HT regulated PSU VI

[bob orbell]

Hi all, after converting ( or bodging would be a better description ) my two PSU III's with HT regulators, one at 200 volts and the other at 250 volts and hearing a better sound, this was before my hearing diminished, I would like to propose that Matthew considers adding this fetcher to the range, as it will bring the whole series up to another level, I am sure that it will not be very difficult to achieve, because there is plenty of room in the case, as two of the capacitor positions are not used, the regulator could be fitted here, on a remade PCB. My regulators are based on two transistors and while the 250 volt regulator works OK, the 200 volt goes bang after about 3 months, I am sure that someone like John could make a better one that would stand the test of time as my knowledge of transistors is limited, to say the least. I look forward to hearing from others. Bob

[bikerhifinut]

As you know Bob, I replaced the guts of my PSU3 with a PCB kit
from Glassware Audio, ( John Broskie's site and shop in the USA< please note correct spelling bob!)
This completely cured the annoying LF instability that I was getting off Phono3S, and my CF preamp which also now is the Aikido ACF. I use ECC82 types but its adaptable to many other valves using the resistor kit supplied. I also fitted the HiFi collective remote volume control board which works a treat once a small mod is made on the power input to the board to enable it to function correctly from 6.3V DC.
It's been totally reliable, uses a pass device rather than transistors to buffer the LDO voltage regulator and its good for up to 50 mA as I remember so plenty in hand for the WD gear I set mine up for 270V HT and then use a simple RC dropper for the phono and pre which works a treat as they both have a constant draw. Theres no measurable ripple or audible hum.
The downside is the cost, I guess as the choke etc is a lot cheaper than a board with associated regulators, the caps would be present on both. If customers were prepared to spend an extra £100 or so then maybe its a worthwhile option but I fear the volumes would be insufficient to justify Matthews development costs.

Andy.

[bob orbell]

Hi Andy, yes I know what you have and it is because of this that I did my own mod ( bodge ) as said I use two power supply's, one for the Phono III and the other for my JB Akidio, but I think it would be quite simple for Matthew to change the PSU III board to include a HT regulator, adjustable or fixed, series or shunt. Lets see what he and John have to say. Bob

[bikerhifinut]

Fair comment Bob, you know where I come from on most things.
I just thought I'd chuck my paltry pennorth in.
I am certain Matthew and his design team could design a reliable board to replace the existing circuitry. So it's whether they think it's viable Ithink?

[John Caswell]

Is there a need for regulated HV supply.
It would probably have to be an SS type.
Series or shunt ( which I don't like frankly)?
Voltage?
Dual for Pre/phono?
The cost of getting a PCB done is reasonable depending on quantities, but in the end it will come down to cost, especially, if say, there is a demand for 20 but only one is sold
And so on,
All comments appreciated.

John

[bob orbell]

Thanks for the reply John, if it could be done, I would take two immediately, and no doubt others would follow, as I see it, 250 volts regulated could drive both Pre and Phono, please correct me if I am wrong, or like me, one supply for each, but I would need 250 for Phono and 200 for the CF, and this could be achieved with just a change of resistors in the divider, again correct me if I am wrong, the choke would not be necessary and the supply should be very clean giving a cleaner sound. Bob