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Modification to Ultrapath

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T

Tubenstein

Member
Joined 2011
#1
Hi All!
My friend is working on an upgrade to hid Ultrapath based on this link. I just wonder anyone has tried it.
Section 6:

ultrapath (1).jpg


https://www.dmitrynizh.com/Ultrapath.htm#a_solution
The attachment is the circuit of his Ultrapath
 
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#3
The discussion goes all over the place on the ultrapath concept. I built the Electra-Print 6A3 pull pull amp with ultrapath and the suggested power supply. It's dead quite. It does take a quiet power supply. Others, such as your link, have modified ultrapath. Try it and see. This is a high voltage circuit.
Regards, HeyBill
 
#4
What do you guys think if using a regulated power supply for both HV and LV? Should the UltraPath Cap lower the value than now which is 470uf 450v?

NormLLY regulated power supply has very low ripples and impedance and should have some effects on the UltraPath circuit.
 
#8
The whole point is that you inject just the right amount of ripple at the cathode so that it is amplified to the plate where it will be in phase and of same magnitude as the B+ ripple - the output transformer then has no ripple across it and no noise at the output. It's an old form of noise cancellation. I will be using it on my next SE 2A3 build.
 
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#10
Bigun said:
The whole point is that you inject just the right amount of ripple at the cathode so that it is amplified to the plate where it will be in phase and of same magnitude as the B+ ripple - the output transformer then has no ripple across it and no noise at the output. It's an old form of noise cancellation. I will be using it on my next SE 2A3 build.
Click to expand...
But on this one there is no adjustment for the "right amount of ripple". It is bound to hum.
 
#11
I've tried but just can't see the advantage to it. Signal voltage grid to cathode is more significant than anode to cathode by a factor of stage gain. For this scheme to be significant at all implies a significant impedance from cathode to signal common, so why not expend the same effort instead into reducing B+ noise directly rather than burdening the output valve with its modulation? Just can't see any upside, except in some extremely cost constrained commercial product, but not in DIY.

All good fortune,
Chris
 
#12
Bigun said:
The whole point is that you inject just the right amount of ripple at the cathode so that it is amplified to the plate where it will be in phase and of same magnitude as the B+ ripple - the output transformer then has no ripple across it and no noise at the output. It's an old form of noise cancellation. I will be using it on my next SE 2A3 build.
Click to expand...
How big is the hum reduction in dB? Can it be calculated (ideally)?
 
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