I am looking for a source of a very small transformer that will supply
125 VAC on the secondary and enough 6.3 VAC with current for 1 or two
small tubes. Something on the order of a 12AX7 or 2. Small physical
size is important. I need to be able to shoehorn the whole thing
inside of a double outlet box.

Jimmie

JIMMIE wrote:
I am looking for a source of a very small transformer that will supply
125 VAC on the secondary and enough 6.3 VAC with current for 1 or two
small tubes. Something on the order of a 12AX7 or 2. Small physical
size is important. I need to be able to shoehorn the whole thing
inside of a double outlet box.

Jimmie

Bell transformers are smallish - but they put out more than 6 V AC.
If you want SMALL, a high frequency drive to a few turns on a ferrite
core it the bill well.

Brian W

On Sun, 28 Mar 2010 20:22:59 -0700 (PDT), JIMMIE
wrote:

I am looking for a source of a very small transformer that will supply
125 VAC on the secondary and enough 6.3 VAC with current for 1 or two
small tubes. Something on the order of a 12AX7 or 2. Small physical
size is important. I need to be able to shoehorn the whole thing
inside of a double outlet box.

Jimmie


May be too big:

http://www.mouser.com/Power/Transfor...rmer&FS =True

On Mar 28, 11:22*pm, JIMMIE wrote:
I am looking for a source of a very small transformer that will supply
125 VAC on the secondary and enough 6.3 VAC with current for 1 or two
small tubes. Something on the order of a 12AX7 or 2. Small physical
size is important. I need to be able to shoehorn the whole thing
inside of a double outlet box.

Jimmie

Hey OM:
Gits' yourself a old busted VTVM the real old ones used a 6AL5 and a
12AX7 and had to have secondary isolation for the plates of the 12AX7.
I remember I picked up a VTVM for 2USD at a radio rally

73 OM
de n8zu

On Mar 29, 8:16*am, raypsi wrote:
On Mar 28, 11:22*pm, JIMMIE wrote:

I am looking for a source of a very small transformer that will supply
125 VAC on the secondary and enough 6.3 VAC with current for 1 or two
small tubes. Something on the order of a 12AX7 or 2. Small physical
size is important. I need to be able to shoehorn the whole thing
inside of a double outlet box.

Jimmie

Hey OM:
Gits' yourself a old busted VTVM *the real old ones used a 6AL5 and a
12AX7 and had to have secondary isolation for the plates of the 12AX7.
I remember I picked up a VTVM for 2USD at a radio rally

73 OM
de n8zu

Hmm, think I got one if I didn't toss it on my last clean up.

Daughter wants a preamp/tone control she can connect between her
guitar and a PA. Circuit design is no problem but fitting it all in
the box she wants it in may be a headache

Jimmie

JIMMIE wrote:
On Mar 29, 8:16 am, raypsi wrote:
On Mar 28, 11:22 pm, JIMMIE wrote:

I am looking for a source of a very small transformer that will
supply 125 VAC on the secondary and enough 6.3 VAC with current for
1 or two small tubes. Something on the order of a 12AX7 or 2. Small
physical size is important. I need to be able to shoehorn the whole
thing inside of a double outlet box.

Jimmie

Hey OM:
Gits' yourself a old busted VTVM the real old ones used a 6AL5 and a
12AX7 and had to have secondary isolation for the plates of the
12AX7. I remember I picked up a VTVM for 2USD at a radio rally

73 OM
de n8zu

Hmm, think I got one if I didn't toss it on my last clean up.

Daughter wants a preamp/tone control she can connect between her
guitar and a PA. Circuit design is no problem but fitting it all in
the box she wants it in may be a headache

Jimmie

You can probably find a suitable transformer at www.oldradioparts.com. They
have a $20.00 minimum, but they have a good selection of new and used parts
of all kinds, including transformers. Download the latest transformer list
at http://www.oldradioparts.com/2a23efl.txt and browse thru it to find a
suitable candidate. You'll probably find just about all the parts you'll
need to build the project from the web site; it's just a bit tedious to read
thru all the lists to find what you need.
I've done business with them before and find them to be reputable and easy
to deal with.

If you can't meet their minimum, you might download the Hammond transformer
catalog from and find the part number of a suitable unit, then search Mouser
(www.mouser.com), Digikey (www.digikey.com), Jameco (www.jameco.com), Allied
(www.alliedelec) and Newark (www.newark.com) web sites to buy.
--
David
dgminala at mediacombb dot net

Dave M wrote:
JIMMIE wrote:
On Mar 29, 8:16 am, raypsi wrote:
On Mar 28, 11:22 pm, JIMMIE wrote:

I am looking for a source of a very small transformer that will
supply 125 VAC on the secondary and enough 6.3 VAC with current for
1 or two small tubes. Something on the order of a 12AX7 or 2. Small
physical size is important. I need to be able to shoehorn the whole
thing inside of a double outlet box.

Jimmie

Hey OM:
Gits' yourself a old busted VTVM the real old ones used a 6AL5 and a
12AX7 and had to have secondary isolation for the plates of the
12AX7. I remember I picked up a VTVM for 2USD at a radio rally

73 OM
de n8zu

Hmm, think I got one if I didn't toss it on my last clean up.

