I was looking schematic of Shiva Bogna
http://www.youtube.com/watch?v=U_e0VFpcKQU
http://www.youtube.com/watch?v=wRifqwuR3hE
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He has a great return and I realized that the design is almost identical to Marshall, so did the regime following; Shiva from Bogna jcm800 mods ...
comments and get back to me ....
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mods for jcm800 preamp for shiva bogner
http://rapidshare.com/files/164954197/jcm800_mods_shiva_bogner.pdf.html
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Bogna original design of Shiva
http://rapidshare.com/files/164929541/Bogner_Shiva.pdf.html
Thanks ...
Andre
Sorry for my English to google!
So what do you want to know?
For those of us that have built a bunch of JCM800's and it's many variants, this isn't anything new.
There's alot of tweaking you can do to that circuit, I usually use a relay to switch between the high and low inputs and make the gain of the high input adjustable.
Quote from: drewl on November 18, 2008, 08:03:15 AM
So what do you want to know?
For those of us that have built a bunch of JCM800's and it's many variants, this isn't anything new.
There's alot of tweaking you can do to that circuit, I usually use a relay to switch between the high and low inputs and make the gain of the high input adjustable.
I want my jcm800 Preamp with considerable gain and wonders whether these changes have I done, leave the preamp with more profit.
my mods
http://rapidshare.com/files/164954197/jcm800_mods_shiva_bogner.pdf.html
Are we supposed to pay to look at your files? Right.
no. he's using a translator. words for "gain" and "profit" can be the same in portuguese, it's a translator error.
For a "more gain" 2204 type circuit, check out the ax84 High Octane.
My peavey Windsor is supposedly a jcm 800 clone. While i never sat down and compared the two schems, we A/B'd it with a really hot JCM 800 and it sounded like a (dare i say it) better version of the 800. If you PM me your email i might be able to hook you up with the Windsor preamp schematic.
The links are not working.
Quote from: DougH on November 18, 2008, 01:13:36 PM
For a "more gain" 2204 type circuit, check out the ax84 High Octane.
That's what I was going to say. Or the SEL. An SEL with a KT77 sounds awesome.
Matt
Quote from: Marcos - Munky on November 18, 2008, 12:12:05 PM
no. he's using a translator. words for "gain" and "profit" can be the same in portuguese, it's a translator error.
Thanks for clearing that up. I feel kind of dumb. So be it.
new mods JCM800 (shiva bogna)
http://rapidshare.com/files/165316399/jcm800_mods_shiva_bogner-19-11-08.pdf.html
The quickest way is to bypass V1a's 10k cathode resistor with another 10k/cap combination....make it switchable and you have an awesome boost!