HT supply

[isaac_teller]

Hello. Is this suitable for the HT of a guitar amp? Current and isolation? Thank you.
https://www.ebay.com/itm/DC-DC-8-32V-to-45-390V-High-Voltage-Boost-Converter-ZVS-Step-up-Booster-Module/322374615632?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m1438.l2649

[shooter]

Output Voltage: +45~390V continuously adjustable (default output ±50V)
 Output Current: 0.2A Max(with input, output pressure related,the higher the output voltage, output current is smaller)

This statement alone would save me $5 
you "max" current guessing happens around 50vdc, by the time you get to some useful vdc for tubes there might be enough to power a 12XX7, You still need a filament tranny.
anytime I see specs talking things like "output pressure" I just move on down the line

[kagliostro]

This has also a heater exit (max 3A) but B+ is rated max 60mA (output voltage is from 150V to 420V) and I don't think they are available at max Hig Voltage output

it will be good for small amp or preamp

https://www.ebay.it/itm/DC-12V-to-150V-420V-DC-High-Voltage-Power-PSU-Board-f-Tube-amp-Preamp-Filament/173034019336?hash=item2849a19a08:g:n~IAAOSw4qxap6GE



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The Step Up you posted

https://www.ebay.com/itm/DC-DC-8-32V-to-45-390V-High-Voltage-Boost-Converter-ZVS-Step-up-Booster-Module/322374615632?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m1438.l2649

seems to be able to give around 100mA @ 390V (40W max .... OK, peaks of 70W are allowed, but 40W max)

Franco

[silverfox]

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The Step Up you posted

https://www.ebay.com/itm/DC-DC-8-32V-to-45-390V-High-Voltage-Boost-Converter-ZVS-Step-up-Booster-Module/322374615632?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m1438.l2649

seems to be able to give around 100mA @ 390V (40W max .... OK, peaks of 70W are allowed, but 40W max)

Franco

That doesn't look like 40 watts. Also, is this something recommended for audio? When I've suggested something like this in the past there was the caveat- It may generate a lot of noise.


silverfox.

[shooter]

FWIW, For the price, if you like to tinker and play with electronics as a hobby, there WILL be a use down the road if it can't do tubes.  The switching is at 75khz (IIRC?) which shouldn't bother tubes, but from my experience, any time I get an amp near a poorly made switching supply, I get noise in my otherwise quiet amp

[silverfox]

75 khz could probably be filtered since it's so far above the audio range, and it could be put in a properly cooled Dog House.


silverfox.

[Tony Bones]

The doghouse is important. Filtering the supply itself is not too hard, but switchers tend to radiate a lot of EMI at the switching frequency and harmonics. You might get away with just putting something like this at the far end of the chassis, but putting it inside a grounded box helps.

[silverfox]

Another possibility might be, raising the amp ground 5 or 10 ohms above inverter and earth ground. Recently saw a circuit that did that.


silverfox.

[kagliostro]

..... is this something recommended for audio?

So they say in the description

DC12V boost, with a set of filament and a set of high voltage, two sets of voltage adjustable
 
Input voltage: 12VDC
 
Output high voltage: 150V-420VDC, 1.25V-12V DC filament voltage regulator is adjustable
 
Due to the use of high-frequency switch, no effect on the audio, signal to noise ratio is very high.
 
The max of the current of the High-voltage output is : 60MA
 
The max of current of filament output is:  3A

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That doesn't look like 40 watts.

The image is referred to the first link, not those you posted, the circuit on the image spec say 60mA


I told

it will be good for small amp or preamp

Franco