Here’s one of the compact KT-88 SET’s I built. I’ve built some crazy amps so I don’t like to post up project builds that are a failure.. and I’ve built many.
Doing some QA on this one. This one is quite the joy. Ran out of copper bar stock, so this one took the lead and finished it up.
More pics to come.
Doing some QA on this one. This one is quite the joy. Ran out of copper bar stock, so this one took the lead and finished it up.
More pics to come.
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I used 2 Hammond aluminum chassis, 10x6x2. They’re like tin cans, but they’re inexpensive and I prefer aluminum. I cut tops out of .125” aluminum and braced the front and back from the inside with .125 aluminum. Another piece for the back as well.
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How do you get on with KT88s? I have a SE with octal sockets and of all the EL34s and 6L6 types I tried, using triode mode, the only ones that were any good at all were Sovtek 6L6WXT+. The EH ones also look to be the same. The rest didn't sound good for various reasons.
I built these amps from an existing one that was a twin monoblock packaged into one chassis. It was designed to run el34s or KT88/6550s and was already strapped for triode mode. It needed a lot of work - I got one side working and I really liked it. I was going to have to fix some really questionable soldering and replace all the tube sockets and grid resistors and the chassis had some cosmetic damage so I figured with all that work, I’d just strip it and repackage it into something I would like better.
I burned this amp in for a while on a GE6550 before before putting in a previously used Sophia KT88. The rectifier and 6sn7 are new, as well as some caps and resistors in the amp, so it’s still burning in.. there’s some ugly moments and some joy moments at this period, but overall I’m pretty thrilled as there is no rework needed!
I burned this amp in for a while on a GE6550 before before putting in a previously used Sophia KT88. The rectifier and 6sn7 are new, as well as some caps and resistors in the amp, so it’s still burning in.. there’s some ugly moments and some joy moments at this period, but overall I’m pretty thrilled as there is no rework needed!
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There wasn’t a good one I could find. Give me some time on it. I’ll compile all my notes as this was a reverse engineering project.
Are you using triode mode? I ask because I haven't tried KT88 or 6550 in mine, and wonder how they compare in triode.
I can start moving on with second one. Here’s the power supply layout. 2 new nichicon 33uf 450v and an FT 47uf 500v with a choke.
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I can use a 5u4 instead of the boutique Sophia 274b. I have a pair of the Sophia KT88s. I’m not sure if I want to buy another 274b or a Sophia 6sn7- I’m considering changing the 6sn7 to a 6n1p or 6922.