm a bit confused with those 5-band resistors. I'm not quite sure how to read them...

oh7hhi wrote:Schematic is almost finished, I'm a bit confused with those 5-band resistors. I'm not quite sure how to read them...

Try this:
http://www.electronics2000.co.uk/calc/r ... ulator.php

culturejam wrote:

oh7hhi wrote:Schematic is almost finished, I'm a bit confused with those 5-band resistors. I'm not quite sure how to read them...

Try this:
http://www.electronics2000.co.uk/calc/r ... ulator.php

Thanks! Now I got it finished.
I will draw a better version tomorrow and post it here.

So, here it is. I'm not absolutely sure about those diode types, I don't want to take them off since it's not my pedal.
If you find mistakes, please tell. This is my first tracing so go easy on me !

A 100uf emitter bypass cap, eh? Interesting.

culturejam wrote:A 100uf emitter bypass cap, eh? Interesting.

Yeah, well I guess there's nothing new. Hornby-Skewes booster also uses 80uF bypass cap...

I would be VERY grateful if someone has interest and spare time (and skills which I don't have) to do some kind of layout for this . No need for all those mini switches, couple of sockets would be fine ...

Since I don't have any 2N5459's, can I use J201 instead?
I guess it won't make big difference...

OH! long time since I saw my last ThunderTomate!. I thoght really that he impproved his work, seems the same as a few years...

Check the datasheets of the 2N and compare them with the J201

Thanks to 'oh7hhi' for sharing the schematic with us.

I'm thinking of building one for myself, having read a couple of excellent reviews in Guitarist and Guitar Buyer mags.

However, both reviews clearly state that the first three switches "select the treble booster tone, while the other five are for setting the desired amount of fatness" (Guitarist Mag - July 07 - the wording in Guitar Buyer June 07 implies the same).

This makes me wonder if the supplied schematic is correct, as it shows all eight switches (and their associated caps) in parallel. Should the first three switches be as shown, and the other five be somewhere else in the circuit ?

Any suggestions from the learned gurus (of whom I am in awe) would be most welcome.

Cheers.

Hi!

Here are the pics again. I wish there was an "edit" button to change image link ...
There you can see that the dip switches are all in parallel.

Wow 'oh7hhi' - thanks so much for taking the trouble to post the pics. Re-e-eally appreciated.

As you say, the switches and caps are definitely all in parallel.

I hope I didn't offend by questioning your schematic - but the reviews implied that the circuit was different.

I am pleased to stand corrected, and will proceed with construction.

Just out of interest, have you noticed any difference in tone, say when using switch 1 (4n7) and one of the five 'fat' switches (also 4n7) ?

Once again, sincerest thanks for your help.

No problem, I've also read the same thing from the manual.

If I remember right, there was no difference which one of the 4n7 caps was "on". I had this pedal only for few days... I like ROG's Omega boost more .
I guess they wrote that instruction to make things simple or something.
I liked it best when switches three, four and five were "on" and cut was around 11 o'clock (with my 18watt TMB). That cut control is pretty neat especially if you happen to have transistors that sounds harsh!

oh7hhi wrote:So, here it is. I'm not absolutely sure about those diode types, I don't want to take them off since it's not my pedal.
If you find mistakes, please tell. This is my first tracing so go easy on me !

That schematic is correct.

Lucifer wrote: However, both reviews clearly state that the first three switches "select the treble booster tone, while the other five are for setting the desired amount of fatness" (Guitarist Mag - July 07 - the wording in Guitar Buyer June 07 implies the same).

This makes me wonder if the supplied schematic is correct, as it shows all eight switches (and their associated caps) in parallel. Should the first three switches be as shown, and the other five be somewhere else in the circuit ?

Any suggestions from the learned gurus (of whom I am in awe) would be most welcome.

Cheers.

All those caps are wired in parallel, in fact it would be better to have only four switches for four caps, the misconception on the reviews comes from the owner's manual.

oh7hhi wrote:Since I don't have any 2N5459's, can I use J201 instead?
I guess it won't make big difference...

It's not a great idea to put one J201 on Q2 because cut off voltage is too low and them distortion appears at medium output levels, the 2N5459 is intended to cause asymmetrical hard clipping only when it's strongly driven while the BC550C causes asymetrical soft clipping (it's intentionally mis biased) on the other half of the wave.

rgm wrote: It's not a great idea to put one J201 on Q2 because cut off voltage is too low and them distortion appears at medium output levels, the 2N5459 is intended to cause asymmetrical hard clipping only when it's strongly driven while the BC550C causes asymetrical soft clipping (it's intentionally mis biased) on the other half of the wave.

Yeah, I noticed that too. It distorts in a very ugly way with J201's.
2N5459 is recommended...