Just how important are "matched" tubes?

rklein · « **on:** 17 Dec 2010, 08:20 pm »

I am currently running a Nightshade Audio NS60-SE tubed amp with a matched quad of Genelex Gold Lion KT-88's. I would really like to try some Black Treasure KT-88's but with all of my recent audio purchases: my new amp, new Nightshade Audio Beacon III tubed pre, Jasmine 2.0 phono stage... I am trying to get off somewhat cheaper on my tube purchases.

Fellow AC member, Gopher has mentioned he has bought tubes from the following website:

www.goodcomponent.com

They have Shuguang Treasure KT-88's for $150/pair packed in a "luxury box" and $110/pair packed in a black paper box. Now this is significantly less expensive than say Grant Fidelity. However, Grant Fidelity will test and match up a quad of KT-88's(grade A) for $480 and factory matched(grade B) for $325. Even the grade B KT-88's are $105 more that the "black paper box" KT-88's.

I am also looking for 6SN7's as well. I need three in my pre and three in my amp. I am looking at the Create Audio tubes at $80 a pop. Grant Fidelity has the Black Treasure CV181-Z's for $270/$200 per pair, depending on grade A/B. However, goodcomponent has them for $170/$110 per pair depending on how they are packed.

This thread is not intended to pit vendors against each other, but for me to ascertain how much stock to put into matched quads, matched pairs, matched by the vendor as opposed to matched by the factory, etc.

Let's face it. Shuguang Treasure Grade A tubes for what I am looking at will cost a total of $1,290 as opposed to the same tubes which are black paper boxed for $550.

Any insight on this subject would be very much appreciated.

Randy

turkey · « **Reply #1 on:** 17 Dec 2010, 08:34 pm »

Quote from: rklein on 17 Dec 2010, 08:20 pm

This thread is not intended to pit vendors against each other, but for me to ascertain how much stock to put into matched quads, matched pairs, matched by the vendor as opposed to matched by the factory, etc.

Most amps benefit from matched output tubes, or even other tubes depending upon the design. There are also amps where it's less critical.

Blair is probably the one that can give you the best answer on this topic.

FullRangeMan · « **Reply #2 on:** 17 Dec 2010, 09:43 pm »

Hello, My two cents are:
150 Obamas are a lot of money for any popular tube as 6550 or KT family. Fender Music pay less than one dollar for the small pre tubes(made in China).
If your amp have individual Bias for each power tube, matched tubes are not obligatory, unless Niteshade say otherwise.

I do not believe on tubebrokers tests, but I hear about VintageTubeServices and Upscale Audio do some test, I suspect these test are for short-circuit only(capacitance or mega-ohms resistance).
I wonder what a tubebroker will do with a less powerful tube, say 70 per cent of the regular emission??

At a forum in my country VTS are famous for great sound tubes in all tubes of the lot ordered, UpscaleAudio no even ship to Brazil.
Others tube brokers send us 1 or 2 tubes with problems of noise etc in a order of 4 or more tubes.
Seems you are a USA resident, in this case Iam sure you will be better served than us overseas buyers.
Regards, Gustavo

>Never go to a psychiatrist, adopt a cat or dog from the street. On the streets pets live only two years average.

Ericus Rex · « **Reply #3 on:** 17 Dec 2010, 10:01 pm »

Hi Randy,

I'm sure Grant's testing is better than Shuguang's since they use a state of the art Amplitrex. But the factory matching is probably good enough for most applications. You just have to decide whether or not it is worth it to you to have them matched to this degree.

As for matching, if the tubes are individually biased on your amp you don't need to use matched tubes. You may get a slight gain difference between the tubes if they aren't matched but I doubt you'd notice it. If your amp biases the pair of tubes (and not individual tubes) then you MUST use matched pairs. The danger of not using matched tubes with this amp design is that one tube will handle more current than the other and get much hotter than the other, resulting in inevitable failure, which could take out amp components.

