Did Leo ship Fenders with matched output tubes? I bet not...

[premiumplus]

And, although the tubes at the time were held to a much higher qc standard than today's Chinese / Russian crap tubes, I bet they were not within 2 mA of each other.
So I have a challenge for you all. Do you have an outstanding sounding amp that you are willing to pull the tubes from and check with your bias-rite or whatever methodology you prefer, and test to see how closely matched they are? Not how they WERE when purchased, but how they are NOW. It should be interesting to see.
Now just to show that I'm not completely lazy, here is my first one:
A RI 59 Bassman, sounds stellar, 5881's running at 43.7mA, and 39.2mA. 4 1/2 mA difference! I was careful to match them when I put them in but they have drifted. And I didn't hear any difference in sound.
My point is this: Is it truth or hype about matched output tubes? And while we're at it, what about matching the gm or mho of PI tubes? I think we may see that a little crossover distortion is a good thing in a tube amp!
Come on, I showed you mine...what do YOUR amp's tubes idle at?

[Fuzzer]

I mismatch my amp's tubes by 3-4 [mA] on purpose (just like how it sounds when reach the 2 [mA] difference 'threshold'), but there begins another problem, the hum.
According to what you observed, they should be now like 8 [mA] away from each other.
The amp is a Vibrolux Reverb, pretty strange 80's model with a black panel but doesn't say '-Amp' like original blackfaces; anyway, it works really well for me.

[soulsonic]

I hardly ever bother matching when I retube my low-powered cathode biased amps - it doesn't seem to ever matter. With bigger amps, I like to get matched sets mostly because I hate it when I get the bias of one tube into a good range, but then the other one is way too hot; I've had that happen a bunch of times with mismatched sets. I think being off a few mA is no big deal, and I agree that it likely isn't going to hurt the sound - BUT, putting in random tubes can result in sets that are so grossly mismatched, you would need individual bias pots on each tube to even be able to keep half the set from redplating while the other half was stone cold. Other than the hum, mismatched sets can cause mismatches of current in the OT primary winding and possibly add distortion - which could be cool in an guitar amp, but would probably sound rotten in a hi-fi. I'm pretty anal about proper biasing in my hi-fi (Dynaco ST-70).

[JHS]

American tubes were better in those days and had superior quality. Leo himself listened to every amp and Fender delivered it after he was satisfied with it's sound.

Matched tubes are crap! After 24h of use your matched set has been morphed into an unmatched set.
The output transformer isn't matched, the coupling caps are not matched and the Rs are not matched. In a fixed bias and class A amps they are complete nonsens.

So why use matched tubes?

What you need are quality tubes and if the current differ about 2-3mA, don't bother, you won't hear much differencs to a "pefect" matched set.

The tubes can be matched to perform perfect in the amp with a split bias control, but the sound will be sterile and cold. With slightly "unmatched" tubes (1-2mA) the sound has more overtones and IMHO is more musical.
It's more important to give the tubes a 24h burn in befor adjusting the bias, the tubes will work more stable.

Same with the grade ranking. If you calculate the current flow for an amp with GTs or similar ranking from 4 to 7 and set the bias current to the average value you can use those tube w/o rebiasing. The current flow around the average value will be 2mA max, that's in the tolerance.

JHS

[uncleboko]

Oh for heaven's sake, buy an amp, plug in and worry about your playing! Do you think Jerry Donahue when he walks on stage thinks "I wonder if my amp's output tubes are matched?"

[Fuzzer]

Oh for heaven's sake, buy an amp, plug in and worry about your playing!

Absolutely right.

[gght]

Wait,..... you mean all this stuff here isn't just about the technology...... people actually really PLAY through these things?????
No way!!!!!!!!!

[vince]

[...]
Now just to show that I'm not completely lazy, here is my first one:
A RI 59 Bassman, sounds stellar, 5881's running at 43.7mA, and 39.2mA. 4 1/2 mA difference! I was careful to match them when I put them in but they have drifted. And I didn't hear any difference in sound.

But - I had two pairs of JJ's 6L6.
And - when 1st pair biased correctly (35mA per tube) - 2nd pair was biased
only 17mA (!!) per tube.

regards
V.