Preamp Deal of the Century

Here is a link with some more info on transformer hum induced by DC on your AC line.
http://www.diyaudio.com/forums/showthread/t-83784.html

Thanks for the thoughts and observations on the hum issue. I will check the voltage at my panel to see if it really is 120v. I have also tried unplugging all components except the pre with all other breakers off to see if it was interference from another component but there was no change. It's not a major issue because it is only noticeable from a few feet away. I will also check the bolt tightness. I had not considered that because it's a new unit. Thanks again.

Thanks for the explanations everyone. I am fortunate enough that my Chenin, after making the initial mistake of swapping tubes right away as soon as I received it, only had one small issue since 2004. I have this paranoia about the R channel on the phono a little lower in output than the L channel at identical gain pot settings. I wrote my concern to Mick and he sent me an schematic diagram to measure the voltages and make proper adjustments. After that, it's been working fine (knock on wood as I type this!) so far without hum or hiss for almost three years now.

regards

In my latest effort to deal with the "glaring" issue associated with my Cortese referred to above, I acquired and tried the RCA gray glass (actually, the earlier "lightening bolt" logo 6SN7GTs that preceded the VT-231 incarnation) and the KenRad 6SN7/VT 231s. In my system, just as in Ooslik's, the RCAs sounded somewhat bright and glarey here and there. The KenRads virtually eliminated the stridency entirely, but a bit of the upper midrange lost a touch of the air and ambient detail I had with my Raytheon 231s and General Electric 6SN7GTBs. I then replaced my Tungsol 5881s with some Sylvania 5881s, and restored just a bit more of that ambient detail. The trick involves getting involving upper end detail and musicality without the glare or stridency. Now, I feel more confident than before about getting there. My next step is securing a good, but not super expensive moving coil. (I've been using the low output--1.5mv.--Grado Sonata.) I also should soon be receiving those Tungsol 6SN7/VT231 Round Plates. Incidentally, in case I failed to relate before, I did not make a single tube roll until I arrived at 200 hours burn in of both the phono and linestages of the Cortese.

Tube rolling with the Supratek pres can be an expensive road to go down resulting in minor effect if any at all.I sold my phono grade black glass Tungsols 6sn7s when the going price of them reached $300,I more then doubled my money. The only select pairs of 6sn7s I have left in my stash are the formidable and attractive looking Sylvania metal base A and the W vintage. The best results were had with a $20.00 Bendix 6106 rectifier and apair of $8.00 Sylvania 6F6gs n.i.b. I have a dozen metal base rectifiers.Philips MiniWatt,BugalBoy, Mullard. N.O.S. select pairs of Genelex gray glass brown base KT-66. Select pairs of early vintage Telefunken,Seimens and Philips moving coil phono select.Right now in my phono stage Im using a $40.00 n.o.s. pair of PCC88 Telefunkens and a pair of R.C.A. 6c4s with excellant results. I gave all these mentioned above $$$ agood lengthy listen. The Bendix ,Sylvania and the $50 for a matched pair Sovtek Kt-66 have the best effect myself and others have found.....You really want to find out what your system can do? If you play vinyl, look into changing your tonearm wire to Nordost Valhalla and your interconnects to your phono stage with the Nordost new line. Far and away the best move you could make.And for a LOT LESS money then tube rolling with your Supratek pre......