Asking for trouble with these tubes?

[Radioboy950]

My amp uses 6L6GCs, but I’d like to try the (reissue) Tungsol 5881, a lower rated 23 watter.
Plate voltage reads 460.
Would I be safe if I set bias around 30mA?
Or is it too risky to use a tube with a lower power rating?

 

[tunghaichuan]

My amp uses 6L6GCs, but I’d like to try the (reissue) Tungsol 5881, a lower rated 23 watter.
Plate voltage reads 460.
Would I be safe if I set bias around 30mA?
Or is it too risky to use a tube with a lower power rating?

Found this link after a quick net search:

http://thetubestore.com/tungsol5881.html

Makes sense to me.

However, if you bias at 30mA, the tubes are only dissipating 16W at idle which is about 60%. Normally I like to bias an amp at about 70% max dissipation, or 35mA in this case.

Keep in mind that there is a 400v limit on the TS 5881 reissue. If these were NOS, I might consider it, but Russian made tubes are another story. In fact I have a set of real Tung Sol 5881 tubes from the 50s. I put them in an amp with 500v on the plates. I biased them up to 40mA with no problems. But I didn't leave them in the amp that long.

I'd probably use the 6L6GC-STR from the above link.

tung

 

[Radioboy950]

Keep in mind that there is a 400v limit on the TS 5881 reissue
tung

Hmmm...one of those ideas that looks better on paper, I suppose.
Not worth blowing up a Rivera.

 

[tunghaichuan]

Hmmm...one of those ideas that looks better on paper, I suppose.
Not worth blowing up a Rivera.

Definitely not. If those tubes short out and smoke your output transformer, you're looking at a very expensive repair.

tung