I have a design for that, im currently trying to roll my own switcher.
Wurth electronic https://nl.mouser.com/datasheet/2/445/750311911-1723887.pdf
Wurth electronic https://nl.mouser.com/datasheet/2/445/750311911-1723887.pdf
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Also the second one has a separate 18VAC output you could use a multiplier from (or to boost or buck the main B+)
That second one is interesting. But I'm not so sure it makes sense as a replacement for a HV power transformer. Let's look it it closely. It claims 500W. Even if that's true, I doubt it's more than 90% efficient, so it's wasting 50W of power and heat. But you need to feed it from another SMPS that is also at least 500W and <90% efficient. So now we have at least 100W wasted power and heat. And we spent maybe $50.
But you can buy an Antek 450V 400VA toroidal for $57 that also has 6.3V windings. And I'm sure the efficiency is better than 80%. And much less complicated, I'm going to guess an order of magnitude better MTBF. And probably smaller footprint.
But you can buy an Antek 450V 400VA toroidal for $57 that also has 6.3V windings. And I'm sure the efficiency is better than 80%. And much less complicated, I'm going to guess an order of magnitude better MTBF. And probably smaller footprint.
450V would end up being 636V - almost useless in most amplifiers - My designs all use 320V B+ now. 400VA is only good about about 250W DC. Enough for most amplifiers of course. Indeed the transformer I replaced with this set up was 572VA.
Also, 57$ US, plus 48$US for shipping by USPS, and then 20% on top of it for duty and tax when it gets to Canada. The 6.3V windings are useless unless you want to run AC heaters.
A better alternative for me would be the VPT230-2170 500VA. It'll make the 320V the amp would be expecting and you can use a 12V smps for heaters.
If you want to duplicate this with Hammond transformers, expect to pay a lot more, too 🙂
My transformer input amp has a power factor of 0.7, this had a PF of 0.99. This matters in some places where you're charged for apparent power, and the linear supply will waste almost as much heat in winding loses and heat wasted on filtering. Just my 2 cents anyway 🙂
I just paid 66$ plus tax for a 20VCT 100VA Hammond transformer. 57$US for the one you mentioned is a great deal! Too bad they are only a good deal for people in the USA.
FWIW I've used the small one to power an entire EL84 amplifier from a 12V 10A brick. 40$ for the entire power supply is good for me.
Also, 57$ US, plus 48$US for shipping by USPS, and then 20% on top of it for duty and tax when it gets to Canada. The 6.3V windings are useless unless you want to run AC heaters.
A better alternative for me would be the VPT230-2170 500VA. It'll make the 320V the amp would be expecting and you can use a 12V smps for heaters.
If you want to duplicate this with Hammond transformers, expect to pay a lot more, too 🙂
My transformer input amp has a power factor of 0.7, this had a PF of 0.99. This matters in some places where you're charged for apparent power, and the linear supply will waste almost as much heat in winding loses and heat wasted on filtering. Just my 2 cents anyway 🙂
I just paid 66$ plus tax for a 20VCT 100VA Hammond transformer. 57$US for the one you mentioned is a great deal! Too bad they are only a good deal for people in the USA.
FWIW I've used the small one to power an entire EL84 amplifier from a 12V 10A brick. 40$ for the entire power supply is good for me.
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Right. Some of these things are very location-sensitive when it comes to price. I'm old enough to remember driving across to Windsor to fill up because gas was cheaper on your side. That was a very long time ago 🙂
Holy excrement! That must have been awhile ago! I can't ever remember a time when anything was cheaper in Canada than in the US LOL
Still true today. Sort of. Electricity is cheaper in QC than the US. So if you live in upstate NY or VT or ME and drive a Tesla, you could cross the border and fill up cheaper 🙂
Then you could hook up your tube amp with SMPS supplies directly to the Tesla and not need the 120 to 12V supply.
Then you could hook up your tube amp with SMPS supplies directly to the Tesla and not need the 120 to 12V supply.
Right now I’m tinkering with using an external source to replace the heater supply for my HH Scott 222C. The six power amp tube heaters come from the 6.3AC winding. The preamp’s four 12AX7s are now powered by the 50V transformer winding, rectified for DC. My thinking is it would take some of the heat off the transformer, seeing as the heater supplies account for some 20% of the amp’s 170 Watt power input.
The bias supply for the four 7189 output tubes (actually Russian equivalents) also comes from the 50V winding, but I’m concerned about using a more complicated external device, given the potential for some expensive smoke.
It’s not a museum piece, it’s my everyday amp. I’ve done extensive revisions to the amp following the design of the late Chuck Hansen. He did a four-part series in AudioXpress back in the 90s on rebuilding the 222C, using it as the basis for an amp with a dual-mono power supply. Those articles can be found floating around on various sites. It sounds terrific but I’m always curious about how much closer I can get to that last one percent and the tinkering is fun.
I grew up not far from Ontario, in Buffalo and then Cleveland. My dad always took us up to Bass Lake near Orillia every summer when I was a kid. He said the fishing was better. Later on, at college in upstate NY, my buddies and I would drive up over the St. Lawrence and bring back a couple of cases of Molson’s Brador.
