5881 question

[lowbrow]

I've just finished rebuilding my Silverone 1484 head. It's pushing about 475 volts on the plates and calls for 6L6GC tubes.

I have a factory matched pair of NOS USA made Tung Sol 5881 tubes. On the box, it says they're rated for 450 volts maximum on the plates. Should I be running these, or am I risking my newly built amp? Should I just bite the bullet and put some new 6L6GCs in it until I can locate some vintage glass in my price range?

Here's the specs printed on the sie of the Tung Sol box:

[ThermionicScott]

Okay, just checked the schematic... it's SS-rectified, but the screen voltage is a little under the max. What does your screen voltage measure?

Old TS tubes are robust, but since they aren't making any more, I'd probably err on the side of caution and use 6L6GCs...

- Scott

[lowbrow]

Okay, just checked the schematic... it's SS-rectified, but the screen voltage is a little under the max. What does your screen voltage measure?

Dunno off hand...I'm at work and it's at home, so I'll have to check..

Old TS tubes are robust, but since they aren't making any more, I'd probably err on the side of caution and use 6L6GCs...

I'm thinking I may just do that...I love the sound of these, but after all the work and expense, I'd hate to risk the amp because one of the tubes essentially melted down.

[MWJB]

If the Tung Sols are matched & sound good use them. They are the tube of choice for 5F6A Bassmans, which run 470vdc (+/- 10v). No point spending a couple of hundred dollars on tubes just to put them on the mantlepiece.

15W per tube should be plenty regarding plate current.

[Chuck H]

No, sorry. Those tubes are no good for that amp. Send them to me and I'll send you a pair of 6L6GC's that'll be perfect

Chuck

[lowbrow]

Well, I decided to pull them from the amp before I took it to practice last night. All I could lay my hands on at the time was a new set of Ruby's from Peavey. They sound OK...definitely not as good as the Tung Sols, but in a pinch I was OK with it.

I think I may sell/swap these for some vintage 6L6GCs and not worry about it....maybe....in any case, I love the box they came in, so I thought you all might like to see it:

[MWJB]

"No, sorry. Those tubes are no good for that amp. Send them to me and I'll send you a pair of 6L6GC's that'll be perfect" - Ha ha! Let's not forget those crappy old NOS RCA 6V6s, 315v max on the screens...let us take them off your hands & we'll, er, "recycle" them! ;-)

Lowbrow, y'know that the data sheet for a 6L6GC states 450vdc max on the screen, unless fed buy a OT tap? Whoops, rules them out for nearly all brown tolex Fenders (except Vibrolux & Tremolux), Tweed Bassmans, etc....Ignore that too. 6L6GC (like 5881) may have to cope with 510vdc+ on plate & screen....and they do.

[lowbrow]

This is reminding me of my SF Champ. I went through it not long ago and was a bit surprised to find such high voltages everywhere. The 6V6 is getting around 390 volts on the plates and screen grid, which worried me.

Everyone assures me that's normal though and that the NOS Tung Sol I have in it will be perfectly fine. I gotta say, so far so good and it does sound mighty damn good!

[ThermionicScott]

That *is* a pretty sweet box. I'll defer to the experts as to whether the tube will survive in your amp.

- Scott

[Diablo]

Any of you folks have fantasies about time travel back to the 1960s and buying thousands of brand new tube?......

[txstrat]

Any of you folks have fantasies about time travel back to the 1960s and buying thousands of brand new tube?......

I do, since the "Back to the future" movies. Remember Marty McFly playing a 345 with a narrow panel Super (at least I believe it's a Super 5E4A).
tubeswell, your ears should be ringing.

[tubeswell]

I do, since the "Back to the future" movies. Remember Marty McFly playing a 345 with a narrow panel Super (at least I believe it's a Super 5E4A).
tubeswell, your ears should be ringing.

Yes I was just thinking the same thing, and he had the audacity to kick that amp for touch (I wonder if it was a real amp or just a movie prop)

[ThermionicScott]

Yes I was just thinking the same thing, and he had the audacity to kick that amp for touch (I wonder if it was a real amp or just a movie prop)

It wasn't as "vintage" back in 1984 or so.

[Bill Moore]

I got some tubes from a customer last summer, who used keep them around to fix his TV's. Got 2 12AX7, 2 12AX7A, and 2 12AT7, The RCA boxes had 9-60 on the flap. I forced $50 on him, he complained it was too much.