Preamp Deal of the Century

Hi Slowhand. To the best of my knowledge, they are exactly the same tube. Every one of my examples[more than 50] seem to be identical in every way.... from the plates,to the micas and the side getters. I honestly believe they are all the same tubes regardless of whether they were labelled gta's or gtb's. General Electric made tons off these tubes over the years and many were relabelled for other companies such as Emerson, Philco,Raytheon, Westinghouse, Silverton etc. The 6sn7 octal was probably the largest single production tube ever made.

Hi Gang.I am curious. Has anyone here ordered the cortese with the 6j5 tube option? The 6j5 triode tube is basically 1/2 of a 6sn7 dual triode. The current market value of the 6j5 family and equivalent substitutions are very attractive when compared to the better nos 6sn7's. I think Mick used a pair for each channel for full gain in the line stage. What I find attractive with this toplogy is: it allows one the option of using just a single 6j5/channel for those with highly efficient speakers,or amplifiers with high sensitivity, or using two of these for higher gain without the switch in the circuit. Supratek preamps that employ the 6sn7 dual triode like my syrah, also utilize a gain switch for each channel to allow for this.I also noticed that the new Supratek Grange preamp also employs the single triode 6j5 as well as the currently produced clone of the rare Western Electric 101D balloon type directly heated triode in the line stage. There are probably more 6sn7's available to us for voicing the syrah or cortese, however.... the 6sn7 preferences in my syrah.....the tungsol round,kenrad blackglass, and the sylvania wgt metal are all obsenely expensive to acquire today and seem to be getting more so all the time. It seems that Mick has accumulated a supply of the nos 1947 vintage 6j5g and he is supplying that tube with the Grange. Any thoughts here?

Hi Jazzdude. I too have a ton of nos 6sn7's and was seriously considering converting my new cortese to accommodate the 6sn7 mainly because I wanted to compare it to my Syrah. Now... I am not so sure. Before I do so,I am going to try a bunch of nos 6j5's and equivalents. I am very impressed with the old 6j5 shoulder shaped glass bottles in the cortese. Unlike the 6sn7,there are many substitutes and electrical equivalents of the 6j5 that can be used to voice the cortese and they are certainly a hell of a lot cheaper to acquire than any of the better sounding 6sn7's.

I recently purchased a used Cortese and I would like to try some other tubes and I would appreciated some recommendations. In the main unit I have 6SN7GTB TUNG-SOL and Tung Sol electric pearl 12B4A ,then moving toward the front Philips 6922,then move to the front are 6C45N 8711 and I can't read a name on the tubes. In the power supply I have SOVTEK 5881/6L6WCG and in between that I have a Mullard GZ33 .What tubes can I replace and what should I purchase ?
Which tubes are for the phono stage ?
I have Wavelength 300b amps with WE300b's or KR300b's and Cain&Cain Single Horn Bens Speakers.
In a few months I will purchase a Bix Turntable and I could also use suggestions for a cartridge that will match the Cortese .
Thank You
Bill