Coliseum running KT88

[Firefight]

Looking for opinions on running KT88s in my Coliseum? I know the transformers are possibly sized to run them at the optimal range for a KT88.

 

[MisterMojo]

I, too, would be interested in this....

 

[Firefight]

I'll just ask Mike tomorrow....

 

[Firefight]

He gave us the thumbs down. There's still hope, mere mortals can't handle the coli as she sits now anyway

 

[MisterMojo]

Thanks for the update! Running 7581A’s in mine and would have been interested to see if KT88’s would work....

 

[Joey1970]

Lots of headroom in the 7581a. A coli loaded with them would be brutal.

 

[MisterMojo]

Yes, the 7581A’s are quite musical and brutal in it!

 

[Firefight]

Well if those are what you say they are I'll see what Mike has to say too. Obviously he is beyond all of you.

 

[MisterMojo]

I spoke with him (Mike B) a couple weeks back regarding tubes for Coli’s along with other amp service things. Was looking for info on alternative power tubes to STR 415’s. Since Coli’s run such high PV, he recommended JJ 6L6GC STR or TAD 6L6GC STR for current production, STR 415’s (of course), or JAN Philips 7581A’s as vintage options.

 

[xdg999]

My c+ and 3+ Coli's are both Simul so I use 415's and 416's in them. If I use all 415's I put 415's in the center sockets that draw less current.

 

[Joey1970]

416's in the center sockets(Class-A) would draw less current than 415's in a Simul-Coliseum, I would think. It does so in the 75/15 watt amps, different sockets for different amps. I've had a couple of Coli- Mark III's , so I know.

 

[xdg999]

I'll have to check the the current draw of each in the amps. If I'm using all 415's I'll put a pair in the center sockets that draw around 20 - 22ma's on my Maxi Matcher. I'll put quad in the other sockets that draw around 30 - 32ma's.

 

[stephen sawall]

KT66 might work. They sound kind of similar to a KT88. I would ask Mike before doing it....but it is in the 6L6 family.

 

[Firefight]

The heater current required by KT66s is enough to kill the power transformer on some 6L6 amps. I would consult the Oracle lol