• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Look for high-voltage regulator projects

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#165
Some notes on the thermal drift. The biggest source of drift is Q3 with Q1 allowing a minor drift. To see what is going on measure the voltage on C2 during warm up.

The reference CCS is not thermally compensated. Drifting 1.5% as the circuit warms up is normal. If you want to play around with this change the temp of Q3 using hot air or circuit chiller. You will see lots of change. The drift caused by Q3 will be directly measurable on C2. The gate to source voltage of Q1 will also change with temp.

Don't go changing the values of R7 and R15 unless you have the equipment to verify what you are doing. R7 likes to below 50 ohms, all the way down to 0 ohms. See post 89 for more details on how the value of R15 was chosen. If you stick a 1K resistor in the R15 position you will have a nice oscillator.

My suggestion is to let your circuit warm up for a minimum of 20 minutes before doing the final voltage adjustment.
 
#167
Hey Jan,
Downloaded your T-reg article from Elektor. Looks versatile and simple enough to work troublefree.

There are two electrolytics at the output. Thought of replacing them with one 2,2u or smaller filmcap. Is the value critical and how much does it influence Zout?

Any chance of a complete mainboard kit for the lazy guys😉 ?
 
#168
No poroblem to replace it with one cap, but since the output can be up to 500V, I thoght two caps of 300V or so would be cheaper than a 500+V cap.
Don't use a film cap; this one is for stability and needs to be lossy. Just use a cheap electrolytic.
There's no impact on reg performance or Zout.

I'm going to produce a bunch of reg boards only, so without the rectifier and without the delay, for a 6080-type type that will also accomodate the MOSFET version. I will have boards left and will sell them at around $10.

If anybody wants to do a Group Buy on the main board or any other boards, I can also support that. If somebody would collect the orders I can get the boards very cheaply.

Jan Didden
 
#169
I'm going to produce a bunch of reg boards only, so without the rectifier and without the delay, for a 6080-type type that will also accomodate the MOSFET version. I will have boards left and will sell them at around $10.
Click to expand...

Nice Jan!
Suits me fine as I have a good stock of NOS ex military 6080s. Will you also sell complete populated boards or is it PCBs only? Will need a few either way!
 
#176
Wavebourn said:


It seems to me both values must be increased. Try both 1K and check if oscillations stopped, then gradually decrease while it's still stable. 10 Ohm looks like a drawing mistake.
Click to expand...


If oscillations persist, try a small ferrite bead in each mosfet gate and drain leads. Another trick to check for RF oscillations which one cannot see on an oscilloscope is to ramp the input voltage up/down with load on psu o/p and bring an AM radio close by and listen for whistles and cat calls.
Remember a mosfet has a fantastic gain and natural instinct to oscillate.

richy
 
#177
revintage said:
Hey Jan,

Great, as I found out when I reread the text! This must be the virtues of the floating regulator.

What do you consider being the lowest acceptable voltagedrop over the 6080, 100V?
Click to expand...


Not sure, probably lower as this is a tube specifically designed as a series reg tube. Probably 50-60V. But you must also take in account the input ripple. So with say 20V pk-pk ripple (depends on load current and cap values) you need to make sure the min input (bottom of ripple) is still above minumum Uak.

Jan Didden
 
#178
A couplr of people have mailed me about borads for my T-reg regulator (hi Siggi!).
First of all, I don't have those boards shown in the Elektor and AudioXpress articles, but you can order them through the Elektor website.
Secondly, I've made a couple of designs that I have ordered for people and I either have a few left or I could order more. These are regulator boards only, no rectifier, no delay circuit . You feed it raw DC and heater, out comes tightly regulated low noise DC:

6080 board: this one accepts tubes of the 6080 variety (6528, 6336 etc) OR one DN2540 with heatsink. Board size about 3.8*2 inch (9.5*5cm). Up to 1A with DN2540, 500mA with tubes. Vout max 500V.

EL84 board: accepts tubes of the EL84/EL86 variety OR one DN2540 with heatsink. Same size. Up to 40mA (tube) or 1A (DN2540). Vout max 500V

DN2470 board: accepts one or two DN2470's. Size 3*2 inch (7.5*5cm). Up to 300mA with 2*DN2470 (this is an SMD MOSFET). Vout max 700V

I'm not in the pcb business, but if there's a need for a group buy or individual needs I'll suppott that as good as I can.

Jan Didden
 
#180
power

Congratulations Jan! How nice that somebody took the time and effort to build a new radical HV power supply at last! I am about to build the thing with 6C33 pass element as the main PS for my 6C33 Se amps. I would like to ask if I can possible substitute the HV transistors you are using with what I got at the moment, which are MPSW42 & MPSW92, is it possible or I have to get the exact japanese you used? (i am also interested in some boards if available)

Thanks again!
 
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