The importance of matched EL34s?

[asd123asd234sdrf]

I recently bought a "matched pair" of vintage "NOS" UK Brimar EL34s off eBay for my Origin 20C. One died within an few hours of play time. It has much less getter flashing on it to begin with compared to the other one. I smelled some burning, and the tube is white on top now, and has no lit filaments. So I changed it out with the EH EL34s I was using before. Sounds-wise, everything is good with the "mismatched" pair.

Is there any reason or need to get another matched pair? Or just run them as is? I would like to get another NOS tube, as they did sound noticeably better than the pair of EHs, but I'm not certain that I need to give a crap about them being matched.

Thanks!

 

[anitoli]

Tube amps being tube amps nothing will ever be perfect, But a slight mismatch isn't anything to really worry about. If the tubes are too far apart you will notice an increase in hum. Just curious what did those NOS tubes cost you? Was it worth it to have one immediately fail?

 

[Matthews Guitars]

A perfect match keeps even order harmonic distortion to a minimum. The point of matching is to reduce distortion.

But you might LIKE a little bit of output stage grind from a slightly mismatched pair.

On the flip side, a perfectly matched and balanced output stage will generate odd order distortion when pushed to overdrive, and that's not a sweet sound.

 

[Dogs of Doom]

you can balance them w/ bias, but... then they will be running at different volts/amperes. The one that is lower will be running at the same output spec, as the other, but will be getting more throttle from the amp, causing the tubes to wear at different paces, furthering the distance in performance between the 2...

if you are pushing 30% more juice through one tube, it will wear faster at that rate, even though it is putting out the same...

 

[PelliX]

It has much less getter flashing on it to begin with compared to the other one.

It's a common misconception that the size or appearance of the getter flash has anything to do with the quality, tone or life expectancy of a valve. As you unfortunately noticed, if it turns milky that means the seal on the valve has breached. That's the only practical thing to judge optically when evaluating a valve.

Is there any reason or need to get another matched pair? Or just run them as is? I would like to get another NOS tube, as they did sound noticeably better than the pair of EHs, but I'm not certain that I need to give a crap about them being matched.

No, as anitoli pointed out a mismatch will simply result in hum and similar issues. You may even get a wonderful one-of-a-kind tone by mismatching - unlikely but not impossible. These are cathode biased amps, meaning you don't need to consider setting the bias individually or compromising as you might have a single bias control for a pair of (differing) valves. Plug 'n' play.

 

[asd123asd234sdrf]

Just curious what did those NOS tubes cost you? Was it worth it to have one immediately fail?

$100, so not terrible to have one fail. If I'd paid what some Mullards go for, I'd be pissed...

Looks like I'll just say screw it and put whatever tubes I want in. A little hum is fine, as I don't play out.

Thanks for the input everyone!

 

[Matthews Guitars]

Let me ask here, because this topic is active....how would any of you rate NOS Magnoval tubes from the late 80s?

Here's just a sample of a deal I'm working on....

There is a vastly larger number of 6L6 and 6550 types in the inventory than EL34s, but there are some ELs, anyway....


How do these rate?

 

[Dogs of Doom]

probably pretty good...

some people like to talk smack about Ei, but I have a pair of '80s 12AX7 that are pretty good.

 

[Spanngitter]

EI EL34 are equal to Siemens EL34 as Siemens sold the machinery they used to EI.
However, the quality twindled down over time and a lot of faulty EL34 have been produced the last year(s) before EI in Nis shut down due to the war...
AFAIK some of the machinery has been rescued by the UK Valve Project and is undergoing restauration and hopefully reuse again...

 

[StingRay85]

The Ei EL34 is completely different than the Siemens EL34 (RFT). Siemens never produced a EL34. Its either relabeled Mullard or relabeled RFT

 

[paul-e-mann]

$100, so not terrible to have one fail. If I'd paid what some Mullards go for, I'd be pissed...

Looks like I'll just say screw it and put whatever tubes I want in. A little hum is fine, as I don't play out.

Thanks for the input everyone!

Yeah dont worry too much about matching, I'm running some ugly tubes in my 1959 and it sounds fine.

 

[anitoli]

In the ballpark if adequate. I mean look at the tolerances of most of the parts in a tube power amp.......... anywhere from 5% to 20%. It doesn't appear to me that the manufacturers are too concerned with pin point accuracy.