Winged C SVEL34

[lea_hc]

Hello everybody,
I must purchase 8 pairs of Winged C SVEL34. My choices on tube providers are tubeman ($40/pair) or tubedepot ($50/pair). As this tube providers do a thorough ranking of tubes, I wonder if $40 means less quality than $50 pairs.
Thanks in advance

[J Martin]

Write and ask them what the thier procedure is for burn in and matching.

[Gtr_tech]

Price has nothing to do with it. The old Svetlana or "winged C" or SED stuff is getting up there in price because production is either halted or severely crippled by the russian mob. Ask Mike Matthews of EH about that
Why not go with the JJ El34s? I've been using them for a while and they are a durable and good sounding tube.

[lea_hc]

Hi Gtr_tech,

About JJs EL34, I've read too many redplates issues. It seems
that just only the Eurotubes.com's ones are working fine.
As the reliability is a big matter for me to deal with, I'd prefer walking on a more sure way.

Kind regards

[lea_hc]

Hello J Martin,
I think that anything I would question them would be answered with unobjectionable arguments...

Regards!

[J Martin]

I have been using JJ's for years with no issues. And I have gone through hundreds and hundreds of them.

[Enzo]

lea, think of it this way:

if one store sells Fender strings for $5 a set, and another store sells Fender strings for $6 a set, do you think the $5 ones are of lesser quality?

[lea_hc]

Hi everybody!

Thanks a lot for your help.
J Martin, I have already been told about buying JJs. It seems to be the logic decision. I was just a bit afraid of bias stability, going through the redplate situation in a short term. But many other people have reported no problem anyway.
Enzo, I don't think that any store could rank a set of strings, but tubes are thoroughly tested and ranked before being sold.
Gtr and Enzo, do you agree with the JJs choice?

Have a nice weekend!
Lea

[Enzo]

I think JJs are fine tubes.


You are correct, no one ranks strings, but when sellers test their tubes and sort them. I don't see that much difference in the results. So my point was that when there is a $10 difference in the price of tested and rated tubes, I think one seller just made $10 more profit than the other.

[Amp Kat]

I'm not sure all tubes are tested first either. Many Distributors simply don't have time or personel to do it. Reliable issues for tubes are hit and miss and there are some out of box failures. IMO red plating is caused from bias and output section problems that were most likely caused from a shorted tube in the first place. I've had good success with all the JJ's but it is a good feeling knowing a place like Euro does test them and correctly match them.

[Enzo]

Well, any that are sold as matched had to have been tested to some extent.

[Mark Black]

So far (in my experience at least) it doesn't seem to matter who is selling, testing, or ranking tubes - you will still get dogs on a regular basis. No matter the brand (although some seem to be worse than others). I'm talking about the ones that show up after 8 or more hours of burn-in, where microphonics, internal shorts, poor emission, and poor match make themselves more evident (just when you thought the job was done). Or the supposedly-matched tube sets that reveal themselves as anything-BUT-matched at actual operating voltages right out of the box.

No one I know of tests or burns tubes in actual amplifiers at actual voltages for that kind of time before selling them as matched & burned. I guess if they did nobody would pay the price (maybe in audiophile-land).

Just for the sake of investigation sometime try a supposedly matched set of tubes burned in at say 60% max dissipation for 6 hours. Then double-check the match. Then reduce to 50%, and then increase to 70%, checking match at both extremes. Differences at extremes point to different "curves" in transconductance.

This of course is all aside from any discussion of whether tube mis-match is a good or bad thing - that's a whole 'nuther topic. These days I'm pretty happy when tubes don't red-plate or get noisy after a reasonable burn-in period and if they still match (within reason) at idle I'm ecstatic!

I wish it was better - I guess we should count ourselves lucky anybody bothers to make tubes at all anymore...

[Amp Kat]

That's part of my point Mark that some say they are matched and they really aren't and I know from one tube source that has told me they don't test tubes and the reasons why yet I see a marketing scheme on their logos as matched pairs and quads. Tubes in large batches made by the thousands are grouped in those batches and for the most part are most likely matched somewhat close but as Mark says sometimes they aren't and sometimes they are not even good. Unless you have a bias rite or do a shunt on both tubes or current sense on both tubes or sides with multiple setups, it can go unnoticed if they are somewhat close and it sounds good. As time goes by they will drift apart anyway and unless you have dual bias pots it's sometimes a moot point. For distortion players it could be a blessing in disguise if you get that right amount of asymetry without the hum.

[Gtr_tech]

That's part of my point Mark that some say they are matched and they really aren't and I know from one tube source that has told me they don't test tubes and the reasons why yet I see a marketing scheme on their logos as matched pairs and quads. Tubes in large batches made by the thousands are grouped in those batches and for the most part are most likely matched somewhat close but as Mark says sometimes they aren't and sometimes they are not even good. Unless you have a bias rite or do a shunt on both tubes or current sense on both tubes or sides with multiple setups, it can go unnoticed if they are somewhat close and it sounds good. As time goes by they will drift apart anyway and unless you have dual bias pots it's sometimes a moot point. For distortion players it could be a blessing in disguise if you get that right amount of asymetry without the hum.

An output transformer doesn't present a perfectly matched load to the output tubes, so dead nuts matching isn't needed. Close is close enough.

[Gtr_tech]

So far (in my experience at least) it doesn't seem to matter who is selling, testing, or ranking tubes - you will still get dogs on a regular basis. No matter the brand (although some seem to be worse than others). I'm talking about the ones that show up after 8 or more hours of burn-in, where microphonics, internal shorts, poor emission, and poor match make themselves more evident (just when you thought the job was done). Or the supposedly-matched tube sets that reveal themselves as anything-BUT-matched at actual operating voltages right out of the box.

No one I know of tests or burns tubes in actual amplifiers at actual voltages for that kind of time before selling them as matched & burned. I guess if they did nobody would pay the price (maybe in audiophile-land).

Lord Valve at NBS Electronics in Denver does. He was unsatisfied with the Maxi Matcher so he built his own testing/matching/torture equipment. He goes pretty far out of his way to know the score on pwr tubes before he offers them for sale.