The bias supply for the four 7189 output tubes (actually Russian equivalents) also comes from the 50V winding, but I’m concerned about using a more complicated external device, given the potential for some expensive smoke.
It’s not a museum piece, it’s my everyday amp. I’ve done extensive revisions to the amp following the design of the late Chuck Hansen. He did a four-part series in AudioXpress back in the 90s on rebuilding the 222C, using it as the basis for an amp with a dual-mono power supply. Those articles can be found floating around on various sites. It sounds terrific but I’m always curious about how much closer I can get to that last one percent and the tinkering is fun.
I grew up not far from Ontario, in Buffalo and then Cleveland. My dad always took us up to Bass Lake near Orillia every summer when I was a kid. He said the fishing was better. Later on, at college in upstate NY, my buddies and I would drive up over the St. Lawrence and bring back a couple of cases of Molson’s Brador.
So your 50V rectified is about 70V then? Of are you saying it's 50VDC after rectification?
110V is a lot higher, but if it's for bias there's hardly any current do you can use the 110V supply and a resistor/zener shunt regulator for it. Could put it in a Sucrets tin or something and power it with a small 12V brick. Your 12AX7 could be rewired to work in parallel from 12V, they you could just use an external brick - no DC boost. Transformer would run cooler without the heater load although 8 watts isn't a big deal in the realm of power transformers.
How hot is it that you're concerned? I have Hammonds that run at 95°C that don't care at all.
110V is a lot higher, but if it's for bias there's hardly any current do you can use the 110V supply and a resistor/zener shunt regulator for it. Could put it in a Sucrets tin or something and power it with a small 12V brick. Your 12AX7 could be rewired to work in parallel from 12V, they you could just use an external brick - no DC boost. Transformer would run cooler without the heater load although 8 watts isn't a big deal in the realm of power transformers.
How hot is it that you're concerned? I have Hammonds that run at 95°C that don't care at all.
It comes out of the bridge rectifier at about -56 V. After the RC filter section it’s -50V for the in-series 12AX7s, for the bias supply it’s taken down to about -42 and the individual bias circuits provide further reduction to provide 22mA for each grid. I haven’t had it on the bench to see how removing the heaters affects the bias side. I haven’t had time to think about it enough, so at this point my ideas are 1/8th baked. Well, maybe just defrosting.
I’ve got an order in to Mouser for the parts in Art Granell’s design for a heater power supply. When I get that together I’ll have a chance to see what if any effect it might achieve.
Unique Tube Heater Supply
But that may be delayed this darn Mediterranean climate of Western Oregon which means I have to start working on the garden. At least get the rose bushes mulched and the lawn mown. If you let the hawkweed and the blackberries gain a foothold, it’s a lot of work removing them.
I’ve got an order in to Mouser for the parts in Art Granell’s design for a heater power supply. When I get that together I’ll have a chance to see what if any effect it might achieve.
Unique Tube Heater Supply
But that may be delayed this darn Mediterranean climate of Western Oregon which means I have to start working on the garden. At least get the rose bushes mulched and the lawn mown. If you let the hawkweed and the blackberries gain a foothold, it’s a lot of work removing them.
When you use PC PS, which connectors use to feed 12v? Since I saw your images hook up more than 1 yellow wires. How much current need for the board at 12v? I am not sure if every PS connector has the same current.
Generally, all the yellow wires are in parallel. Most of the time the PS has #18 wire. You need to calculate the current carrying of the wires vs the load you have, but generally the more, the better.
In theory, you can try and claim 15A from only wire, if it's short enough...
As far as max current for the inverter board, which one are you using?
FWIW, using the 12V - 280V module, I can supply it with a 3A regulator to run phono, line, and buffer stages. For most anything but a power amplifier, you can use 1 or 2 wires...
As far as max current for the inverter board, which one are you using?
FWIW, using the 12V - 280V module, I can supply it with a 3A regulator to run phono, line, and buffer stages. For most anything but a power amplifier, you can use 1 or 2 wires...
I have read every single page to get all the idea except the current from PC PS. I think I got almost all the discussion in here. 🙂 Your reply is very helpful.
150W DC 12V-24V: 3A
500W DC 12V-24V: 5A would be enough for 400v/500mA DC?
150W DC 12V-24V: 3A
500W DC 12V-24V: 5A would be enough for 400v/500mA DC?
400W*.500mA=200W. 500W should be enough to power it. I derate every rating on cheap stuff to 40%, so you're right on the dot. A 200$ ATX will actually put out it's nameplate rating at 50°C... Most of the stuff I used in those builds didn't. Still, getting 80W out of a 200W supply is still good when it only cost 30$.
I have access to a lot of PC ATX PS from 350w-750w. I hate to throw away these things so I will save some for the projects 🙂 I have searched about this on google for a while back but didn't catch on your thread until today. I will order a few to try to see what happen. Thank you so much.