Perhaps a dumb question but can the amp run 6550s?
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Just because the tube fits the socket, doesn't mean the amp runs the tube.
Bias is set on the amp. Changing tubes doesn't change the bias. 50 to 90 is nothing in terms of harm, certainly nothing to cause such a show as this.
Clearly you have other problems. The lack of relevant details and providing irrelevant info being a bit of a clue as to the biggest one.
A 6550 tube is not a direct substitute for an EL34 tube.
Hopefully the amp was not damaged by installing the 6550 tubes in the amp.
El34 data sheet
6550 data sheet
I was just making a point nothing more
i have been using tubes for over 40 years
and owned a Audio store I know how to bias tubes. My point was a lot of eBay sellers don’t even check the tubes they just
go by what the mfg state I later checked
with a textronics tester 2 tubes were at over 100 most ma meters go to under 90.
that is why you buy tubes that should be within range under 70 ma for sure
6550-kt88 50-60ma is the norm
In the last 12 months, I've purchased around $1k worth of NOS tubes from sellers on Ebay. Zero problems. Years ago, when I had an amp that used 6C33 tubes, I purchased at least $500 worth from sellers in Russia and the Ukraine. Zero problems. I always purchased from sellers that had 100% positive feedback.
I have had 2 bad experiences on eBay. Not for tubes, but for other audio equipment. In one case, it was an Acrolink cable that never materialized after waiting 9 months. The other was on an amp that arrived broken (not from shipping) and had a very hard time getting a refund. Too many amateurs selling on eBay so now I avoid at all costs.
agree with Stereo5 on why would anybody buy tubes off of Ebay ?
if you knew your friend was going to get tubes, why not suggest getting them from a tube dealer that would have the tubes matched / tested ???
there was another thread recently about someone getting tubes from Ebay and they are all shocked that they were junk. duh.....
Saying that every tube seller on ebay is bad is a bit of a head scratcher. I bought two matched quads of KT120’s back in October from ebay for my Rogue Audio monoblocks and no issues whatsoever.
I just biased my amps today and the tubes in one amp had not drifted at all, and in the other amp, a couple of tubes were just a hair off. That particular seller has about 19000 transactions and 100% feedback. I would keep an eye on those numbers when considering making ANY purchase from ebay.
I’ve bought tubes from Brent Jessee and a couple have had had issues. That doesn’t make him a bad seller. He arranged to get me new ones pronto and was super helpful when I had questions about the best tubes for my gear, listening preferences, and budget. I recommend him highly.
I’ve also had issues with Sophia Electric tubes. Same thing, they got me new ones quickly and were easy to deal with. I’d also recommend them.
I don’t know how the other seller would have responded if I had problems, since I haven’t.
Exercise common sense and good judgment when buying from ebay, the same as you should when making any online purchase. Don’t lump all sellers into one bucket because of a couple of bad ones.
+1 Big_Greg. Very well said.
I've made a few tube purchases on eBay, with 100% perfect results as verified both sonically and on my Hickok tube tester. Of course the purchases were made after thoroughly checking out the seller's feedback/feedback left for others/other items for sale, etc., to get an idea of what kind of person I would be dealing with.
On the other hand, I've had issues with tubes purchased from both of the well known sources Big_Greg mentioned. Which ultimately were resolved reasonably well, although I'm not sure that would have happened if I didn't have a tube tester to help diagnose the problems.
I had problems with two NOS Mullard CV4003 tubes. One went microphonic after a week and the other after six weeks. I paid almost $100.00 each at the time. Lucky for me Kevin Deal backs up his tubes and I got replacements that lasted a long time. The ones I bought were Upscales highest grade. I guess any 40+ year old tube can have problems.
It’s hit or miss. Recently bought a nos Siemens 6922 off eBay. Got it and checked it out on my Hickok. Tested at 1500 which is really bad. It doesn’t sound bad after I compared it to a newer gold lion but I was disappointed. That tube was 100$. Tube selling is big money and many of these sellers don’t test them properly.
Call me confused.....
audioman58 OP said:
To all out there who have Vacuum tube Amplifiers .
audioman58 OP1,581 posts
KT150 tube datasheet
I've bought a lot of vacuum tubes from many EBay sellers. I guess I've been really lucky.
That being said, My favorite seller is LeedsRadio on Etsy. I can recommend them without hesitation.
Since I don't have any tube testing equipment, I'll just have to continue to rely on good luck and careful examination of buyer feedback.
A couple of years ago I bought a PS Audio BK preamp (the latest one) from a seller here on Audiogon. He replaced the stock tubes with two tubes he bought from The Tube Monger. The seller claimed that the preamp sounded MUCH better with the new tubes, He also provided the original factory tubes. The distortion coming out of the preamp was so bad I couldn't get an output to my computer to produce an undistorted wave file! I sent the tubes to PS Audio who checked them and told me to throw them out. I reinstalled the factory tubes and the preamp performed perfectly. I'd say that the seller was a "tube roller wannabe". If the preamp had tubes that PS Audio felt were excellent and reviewers agreed, why mess with perfection. Joe
I just looked over Canary's listing on their EL34,,,does anyone see where it says the EL34's can be swapped out?
The amp looks to me like a EL34 amp and no other tube allowed.
I just can not lay the blame on the tube quality.
I looked last night and couldn’t find one built by Canary that supported El34 as well as 6550 tubes either. Maybe the OP will chime in and post the model number and a Web Link.
Black Ice Audio makes a couple of amps where both EL34 and 6550 tubes can be used. The Fusion F-22 and the Fusion F-35
One thing for sure if the amp came with EL34 tubes and the owner pulled the EL34 and installed 6550 tubes he should have first cut back the bias pot setting before powering up the amp. If he did not, he probably caused damage to the 6550 tubes. Good thing the guy didn’t buy the 6550 tubes from UA. He could forget about getting a refund.
Here is a good video on the subject.
Direct tube substitutions.
I would never buy tubes off eBay. That was the first mistake.
I've bought all kinds of Valves from eBay. A good visual, and a way to check is the only way a valve goes in my units, ANYWAY. I don't care who sold it... It has to get to you somehow, THAT alone is a reason to check it.. Normally, no problem, but there is that 20 foot slide across the the UPS, FEDX, USPS, trailer floor, into the brake lining being transported on the same trailer.. That's also had lawnmowers, condoms, and laddies brasseres (some men too) all on the same cargo run...SQUASH comes to mind....I've had a bad one or two, all signal valves though no power valves...just cheap, burn out before you could blink an eye stuff, with power valves.. 6L6 stuff usually.. Solvex is pretty good for the most part..
I like um...I just don't trust um....
You know I though about what you did. That can't work their wired different, I don't think you can swap that valve. I'm not an EL34 guy.
Where's the bass?? But really, I don't think it's interchangeable.. Two different animals all together.. A guy told he could do it with VTL, from KT90, to EL34, with a flip of a switch, and of course a rebios (maybe he had some type of auto bios). My VTLs no switch, 6550, Kt88 or 90s no EL34 for sure..They are wired different...No plug and play....
Yeah EL34's seem not same league as 90/88's/6550's. Seems altogether dif design. Its like a minature 90.
I know there are quite a few audiogoners who havea negative bias on buying tubes from ebay sellers.
I've bought quitea few lately and have no issues.
Nearly all test as seller states.
The reputable dealers prices are out my budget, ebay offers a opportunity to purchase these fine NOS tubes. Test strong is OK with me. Sonics on a strong tube will be identical with a NOS.