Which old tube amp to restore?

[DEMENTED]

In my recent fevered quest to acquire a tube stereo system I have wound up with 3. I need a little help on deciding which one to have refurbished...caps, tubes, resistors, tubes etc. It will be driving a pr. of Klipsch KG 4 speakers.

1) Original Dynaco ST-70 and Dynakit PAS-2 EL34 powered.

2) The Fisher 500-B intergated 7591 powered

3) H.H.Scott 222B EL84 powered

All I can offer is that I prefer EL34 powered guitar amps.

[Guest pirateflynn]

In my recent fevered quest to acquire a tube stereo system I have wound up with 3. I need a little help on deciding which one to have refurbished...caps, tubes, resistors, tubes etc. It will be driving a pr. of Klipsch KG 4 speakers.

1) Original Dynaco ST-70 and Dynakit PAS-2 EL34 powered.

2) The Fisher 500-B intergated 7591 powered

3) H.H.Scott 222B EL84 powered

All I can offer is that I prefer EL34 powered guitar amps.

Boy, this could be a good one for JohnnyB. I have an old Dynaco ST-70 that has worked out well for me but I've heard some really good things about the Scott EL84 systems.

[Moose]

Dynacos sound good-ish, but aren't particularly good. What I mean is, they're like the entry-level to audiophile tube stuff. They have a distinct coloration and a good bit more distortion than is optimal. However, they're easy to work on and used to be relatively inexpensive for what they were.

The Fisher is not super-audiophile, but has lots of power and sounds good. Really a cool vintage piece, too, so you get the vibe of the bitchenest of the bitchen from the late 60s. This would be my choice of the three, but mostly for cosmetics.

I have never heard the 222-B, but it might be a cheaper restore than the 500B. It's probably better suited to just driving speakers, being an integrated amplifier without the radio dial and all that. They're supposed to be underrated and reasonably good sounding. This is what I'd recommend for someone else to restore.

YMMV -- after a year's research and longing for a tube hi-fi amplifier, I never did buy one. I still listen to music through self-powered studio monitors.

[LostArt]

i have an st 70 and it is a great amp. if you are interested in changing the sound there are tons of mods out there.

I would find a different preamp although many love the dyanco preamps.

dynaco is probably the hamer of tube amp gear (LOL)

the fisher is a highly respected piece of gear. I am just not into integrated stuff so i sold mine years ago

I am not sure about the scott piece although many of them sound great.

bottom line is any tube gear is a step up from solid state. IMHO

[tomteriffic]

The Dynacos are pretty easy to work on.

I've no direct experience on the Scotts other than my father-in-law's old system, and it sounded pretty decent with most material I heard on it.

I don't know if it's the exact model, but one of the top esoteric/hi-fi hysteria sites has been taking old Scott EL84 powered integrateds, as well as tuners and receivers and tweaking them up. Naturally they rave about them, but there you are.

Mapleshade Records

[Guest pirateflynn]

Mapleshade Records

Yeah, that Mapleshade website sure caught my interest a while back. I almost pulled the trigger. The old Dynaco sounds good so I stopped looking around ... for now!

[JohnnyB]

For cleanest sound of the brands mentioned, I'd lean toward the Scott amps, and Heath as well. I remember a Fisher tube tuner that sounded lovely. The Dynacos are very popular, and Dyna always delivered great value. They persist in fairly large numbers today because there were a lot of them to start with, they're relatively easy to maintain (so I've heard), and lend themselves to aftermarket modifications that elevate their performance.

Still, of the three, I'd go for the Scott. If you have the funds, the way to go would be to restore all three, keep the one you like and sell the others.

Another EL84-based contender more in the Scott/Heath vein is Eico. If you can get along with 14 wpc, you'd be hard-pressed to improve on the HF 81 integrated amplifier.

Kind of slick-looking in its own utilitarian way.

[Mike Lee]

For Hi Fi, wouldn't 6L6 or 6550 tubes be more appropriate than EL34's or EL84's? The American tubes always seemed to be "cleaner" to me in guitar amps, lacking the midrange grind of the Euro tubes. I suppose it doesn't make a huge difference if you don't run the thing into distortion, but I would think a 6550 based Hi Fi amp would have a truer sound and much more headroom.

