bogner ecstasy schematic

[deadastronaut]

right before i go away for a while im going to throw this in the ring!......

its a bogner ecstasy schematic.....(some russian dudes)

http://dl.dropbox.com/u/7464107/Bogner%20Ecstasy%20schematic.pdf

i was trying to get this done before the 666 comp..(good luck guys), i dont envy rick and slade for having to judge).but hey im out now ..so here it is...

will convert to vero when i get time...just for fun..

anyone know what the 2 ground switches do?...ive heard this and it sounds well good...boogie'esque...have fun..

i expect to see this built when i get back!..

see ya. rob.

[igerup]

They look some kind of Boost/Fat/Drive-switches to me.

[anchovie]

SW1 reduces the amount of signal going into Q2 by changing the ratio of the attenuating voltage divider. On the amp, this is a relay and is normally closed with the footswitch offering a gain boost.

SW2 increases the gain of Q2 by halving the source resistance and bringing a bypass capacitor into play. This is the "Structure" toggle on the amp.

[Kearns892]

I'm guessing this is just the preamp?

[anchovie]

Yes, adapted for JFETs.

[demym]

I've tried to build this following the posted schematic...

But it has some problems; for example Q3 doesn't bias right with a 100k trim (the spot point is probably at max trimmer turn); also, the Structure switch changes the bias of Q2 (i have to retrimmer when engaged...), as it effectively halves the source resistor...

Deadastronaut, did you succeed in building this ?

thanks

[deadastronaut]

I've tried to build this following the posted schematic...

But it has some problems; for example Q3 doesn't bias right with a 100k trim (the spot point is probably at max trimmer turn); also, the Structure switch changes the bias of Q2 (i have to retrimmer when engaged...), as it effectively halves the source resistor...

Deadastronaut, did you succeed in building this ?

thanks

hi denym. no i never got round to building this, i read your problem on the other thread...not sure how to get round that!..
some of the more experienced guys might be able to advise on that!..
i do love a good amp emulator though...there are some russian designs that  sound cool..
they have taken it down now from the site now though..but i think i still have the schematics for a couple of them somewhere on my drive..!!!
if not , i remember emailing them to bryan ' brymus' and i'm sure he'll send em to ya!..cheers rob.

didnt anchovie say something about your problem above?..

[Zapp Brannigan]

Deadastronaut, I've almost broken my eyes when tried to read the schemo you posted. For you and the rest of Jfet-maniacs I post this:
http://www.guitarjfet.ru/index.php?option=com_content&task=view&id=32&Itemid=34
Sorry, but debugging instructions are in Russian, but they are translatable (I could do it, if anyone needs)
Schematics:
http://www.guitarjfet.ru/images/stories/articles/preamps_jfet/boogazzy.JPG
PCB layout:
http://www.guitarjfet.ru/images/stories/articles/preamps_jfet/boogazzy_pcb.GIF
Threre is one thing about this stompbox - it  uses КПС104А twin-jfets, which can be replaced with matched pair of J201. Good luck you all!

[deadastronaut]

Deadastronaut, I've almost broken my eyes when tried to read the schemo you posted.

ha ha.....pdf zoom?..

yep thats the page i was talking about...cool sounds..nice one..

[Zapp Brannigan]

Deadastronaut, I've almost broken my eyes when tried to read the schemo you posted.

ha ha.....pdf zoom?..

yep thats the page i was talking about...cool sounds..nice one..

Even zoomed, it is hardly readable... I see everithing well starting from 150%, and 300% is OK (I would say it's perfect), but unconvenient to read the whole schemo.
P.S.: Anyway, you must confess that picture I posted is much better to read, and besides it contains bypass circuit, not only "dirty channel".

[deadastronaut]

ok i confess...

[Zapp Brannigan]

ok i confess...

Good boy!

[Zapp Brannigan]

I've tried to build this following the posted schematic...

But it has some problems; for example Q3 doesn't bias right with a 100k trim (the spot point is probably at max trimmer turn); also, the Structure switch changes the bias of Q2 (i have to retrimmer when engaged...), as it effectively halves the source resistor...

Deadastronaut, did you succeed in building this ?

thanks

No chance to make it sing without a scope. The tuning procedure in this case is not only setting bias voltage.