SET Asylum

Single Ended Triodes (SETs), the ultimate tube lovers dream.

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Recommend driver for SE KT88

Posted by Pabloaguas on September 12, 2023 at 12:34:36:
Hi Inmates,   

I'm wondering if any experts can recommend driver topology for my SE (Tetrode Mode) KT88 amp?  

Background- this amp started as an Audio Note Kit 2 SE 6550 amp. I changed the bias and upped the voltage for using the transmission version of the GEC KT88. I have 555v of Anode to Cathode voltage and have 285 on G2, but might want to go into Triode mode someday... just not sure if 555 volts in triode mode would kill the tube... I guess that is another question.

This amp originally had a very poor design of a SRPP 12ax7. This SRPP got changed later to use 5751 and then recently changed droppers to use e80cc. I eventually deleted the input tube stage(the 6SN7) because the extra gain was not needed.   So now, I'm wanting to just abandon the SRPP, and drive the KT88s with a SE topology driver- maybe just a good-old voltage gain stage with a single section of a dual-triode. I read here that a single section of a 5687 is an excellent driver for the SE KT88.   

Can anyone with direct experience comment on what types of circuits and tubes they have found to be best for driving the SE Kt88?  Thank you in advance for your suggestions.