The schooling continues... preamp tubes and master volume (and NPD too!)

[Dolf]

I've played a few genz benz (not the pearl) and wasn't blown away. Have you any others with good results?

 

 

Their high gain stuff is mediocre at best, IMO.

 

Their acoustic line (the Shenandoah) are really nice and their cabinets ROCK.

 

 

The Black Pearl stuff is tits, try it out.

[jhamnett]

Well, closest Genz-Benz dealer is about an hour away, not cool.

 

I'll pop into a shop on the way home and see if they have any used deals.

[jhamnett]

Saw a Traynor CV50BLUE for $550... worth it?

[jhamnett]

Bump? Any opinions on the Traynor?

[spentron]

But isn't the master usually AFTER the poweramp??

Never, except maybe 1/2 watt amps. That would be a "power attenuator" and is a much bigger deal.

Well, I actually found a schematic for that amp. It is arranged: tube stage 1 => volume/drive switched controls => tube stage 2 => tone controls => tube stage 3 => EXTRA tube stage on Drive only, includes master volume => ZENERS => effects loop => reverb circuit => power stage.

So the clean channel has 3 tube stages before it even gets to the effects loop. Each of these is full gain, although there is loss between the stages. This definitely is capable of crunch on the clean channel.

What I'm not sure about from the schematic is where I've marked "ZENERS". These may be a protection function only, but it looks to me that they add distortion to the clean channel (or if master is cranked on Drive) at a lower level than the tube drive. Note the added Drive stage is very simple so except for more gain, the biggest differences are that Drive disables Bright and that clean adds SOLID-STATE clipping. Looks to me that you could add a trimpot across these diodes (cathode-cathodes) to attenuate the signal enough to not distort them (and reducing volume).

[jhamnett]

Never, except maybe 1/2 watt amps. That would be a "power attenuator" and is a much bigger deal. Well, I actually found a schematic for that amp. It is arranged: tube stage 1 => volume/drive switched controls => tube stage 2 => tone controls => tube stage 3 => EXTRA tube stage on Drive only, includes master volume => ZENERS => effects loop => reverb circuit => power stage. So the clean channel has 3 tube stages before it even gets to the effects loop. Each of these is full gain, although there is loss between the stages. This definitely is capable of crunch on the clean channel. What I'm not sure about from the schematic is where I've marked "ZENERS". These may be a protection function only, but it looks to me that they add distortion to the clean channel (or if master is cranked on Drive) at a lower level than the tube drive. Note the added Drive stage is very simple so except for more gain, the biggest differences are that Drive disables Bright and that clean adds SOLID-STATE clipping. Looks to me that you could add a trimpot across these diodes (cathode-cathodes) to attenuate the signal enough to not distort them (and reducing volume).

 

 

Yeah, I remember hearing that the amp uses solid state clipping... I actually dimed the amp without the volume pedal (but with earplugs) and the tone was crazy. I think an attenuator would be the best option, but I found the Traynor on craigslist and think it might be a good deal, since I can get $450 or $500 for the HRD. It uses EL34s and has a master volume, which is more what I'm looking for. I'll be trying it tomorrow, we'll see how I likes it.

[surferbeto]

Sound advice. I might stop by GC on the way home (I know, I know, but it's the only place on my route).

 

 

 

 

No shame there, amigo. That's what GC is for: to try out equipment that you then go and buy elsewhere for less.

[petejt]

I would go Graphic EQ, and take the level slider down to where you want it. The cool thing is that you can also have control over your tone going to the speaker that way, and, if you need to, improve clarity, bass response, create a mid-boost, or just tailor your tone specially to your venue/room while also reducing your output volume to where you want it. And the perfect box for this? The almighty Dano Fish and Chips. . . $30 worth of solid win.

Exactly . I can't wait to get one of these.

[jhamnett]

Exactly . I can't wait to get one of these.

Regardless of whatever I do with my amp situation... I have one of these in the mail!

[spentron]

 

Yeah, I remember hearing that the amp uses solid state clipping..

 

I wouldn't agree with that characterization in normal use. Without your extra master volume in the effects loop, the power stage distorts first. On the Drive channel there is a master volume setting that can OD the power stage and is otherwise all preamp tube. In other words, the only case with substantial SS clipping is the one you prefer.

 

On thing is the EQ is mostly pre-distortion. Try setting it very bright or no bass on the Drive channel and then use an EQ in the loop.

 

They would have has to set up the clean stage explicitly as a tube clipper to protect the bit of SS circuitry that follows: the FX loop switches in 2 opamp stages (atten/drive and level recovery) and the reverb circuit is SS although the dry path there is tube.

[StratStevo]

This really isn't an answer to your question but....anybody owning a Hot Rod Deluxe/Deville should try 12AU7's in the V1 & V2 slots. The swap makes the Drive and More Drive settings a viable option, the amp in general becomes more dynamic and usable. On the Normal channel what once was done on volume setting #2 now requires #3, but volume in that line of amps has never been an issue...the big gain with the 12AU7 swap is less gain across the board, it's the classic less is more story

[jhamnett]

OK, so I will definitely be getting an attenuator for this amp, probably a Weber (least expensive). Then I think I'll try a few different tube combinations, get some new 12AX7s, maybe some 12AU7s, some 6V6/KT66/Yellojackets with EL84s in the poweramp section.

 

I'll still make the mods I was going to make to the circuit (just clip one lead for better tone stack, replace linear master pot with an audio one). Hopefully I'll find the right combo (although I think the attenuator will make the most difference).

 

Thanks for the help!!