ruffrecords
Well-known member
That looks like it. There are other dual ones but they are low voltage. I have tagged the HV schematic at the end of this post. It is basically a discrete diff amp using a TL431 as a reference. The diff amp uses a pair of MJE13003 transistors. The TL431 is the set point so the minimum output noise is defined by the TL431 noise plus the ability of the loop to reject supply hum. The latter depends on the loop gain which I think is defined by the product of the MJE13003 beta and the bypass FET gain. Unfortunately the beta of the MJE13003 lies in the region of 8 to 40 so this might give us about 20dB lower ripple than the simple zener circuit.
I found one on eBay in the uk:
https://www.ebay.co.uk/itm/1pc-GZ34-5AR4-Kubota-Low-noise-Audio-adjust-HV-regulator-for-tube-amplifier-PCB/201343461287?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m2749.l2649
so I have ordered one to try out.
Cheers
Ian
I found one on eBay in the uk:
https://www.ebay.co.uk/itm/1pc-GZ34-5AR4-Kubota-Low-noise-Audio-adjust-HV-regulator-for-tube-amplifier-PCB/201343461287?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m2749.l2649
so I have ordered one to try out.
Cheers
Ian