Vacuum tube ! And Warnings

Perhaps a dumb question but can the amp run 6550s?

what model amp is it?

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.

Prudent step one, before inserting new tubes(when possible): turn the bias to zero.     That's after one has ascertained amp/tube compatibility.

The amp in question can take el34- kt 150s

It is a custom canary amp

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

I would never buy tubes off eBay. That was the first mistake.  

I tend to disagree as there are some long term excellent dealers on eBay. The trick is finding them, that’s all. I bought a whole bunch of tubes on eBay about 6-8 years ago , everything from Chrome Domes to Badboys to WWII Tung Sols, always had great results. 

stereo5
"I would never buy tubes off eBay. That was the first mistake."

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.....

“Not for tubes.” There it is! 🤗

my friend bought them ,and told me after he had them in his possession.
i told him ,he is sending them back 
pronto tommorow ,it was a very valuable lesson learned and luckily no damage .

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.

I am baffled here you put tubes in an amp that can't use 6550s? You said EL34-KT150 does that include 6550s? If not its not the fault of the tubes wherever they came from it's user error.

Some Quicksilver amps can use a number of tubes.... the bias pot has enough range but like rodman said turn the bias completely counter clockwise first then slowly up to bias spec.   My QS can use EL34, 6L6, 6550, Kt66, KT77, KT88, and some others.   

hello Jond  the amp can take anything from El-34,  KT-88-6550 kt120,kt150s

+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.

Regards,
-- Al
 

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. 

03-08-2020 6:14pm
hello Jond the amp can take anything from El-34, KT-88-6550 kt120,kt150s

Is this the same amp you are selling here?

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. 

Every few months there is a thread titled "Where Do Buy Tubes" or "Good Tube Vendors".  Good Reading.

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.

I've had great luck from Ebay tube sellers, including one guy in the next town who delivered the tubes himself to my mailbox...twice...

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

Plus for Brent Jesse.

I bought, didn't like the sound of a brand I had selected, he allowed me to burn them in, then decide, then return them, sent me my alternate choice (I know I like their sound, had some in stock), which cost less, and refunded the difference to me.

A true gentleman.

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.
https://www.canaryaudio.com/M70.html

I just can not lay the blame on the tube quality.

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....

Regards

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....

Regards..

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. 

eBay is a marketplace, a good one, with information about sellers and feedback. Bad sellers don’t last long there. Sellers selling tubes are like any other sellers, they are subject to the discipline and the systems in that marketplace.

Buying tubes in a marketplace like eBay requires knowledge of what you are buying and what types of risk it entails. It requires understanding how tubes are tested and how they may fail and what happens to the equipment if a failure occurs. For example a power tube failure in a high power tube amp can damage the amp, whereas a noisy or bad small signal tube will just give you some noise in your buffer or preamp.   It is also important to understand the limits of tube testing and how it is imperfect it can be in terms of determining the health and proper operation of the tube under real load.  Furthermore, we are dealing with fragile miniature glass devices here, some 50 years old with microscopic metal wound wires, then being shipped through postal or courier services.  Sometimes issues will arise even if the sellers are honest and conscientious.

Bad sh*t happens when newbies don’t take time to learn and understand in depth what they are dealing with with vacuum tubes and try to buy tubes off eBay to save a few bucks and get burned, figuratively and literally.

I have bought thousands of dollars of tubes, old stock and new stuff, from eBay and my problem rate is very very low.

I've recently learned of low microphonics and testing.  Does anyone have experience buying matched tubes that also have low microphonics?

I've bought many "tested" tubes over the years from Ebay and elsewhere, and none of them have been microphonic. Most tubes were bought from sellers with return policies.

Would never buy tubes on ebay as they sell garbage tubes.

Bought hundreds of tubes on Ebay without any issues. I can imagine the dude's face when it went bang though. 

I know this is an old post but you sound like you have no idea what you are talking about.  How do you know the amplifier itself didn't have any problems?  Sounds from the description you gave that you destroyed the tubes with a bad amplifier and then blamed the seller and returned them.  I am an eBay retailer and I run my tubes through a battery of testing, including a custom curve tracer, with all relevant data points.  I'm kind of tired of people crapping on eBay retailers like all of us are scumbags or something, and the only good retailers are the two or three everybody always mentions.   I'm not going to advertise my business in this thread, because that is not why I'm here.  I have a large presence on eBay operating out of central Florida, that's all I'll say.