Well, new here since I just recently picked up a second hand ST 70 built by Bob Latino. I really wanted to build one of Bob's kits myself, but the opportunity to pick one up second hand came up on Audiogon (with a cage!). I couldn't resists. I was especially excited since the seller claimed there were hundreds of dollars in upgrades that had been done to the amp and was supposedly in pristine condition. Well, buyer beware...sort of. I am glad to have and there is nothing that can't be fixed. As you can see in the photo, there are many boutique caps installed on the underside of the driver board by the sellers tech. There are additional large solen caps on the top of the driver board (not shown). It looks like all of the upgrade caps installed have be reupgraded? The problem is, though, the amp hums and makes fizzy sounds, and just blew a fuse tonight. I swapped tubes around, rebiased..In short, everything I knew to do prior to the fuse blowing. What I am wondering, compared to photos I have looked at of an upgraded driver board, are there caps that are not needed or could possibly be contributing to the hum and fizz? Hmm.
A couple of other things. What is the bias value for the KT 88s on the ST 70?
What are the little adjustment pots on the underside of the driver board all about?
I wanted a project...Looks like I got a project!
-Phil
A couple of other things. What is the bias value for the KT 88s on the ST 70?
What are the little adjustment pots on the underside of the driver board all about?
I wanted a project...Looks like I got a project!
-Phil