Electronics > Projects, Designs, and Technical Stuff
Planning to build benchtop 500V tube PSU, help needed.
basinstreetdesign:
TERRA Operative:
What's the big deal? Don't listen to the nay-sayers. If you can get the transformer you want then that's the biggest problem out of the way. All the rest is small stuff. But study the power supplies that the Tek guys put into the 500-series scopes as there are many lessons on efficient, high quality design there. I did here:
https://www.instructables.com/id/Tube-Power-Supply/
Admittedly the power transformer is from one of those scopes since I couldn't find a suitable one otherwise (and I, as well, was trying to build it from junk-box stuff, cheapskate that I am) but it serves very well. I stole the basic fundamental circuit for the HV section from the old scope and much of the -100V regulator from there as well and all the rest is mine. Its about 8 years old now and hasn't made a room full of smoke yet so I'm thinking it can't be so bad.
Anyway, there is no problem with several pass tubes in parallel as long as they are halfway-well matched.
I like the idea from your original schematic that allows the output to go to zero but I doubt that less than 50V is often useful, the LV tube enthusiasts notwithstanding.
TERRA Operative:
Ha yeah.
I just want to build a tube based PSU for fun that I can use for building more tube stuff. The key word is 'for fun'...
Like I don't care if it isn't gold standard efficient or hasn't got perfect mV level regulation, it's for prototyping valve circuits which don't care about that stuff anyway, just so I can try out tube stuff without having to build a power supply every time.
I want to do it old school for old school sake and *for fun*
I think I might just drop this thread and build it myself as I feel like it, there's too many wildly different opinions and naysayers here telling me to just buy some premade unit, completely missing the point of this DIY thread to start with.
TimFox:
A bit of my history building a simple tube regulator for a theremin (fixed 250 V output).
I used a triode-connected 6Y6GA as the pass tube (low voltage drop) with a 6SH7 pentode error amplifier and a 0A3 75 V reference. The first build had a high frequency (roughly 70 MHz) parasitic oscillation, which I cured with a stopper resistor between the 6SH7 plate and the 6Y6 grid. Thereafter, I was paranoid about oscillation, and looked carefully at the output. The 120 Hz ripple was acceptable, but I found a similar amplitude line-synchronous component at precisely 10 Hz. I futzed around with the circuit near the 6SH7 plate, but only the amplitude changed—the frequency remained 10 Hz. While I was going crazy, my wife suggested that maybe I was picking up something, rather than an oscillation. I disagreed, since the only two things powered on were the oscilloscope and the soldering iron. Shutting the iron off removed the 10 Hz signal. The soldering station and DUT were both connected to the bench outlet. Apparently, the servoed soldering station at idle, with a zero-crossing switch, was in a limit cycle at 10 Hz, synced to the 60 Hz line. This must have modulated the heater of the 6SH7 and put a 10 Hz component into its input offset. A dual triode diff amp would have had less response to this heater variation.
001:
hi
How are You? No posts for a long time :-//
Wolfgang:
Hi,
sorry for no progress, but still searching the web for some realistic tube SPICE models.
Wolfgang
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