Post by mikekca on Jun 26, 2008 12:44:00 GMT -7
Mike ...
Just dropping a note here .... on Sunday, yesterday, I went over David Amussen's custom Fender Vibroverb BF at my place. He had a number of tubes in the amp that he said came from you. The two 12AT7s were Mullards from you and there were a number of NOS 12AX7s.
In my normal process of blueprinting I pull each tube and spec it for plate current, transconductance, plate resistance and gain. In every case the tubes that came from you were not only dead on design spec but in the case of the two 12AT7s they had matched triodes.
I showed Dave examples of how current production tubes fare .... on the 12AT7s how they are off by over 40%, weak in plate current and TC and how poorly matched they were. I also ran true gain tests on the 12AX7s and all your supplied tubes had gain that was over 95% while new tubes were in the 80-85% range at best.
Taking two of the same make of 12AX7 in V2 (the channel he uses), one with 95% gain and the other with 85% gain Dave easily noted the difference in performance. He was surprised that such a "small" difference in spec made such a large difference in performance until I explained that the first gain stage is just that ... the first stage ... and other things kept amplifying the good or bad down the line.
He also saw how one of your 12AX7s in V4 versus a new production tube made a noticible change in this position that many Fender folks feel didn't matter.
The bottom line here I suppose is this .... every tube that came from you was a spectacular tube. In the case of the Mullard CV AT7 types he had some extras that he said came from you and these were all tested on my gear and curve tracers .... and every one was great.
Thanks for continuing to do what you do so well.
Myles
Thanks Myles!