Peavey Power Transformer 705-18718

[tubemonster]

I picked up a Peavey VTX Series Classic for 40 bucks.

It's missing the speakers and has a few other issues
.
I'm leaning more towards doing a rebuild in the chassis rather than repairing it, but not sure at the moment.

I'm wondering if I may be able to use two or three 12ax7's rather than the solid state preamp.

The power transformer is a 705-18718 and I can't seem to find any info on it or another Peavey schematic with the same transformer part number on it.

Any chance someone happens to know if this power transformer will handle three preamp tubes along with the two 6l6gc's the amp already uses?

I know I could always use a filament transformer for the preamp tubes, and I probably have a couple different transformers on hand for it, but...
It'd be nice to know ahead of time if I'd have to use one or not, before I start laying stuff out and cutting holes in the chassis.

Here's a picture of the power transformer.



The cab is still in nice shape and made of plyboard.
The OT tests fine.
All and all some nice bones for a diy custom build I think.

[glebert]

I was hoping they had also used that transformer on one of the bigger amps like an Artist VT or Deuce but it doesn't look like it. I think mostly you are going to be worried about heater current, and you would have to power the heaters from the 6.3VAC or the +/-27VDC. If nothing else you can add a separate filament transformer.

The 6L6 heaters should be about 1 amp each, and 12AX7 about 300mA each (I think), since there is a 6A fuse on the 6.3V tap maybe it can do it (???)

Schematic here: https://www.thetubestore.com/lib/the...-Schematic.pdf

Personally I really like the hybrid Peaveys, I would try to get it working as is before I would tear it apart. SS pre and tube power was good enough for Leo Fender and the Music Man amps.

[tubemonster]

Ya, I couldn't find a Peavey amp with four 6l6gc's using this PT either.
I really like Peavey amps over all, always have.
To save it as a Peavey, for me anyways, that means coming up with a couple a scorpion speakers.
If I already had the scorpion speakers I'd resurrect the amp for sure.
For a rebuild I essentially already have everything I need including speakers for it.
I'm pretty sure I have a transformer or two for the preamp filaments in my transformer stash, not real expensive if not.

I had an Alamo hybrid bass amp head a while back - it sounded great for guitar.
I had a bunch of Peavey amps - a few Triumph Ultra's.
A big ole Peavey bass head/cab - that was a power house for sure.
My most memorable and missed Peavey amp was my Vulcan series 500 that sat on top of a 6x12 concert stack/cab - now that thing was loud - lol...
I did really enjoy the couple of Peavey chorus amps.
Man, now that I think about it, I've gone thru a bunch of Peavey amps over the years - lol..

Had a Peavey Destiny Custom guitar for quite a while - was a nice gig'n guitar - I miss that guitar - never should have traded it off to my buddy...

Anyways, I guess I'll have to think some on this vtx classic..

[glebert]

Never heard of a Vulcan, that one is definitely an "odd bird." (groan).

I'm currently working on a Roadmaster SS Super Festival Series, solid state pre and 4x6550 power amp. I also have a Roadmaster Vintage Tube series (6x6L6), and an all tube VT300 bass head (4x6550).

Here is me using an Artist VT as a bass amp. I'm now using it as my main guitar pedal platform.

[tubemonster]

I'd say very cool

Those are some monstrous amps you've got listed above.

That amp head in the video reminds me of the peavey series 400 bass amp I had with fuzz built in - was a nice bass amp.

[Enzo]

Peavey transformers were always robust. I doubt an extra amp off the thing would matter much.

Two 6L6s is 1.8A, three 12AX7 wired for 6v is another 0.9A., so 2.7A total.

You have the extra winding for the op amps, and it could easily be repurposed to make a DC supply for 12AX7s. You could wire them in series like Peavey did on many recent era models. You can wire them as 6v or 12v for convenience. At 12v, two needs 24v and three needs 36v at 6v, three is 18v. or a pair 12v. Any of those supplies is easily made from that winding.

The information on the schematic is sufficient for servicing the amp. The DC voltages on the supplies are listed, inferring the AC voltages. And currents are sufficient for the job. Schematics are not meant as guides for substitution.

[J M Fahey]

*Your* amp your choice of course, but that´s not a plain vanilla generic SS or hybrid amp but a killer and unique one, personally I´d hate to lose that excellent *optical* Phase effect just to get some "more tubeish" sound out of it, there´s tons of "other" amps out there worthy of the conversion: if anything I´d use a Tube pedal (single 12AX7 is more than enough) to give it lots of flavour.
Adding the classic 12AX7 gain stage + cathode follower tone stack driver between preamp and power amp, followed by its own Master Volume would be a step in that direction.
And *one* 12AX7 filament will be very safe and would require just one socket hole.
Again, it´s your amp

[tubemonster]

I hear ya on reviving the Peavey VTX Classic opposed to pretty much gutting it for a custom amp, it's what I'd rather do honestly.
I guess I could revive it and just bide my time on a pair of Scorpions for it.
I know I could use other speakers (and I have some), but to me the Scorpions are part of the reviving equation.

Using it for a custom amp is mainly due to not having the scorpion speakers, it's not really to convert it to an all tube amp, but I pretty much have everything I need for the all tube custom build.
For the Peavey revive I don't think I have all the electrolytic's, not to mention the speakers.
It also needs one of the connectors, reverb tank, and... lol...

Oh well, I guess I'll first go thru and try to revive the amp first, then if that gets to looking too expensive or something I can always rebuild.
I think I have a couple reverb tanks from some other peaveys around here some where - maybe they're a match.
Besides, I really do dislike the thoughts of neutering an older USA Peavey amp

When I start working on it, which may be a while, see what happens, I'll try to come back to this thread an kind of share the experience type thing.

[J M Fahey]

Please do, either way

[Leo_Gnardo]

Coincidentally 705-18718 is the same PT I was searching for half a year ago. The amp I was trying to repair, Triumph 60. 5 preamp tubes, so I think your iron should be able to handle the same. And now I know to look for demised VTX Classics as potential transformer donors.

[g1]

Nice find Leo. For some reason the forum won't let me upload the schematic right now but it's available here: https://elektrotanya.com/peavey_triu.../download.html

[Enzo]

Oh cool, If the Triumph used it, I checked the VTM, sure enough, there too.

[tubemonster]

Well cool deal on the Triumph 60 using the same power transformer - thanks for the heads up you guys
I guess whether I revive or custom build I should be good to go.
I guess I should have went thru a few more peavey schematics when I was originally looking

Either way, when I start working on it I'll try to tag everything to this thread.
It may be a while before I get to actually working on it though.