tube power supplies, switchmode

O.k. so I stumbled onto this.

If I read the data correctly, I can get a B+ of 300VDC @ 500miliamps.  Filtering the output would be necessary as it is a smpsu.

https://www.mouser.com/ProductDetail/MEAN-WELL/ELG-150-C500A/?qs=bB7QTEcmLuPOuYcUQ2%252brRw%3D%3D&gclid=EAIaIQobChMIjfawq9XV2QIVzVx-Ch2KaQFEEAQYBSABEgK0XPD_BwE

Pretty high THD. 

Yeah but THD gets better with load - only 6% with 115VAC input and 50% load. Although it's constant current so at 250mA it's probably only going to put out ~225VDC. Or just add a few chokes and caps and a capacitance multiplier and see what happends.

I don't do tubes but it certainly looks like it could work.

Looks like there are a whole bunch of higher voltage supplies that might be new. Like LPC-150-350 which can make up to 430VDC.

The spec sheet certainly seems to imply that the output voltage is constant with a load below the rated current. I had always dismissed these before as constant current but they may be quite usable. It will need some additional smoothing but with a high switching frequency that should be no problem. Probably worth buying one just to try it out.

Cheers

Ian

The THD is the utility company's problem. It draws a non-sine input current. A transformer-rectifier supply draws a VERY non-sine input current. This is probably "cleaner".

Yes, it is clearly steady 315V DC up to about 90+% of rated current. When your tube shorts, it won't get more than rated current. This may be below the melting-point of your output transformer.

You always need to clean raw DC. This may clean-up easier than raw 120Hz.

I have a lump about that size in my new 120Watt LED floodlight. It looks well-made. For the price they get for the floodlamp, and the trouble to repair/replace a floodlamp this big (23 pounds, wants to be 20 feet up on a 2" mast), it better be.

Hmmm constant current ,
Probably work ok for class a preamp stages ,where the current doesnt vary appriciably ,
maybe not so good for a  poweramp .
I dont fully understand how THD comes into the equation ,isnt it a dc voltage were looking for, is it just another way of quantifing the noise on the output of the supply ,maybe you could elaborate Emrr.

So the THD is more about about what your doing to the mains supply waveform ?

Aahhh, I missed the 'input' header on that.  What I usually see coming out of the wall here is 2-3% THD on 117VAC. 

It became time to replace the microwave here lately ,of course being a scavenger I pulled out all the electronics bits and bobs for the junk box before I recycled it , kind of nice looking 2100volt 1uf cap in them ,I ended up leaving the transformer in as 2000 odd volts Ac  I couldnt really think of any use for ,maybe a tube transmitter or something , the lams were welded so no chance of using it as a donor for a rewind .

this poses some good feedback for a test unit. Now to add one  for the heaters and for phantom power.

pucho812 said:

this poses some good feedback for a test unit. Now to add one  for the heaters and for phantom power.

Click to expand...

I exclusively now use 12V heaters so there is lots of SMPSU choice for these. I use Meanwell for this also.

Cheers

Ian

Been usg them for phantom at least 5 years now. 

PRR said:

I have a lump about that size in my new 120Watt LED floodlight. It looks well-made.

Click to expand...

Care to share a link to them? If they make a 12VDC input version, I am definitely interested.

My use is for temporary lighting on tripods. Doing live sound production, sometimes out in the middle of nowhere, the generator guy doesn't want to wait until the band, sound, lighting, and the stage loads out. So the prick just cuts off your tails, and drags off the genny. What a dickhead.

I already made up a quad of 12V / 50W LED floods with 12V/12AH battery packs, these suffice, but brighter at night would be safer for the various crews.

Gene

There was a power supply I saw not too long ago that would habe made a good B+ supply that could tap off of 12v. It was cheaper than this too, I'll look for it again when I get to a comp

Tubetec said:

I ended up leaving the transformer in as 2000 odd volts Ac

Click to expand...

Dude, no.

No no no.

Save those, even though the core is welded, the HV winding can be removed, as it is usually a separate winding. Use a chisel, whatever.

Throw about 5 turns of #4  flexible welding cable around it where the HV winding was, and you got a nice spot welder supply of 1KW+.

https://www.youtube.com/watch?v=0md3HyohxCk

Gene

i bought one  8)

ruffrecords said:

I exclusively now use 12V heaters so there is lots of SMPSU choice for these. I use Meanwell for this also.

Cheers

Ian

Click to expand...

The Mean Wells were recommended for guitar effects... from what I've read most SMPS' are prone to pick up RF noise, the one I have (PD-25B) in my current build caused an interference from a soldering station that was on next to it.

emrr said:

Been usg them for phantom at least 5 years now.

Click to expand...

Preferred model(s)??

Cheers

Ian

efinque said:

The Mean Wells were recommended for guitar effects... from what I've read most SMPS' are prone to pick up RF noise, the one I have (PD-25B) in my current build caused an interference from a soldering station that was on next to it.

Click to expand...

The PD-25 is an open frame SMPSU. It is meant to be housed in a screened box. I us the LRS series which are enclosed in a metal case.

Cheers

Ian

Thanks for the tip Gene, I should have googled first ,to late now  :-\

In reference to the use of Smps for guitar stomp boxes ,this is one place Ive seen problems of spurious noises appearing where several different supplies interact, Ive also seen issues where certain types of stomp box such as ones with BBD's have malfunctioned and or died mysteriously using smps's,cant be sure of the cause but I have my suspicions. Again just because we cant hear 75khz switching mush doesnt mean its not having an effect on the sound , the old way of powering multiple effects stomps off a generous linear supply and a splitter cable just means less head scratching and unpredictable behaviour , for me at least.Im not suggesting a well designed ,screened smps with extra filtering cant work ,but these wall warts are a liabillity in a live or studio situation .