[JohnnyB]

For Hi Fi, wouldn't 6L6 or 6550 tubes be more appropriate than EL34's or EL84's? The American tubes always seemed to be "cleaner" to me in guitar amps, lacking the midrange grind of the Euro tubes. I suppose it doesn't make a huge difference if you don't run the thing into distortion, but I would think a 6550 based Hi Fi amp would have a truer sound and much more headroom.

The 6BQ5 is an American tube. All the tubes have their strengths and weaknesses. There's just a class of enthusiast who likes the top-to-bottom coherency and tighter bass of the 6BQ5/EL84, and is willing to put up with the 14 wpc limitation and seek out extra-sensitive speakers to enjoy these amps at their best.

[LostArt]

7591's are probably the most hi fi tubes.

that is part of the reason why ampeg circuits were designed with them. they wanted the higest fidelity and quality of sound.

I have a citation II that I use genelex kt 88's in (originals not reissues) and it sounds awesome.

[mc2]

In my recent fevered quest to acquire a tube stereo system I have wound up with 3. I need a little help on deciding which one to have refurbished...caps, tubes, resistors, tubes etc. It will be driving a pr. of Klipsch KG 4 speakers.

1) Original Dynaco ST-70 and Dynakit PAS-2 EL34 powered.

That's the reason 80 percent of the original SUNN amps from 1965-66 only have the preamp and are missing the amp section. The hi-fi freaks gut them to make a tube stereo system.

[Joe G]

If you are doing the repair yourself, because so many amps were built and sold, you achieve the benefits of economies of scale, and IMHO that makes the dynaco amp the best candidate for rebuilding. So many highly regarded audio engineers have competed against each other over the years putting out upgrade kits for the Dynaco products. As a result, there are still a few upgrade kits available and/or partial rebuild drop in boards that will make that thing sing.

I built both the dynaco solid state and tube amp kits years ago from SoundValves and right now, I think the best upgrade kit available for the dynaco 70 is put put by Frank Van Alstine www.avahifi.com. He calls it the Ultimate 70i and that'll set you back $500 for the kit, $900 if he does the work, $150 for bare pc boards and plans.

There used to be several other options in kits and rebuilds out there, some are: Ernie Borbely, SoundValves, Curcio audio and tubes4hifi.com. You could probably do an Ebay search and find one of these amps already rebuilt for around $500 or less, or find an amp upgrade kit there for sale.

Having said all that, if you do not have even basic soldering skills, you should not attempt the kit, and if you plan on paying for the work to be done, it would not be cost effective to do this and it would be better to just sell what you have and buy new. However, if money isn't a consideration and you want some cool vintage, then carry on and good luck.

BTW, if along the way you need a preamp, shoot me a pm if you are interested in either a Dynaco Pat-4, Pat-5 or a RF/Hafler RF2000 bi-amping preamp.

[LostArt]

I have dynaco branded 6an8 tubes NOS NIB if you need them

[DEMENTED]

Thanks for the replies guys. Problem is you all had different opinions to offer and I don't know what I wanna do still. I also picked up a "Craftsmen 10" tube FM tuner and a Garrad Type A turntable. I'm considering selling it all and buying a unit ready to go...any tube audio freaks out there?

I have dynaco branded 6an8 tubes NOS NIB if you need them

I might take you up on that Al....how much?

[JohnnyB]

Thanks for the replies guys. Problem is you all had different opinions to offer and I don't know what I wanna do still.

The Scott--cleanest, most accurate, and tightest bass (important in tube amps).

Or if getting restoration parts is difficult, the Dynaco -- good all around sound and easiest to restore.

Fisher was good, but sort of mid-fi by comparison.

[DEMENTED]

I am keeping the Scott, sold the other two. Now I need to find a reputable guy to restore it mechanically. Cosmetics are real nice as is.

[Guest pirateflynn]

Well, I'd like to know what you think once you get it together.

[JohnnyB]

I am keeping the Scott, sold the other two. Now I need to find a reputable guy to restore it mechanically. Cosmetics are real nice as is.

I wonder if Mapleshade would perform the service, since they restore, upgrade, and sell vintage EL84-based Heath and Scott amps.

I have no experience with this outfit, but they have an appreciation for Scott amps. I'm sure if you google you'll find many American tube gear restoration specialists.