Peavey Classic 30 - Boosters

[DougH]

I'm not familiar with the Classic 30, but a Unidrive is a good high-gain booster. Use that and scoop the mids- makes a most excellent metal tone, dood...

[raulgrell]

So, to sum it all up: An 8 ohm speaker is fine, as long as one doesn't use the extension cab output, because that is parallel with the original speaker, and it would make the impedance of the speakers less than 8ohms...

I hope that's it...

Still had no comments about the booster between the preamp and the power amp... Is it simply too stupid that I shouldn't either consider it, or so amazing you don't want to share it?

I'm not familiar with the Classic 30, but a Unidrive is a good high-gain booster. Use that and scoop the mids- makes a most excellent metal tone, dood...

Hmmmm... I can't help but think the "dood" is there for sarcasm... I'm guessing it's about the mid-scoop... Don't worry, mid scoop aint my thing...

[DougH]

"dood" is there for humor only. Forgot the smiley, here you go: 

FWIW I've used metal tones a few times, depending on the song using this approach and it sounds great (and I've gotten good compliments on the sounds from others).

[newfish]

Booster betwixt Pre and Post amp is fine.

You won't get *as much* crunch - in fact, this is a good way to get a 'solo-boost' without really changing your tone.

A friend of mine has an LPB on his effects loop for just this reason.

His tone (Epiphone Sheraton into Vox AC30) remains the same - just gives him a volume boost.

I imagine a Treble Booster would change things somewhat though...

[jayp5150]

So, to sum it all up: An 8 ohm speaker is fine, as long as one doesn't use the extension cab output, because that is parallel with the original speaker, and it would make the impedance of the speakers less than 8ohms...

I hope that's it...

That's exactly it. The jack says 16ohms because the stock 16ohm speaker and a 16ohm cab gives you 8ohms. That's why I suggested installing a plug/jack for the internal speaker that way you can easily unplug it and pump that thing through a 4x12 (or whatever)

A mate of mine has a Harley Benton 1 x 12 extension cab - with selectable impedance - which makes a lot of sense in my book.

How does this work? Dummy loads? This would be a cool thing to have.

[slideman82]

I've done that triode-to-FET conversion of the C30 preamp, and without using very high gain FETs, I decided to reduce that 1M resistor that's after 3rd triode, if I'm not wrong, and more distortion was created. You could try this, I think. And if you use 12BZ7 instead of AX7 (watch out for the phase splitter, that must not be replaced), you'll probably distort more!
That's a great amp, one of the best, IMHO, but, change that Blue Marvel for a Cannabis Rex, brighter than a Vintage 30.

[petemoore]

  Vintage 30...lookout, loud yes...if you like 'warm' though, there are less agressive sounding speakers.
  I guess the C-30 has a fixed amount of transformer windings, hence the [relatively high] ohmage minimum. I would work with that output section unchanged, and fit speakers/ohmage to that..only a slight inconvenience.
  Ohmage selectors...if it's all hardwired [jacks wired to transformer taps], that's one thing, indroducing electro-mechanical switch in that position [between speaker and OT] is something I would avoid or modify around to a hardwired configuration.
 

[raulgrell]

Booster betwixt Pre and Post amp is fine.

You won't get *as much* crunch - in fact, this is a good way to get a 'solo-boost' without really changing your tone.

A friend of mine has an LPB on his effects loop for just this reason.

His tone (Epiphone Sheraton into Vox AC30) remains the same - just gives him a volume boost.

I imagine a Treble Booster would change things somewhat though...

I was wondering if I could get the output of the clean stage, crank it, send it through the cranked booster, into the power amp in hope that it will get me more of the sweet-azz power amp OD?

I'm guessing I'd have to power the booster at a much higher voltage than the standard 9V, right?

Chances are, I'd also have to sub the driver tubes to something a bit cleaner to avoid triode distortion (they need to be high gain, though, right? to drive the output tubes?)

I've done that triode-to-FET conversion of the C30 preamp, and without using very high gain FETs.....

Happen to have a schematic? or is it really, literally, a straight triode to fet conversion?

First time I actually look into tubes this much... My Epi Valve Jr ended up being a lot simpler...

