Max PD for SOVTEK 5881WXT?

[BlackCrowe604]

Good Day, hope everyone is well.

I'm looking at SOVTEK5881WXT specs (old copy)... and the PD value is a bit of a mystery? Hoping some of the fine folks on this forum may be able to confirm or deny!

Seems like these are 6L6 with a different base? Sources I found online state max PD @ 20W.

Just wondering if I should treat these as 20W or 25W when biasing?

Thanks!!

[tubeswell]

If you’re talking about the 6P3Se (with the ‘wafer’ base), which is a 5881-equivalent tube, the published Pmax is 20.5W, but people have run these as 25W or even 30W tubes (although personally I prefer to follow the datasheet). These tubes are highly durable and long lasting. They’re spec’d for high Gs for military use. They don’t sound too bad in guitar amps either.

https://www.tubeampdoctor.com/en/5881/6l6wgc/6p3s-e-russia/sov.

[acheld]

I've been using 5881 and the 6P3Se over the past few years, and bias to a max PDiss @ 23W.  I've had no problems at that level, and can not tell the difference (sonically) between the branded 5881's and the 6P3Se's.

As Tubeswell has noted, folks run these tubes all over the place, and even RobRob's tube bias calculator gives you several options as high as 26W.  That seemed high to me, and I run them a little lower.

That said, the 6P3Se tubes are built tough.  One of the operating limitations that caught my eye is that they should not be operated when the ambient temp is above 180C and the filament voltage is above 6.3V "at the same time."  Well, alrighty then, note to self, don't put the amp in an oven . . .

[BlackCrowe604]

Thanks tubeswell & acheld.

I found RR's calculator, and wound up using 26W based on that. The tubes I had were just branded SOVTEK 5881WXT, no other markings.

Had to get it up and running and to the gig on Friday, it worked out. Maybe I'll adjust to cool it down a little in the future.

Seems like there is still a bit of mystery around these tubes! Sounds like I don't need to worry about it too much.

Thanks everyone!

[mresistor]

are you talking about the coin-base tubes?  Yes I see you are..    I was thinking of 6P3S    without the e

[HotBluePlates]

Original 6P3S-E data sheet says 20.5 watts (2nd page, as "20,5 Bt")

EHX is printing the same thing on their 5881WXT data sheet.

However, many folks run them hotter than that.

[pdf64]

As I see it, the fundamental problem with such info is the lack of context; what does it actually mean, what’s the basis of the rating system used, what’s the expected operational life at the noted dissipation etc.
Without that, it’s not really feasible to assess how it might compare to the absolute max / design centre / design max rating systems.
Hence empirical reports become about as useful as the info.