I traded a restored PL4000 Autocorrelator for this DIY (P. Millett styled, I think) amp. It was built several years back and I believe I found the Link that Pete M. has posted concerning this amp. http://www.pmillett.com/6B4G_push-pull_amp.htm Can you guys confirm this? And, what the heck output tubes are the ones installed in this amp? Their like 6B4G's but with the Plate connection on top(?). Edit: their 6A8G's The amp operates but requires some gain to get up to listing levels and seems to clip easily (Maybe because its missing the second 6SN7 on each channel?). If listening at lower levels' it sounds really nice. I haven't checked it out completely. The friend threw some tubes in it from his crazy mixed up stash, so the tubes condition is questionable. I plan to rebuild this in a different chassis and cleanup the rats nest of point to point build on the bottom side. Fairly new to the tube gear and this is the first time re/building something like this. Please - no comments on whether or not the trade was in my favor I completely understand the safety concerns for the tube gear and consider myself a pretty good solid state repair tech.