High headroom and overdrive in the same amp

[Leevi]

I'm looking for a circuit for an amp that provides both high headroom
and very strong distortion. The mode could be switched by a pedal.


Any ideas?


/Leevi

[tubenit]

The D'Mars ODS is the closest I have personally found to that.  And I think if one adds an active FX on board you can get that even more so.

With respect, Tubenit

[Leevi]

Thanks for your fast response Tubenit. I forgot to mention that the max power
of the amp should about 100W. Two cathode biased 6K6 provide much less?


Fender 4x6L6 power amp is optimal for clean and Marshall 4xEL34 for distortion.
Since it's difficult to combine two different power amps I think
the clean/overdrive mode should be solved in the preamp?


/Leevi

[HotBluePlates]

I'm looking for a circuit for an amp that provides both high headroom and very strong distortion.

This statement sounds like the customer doesn't know how to verbally express what they want.
 
Unless they want something like a Dumble, like Tubenit suggested. Or a master-volume 100w amp of any kind, plus whatever flavor of preamp distortion you wish to add. Or a clean-only 100w amp and pedals.
 
Maybe the customer means, "I wanted to be able to get the exact same distorted sound and feel at any volume level, from quiet to very loud. Regular amps get more-distorted and mushier as I turn them louder."

[printer2]

I read the same request every couple of months or so. Worded differently, 'I like my output tube distortion but I want more clean headroom but at the same average volume'. So more power for clean, less power for dirty. (this is assuming preamp distortion is a dirty word) So the solution to (this) request is a high power amp with a VVR.

[Tone Junkie]

The answer is simpler than that. The original D'mars was 2 6l6 tubes if I remember right, not very hard to make it 4 6l6 tubes with adjustible bias instead of cathode . Chime in tubnit if Im incorrect
just my 2 cents.
Bill

[Leevi]

It's not a problem to add an extra switchable amplification stage to preamp
but that's not the whole solution if you want to keep the volume level equal in both modes.
Then you should be able to control the volume as well. One option is to have two switchable preamp
channels with own volumes.


/Leevi

[jazbo8]

So it seems like you need clean and overdrive tone at roughly the same SPL, then please take a look at the Trainwreck Express, it's well known for its clean to mean transistion, i.e., similar SPL going from clean to overdrive via pick attack, picking and/or guitar volume knob. For 100W, you will need to double-up on the output tubes and of course use a larger OPT.

[tubenit]

The answer is simpler than that. The original D'mars was 2 6l6 tubes if I remember right, not very hard to make it 4 6l6 tubes with adjustible bias instead of cathode .

Exactly.   

With respect, Tubenit

[Ritchie200]

Ok, I'll throw my hat in the ring!  Why not build what is essentially a Hoffman/Marshall 50 with a hot switch option and KT88's in the OP section.  At roughly the same voltage you will get about 75 watts and loads of headroom, a sweet sounding output tube (6L6....ewww), and good classic preamp grind if needed.  You will be replicating a Park 75, one of the best sounding amps Marshall ever built - behind the Major, of course! OR, sub in a 2204 preamp section for more grunt.  Maybe Ed will chime in here as he has built several KT88 and KT120 tone monsters.  IMHO, headroom has to sound good and BIG, not just clean.  I don't think you can beat a KT88 for that.

Jim

I still like this clip to show off the KT88's sonic ability.  Although turned down slightly at the guitar, nothing is lost at the amp.  Turn it up and it wails.
Ritchie Blackmore - Greensleeves live 1977 HD