Chasing a clean channel with my high gain amps.

[Tone Junkie]

Finally I'm just going to bite the bullet and build a stereo output amp . Ive been taking two heads to jam with with , one a fender clone the other a JCM800 clone a bit hot rodded with 2 gains and 2 MV switchable. I'm switching between the 2 depending on what I need. Will probably stay with the a/b footswitch because I can then use both channels with my harmony pedal
I finally got to this point because I cant get a great clean channel . Ive built an SLO clone a VHT clone and several other high gain amps. the clean channels by the time you get loud enough to match the high gain channel is not very clean anymore. I don't like just using a clean channel with pedels. So 2 6L6 output for the clean channel. 2 EL34 tubes for marshall side. Shopping for best fender clean channel.What are your thoughts .
Thanks Bill

[TIMBO]

Hey Bill, This is form my latest restore.

Could get it to 9 before breakup, pretty clean a jazzy.
Could sub the 6CA7 for 6L6 and use Vibroluxe OT

[Blind Lemon]

Leave your power section and PI alone for a while and roll in some lower gain tubes where you have 12AX7s. 12AU7,AY7, 5751. See if you like the tone, cheapest and easiest way to begin.


At least it will give you a base line if you need to rework the circuit.


BL

[SILVERGUN]

So 2 6L6 output for the clean channel. 2 EL34 tubes for marshall side. Shopping for best fender clean channel.What are your thoughts .

Sluckey's TDR in it's final form with 6L6s is hard to beat.

Go to the bottom of the page to see the updated version:
http://sluckeyamps.com/tdr/tdr.htm

[SoundmasterG]

You can have a very nice clean channel using a 12AU7 and a 12AX7 gain stage, with a 12AX7 CF, then add a master volume to this channel and your high gain channel, and after the master volumes use a single mixer stage using a 12AX7 and local NFB on that tube. You can adjust the gain of each channel with the NFB stage so they match each other before going into the PI. Merlin's book has info on mixer stages as does Kevin O'Connor's books. The example I just gave using a single mono output stage instead of a stereo stage, but it is much simpler than building a stereo amp and works fine. No compromises on either channel as far as tone or gain.

Greg

[pdf64]

Finally I'm just going to bite the bullet and build a stereo output amp . Ive been taking two heads to jam with with , one a fender clone the other a JCM800 clone a bit hot rodded with 2 gains and 2 MV switchable. I'm switching between the 2 depending on what I need. Will probably stay with the a/b footswitch because I can then use both channels with my harmony pedal
I finally got to this point because I cant get a great clean channel . Ive built an SLO clone a VHT clone and several other high gain amps. the clean channels by the time you get loud enough to match the high gain channel is not very clean anymore. I don't like just using a clean channel with pedels. So 2 6L6 output for the clean channel. 2 EL34 tubes for marshall side. Shopping for best fender clean channel.What are your thoughts .
Thanks Bill

To me it makes more sense to add the high gain channels to the Fender clone, as that it loud and clean enough for your needs.

[jjasilli]

If you really must have 2 different sets of power tubes, I think one way to do this is to have both pairs of power tubes hooked-up to the OT primary.  Use a SW to toggle between cathodes lifted from ground on EL34's while the 6L6 cathodes are grounded; and vice-versa.  Only one pair of tubes will be ON at a time.  Only one OT needed.  At 450V, the primary impedances of both tube types are close enough. 


If your design gets the primary impedance needs too far out of whack from ea other, then maybe arrange to SW OT secondary taps to reflect back a better primary impedance.

[Tone Junkie]

Thanks guys all good ideas , Must pull out merlins book and tut to look them over. I have been using merlins ideas from his power section book . cleaned up the PI and cut a little power tube distortion for my cleans with that . In my fender clone Im using 12ay7 first tube 12at7 PI nice cleans. Gets good and loud but nice and clean.
Thanks Bill

[Tone Junkie]

I was going with 2 output transformers . To clean that problem up.
thanks good ideas all around.
Bill

[dscottguitars]

I have used this preamp for my clean channel with 2-6L6s. It's very loud and almost no breakup when cranked. The key is using two tubes and wiring the a and b into one parallel full double triode. It helps with headroom and using the stated cathode resistors in parallel actually doubles their value and give more headroom. I'm no expert by any means, I have just got this through some trial and error.

[dunner84]

I recently added the SLO overdrive channel to my ab763... Amazing. Ab763 is lite variety, so only the normal channel, no reverb, no vibrato. The two channels are completely independent preamps, and share a common larmar master volume. The power section including the phase inverter is all ab763 topology, and uses 6l6

I use a radial aby switch for channel switching.. the only problem I encountered was the SLO circuit did not love my 2x10 speaker configuration. (Weber 10f150 and celestion gold). And the ab763 did not love the 2x12 celestion gm70s.
 I found a beautiful happy place with 12 inch celestion gold's. The amp does sparkly, chimey fender cleans, pushed fender crunch when cranked, or with use of the RAW control at reasonable volume, and the SLO side goes from vintage marshal drive to full modern high gain, and I can switch between the two sides without issue. The amp happily stays clean at gig volume over a loud drummer. I am yet to play it with a wide open master volume at a gig.
My band is getting together Friday night, and I can take a few audio clips if you like.

[DummyLoad]

super reverb or twin reverb. kick the tremelo and the normal channel to the curb.

another one of my favorite clean amps is the ampeg V4, however, they tend to be unreliable, use esoteric tubes, and are very difficult to work on - esp. the control board.   


--pete