single tube replacement advice - EAR 534 amp by Tim de Paravincini

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hyperhead

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This amp has been serving me well for years now, and I just love it.

One tube on the left side went dark a few months ago (the front tube in the attached photo). I replaced the dark tube with one from a set of 4 that I purchased from Antique Electronic Supply. With the new tube in place, when the amp was turned on, within 15 seconds I saw smoke coming from below the tube, which freaked me out! I cut the power and returned the faulty original tube.

Since then the amp still works pretty damn well, thankfully, with only a tiny bit of noise on the left when not playing music.

I ordered a new JJ Electronic E34 tube from Antique Electronic Supply (still in the box shown in the photo).

Do you think I should try it again with the new tube? Or does it require replacing all 4 on the left side with a bundled batch of JJs? I assume smoke is friggin catastrophic, but I'm not experienced with these so maybe not?

Dan Meinwald is the only experienced technician who did a maintenance service on this amp about 10 years ago, but he's not so available at the moment -- and maybe this is a really simple task. I'm gun-shy after seeing smoke!

Your thoughts & recommendations would be greatly appreciated.







FullRangeMan

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This amp has been serving me well for years now, and I just love it.

One tube on the left side went dark a few months ago (the front tube in the attached photo). I replaced the dark tube with one from a set of 4 that I purchased from Antique Electronic Supply. With the new tube in place, when the amp was turned on, within 15 seconds I saw smoke coming from below the tube, which freaked me out! I cut the power and returned the faulty original tube.

Since then the amp still works pretty damn well, thankfully, with only a tiny bit of noise on the left when not playing music.

I ordered a new JJ Electronic E34 tube from Antique Electronic Supply (still in the box shown in the photo).

Do you think I should try it again with the new tube? Or does it require replacing all 4 on the left side with a bundled batch of JJs? I assume smoke is friggin catastrophic, but I'm not experienced with these so maybe not?

Dan Meinwald is the only experienced technician who did a maintenance service on this amp about 10 years ago, but he's not so available at the moment -- and maybe this is a really simple task. I'm gun-shy after seeing smoke!

Your thoughts & recommendations would be greatly appreciated.


Do you think I should try it again with the new tube?
NO, after the smoke the amp was damaged.
Unplug from the wall and send it for repair.
Or does it require replacing all 4 on the left side with a bundled batch of JJs?
If the amp have individual Bias you can replace one tube.
If the amp have Bias in pairs of tubes you can replace tubes per pairs(matched pair).
I assume smoke is friggin catastrophic, but I'm not experienced with these so maybe not?
The smoke was a resistor or capacitor die out.

How is the Bias in this amp ?

hyperhead

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Do you think I should try it again with the new tube?
NO, after the smoke the amp was damaged.
Unplug from the wall and send it for repair.
Or does it require replacing all 4 on the left side with a bundled batch of JJs?
If the amp have individual Bias you can replace one tube.
If the amp have Bias in pairs of tubes you can replace tubes per pairs(matched pair).
I assume smoke is friggin catastrophic, but I'm not experienced with these so maybe not?
The smoke was a resistor or capacitor die out.

How is the Bias in this amp ?
Thanks FullRangeMan.... This amp is self-biasing.

FullRangeMan

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Thanks FullRangeMan.... This amp is self-biasing.
Nice, do the owner manual allow replace just one single tube at a time?

RPM123

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I would not mess with it, just send it in to a repair facility.

BTW - I used to own that amp and when I decided to try different tubes, Tim recommended KT77's. Check out the Gold Lion brand.

hyperhead

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I would not mess with it, just send it in to a repair facility.

BTW - I used to own that amp and when I decided to try different tubes, Tim recommended KT77's. Check out the Gold Lion brand.

Thx RPM123. You're right, of course. Why should I take any chances on a piece as great as this one--especially when I'm not feeling 100% confident to DIY it? I'm in Southern California. You wouldn't have any recommendations of repair shops around here would you? (Other than the great Dan Meinwald, that is.)  :)

As for KT77s... I'll start reading up on those. That's a heavy endorsement; from Tim himself.

