HV Power Supply Recommendations

[Cary]

I am looking for recommendations for a variable high voltage power supply for various tube amp projects. One that I had looked into is the Heathkit SP-17A. Can someone give a recommendation on other supplies?

Thank you,

Cary Chin

[mcandmar]

I have a Heathkit SP-2717, great bit of kit but due to its age you’re going to have to go through them and replace the electrolytics, measure all the carbon comp resistors, and test all tubes. But that is all part of the fun right?

In real world use i find it invaluable, i much prefer having analog current and volt meters because you can see what is happening real time.   One feature it is lacking is the ability to set a current limit which could be useful.

Note there are a few versions, IP-17,SP-27,SP-2717,IP-2717 etc.  The early models used a tube rectifier and a string of gas regulator tubes for the negative supply, the later models used diodes and a string of Zeners for the negative supply. My SP-2717 is all tube based.

[Paul Birkeland]

Buy what you can find locally, you don't want to pay to ship these things!

[Deke609]

A simpler and likely cheaper solution was recently suggested on another forum: pair (1) a variac, e.g., 120VAC input with variable 1 to 130VAC output, with (2) a power transformer with high voltage secondary -- e.g., 120VAC to 600VAC (or whatever value you want) with suitable current rating.  And then put your meter on the secondary and adjust its voltage by varying the output of the variac.

This will give you variable AC high voltage. You'll need a rectifier and smoothing circuit (e.g., some diodes and a few caps and resistors) for clean DC.

cheers, Derek

[Doc B.]

Old Lambda tube supplies are nice. Holy crap I just looked at the prices on ebay. All you guys getting into tubes sure have ruined the good deals I could get in the 90s. Back then I could buy those at any swap meet for $25.

[Deke609]

... Holy crap I just looked at the prices on ebay. All you guys getting into tubes sure have ruined the good deals ...

Hear, hear! And I blame Bottlehead for getting so many people into tubes. Like me, for instance. And so ... err, well, I guess none of us here can really complain.