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Audio Research CA50 + tube rolling

I recently purchased an ARC CA50 which I like a lot. It betters the Cary SLI-80 sig IMO but that's beside the point.
My question is about tube rolling. Has anyone tried rolling either power or driver tubes in the CA50 and what were the results ?

The only info on the net regarding this is somewhat paranoid thread on diyAudio advising against this and suggesting that ARC designed this amp around Sovtek/EH 6922s
Personally I don't buy it.

I contacted ARC and spoke to some bland dude who I don't think even knew what the CA50 was.
He blurted out something about adjusting the voltage on the side panels of the amp if I want to change the driver tubes.

Anyway, your thoughts, suggestions, advice and experience (good or bad) with tube rolling in this amp will be greatly appreciated.

Thanks in advance to all replies.
akanrg
akanrg OP
15 posts
 
p.s. is there anyone out there who actually owns the CA50 and tried tube rolling with it ?
rodman99999
6,032 posts
 
7308/6922/6H23/E88CC/CV2492/E188CC are all just 6DJ8 variants, and direct replacements. No voltage adjustment should be necessary. Any paired tubes in any circuit should be balanced/matched, triode to triode and to one another in the case of his 6922's. Any responsible tube seller would have seen to that(like Kevin at Upscale), if the application was mentioned.
testpilot
896 posts
 
I had a CA50 and the ONLY thing that I really disliked about it was the fact that the voltage needed to be changed/adjusted whenever your swapped out the driver tubes. I would call AR back and ask to speak to someone more seasoned, they will be able confirm the procedure. Yes, you can just drop in new tubes w/o adjusting the voltage but it will not be optimized plus it will shorten the tube's life. The CA50 is not a friendly tube roller's amp. Also, AR uses the Sovtek because the circuit is tough on tubes and the Sovtek have a reputation for being rugged. I tried using NOS tubes but the amp ate them within 6 months (I never adjusted the voltage) and I did nit want to send the amp back to AR as they requested.
akanrg OP
15 posts
 
Testpilot, which NOS tubes did you try ?
testpilot
896 posts
 
I used 4 different tube sets.

Favorite - Amperex 7308 white label. Caveat, the amp eats up these tubes. I went through two sets in 8 months...no more.

Ediswan CV5358 - I liked these tube a lot. These tubes gave the amp some added jump. The highs are a tad rolled off, but that was okay since I was using the amp with CD only.

Valvo 6922 - nothing special in this amp. Did everything okay and they were durable.

Amperex Bugle Boy 6DJ8 - I settled on these tube because the amp and tubes got along. A touch of the magic of the Amperex 7308 and gave the amp some needed dynamics with a nice bottom end.

If you really like to roll tubes, these is not the best amp, but it is a keeper. I wish it wasn't so big, otherwise, I would have kept it for a second system.
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