Wayner · « **Reply #4 on:** 17 Dec 2010, 10:15 pm »

I personally think that tube failure usually happens at 2 extremes of time, either right away or not for a long, long time. If it's not for a long time, then replace the pair. if it's a short timer, then the tube probably was a defect. I'd take my chances on replacing just the one, but it would be nice to have a tube tester to see how far apart a pair might be. Good tube manufacturers have a tighter tolerance.

Wayner

Gopher · « **Reply #5 on:** 19 Dec 2010, 03:15 am »

I won't chime in on the issue of whether to support domestic distributors or buy direct from China for a discount or even the quality of matching, but I want to add a side note consideration.

If you resolve to purchase from Goodcomponent, skip the 'luxury box' I bought a pair of Red Label 845Bs from them (which shipped Friday and arrived Monday from China) and they came with the 'black paper box' It was very well packaged and the normal attractive factory box which is hard cardboard and custom foam inserts.

I also just took delivery of a Pavane tube which was actually purchased through Grant. The box about the same quality but red and the foam insert isn't quite as custom (the 12au7-t slides around inside). I wouldn't pay $1 more for this style of box--it was no safer for transit and is kind of a joke IMO.

I don't know what the black treasure boxes look like, but comparing standard Shuguang power tube boxing with Luxury/Reference series Shuguang Pavane boxing it is a no-brainer to me. Save the dough!

Edit: I'm going to go ahead and comment on what I said I wouldn't. You can request matched tubes from Goodcomponent--I don't know what they use for matching, but there are other kids on the block capable of matching tubes close enough the equipment failure won't be an issue. It's also worthy of noting the appart from Treasure tubes, Shuguang has a Treasure series of amplifiers built around these tubes to showcase their capabilities (I'm personally using a pair of their S845 monoblocks). Whatever their factory matching process/equipment is has them comfortable enough to use their matched pairs in their own reference line of equipment where there are no external factors to blame for a less then perfect showing.

TONEPUB · « **Reply #6 on:** 19 Dec 2010, 03:29 am »

Wayner is pretty much on the money. Most of the guys I know at CJ and ARC have told me that tubes will usually blow at turn on, 100 or 1000 hours typically.

I've always been under the impression that matched power tubes are only necessary if you can't set bias individually. Getting signal tubes matched in a preamp will definitely help channel balance and testing for noise is a must, especially in a phono stage.

Both Vintage Tube Services and Upscale do fairly extensive testing to match gain and test for noise. I've dealt with both and have received tubes that were much better than buying off the shelf. I would highly suggest either and recently have had excellent luck with Grant fidelity as well.

Sure the mfrs buy the tubes in bulk, but they do the same thing that the best brokers do. When I visited ARC recently, they had a complete area of the shop dedicated to tube testing, matching and burn in.

rollo · « **Reply #7 on:** 19 Dec 2010, 04:40 pm »

For a phono section or preamp a must IMO.

charles

bunky · « **Reply #8 on:** 19 Dec 2010, 04:49 pm »

Quote from: TONEPUB on 19 Dec 2010, 03:29 am

Wayner is pretty much on the money. Most of the guys I know at CJ and ARC have told me that tubes will usually blow at turn on, 100 or 1000 hours typically.

I've always been under the impression that matched power tubes are only necessary if you can't set bias individually. Getting signal tubes matched in a preamp will definitely help channel balance and testing for noise is a must, especially in a phono stage.

Both Vintage Tube Services and Upscale do fairly extensive testing to match gain and test for noise. I've dealt with both and have received tubes that were much better than buying off the shelf. I would highly suggest either and recently have had excellent luck with Grant fidelity as well.

Sure the mfrs buy the tubes in bulk, but they do the same thing that the best brokers do. When I visited ARC recently, they had a complete area of the shop dedicated to tube testing, matching and burn in.