[comfortably_numb]

Build a simple booster and just try it!  It certainly won't hurt anything.  And please do report on your findings.

[petemoore]

  I remember it as simpler...no matter
  go to the non-distort-o channel, turn the volume up, try a different speakers and repeat.
  Then use a booster...look for volume increase with boostage at lower volumes, but output/speaker tones at higher volumes, no real reasons I ever found to exceed the volume of what an amp already does, at least not when on a tone-quest.
  Lower volume boost raises the volume and may have the largest usable tonal change boost does.
  Once the amp is 'up', mud may enter in increasing amounts as volume is increased.
  It's all about the tone of the speaker and amp, though any boost adds a touch of shine or whatever you call it.
  Some of these guitar pre-amps can cleanly output a highly boosted input signal...good for power tubes distortion, EL84 flavors.
  I suppose the pre-amp distorters deserve mention [just working with the LV boxes between guitar and amp seems to work the better' wonders], I like the pre-amp to be a regular 'ol 12a_7 or similar, part of that is experience, and lack of it [something about breadboard tubes, namely high voltage, dissuades me from messing with tweeking tube pre-amps, that and I've never met one I really liked, they're heavy...I just generally avoid them and look to see how easy the output portions are to get distortey-good tones from. Yupp...lazy, scared and the little 9v tone-twisterz just make sense and hence tend to get to being great sounding.

[raulgrell]

Build a simple booster and just try it!  It certainly won't hurt anything.  And please do report on your findings.

Ok! Ok! No need to get your knickers in a knot! I love that expression!

I had some issues with the delivery, it'll only be here end of next week... In any case, it gives me time to build the boosters and find myself a nice mic to record a proper sample...

[grolschie]

Build a simple booster and just try it!  It certainly won't hurt anything.  And please do report on your findings.

Perhaps the Omega or the Sparkle Boost?

[slideman82]

I've done that triode-to-FET conversion of the C30 preamp, and without using very high gain FETs.....

Yeah, that's right, there's a schemo around there, I think in Aron's gallery, don't remember the user. Just experiment with different FETs, because clean won't be clean and dirty will be too dirty.

[d95err]

There seems to be a bit of confusion about speaker impedance and tube amps in this thread. This is the deal:

Tube Amp: Too low impedance on the speaker(s) is OK (as long as it's not way off). Too high speaker impedance could result in problems.
Solid State Amp: Too low is dangerous and can blow the output transformers. Too high impedance is OK.

For some reason Peavey get this wrong in the manual and talks about "minimum impedance" even though it's a tube amp. As a rule of thumb, a 2:1 mismatch low orhigh is OK for a tube amp.

About the Classic 30, when you plug in something into the external speaker jack, the amp automatically switches to 8 ohm mode. So an external speaker should also be 16 ohm (as it says on the jack). Plugging in an 8 ohm speaker is OK, although the output power will be unevenly distributed between the internal and external speaker (one will get 1/3 power, one will get 2/3 power).

If you want an 8 ohm speaker as the built in speaker you could try one of three things:
1. Just change the speaker and ignore the impedance mismatch (should work fine)
2. Change the speaker and plug in an empty plug into the external speaker jack (the amp will now run in 8 ohm mode)
3. Re-rout the output transformer leads internally to use the 8 ohm tap for the internal speaker.

[raulgrell]

There seems to be a bit of confusion about speaker impedance and tube amps in this thread. This is the deal:

Tube Amp: Too low impedance on the speaker(s) is OK (as long as it's not way off). Too high speaker impedance could result in problems.
Solid State Amp: Too low is dangerous and can blow the output transformers. Too high impedance is OK.

For some reason Peavey get this wrong in the manual and talks about "minimum impedance" even though it's a tube amp. As a rule of thumb, a 2:1 mismatch low orhigh is OK for a tube amp.

About the Classic 30, when you plug in something into the external speaker jack, the amp automatically switches to 8 ohm mode. So an external speaker should also be 16 ohm (as it says on the jack). Plugging in an 8 ohm speaker is OK, although the output power will be unevenly distributed between the internal and external speaker (one will get 1/3 power, one will get 2/3 power).

