Bullet Proof 6L6GC Recommendation PLEASE

[ReidK]

Could be new production 7027 are no more than a 6L6. I have not checked myself. Just trying to give options

There's actually evidence that a lot of US 7027As were just relabelled 6L6GCs.

http://www.triodeel.com/7027.htm

Reid

 

[Tubelab_com]

Many 7027's were actually 6L6GC's with an "improved grid". The 7027A is a different animal with bigger plates.

Now that I said that, realize that the 7027A came late in the vacuum tube era, and many manufacturers were sticking just about anything that would fit in the glass to fulfill contracts. There were many reports of 7027A's blowing up in guitar amps. Enough to give the tube a bad reputation among guitar players. Who knows what the tubes really were.

I have seen 6AV5 sweep pentodes rewired and labeled 6B4 (a DHT). I have also seen 6BG6's (a sweep tube derived from the 6L6GB) with 7027A guts inside.

 

[7N7]

Many 7027's were actually 6L6GC's with an "improved grid". The 7027A is a different animal with bigger plates.

Now that I said that, realize that the 7027A came late in the vacuum tube era, and many manufacturers were sticking just about anything that would fit in the glass to fulfill contracts. There were many reports of 7027A's blowing up in guitar amps. Enough to give the tube a bad reputation among guitar players. Who knows what the tubes really were.

I have seen 6AV5 sweep pentodes rewired and labeled 6B4 (a DHT). I have also seen 6BG6's (a sweep tube derived from the 6L6GB) with 7027A guts inside.

Thanks Tubelab for your comments about the Sovtek 5881s in an earlier post.

I regret to say that I once blew fuses, substituting 7027As for something else; the problem of course was that the 7027A has an extra G2 pin - No 1 which can be a bit of a disaster!

Reading through this thread I have observed some curious claims for anode (plate) dissipation. The GEC ("Genalex") KT66 is rated by the maker at 25W Pa using the Design Centre System and 30W Absolute Maximum. Another example is the original spec for Tungsol 5881. Tungsol states 400V anode and g2 but this is using the Absolute Maximum system. I suspect that the 5881 was simply a ruggedised 6L6GB (360V/270V)

7N7

 

[anatech]

Hi kstagger,
All my data shows the 5881 at 25 W (2W isn't a big difference) and the 6L6GC at 30 W. You have to get up into the 7581A for a 35 W plate. I do agree completely that a 5881A replaced a 6L6GB which had the lower ratings you've noted.

Philips is an economy producer. That means cheap tubes and includes the Amperex line (only the name was changed for North America). Same cheap stuff as Philips though. Of course, Philips would buy from Siemens and other manufacturers as well. This was very common amongst all tube lines. That explains the good tubes.

Great page! I'm not sure how accurate it is though.

I had requested the actual specifications of the Sovtek tubes from the New Sensor a few times. They didn't have them. I can believe they are Russian tubes and not quite the same. The glass is heavier as you've noted, but no way will their 6L6WXT stand up to what normal 6L6GCs should. Almost all new 6L6GCs I have purchased don't either though. The consistent exception is the Electroharmonix line. Plus, they sound very good. Try them.

6EU7 is about as weird as I get for audio.

-Chris