NOS Russian 6Pi6c Beam Tetrodes

[tubeswell]

I scored a few of these to try in a tweedy thing.

Anyone used them before? Specs are here:

Tales From The Tone Lounge: Russian Tube Specifications!

[unparalleled]

Originally Posted by tubeswell

I scored a few of these to try in a tweedy thing.

Anyone used them before? Specs are here:

Tales From The Tone Lounge: Russian Tube Specifications!

I have several types of "Reflektor" brand (these bear the brand logo) valves, they are good quality and long life.
Have not tried that particular one.

[Wakculloch]

Those specs make no sense and may be for a 6P3S.
Did you get the russian spec sheets with the valves? I'd try searching Frank's under 6P6S for a more reliable data sheet.

[tubeswell]

Found it thanks Wakculloch - I should've looked there to start with. Cheers

[stingray_65]

I used those exact tubes in my 5E3 and they sounded great untill I found some NOS RCA 6V6's

I havent had them in an amp since.

it's not like they sounded awful, its just every thing else i've rolled in there since had so much more "depth?"

they work and there was nothing tonaly distateful.

just my .02 from personal experience.

Ray

[tubeswell]

Thanks for that $.02 Ray - that was money well-spent. What were your voltages like (if you can recall?), and how hot were you running them? (And what was the Pri Z?)

Unusual that they have a -12.5V bias voltage (whereas 6V6 is somewhere around 18-20V). I read somewhere that they don't tolerate much variance in their operating conditions.

[stingray_65]

I'll drag out the 5E3 today and read the voltages. I did not alter the amp for the tubes at all, just rolled them in. I also remember when I was doing the trouble shooting tha my voltages were high across the board and I simply attributed that to higher modern mains voltages

I had gotten the tubes on e-bay as they were packaged as a tube set for the deluxe.

please remember this was my first amp build in 20 yrs and I simply used what I had.

the one nice thing I did get out of that set was a NOS sylvania 12AY7. the rest have all been replaced, even the 5Y3 reecto.

The OT is an older Triode Electronics paper bobbin. It's not the newer one they sell now with the ultralinear taps, so I'm guessing its a 6K6 on the primary.


Ray

[tubeswell]

I've heard someone else say that they had a pair in a 5E3 where tubes were idling at 45mA! What with the -12V recommended grid bias, I wonder whether these are just naturally hot running tubes?

[tubeswell]

Actually scratch that - I missed the bit in the data sheet where the recommended plate voltage is 250, with about 46mA plate current. (I was looking as the 350V max plate voltage rating thinking that was the idle voltage). Still if anyone has any opinion of the capability of these to take higher voltages, feel free to chime in. (If not I'll do a TTD test when I get around to it).