If you want an 8 ohm speaker as the built in speaker you could try one of three things:
1. Just change the speaker and ignore the impedance mismatch (should work fine)
2. Change the speaker and plug in an empty plug into the external speaker jack (the amp will now run in 8 ohm mode)
3. Re-rout the output transformer leads internally to use the 8 ohm tap for the internal speaker.

Thanks for clearing that up!

Here's the link to the Amp sim in MartyMart's gallery - http://www.aronnelson.com/gallery/main.php/v/Martys-layouts-and-photos/Classic35new.jpg.html ... in case anyone wanted it...

[Mojah63]

I've been playing a Classic 30 for a while now....

1 Ditch the speaker.... I know it's been said before... I ended up with an old greenback (1974) in it with another in an extension cab.
  The amp sounds better with an 8 ohm total load. I use 2 16 ohm speakers with the extension jack

2 Re-tube it and add adjustable bias for the power tubes... JJ's are decent.. tungsol 12ax7 4 v1

I like to run the bias hot, my amp breaks up with the volume around 5-6 which is fine in the loud cover band I'm in now.
My board has a germ full range booster, a silver screw MIJ Boss ds-1
I have other fx's but those are the ones that I use 4 dirt.  I only use the clean channel..
Another thing about the 30, it doesn't have a master volume so it's hard to push the preamp 4 distortion. A 1meg pot
inserted in the fx loop would work. There are boxes on Ebay 4 that 2. Using the FX loop would put an opamp in your signal path...
Some people don't like that, I have no opinion on that.

I wouldn't hook a tube amp up to a lower load than the output transformer tap is designed for. It's a quick way to fry it. Every
tube amp book I've read strongly advises not to.. A higher impeadence load is OK... It will draw less current...

I really like the amp... It beats hauling around a stack and it's plenty loud enough...

[nooneknows]

Hi,
I had a C30 too, it substituted my JCM800 when I play in club, but... I heavily modded it. I wanted a more Fendery sound and now it sings in a wonderful way. Have a look at www.blueguitar.org as stated before, it's very intersting.

The most significantly mods I made are:

- discarded the original cone (bleah...), I put a Jensen C12K (huge difference)
- raised the plate voltage
- changed the tone stack to fender values.
- switched to cathode bias (instead of fixed bias).
- changed the first two tubes with 5751 (lower gain than 12AX7).

For the pedal, the C30 eats anything, it's not a snob like a Fender Twin, anyway I use most a Red Snapper (it has a lot of volume, indeed) and a Jack Orman Mini Booster, both sounds killer with the amp in clean and dirty channels, give them a try.
I tried edgier pedals (like rangemaster, mosfet booster, etc.) but it seems the EL84s are bright for themselves ending up in a too much shrillier sound, at least to my ears.

ciao

[jayp5150]

There seems to be a bit of confusion about speaker impedance and tube amps in this thread. This is the deal:

Tube Amp: Too low impedance on the speaker(s) is OK (as long as it's not way off). Too high speaker impedance could result in problems.
Solid State Amp: Too low is dangerous and can blow the output transformers. Too high impedance is OK.

For some reason Peavey get this wrong in the manual and talks about "minimum impedance" even though it's a tube amp. As a rule of thumb, a 2:1 mismatch low orhigh is OK for a tube amp.

About the Classic 30, when you plug in something into the external speaker jack, the amp automatically switches to 8 ohm mode. So an external speaker should also be 16 ohm (as it says on the jack). Plugging in an 8 ohm speaker is OK, although the output power will be unevenly distributed between the internal and external speaker (one will get 1/3 power, one will get 2/3 power).

If you want an 8 ohm speaker as the built in speaker you could try one of three things:
1. Just change the speaker and ignore the impedance mismatch (should work fine)
2. Change the speaker and plug in an empty plug into the external speaker jack (the amp will now run in 8 ohm mode)
3. Re-rout the output transformer leads internally to use the 8 ohm tap for the internal speaker.

I guess I didn't fully understand that myself.

I've been running an 8 ohm speaker for about 2 years now... 

I (very quickly) tried it out this morning with an empty plug in the ext. socket today, and I kinda like the mismatch better It seemed more open and less harsh.

I think it's just time to tear into this and start modding lol. I'm thinking maybe at least match up the impedances, and do the adjustable bias , at least.