Daughter wants a preamp/tone control she can connect between her
guitar and a PA. Circuit design is no problem but fitting it all in
the box she wants it in may be a headache

Jimmie

You can probably find a suitable transformer at
www.oldradioparts.com. They have a $20.00 minimum, but they have a
good selection of new and used parts of all kinds, including
transformers. Download the latest transformer list at
http://www.oldradioparts.com/2a23efl.txt and browse thru it to find a
suitable candidate. You'll probably find just about all the parts
you'll need to build the project from the web site; it's just a bit
tedious to read thru all the lists to find what you need. I've done
business with them before and find them to be reputable and
easy to deal with.

If you can't meet their minimum, you might download the Hammond
transformer catalog from and find the part number of a suitable unit,
then search Mouser (www.mouser.com), Digikey (www.digikey.com),
Jameco (www.jameco.com), Allied (www.alliedelec) and Newark
(www.newark.com) web sites to buy.

Oops... I forgot to paste the URL for Hammond's power transformer page.
It's http://www.hammondmfg.com/5cpwr.htm.
You should also download their cross reference guides at
http://www.hammondmfg.com/5ccross.htm to find suitable transformers from
other manufacturers to get the best price.
--
David
dgminala at mediacombb dot net

On Mar 29, 6:31*pm, "Dave M" wrote:
Dave M wrote:
JIMMIE wrote:
On Mar 29, 8:16 am, raypsi wrote:
On Mar 28, 11:22 pm, JIMMIE wrote:

I am looking for a source of a very small transformer that will
supply 125 VAC on the secondary and enough 6.3 VAC with current for
1 or two small tubes. Something on the order of a 12AX7 or 2. Small
physical size is important. I need to be able to shoehorn the whole
thing inside of a double outlet box.

Jimmie

Hey OM:
Gits' yourself a old busted VTVM the real old ones used a 6AL5 and a
12AX7 and had to have secondary isolation for the plates of the
12AX7. I remember I picked up a VTVM for 2USD at a radio rally

73 OM
de n8zu

Hmm, think I got one if I didn't toss it on my last clean up.

Daughter wants a preamp/tone control she can connect between her
guitar and a PA. Circuit design is no problem but fitting it all in
the box she wants it in may be a headache

Jimmie

You can probably find a suitable transformer at
www.oldradioparts.com. *They have a $20.00 minimum, but they have a
good selection of new and used parts of all kinds, including
transformers. *Download the latest transformer list at
http://www.oldradioparts.com/2a23efl.txtand browse thru it to find a
suitable candidate. *You'll probably find just about all the parts
you'll need to build the project from the web site; it's just a bit
tedious to read thru all the lists to find what you need. I've done
business with them before and find them to be reputable and
easy to deal with.

If you can't meet their minimum, you might download the Hammond
transformer catalog from and find the part number of a suitable unit,
then search Mouser (www.mouser.com), Digikey (www.digikey.com),
Jameco (www.jameco.com), Allied (www.alliedelec) and Newark
(www.newark.com) web sites to buy.

Oops... I forgot to paste the URL for Hammond's power transformer page.
It'shttp://www.hammondmfg.com/5cpwr.htm.
You should also download their cross reference guides athttp://www.hammondmfg.com/5ccross.htmto find suitable transformers from
other manufacturers to get the best price.
--
David
dgminala at mediacombb dot net

Thanks guys, I found one transformer in my junk box that should work.
As a matter of fact it is part of an audio phono preamp. Think I made
need a couple more if this works out .

Jimmie

Check Signal Transformer, they are sold by Digi-Key & many others. They make
some dual secondary that are very small but plenty of current for what you
are going to use it for. I used many of them in Progressive Systems for
Electronic Gaming Machines.
"JIMMIE" wrote in message
...
I am looking for a source of a very small transformer that will supply
125 VAC on the secondary and enough 6.3 VAC with current for 1 or two
small tubes. Something on the order of a 12AX7 or 2. Small physical
size is important. I need to be able to shoehorn the whole thing
inside of a double outlet box.

Jimmie

On Mar 30, 2:03*am, "Howard K0ACF" wrote:
Check Signal Transformer, they are sold by Digi-Key & many others. They make
some dual secondary that are very small but plenty of current for what you
are going to use it for. I used many of them in Progressive Systems for
Electronic Gaming Machines."JIMMIE" wrote in message

...



I am looking for a source of a very small transformer that will supply
125 VAC on the secondary and enough 6.3 VAC with current for 1 or two
small tubes. Something on the order of a 12AX7 or 2. Small physical
size is important. I need to be able to shoehorn the whole thing
inside of a double outlet box.

Jimmie- Hide quoted text -

- Show quoted text -

Not clear on the OPs application but ............
12AX7 double triode takes 12.6 volts on its heater at IIRC 0.15 amps?
BTW 12.6/0.15 = 84 ohms (hot).
Another approach if circuit isolation permits it, is to 'drop' voltage
for the heater re-actively by using a capacitor.
If 125v AC is available?
For example 125 minus 12 = 113 volts to be 'dropped'.
The reactance of a capacitor rated for 'peak' voltage of around 180 -
200 volts; RMS = 120v.
113/0.15 = 750 ohms approx. (Since it's mainly reactive no need to get
into a vector diagram!).
Since Xc = 1/2pi.f.C A one microfarad cap. has a reactance of about
2650 ohms.
So 2650/750 = 3.5 microfarad (AC capable). In practice it'd probably
work with anything from 3 to 4 mfd. A not too unusual size of AC motor
cap is 3 mfd. But cap. size consideration.
Just floating an idea. Have only tried this on experimental basis but
it worked!
And IIRC it was a 12 volt surplus WWII tube that we used. The same AC
rectified, filtered with a capacitor, provided B+ for the experiment.