Help finding the proper transformer?

Hi guys.

I was wondering if any of you knew where I might be able to find a transformer that outputs 3.15v for heaters along with 230V for mains. I've never seen this before since all I have ever seen is 6.3v ones or the DC setup. Oh, I should also mention that I would be using 120v primaries. Maybe I could get one with a CT on the heater winding and then use the CT as the low side and regular positive tap as the high side? but then I would lose current I think..

Basically, I'm looking for a power transformer for this:
http://www.faustone.com/pdf/Faustone_Valve_Klipper_schematic.pdf

You don't need 3.15, you need 6.3.  The schematic shows 3.15 at the top and bottom of the upper secondary winding, totaling 6.3v.  A 12AX7 (ECC83) filament will run off of 6.3 or 12.6 volts.

I see. Thanks!  ;D I was starting to wonder why the number was exactly half of 6.3v. Then I started reading this: http://www.fenderforum.com/forum.html?db=&topic_number=674112

But I was still a bit uncertain as to what was going on.

Hm, I guess I just need to know how much current my circuit wants. I wish I knew how to calculate this..

So this
250V @130mA
6.3V @2A
http://www.tubesandmore.com/products/P-T261G6


or this
250V @ 23mA
6.3V @ 1A
http://www.alliedelec.com/search/productdetail.aspx?SKU=70008994

> I wish I knew how to calculate this..

Ohms law rules!

_You_ can look-up the tube data sheets and figure how much 6V it eats.

Your raw B+ is 350V. There's two ways it goes.

A 150K resistor to some junk (a tube). Mr Ohm tells us this can't be much over 2mA. Some understanding of how amplifiers work suggests much less.

A 47K resistor to a lot of junk. Detailed analysis takes a while. Worst case though is 7mA, see if that narrows your choice.

2mA + 7mA = 9mA or less.

> 250V @130mA
> or this
> 250V @ 23mA

It's time for _me_ to take my poorly edge-a-moo-cated butt over to ye old tube datasheet for some objective information.

Thanks PRR.. ohms law is so simple that sometimes I completely overlook where I should be applying it.

V=IR
R=V/I
I=V/R

PRR said:

>

Your raw B+ is 350V. There's two ways it goes.

A 150K resistor to some junk (a tube). Mr Ohm tells us this can't be much over 2mA. Some understanding of how amplifiers work suggests much less.

A 47K resistor to a lot of junk. Detailed analysis takes a while. Worst case though is 7mA, see if that narrows your choice.

Click to expand...

I like this info. so I do the math, and I get this.

Another option for you:
http://www.antekinc.com/as-05t240-50va-240v-transformer/

that's a nice flat guy. I choose him.