Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: tubenit on June 13, 2011, 08:58:56 am
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http://www.el34world.com/charts/Schematics/files/peavey/peavey_heritage_vtx.pdf (http://www.el34world.com/charts/Schematics/files/peavey/peavey_heritage_vtx.pdf)
Young guitarist in a church band has this Peavy Heritage vtx amp that isn't working. The amp did not sound very good when it did work.
He was wondering about my gutting this amp and turning it into something closer to a Vox AC30? Since it had four 6L6's, my first response was that wasn't possible.
However, AFTER looking at the schematic ............... it appears that the PT has a "low power" setting at 262 volts?
I am wondering if that could be hard wired and then run four EL84's?
I am thinking if the PT could handle four 6L6's that it could handle the current of the four EL84's without much of a problem with it?
The OT looks to be good for either 4ohm or 2ohm.
I would completely gut the chassis and try to use the PT & OT and start over with a blank slate. I'd put in a layout board and punch the chassis for preamp tubes.
Does this sound reasonable after looking at the schematic?
With respect, Tubenit
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I think I had the same model amp when I first moved from having a tiny solid state practice amp to my first "real guitar amp." I don't blame your friend for wanting to gut it and start over. It's not what we'd call a colorful amp.
262v is a hair low for an AC-30, however, the power supply will likely be quite underloaded after the transition to EL84's. I think you've got the right idea, but if you want to keep the stock transformer, you'll probably want to put the stock 2x12 speakers on the 2 ohm tap to reflect a higher primary impedance.
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HBP,
THANK you my friend! Appreciate the response and it's always great to hear from my amp building mentor. You got me headed the right direction with all this stuff and I'm grateful.
:worthy1:
Best regards, Tubenit
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Depends how much work you want to do. You could toss the circuit board and build a tube amp.
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that PCB looks "busy". :icon_biggrin:
should be a fun scrap.
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> something closer to a Vox AC30?
I have a 21-foot 3/4 ton plow truck, don't work so good. Can I turn it into something closer to a Miata sports-roadster?
> had four 6L6's, my first response was that wasn't possible.
Not a killer issue. Four big bottles is four big bottles, pint or quart not a big difference. An AC30 preamp is fine, an AC30 driver could be beefed-up.
But any way you slice it, this amp is 100++ WATTS. It was made to play the Devil's Music, LOUD. I've met worship services where it would be OK; others where they'd condemn you and your amp to hell and scrub the sanctuary with holy-water.
If this is an AC30 kind of worship, it might be best to do a minimal fix then sell it to some sinner to buy an AC30-clone. It certainly has the heavy-metal to dominate a sleazy tavern.
It is a very interesting plan. Like they studied all the good ideas of the 1950s, 1960s, and the 1970s; then avoided all of them. It may be too clever to be musical.
Yet it seems to be useful for Dixie tones.
I'd be thinking Fender Bassman 135. BIG amp, UL. If you accept just one channel, it is just two small tubes to drill into the chassis.
The speakers, if original Scorpions, are really-really good in a 1981 kind of way.
> the PT has a "low power" setting
That's good: any 130W amp sometimes needs a 40W setting. But it complicates the biasing.
I think it can be re-done. It won't be simple. It will always be a BIG amp. Owners say "it's freakishly 'eavy", "This sucker is loud." Be silly for it to be 30 watt guts in a 130 watt body.
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It is a very interesting plan. Like they studied all the good ideas of the 1950s, 1960s, and the 1970s; then avoided all of them. It may be too clever to be musical.
LOL. That reminds me of what I tell people about St. Petersburg, Russia. It's a mixture of 1750, 1850, and 1950.
Hey, but great diode collection in that there Peavey, huh?
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PRR and others,
THANKS for the responses (& the humor)! I agree that trying to make a AC30 out of this would not be a best choice.
I personally would use only two 6L6's and make a Tweed Overdrive into it. That way he could have both a clean tone and a overdriven tone of the OD. The Dumblish amps have a relatively clean power section with the overdrive in the preamp. I think that would be a great amp conversion.
However, it's not my amp ............. so I don't know what will unfold with this? As is sometimes the case with younger players, I think he is wanting to emulate the tone of one of his hero guitarists who plays an AC30.
With respect, Tubenit
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As is sometimes the case with younger players, I think he is wanting to emulate the tone of one of his hero guitarists who plays an AC30.
Then this would support PRR's comments but don't forget that the AC30/Vox tone isn't just what tubes and/or preamp is in it. It is a product of the whole inlcuding it's tone stack/frequency response AND one of the if not the biggest contributor - a pair of Celestion Blues.
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I personally would use only two 6L6's and make a Tweed Overdrive into it.
Great idea! IMHO, a 4x6L6 will raise the dead!! :headbang:
With Respect
Best Regards
Rzenc
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> wanting to emulate the tone of one of his hero guitarists
Yeah, gimme Clapton's amp so I will play like Clapton!
Nevermind that the tone heard in studio or concert is highly modified by all the blinky lights in the dark booth. Or that most guitar-heroes use many different amps over their career, and often take whatever is handy and still get "their sound".
Or that if I _could_ play just like Clapton, I'd be just a Clapton Tribute act getting $45 to play slow Tuesday nights at the corner bar. Good to know what Clapton Almond Young Dale et al "do", but no future in "being" those guys. (Except the super rare case where a frontman croaks and the band needs a doppelganger to finish the tour....)
> I don't know what will unfold
No, as you well know, you can't correct misconceptions. We old fools won't change and youngsters already know it all. As a more experienced player and friend, you should probably give a nudge to sway his thinking toward your own experiences. But he also gets nudges from everybody else, and you really don't know what will unfold.
_I_ suspect the VTX is a GOOD amp for what it was made to do, and also a decent carcass for building a different BIG amp on (I have ideas). Either way, I don't want it working hard at any church in my quiet town. And the market value of a healthy VTX is so low, the busted-value even lower, that it can hardly be sold/traded for a AC30. So, White Elephant.