Manley labs has the same thing. I have never had a problem with factory matched power tubes but i believe you should make sure that preamp tubes are well matched. I bought a matched pair of Black Treasure CV181-Z 6SN7's for $124.00 with free shipping from Hanshare Electronics in Hong Kong and they are perfect and sound superb in my Purity Audio Basis linestage. I have a matched Quad of Black Treasure KT66-Z for in route from Hong Kong for $224.00 and free shipping and i dont expect any problems with these tubes either. i will continue to do business with Hanshare unless they give me a reason not to. the high price of these tubes in North America prohibits many folks who could benefit from using these tubes from even considering them as a option....WCW III

Gopher · « **Reply #9 on:** 19 Dec 2010, 05:57 pm »

Sounds like that site may actually be a little cheaper than goodcomponent. The prices look slightly higher, but shipping runs $30+ from goodcomponent. How does Hanshare ship? I really liked the international DHL service.

Rachel @ Grant Fidelity · « **Reply #10 on:** 19 Dec 2010, 06:58 pm »

We got the same question about how important it is to get matched tubes or not all the time, so here is our take on this matter based on our experience:

First, you need to get good tubes then considering matching them. No point to match bad tubes to bad tubes

1. Good tubes or bad tubes are not just about matching. It is also about the 5 parameters: emission strength (in mA), transconductance (in mA/V), heater to cathode leakage, internal gas and micro-phonics. These parameters are ideally to be tested at real working voltage - that's what the Amplitrex AT-1000 tester does.

2. If a single tube does not pass the test of the above 5 parameters, it will only be matched the the same crap IMO. Then what's the fuss about matching, if they are equally bad?

3. For Treasure tubes packed in black paper box or luxury box, the tubes inside the package have been pre-selected by factory based on emission strength tested at factory only - this difference is not visible to end users unless you have sophisticated equipment to verify it. I don't believe human ears can tell the difference of a weaker tube or a stronger tube, unless the weaker tube is at the end of its life causing serious distortion. But certainly a weaker tube will not last long, and only time will tell. When you get a new tube from a seller without seeing the real test results of the emission strength, all you can do is to hope the tube last long. This wish does not seem work out well with Chinese tubes by reading the past history of Chinese tube quality.

4. For Shuguang's own line of Treasure amps, we receive tubes with paper box packaging (for fitting inside the amp package so no luxury gift box is used) but graded by factory as 'Premium'. We all want to believe that tubes installed in factory's own amp should be good, but to my astonishment, a pair of 300B-Z shipped with the amp is tested by us on Amplitrex as 35mA while factory rating is 49mA (just above our minimum requirement of 48mA in our order). This 35mA is at 58% of full emission for a 300B tube and it is NOT acceptable to be put in an amp at all. IMO, these tubes shouldn't have left the factory door, but tubes with such a low measurement are claiming for hundreds of dollars online everywhere online. You decide if you want your hundreds of dollars spend on these tubes.

5. Many KT88-Z tubes from factory as 'Premium' grade is tested at about 100-120mA. These are at 71-86% of full emission strength. We consider them as clearance B-stock and that's why you see the price difference to Grade A tubes. They sound fine in an amp (we use in our showroom equipment sometimes) but they won't last as long as a tube with full emission or close to full emission. Tube ages with emission getting weaker and weaker, eventually they won't be biased to fit your circuit. Do you want to short life tube or long lasting strong tubes? Do you want your tube amp circuit has a part working in more than 20-30% deviation from design or not? Again, these measurements are not visible to end users unless you have the right equipment to verify it.

6. Many 6CA7-Z tubes from factory as 'premium' grade is tested at 70-90mA, few ones are close to 100mA full emission. This is 70-90% of full emission. Again it is your choice to get stronger long lasting tube or not.

7. About 25% Premium grade Treasure KT88 and EL34 tubes we receive from factory has minor heater-to-cathode leakage. Some can be eliminated through a further burn-in process, some won't. Those won't be eliminated will cause the tube fail soon. This is not visible to end users - not even to most vintage tube testers. But Amplitrex AT1000 does the test. Again, it's your choice to get a good tube with no internal leakage, or get one that will fail soon.

