Preamp Deal of the Century

Hi Fiddler. I have an order in for the welbourne labs attenuator,unfortunately they are in a back order position at present. Anyone tried it in a supratek yet? Thanks for the tip on the Mundorfs.

Ecclectique:

"I have saved the best for last as rewiring the tube socket is in order here to accomodate the 7193! The 7193 triode is a strange looking octal tube with plate and grid caps on the the top of the glass. These are electrically equivalent to a 6j5 single triode or 1/2 of a 6sn7. They were munufactured by RCA, NU, kenrad and tungsol as far back as the early 1930's.Many were used in old Juke boxes in their day as well as some early 50's tv sets. This tube just stomps on any 6sn7! Simply said.... there is no going back once you hear it. It's like comparing a telefunken ecc803 to a ge 12ax7, or a we350b to a 6L6. Halographic like no other,dead quiet,microphonics are non existant, super liquidity with incredible clarity,a silky sweet top end that floats into your room,the bass energy and drive of the kenrad vt-231 but far crisper and 3 times as tight. I use the cortese in my main system with my very efficient Tannoy Westminster's driven by VAC pa-90 monos employing the genelex kt-77 output tube. With the 6sn7's in the preamp I have very little room for play with the volume control whereby a single 6j5 is perfect for my application. I have unsoldered the other socket whereby I use only 1 6j5/channel."

You really got my attention with this post.

I have the gain on the "low" setting on my Chardonnay and I still can't turn the volume up past 9 o'clock. I would love detailed info on how to convert my Supratek to use the 7193.

I would appreciate any feedback you have time to provide.

Hi Fiddler. To employ the 7193 in the chardonnay one would have to drill a hole beside each tube socket to accommodate the wiring to the caps . Probably not so good if you ever wanted to sell it. I run my wiring up through the extra tube socket of my cortese as mine is configured for a pair of single triodes/channel as opposed to the single socket dual triode 6sn7 versions . Another way would be to run the extra wiring down from the bottom of the chassis and up the sides if you want to give it a try.The good thing here is the operating points of this family of single triodes [6j5,6c5,6p5,2c22,7193 etc] are the same as the 6sn7 whereby no modifications are necessary to the circuit of the 6sn7 based suprateks. Perhaps you might want to try a 6j5, 6c5, or the 6p5 first as they don't require the grid caps, the wiring change is relatively very simple and would certainly allow you a lot more flexibilty with your gain. The round plate versions of the 6j5 and 6p5 vacuum tubes as well as the 6c5 meshplates sound better than all of my 6sn7's. Trying a few of them first will certainly allow you to hear the voice of this tube family. As mentioned,the 7193 and the 2c22 need a pair of top caps per tube. These top caps a very difficult to source nowadays and it is imperative that they fit snuggly on the contacts of the tube. Not recommended for those with children or pets. You are more than welcome to email me off line for more imfo.

Hi Fiddler

You wrote: "I have the gain on the "low" setting on my Chardonnay and I still can't turn the volume up past 9 o'clock."

Please help me understand why it is important to be able to turn the volume past 9 o'clock? My system sounds best with the Chardonnay set to the "high" setting and I hardly play beyond 9 o'clock.

Fiddler - where did you purchase the Mundorf Silver Supremes? Were the cap values clearly indicated on the caps or did you have to get that info from Mick? Thanks.