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 (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!.. :icon_mrgreen:
see ya. rob.
They look some kind of Boost/Fat/Drive-switches to me.
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.
I'm guessing this is just the preamp?
Yes, adapted for JFETs.
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
Quote from: demym on October 12, 2010, 05:59:53 AM
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?..
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! :icon_twisted:
Quote from: Zapp Brannigan on October 12, 2010, 06:38:48 AM
Deadastronaut, I've almost broken my eyes when tried to read the schemo you posted.
ha ha.....pdf zoom?.. :icon_mrgreen:
yep thats the page i was talking about...cool sounds..nice one.. :icon_cool:
Quote from: deadastronaut on October 12, 2010, 06:49:09 AM
Quote from: Zapp Brannigan on October 12, 2010, 06:38:48 AM
Deadastronaut, I've almost broken my eyes when tried to read the schemo you posted.
ha ha.....pdf zoom?.. :icon_mrgreen:
yep thats the page i was talking about...cool sounds..nice one.. :icon_cool:
Even zoomed, it is hardly readable... :icon_biggrin: 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".
ok i confess... :D
Quote from: demym on October 12, 2010, 05:59:53 AM
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.