Doublej

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I don't know of anyone by name. i would contact Upscale Audio and see if they have a recommendation.

FullRangeMan

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I think he is better served with the EL34 than the KT77 IMO,  would be Interesting know why they rec KT77.

jjss49

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el34 and kt77 are interchangeable

yes i agree with others, send the amp to a qualified technician for check out and repair before trying to put new tubes in to use

if the amp was smoking it has definitely sustained damage

if you are in socal, george meyer av in downtown los angeles is a very qualified repair shop, does factory repair for many top hifi brands

RPM123

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Thx RPM123. You're right, of course. Why should I take any chances on a piece as great as this one--especially when I'm not feeling 100% confident to DIY it? I'm in Southern California. You wouldn't have any recommendations of repair shops around here would you? (Other than the great Dan Meinwald, that is.)  :)

As for KT77s... I'll start reading up on those. That's a heavy endorsement; from Tim himself.

I'm in Northern CA, so I don't have any recommendations near your location. Doesn't EAR have a repair facility in Southern CA, other than Dan?

RPM123

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"The Gold Lion KT77 is a drop in replacement for an EL34 or 6CA7. The sound however is not typical of an EL34 or 6CA7. It is more of a hybrid. The tube delivers all the mid punch you would expect in an EL34 but also has a top end that is more open and bright. It’s definitely got a bit of a 6L6 designed into it".

EL34 / 6CA7 / KT77 Tube Reviews - www.thetubestore.com

RPM123

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Common Wave Hi-Fi is an EAR dealer in LA. I would contact them for advice.

hyperhead

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I don't know of anyone by name. i would contact Upscale Audio and see if they have a recommendation.

Thanks Doublej. I'm checking in with Upscale now.

hyperhead

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el34 and kt77 are interchangeable

yes i agree with others, send the amp to a qualified technician for check out and repair before trying to put new tubes in to use

if the amp was smoking it has definitely sustained damage

if you are in socal, george meyer av in downtown los angeles is a very qualified repair shop, does factory repair for many top hifi brands

Thanks jjss49... I'll check in with George Meyer too. Much appreciated.

hyperhead

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I'm in Northern CA, so I don't have any recommendations near your location. Doesn't EAR have a repair facility in Southern CA, other than Dan?
Hi RMP123... I misspoke earlier. Dan is the EAR dealer, but the service work was done by Mitch Singerman per Dan's recommendation. Mitch isn't as available now as he was then.

BTW, did you sell your EAR 534 about 15-20 years ago via audiogon? I may have your amp. I got it second-hand and it was from N. Cal.

RPM123

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Hi RMP123... I misspoke earlier. Dan is the EAR dealer, but the service work was done by Mitch Singerman per Dan's recommendation. Mitch isn't as available now as he was then.

BTW, did you sell your EAR 534 about 15-20 years ago via audiogon? I may have your amp. I got it second-hand and it was from N. Cal.

No. I traded it in for a Sugden FB-800 at Pitch Perfect Audio about two years ago.

hyperhead

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THANK YOU ALL for your input & advice.

Final result -- I had the amp serviced by a guy in San Diego who had been recommended to me by two reputable stores, and it's a good thing I did. There were fried cathode resistors (which caused the smoke). He put all new EL34 tubes in as mine were at about 55% (after 20 years!) & tightened tube sockets. Cleaned a tiny bit of oxidation, ran it through a battery of tests and everything is within specs now. With the amp back in my listening room now, it sounds as good as or better than I remember it before that one tube went out.

JakeJ

Excellent news!  Thanks for letting us know, too.

Tyson

Which EL34's were they?  55% strong after 20 years of use is pretty damn good.

hyperhead

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They were original to the amp (I assume) because the tubes had the Tim de Paravincini logo painted on them.