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Ok I have the rip off...err Groove Tube (Sovtek) rectifier in it, diodes installed. I turned the amp on and I am going to let it heat up for a little while before I attempt to bias. I was reading up some more on biasing (this is my first time ever having to bias an amp)...and read that the bias will increase a little bit after the amp has run a while, so I wanted to let it run a bit and give it the best possible chance...if it even matters. I really want to see this thing work now...I get nervous because I am so tired of seeing it fail.

Greg

I only have one word: AWESOME! It is biased (just slightly low at .98V). I waited about 10 minutes and tried biasing...well there it is, its working great! It sounds awesome, even though these speakers crappy Aiwa speakers that I used for testing. I am going to have to move it to where my better speakers are soon and give it a real test, but I am sure this is the best the Aiwa's have ever sounded.

I also wanted to note two observations I made while working on the amp with the new recto - the physical vibration in the amp is noticeably less than it was with the JJ recto (is that possible?) - I dont think its just my imagination. Secondly, with the JJ tube, both sides would have a near identical bias voltage when the bias pot was in the identical position, but now, the recto side needs to be turned a little bit higher to have the bias voltage as the other side. I am sure these things dont matter a ton, but I just noticed them, for what its worth.

I really do appreciate all the help that you all provided, hopefully I can learn more about tube gear and contribute in some small way. I definitely got to learn a lot more on this amp build, as I'd said before the S5 K-12G kit I built went perfect so I learned nothing.

(ok, that was a lot more than just one word, but still, awesome is the only word that matters right now)

thanks all!!
Greg

The more a transformer is loaded the more vibration will be felt. Most us old timers have learned that if you power up and hear that distinctive tranny in distress noise/vibration, shut down immediatly and look for a short. If your rectifier was bad and drawing more power from the tranny it would vibrate noticably more.
When you bias your tubes you have to "ping-pong" between tubes. First bias one or one set then bias the other then back to first one. Wash rinse repeat. When you change one set you affect the B+ which changes the other set.

Congrats!
Good show.

That sparked out J/J rectum-fryer tube was probably suffering from some degree of internal cathode to plate shorting, hence drawing excessive current, and otherwise acting strangely in undesireable ways 8^0

The groovetube should be a much better choice, and hold up a LOT better.

Best to ditch the zapped J/J, or justu se it for an ornament...

There are lots of mods / upgrades for the SG K12G amp, just search for "K502" , "K12", "11BM8" , "10GV8", or "16A8" on this forum.

The 11BM8s / 16A8s play better in UL mode than do 11MS8 or 10GV8s.

/ed B