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EL 34 question

I have a VAC PA 35.35 EL 34 push-pull amp, that has had factory upgrades. I was quite happy with it, until I started using a modified SET 300B amp, which has blown the VAC completely out of the water.

I am actually giving thought to selling it, but decided to see if tube rolling might bring it closer in performance to the SET amp.

I have two sets of output tubes that are used, a matched quad of reissue Genelex KT 77, and a matched quad of reissued Mullard EL 34's.

The small tubes are NOS Telefunken 12AU7 and 12AT7, all aound three years in use.

I'm just hoping I can get some insight as to whether better performance can be gleaned from this old amp.

My experience with tubes is recent, lots I don't know, so any old salts that care to help with suggestions would be great.

By the way, the speakers are 94db sensitive custom Tannoy HPD's.

Best regards,
Dan
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islandmandan OP
1,260 posts
 
Thanks guys, for your responses. I have been more than mildly surprised by the improvement wrought by the modest Assemblge SET 300B, however, it does have fresh factory upgrades w/new carbon film reisitors, Jupitor foil and paper beeswax capacitors, and it just seems to keep getting better and better.

I won't give up on the VAC yet though, until I do a bit more tube rolling. It's still a very good amp, with high current output. I'll see how it goes.

Thanks again,
Dan
justlisten's avatar
justlisten
489 posts
 
Hello Dan

Derrick here, I purchased your Plinius. I was a strong EL-34 guy , until I tried the Plinius.

How many El34s do your VACs use?

I have some Fat Boys and you are welcome to try them out if you'd like.

Shoot me a message if interested
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logenn
91 posts
 
I use two different el 34 based amps and depending on the rest of the system if you use real Mullard XF 2 dual halo el 34's, not the reissues, you will get a huge performance boost in areas of midrange depth and image density or riichness. Also with the right input tubes- long plate square halo Mullards from the 1950's-your bass impact and neutrality will also improve markedly. What you will not get is the liquid immediacy of a 300b but again this also comes at a price. To put it another way, if you voice the system around an el 34, much gains are possible with tubes, cables and pc cords , and cartridges, etc
With the 300 b, you have an entirely different blueprint that requires in most cases a different compliment of accessories.
If the set 300 b has enough power it may be the ideal path.
ryriken's avatar
ryriken
164 posts
 
6ca7 Fatboys are very expensive, take alook at e-bay and you will see.
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islandmandan OP
1,260 posts
 
I've got a line on some 6ca7 Fatboys, I'm going to give them a try.

There's no question, the SET 300B is my go-to amp (system sounds its best in forty five years of trying).

I like having an alternative to turn to, for variation, and for back-up. The VAC is a very different beast (about 80lbs; mostly in iron), and has some advantahes for highly dynamic music.

Thanks to all for your contributions. Regards,
Dan
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