If you have been following the Ikezilla threads, here is an update. After the initial test, Shannon added AC coupling between the GC and LTP stages and started tweaking the feedback. He also added a CCS on the LTP and changed the LTP plate resistors to 62K (as in the updated Ike manual). We tested this configuration with a 500V B+ and 70 ma bias and got 0.8% THD at 151 watts at 1k. We were also under 1% THD from 30 to 10K at 151 watts. Still room to tweak, but thats another story.
I know some of you are waiting for schematics, and I have been working on this. Should post something in a week or two.
Anyway, I snagged the prototype back from Shannon to do some additional testing. Today I had a day off from work and the wife and kids, and conducted some listening tests. WOW!!!!
:o
Mind you, these were mono listening tests, so I wasn't sure how it would go. After and hour or so of warm-up, I started cranking and this amp really delivered. I was playing a Sheffield Labs CD "Prime Cuts". which gives a variety of great recorded music. Female vocals, big band, horns, drum solo, and more. The 'Zilla passed every test with flying colors. I was amazed!!! One Apogee Centaur said, "its about time", and the other one said, "what about me."
The music had it all. Detail, natural sound, attack, low end, high end, amazing vocals. Shannon stopped by for some of this and may have his own take. Anyway, I was very pleased and will be ordering parts for the pair very soon.
JT