8. Internal gas - very gassy tube can be visible under the right light but Treasure tubes with black coating makes this more difficult to be detectable. The Amplitrex tester tests gas and any tube with internal gas more than 10% emission will go to garbage bin by our standard. Excessive gas will basically make the tube go on a suicide mode eventually short itself. If you cannot see it or hear the difference of a gassy tube (I don't think many can), it's your choice to gamble on a tube from factory without such a test done.

9. A vendor should not sell a tube more expensive simply because it has a better looking box - it's what you don't see with your eyes matters for a tube. The nice box is just icing on the cake - and it does help with protecting the tubes against rough handling, especially when shipping in large quantity. Gopher says the Pavane tube box is useless - in a way it is, but when you ship hundreds of them the box will protect each pair not to crashing with others. The foam insert is loose for 12AX/T/U7 tubes because they were cut all in one size and they have to fit the taller EL84's.

10. Everyone has their priority in terms of purchase - not everyone needs long lasting tubes if you just want to try out something new for some time then move on. When you order online, keep the above in mind when making your payment. In general, the price reflects on quality. Shuguang isn't dumb - they came up with Treasure tubes with price way way above their generic tubes, they do know good tubes claim high dollars. If a deal online sound too good compared to others, think about what you cannot see might be the reason causing the low price.

From the thousands of Treasure tubes I have personally tested for sale, the factory test results are all over the place, 10-15% of tubes should go straight to garbage bin and 40-50% no where near to be accurately tested. To properly screen and grade the tubes, the price has to be different on different quality grade.

I have had customer who ordered $4000 amp from a top brand but ask me whether he should get the B-stock tube or factory matched tube to save $100 or so, my answer is no. Your amp maker probably has put more efforts in matching the resistors and capacitors, why would you put in tubes to gamble on the quality and your odds are less than 50%?

If you have a so-so quality amp and don't mind to roll the dice with the factory tested tubes, order online from Chinese sellers will indeed save you money to get in the game. But no one knows how long your new tubes can keep you stay in the game. Return / replacement cost to China is not cheap either.

Bottom line is - not all tubes are created equal. If someones tell you the tubes out of the factory are all the same, your common sense will tell you it's simply not true. If a vendor can lie on this basic fact, what else cannot they disguise / twist / manipulate to get you open your wallet? I recall my trips to China (as a Chinese born and raised there) - every purchase is a battle of wisdom and you better have your wallet held tight

It's fun, exciting but sometimes frustrating. Well, that's another topic for another thread.

What you don't see or hear right away does matter in terms of tube purchase, especially the expensive ones. It's all about how much you are willing to pay to get the best you can. I hope everyone gets what their money's worth and happy tube shopping.

Happy tube rolling.

Best,
Rachel

JLM · « **Reply #11 on:** 19 Dec 2010, 07:46 pm »

Wow, impressive (all the way around) reply Rachel.

mjosef · « **Reply #12 on:** 19 Dec 2010, 09:24 pm »

Quote from: JLM on 19 Dec 2010, 07:46 pm

Wow, impressive (all the way around) reply Rachel.

~~A perfect blend of embedded company ad.~~

Edited, no longer relevant.

Gopher · « **Reply #13 on:** 19 Dec 2010, 09:59 pm »

Quote from: Rachel @ Grant Fidelity on 19 Dec 2010, 06:58 pm

9. Grant Fidelity do not sell a tube more expensive simply because it has a better looking box - it's what you don't see with your eyes matters for a tube. The box is just icing on the cake - and it does help with protecting the tubes against rough handling, especially when shipping in large quantity. Gopher says the Pavane tube box is useless - in a way it is, but when you ship hundreds of them the box will protect each pair not to crashing with others. The foam insert is loose for 12AX/T/U7 tubes because they were cut all in one size and they have to fit the taller EL84's.

