Preamp Deal of the Century

Ecclectique, I've tried some Sylvania 6L6 GWA (I think that was the designation) from the 40's. Smoked - gray glass. Anyhow.. they were recessed sounding, dull in the Supratek. In fact, I think they sounded a lot like the Sovetek EL34's the Cortese came with - not great.

I understand that the regulators aren't supposed to effect the sound much but I do hear major differences in the depth of the music with different tubes in that position. Oddly enough, I can hear bigger differences between regulator tubes than rectifier tubes in the Syrah, Chardonnay and Cortese.

The metal 6L6 RCA's had a tremendously wide soundstage yet the music was almost flat sounding - not dull or lifeless - just not deep or 3 dimensional when compared to the TS 5881's in my system.

I'm still searching for a pair of Sylvania 5932's with the dual black plates, as well as some early GEC KT66 to try. If those don't cut it, I'll most likely stick with the 5881's.

On a side note, I got some Mullard ECC32/CV181's to replace my Ken Rads. Neat tubes. I know.. I know... they AREN'T 6SN7's... Oddly enough, they work great in my Cortese but didn't work in a friends Syrah. In the Syrah, the remote volume control stopped working and the gain/dynamics went to about 20% of normal. That's weird because they function perfectly in the Cortese.

Hey BWhite. Hearing the differences between regulation and rectification tubes is certainly not odd or strange,its a "good thing" ... as they do infact impart on the sound of the supratek. Your description of the 6L6 metal seems to parrallel mine... as I also find them rather lacking of air and space in the soundfield,and more so than any other tubes I have tried, sovtek included.I have not tried the 5932 however, the GEC kt-66 and the mullard EL-37 seem to be the closest to WE 350b than anything else I've used.These tubes all seem to add more depth and air to the soundfield without changing the tone of the music.Regarding the use of the ecc-32 in your friends Syrah..... very strange....something doesn't add up here, as they work just fine in mine.Have you tested these tubes? What rectifier and regulators was he using with these?

Ecclectique - I don't have a tube tester so haven't tested the ECC32's. I presume there is nothing wrong with them given that they work fine in my Cortese. The trouble my friend had with the ECC32's in his Syrah and the non-functioning remote volume lead me to believe that the way his Syrah is wired is different than newer Supratek's.

I think his Syrah is the second unit to ever have the remote control - my Chardonnay was the first. Switching the DC power cord between his Syrah and my Chard caused similar issues with the remote volume not working.

At that time, I believe Mick was pulling power for the motorized volume from different places in the pre - experimenting?? Perhaps this is an instance where the different internal electrical properties of the ECC32 vs. 6SN7 come in to play.

Hello Bwhite. Could be a weak rectifier and/or weak ecc-32's. Gentlemen... please do yourselves a very big favour , you "must" get yourselves a good calibrated tube tester!!! Absolutely indispensible,especially when considering the tube rolling everyone is doing here! Most any tube that tests anything less than 90% shouldn't even be a consideration. Even if one is purchasing nos tubes,a good calibrated tester is "imperative" as many NOS tubes right out of the box can fail to meet spec.To be blunt and honest! I think you will be somewhat surprised when you test some of these tubes you are using in the supratek. Matching the 6sn-7's per channel is paramount for top preformance in the supratek.... not to mention.... section to section matching of each of these tubes- which is even "more" important [in all triode tubes]! Check the strength of any rectifier you are using as these will have a large impact on the overall sonics of the preamp.Making a comprehensive evaluation regarding the sound of various tubes makes, types, and vintages of these tubes in any circuit is pretty much flawed without knowing these parameters.For example... A strong rectifier of the same type will sound very different than that exact same tube that tests even 10% less than the stronger one. Do not mean to sound so derogatory gang, however some things are a given and need to be addressed here .....Cheers David

Tube matching is a must with push-pull configurations. With single-ended configurations (like all SupraTek's) it is optional but still a good idea. Ditto the need for a tube-tester, esp for someone who has invested a couple thousand in tubes. A good B&K 747B or TV-7 can be had for just a couple hundred dollars.