Orange AD200B Preamp

[rocket88]

Got bored today and decided to mess with some amp schematics to put together a few tube to FET preamp pedals. First up the legendary Orange AD200B bass amps

MK I


MK III


the only changes from the schematics is the addition of a small cap from gate to ground as suggested in the Fetzer Article by Runoffgroove to help keep the frequency response tube like.

haven't made either of either of these yet, but they should be a good quick build. the one thing i can see changing is that the volume pot may need to be lowered to allow for more output, especially the 1M volume pot of the MK III.

btw, once verified i'll post it over on the main page.

[negativefx]

I owned a MK III and actually had a chance to dime it out at a few gigs... sounded stellar.  Anything less than cranked?  Not so great.   Switched to a Fender Super Bassman and never regretted the swap.  Looking forward to this build... might be able to get that nice Orange snort through my current amp.  :)

[rocket88]

nice. i hope it works out well. my buddy got a MK III and we tested it against the mesa m6 i bought and he started looking for a mesa. from what i gather the MK I really is stellar in with the gain all over the place, and much better than the MK III. as you can see there are a few changes made with the new MK III that could be the cause of the differences.

personally, with orange the older amps up to the 70's are a million times better then the new amps in terms of tone. the newer amps all sound flat, not eq wise but personality wise. if you read the history of orange, Mat Mathias collaborated with Cliff Cooper, creating Orange Matamp. once the company took off Cliff Cooper wanted things to be built cheaper and Mat Mathias refused which caused the companies to split creating Orange and Matamp. i feel like once the split and due to the drop in quality of Orange they really just lost what made them sound so amazing, while Matamp still makes their amps the old school way and still sound amazing, just beasts.

[Guzz]

Hello Rocket, have you tried the layout ? I'm about to since I need a bass practice amp and I was wondering if there was anything I should know before building this.

Cheers !

[rocket88]

I have not had any time to try it, and it was attempted on the main page, but didn’t work. I have to throw it up on the breadboard and see if I can figure it out.

[Guzz]

I guess I'll fiddle with it too, time to bust out the old bag of dodgy chinese J201s !