[jim151]

FREE ULTIMATE 70 AMPLIFIER UPGRADE Will this work for a supper 70

    

FREE ULTIMATE 70 AMPLIFIER UPGRADE

If you have an Ultimate 70, here is all you need to do:
1.    Make sure the amp is cold and unplugged.
2.    Locate the six wires connected to the PC board at the hole in the chassis where the quad filter cap once was located.
3.    Disconnect the two red transformer leads from the eyelets marked RED.
4.    Disconnect the wire from the eyelet marked B+.
5.    Connect the B+ wire to either of the eyelets marked RED.
6.    Connect the two red transformer leads to the eyelet marked B+ (two wires need to go into one hole together).
7.    Readjust bias.
8.    Listen again.

This makes a major sonic improvement by connecting the power to the audio board regulated power supplies after the choke instead of before the choke.

[oneinthepipe]

Yes.  I had my Super 70i upgraded by the factory to an Ultimate 70.  The difference was phenomenal.  If you choose to build the kit, a lot of the wiring changes were already done when the amp was upgraded to a Super 70i.

[avahifi]

If your question is, "Does the wiring changes described for the Ultimate 70 also apply to the older Super 70i design?", the answer is no, it is a completely different power supply design and the wiring change is not applicable.

Regards,

Frank Van Alstine

[Brett Buck]

If your question is, "Does the wiring changes described for the Ultimate 70 also apply to the older Super 70i design?", the answer is no, it is a completely different power supply design and the wiring change is not applicable.

    But the question suggests a good path forward. A Suoer 70 is a pretty decent improvement, the U70 is a huge leap, and the choke mod is another pretty big leap.

    BTW, Frank, did you figure out what in the front end of the circuit cared about the choke being in line?  I had a chance to change my dad's as indicated, and WOW, that made a big difference. I also tried putting a scope on it and, like you said, it didn't seem to make any consequential difference in the supply voltage. But you could sure hear it - like another octave added to the top. It was unequivocal - I could tell even with it just hooked to the TV outputs. Even the old man could hear it and he wears two hearing aids. This is the first tube amp I have ever heard that can objectively match up with the best transistor stuff. BY A LONG SHOT, the best tube amp I have ever heard, regardless of the price (and that's saying something for what some of these yutzes are paying).  Not even close, and it was no match for my Omegastar 260 before. Now it is.

    Something in there is extremely sensitive to the power supply reactance/capacity, but I couldn't for the life of me figure out what it might be. It's must be more than just getting rid of residual AC, because that was almost nothing before. 

     Brett

[oneinthepipe]

Yes.  I had my Super 70i upgraded by the factory to an Ultimate 70.  The difference was phenomenal.  If you choose to build the kit, a lot of the wiring changes were already done when the amp was upgraded to a Super 70i.

Oh, sorry, I am a dummy.  I asked that same question before, and after reading everyone's responses about the U70, I sent my Super 70i to Frank to be upgraded.

[simon wagstaff]

U70 with that simple little mod is amazing.