Actually, my specific point is not only that its useless, but that it is a one size fits all solution. In my limited experience, the standard box and foam inserts were SPECIFICALLY CRAFTED to the tubes they were housing while the Pavane boxes, as you concede, are used for more than just 12a*7 variant tubes. Therefore, in my limited experience, the Pavane boxes aren't just useless, they're actually LESS secure than the standard box.

That said, I respect the rest of your post and it is quite apparent that your matching process far exceeds most. We are engaged in a perfectionist hobby, and your perfectionist matching is definitely appropriate and you deserve to charge a premium for going above and beyond.

I've only ever used one pair of preamp tubes until they sounded appreciably worse than when new, but that is because I change gear more than most. For most sensible people who have and keep equipment, the saved hassle of your process is probably worth it.

Wind Chaser · « **Reply #14 on:** 19 Dec 2010, 11:15 pm »

Quote from: Rachel @ Grant Fidelity on 19 Dec 2010, 06:58 pm

We got the same question about how important it is to get matched tubes or not all the time, so here is our take on this matter...

Wow, brilliant post.

How many people even begin to consider just half of that?

pjchappy · « **Reply #15 on:** 20 Dec 2010, 04:39 pm »

Post away.

Paul

carusoracer · « **Reply #16 on:** 20 Dec 2010, 05:15 pm »

Great response from Grant Fidelity, very well said.

PreAmp tubes that can not be individually biased are nice to have in pairs as mentioned above.

I for one enjoy the Treasure Series power tubes and wish you the best of luck from whomever you purchase from. They are very good.

rajacat · « **Reply #17 on:** 20 Dec 2010, 05:32 pm »

Quote from: zmanastronomy on 20 Dec 2010, 05:21 pm

I purchased a BT CV181-Z from ebay to save a buck. The sound was thin and the image was blurred.

I bought the same tube in grade B from Grant Fidelity and the differance was night and day. Much more solidity and fullness. Imaging was very focused.

I don't know what the differance is, but I've learned from my mistakes. John

Which ebay seller did you buy from?

rollo · « **Reply #18 on:** 20 Dec 2010, 06:27 pm »

Quote from: Wind Chaser on 19 Dec 2010, 11:15 pm

Wow, brilliant post. How many people even begin to consider just half of that?

Since you asked. Upscale and Vintage Tube Service for starters. Any tube vendor worth its weight properly tests tubes before a sale. Saying that it is good to know the extent at which Grant conducts its tube sales. They should be commended. [ yes I said that] .
My only issue with new tubes is the warranty. IMO 30 days from purchase is an issue. You loose time in shipping and if the tubes are that reliable then why not a one year warranty ? Shipping is the biggest issue IMO, NOT the tube. I believe a warranty card should be provided and filled out by the purchaser. When received by vendor the warranty begins.

Now after some issues with tubes I recind my "Buyer Beware " comment about Grant Fidelity. In retrospect it was the tube that failed. It failed within 15 days not grants fault. Full Musics responsibilty which they failed at. I should have purchased the one year extended warranty, oh well live and learn.

charles

rklein · « **Reply #19 on:** 20 Dec 2010, 08:06 pm »

I too have purchased tubes from Andy at Vintage Tube Services. I bought two NOS Sylvania 6SN7's made in the 50's. I remember him telling me the extent on how he tests his tubes. I believe this to be pretty important when buying NOS tubes made back in the 40's, 50's & 60's.

My Nightshade Audio NS-60 SE allows me to use KT-88's, KT-66's, 6L6's, 6550's or EL-34 driver tubes. In talking with other people, one thought is that trying different families of tubes would impact the sound more than buying KT-88's again. However, there are many people on AC and also friends that have already travelled this road and highly recommend the Black Treasures.

While I appreciate Grant Fidelity's in-depth explanation, and may very purchase items from them, I also believe that other vendors who have in some cases 100% positive feedback on different selling sites, would not be able to maintain these ratings if they were making a practice of selling inferior tubes.

I certainly appreciate everyone's responses and will do more due diligence before making my decision.

Thanks,

Randy