amp power supply question

[Berger]

So I'm looking to make up a power supply for the mini tube amps that I've been making. I'd like to move away from the dc booster that I had been using. and move to the true amp setup. I've made a couple amps(firefly's) but they just use one power transformer.

I've been having trouble finding powersupplys that put out 80~100vac, but I have a couple that put out 40vac. Can I tie two together to get this?

Will this work?



Thanks for any help/suggestions

-Berger

[Ripthorn]

I probably wouldn't try that just because it is dangerous and you might get some negative effects from too much voltage across one or both the cores if they are tied together.  What I would do is use a 12vac wall wart and in your amp, use a 12v secondary/115V primary.  Rectifying that and filtering gives me about 120V to send to the tubes, which is getting up there in range for most subminis (most have a max voltage of ~150V).  Works like a charm.  Depending on how much power you need, you can even use the cool encapsulated transformers from Pulse (sold at mouser, etc).  I bought a few for submini preamps that I am going to be building.

[Berger]

Thanks for the suggestion. I was looking through one of my binders and found a print out that describes exactly as you said, so I'll look into that as well.

do you have any part numbers for the "encapsulated transformers from Pulse" so I can take a look at those as well.
Thanks for the reply.

-Berger

[Ripthorn]

I think this is the one that I used.  Four bucks ain't bad in my book.

http://www.mouser.com/Search/ProductDetail.aspx?qs=sPF7iluEOp7VFT9pQ%252b5Fwg%3d%3d

[Berger]

cool thanks!
any chance I could get you to draw something up, as to how you are connecting them up to get the 120 back out?

Thanks for all your help so far!

-Berger

[Ripthorn]

I'm not able to draw one up right now, but just connect your 12vac from the wall wart to the 12v secondary of the transformer.  The other side puts out the 115vac, rectify that and filter.

[slacker]

Have a look at the schematic for the Real McTube, that's uses the back to back transformer trick.

[Berger]

Real McTube! Thats where I remember seeing that. for a moment I thought it was from the shaka tube.

http://www.dogstar.dantimax.dk/tubestuf/mctconst.htm#altps

the alternate power supply here is what I want. Looks like they tap 12v off as well, which would be nice.

Thanks for the help and suggestions guys!

-Berger

[petemoore]

  PRetty slick !
  Gotta watch the current rating on the first transformer, it'll have to power everything including the heaters.

[doitle]

I think this is the one that I used.  Four bucks ain't bad in my book.

http://www.mouser.com/Search/ProductDetail.aspx?qs=sPF7iluEOp7VFT9pQ%252b5Fwg%3d%3d

Oooh neato I may be buying this for some experimenting, I've built the valvecaster and caught the tube bug. It sounds so good!

[Berger]

  PRetty slick !
  Gotta watch the current rating on the first transformer, it'll have to power everything including the heaters.

I picked up 4 2amp 12vac power supplies off of ebay....so I'd that they should be good enough...but that is a great reminder thanks!

I need to check the current draw on the submini heavy watter I made. I know it loads down my 12 2+amp(I don't remember the size) down to 11.8volts. and thats doing the heaters and upconverting,etc

Once again, thanks for reminding me of the current requirements!

-Berger