Sunday, March 14, 2010
retro-thermionic Merlot with JJ KT88 Blue Glass
My son had ordered a valve amp. He wanted nothing on the top plate but valves and transformer. So a front plate holding the volume control and rear plate holding the speaker and input connections was constructed.
The amp is a two stage KT88 based single end UL amp (SE UL). The driver valve is the 6N1P. It is a common Russian valve quite capable of driving the KT88s. In this shot you can see JJ Blue Glass KT88s. I have tried EL34. 6L6, 6V6 and 5881 valves in this map with no bias change. In the EL34 range I have used Black Sables and Siemens (NOS) tubes. But I think over all the KT88 is the best. When this amp went to my son Sovtek KT88s were reinstalled. He was more concerned with the look than the sound.
This amp requires speakers with an efficiency of at least 90db to provide high volumes of music. SE UL amps provide exceptional sound staging, pin-point stereo imaging and a very natural sound. Though they only produce 6Wpc, through efficient speakers, good listening levels can be obtained.
Lookout for the Merlot Black top to be posted on this blog.