10V Filament Transformer for 833 dilemna

Vaxian, Tue May 01 2007, 09:14AM

Hello all,

Starting a new 833 VTTC and want to use a regular transformer for the heater instead of a MOT like my 813 coil.
MOT worked OK but not all that good looking and very heavy.

Any suggestions on where I might find a nice transformer?
I have tried a few catalogs and ebay to no avail.

I want this coil to look spectacular so it needs to be a nice part.

In the parts gathering stage, going to take my time on this coil.

Dan
Re: 10V Filament Transformer for 833 dilemna
Steve Conner, Tue May 01 2007, 09:40AM

You could try Surplus Sales Of Nebraska, they seem to have lots of transformers for tube equipment. I looked on their site Link2 and saw a couple of 10V filament transformers.
Re: 10V Filament Transformer for 833 dilemna
HV Enthusiast, Tue May 01 2007, 11:16AM

If you are buying new, then HammondMFG has nice 10V, 10A transformers. Probably order through alliedelec or newark.

ADDED: Actually, you can use DC for filament voltage as well. In this case, an old PC power supply can probably be modified to give you the 10V, 10A
you need.

Dan
Re: 10V Filament Transformer for 833 dilemna
thedatastream, Tue May 01 2007, 03:03PM

EastVoltResearch wrote ...
ADDED: Actually, you can use DC for filament voltage as well. In this case, an old PC power supply can probably be modified to give you the 10V, 10A you need

Link2 * blows own trumpet *

You can just get away with removing the 5V feedback resistor and putting a pot in series with the feedback from the 12V, adjusting it to get your 10V.
Re: 10V Filament Transformer for 833 dilemna
teravolt, Wed May 02 2007, 03:07AM

you could try C&H sales. they have surplus transformers
Re: 10V Filament Transformer for 833 dilemna
Vaxian, Sat May 05 2007, 05:12PM

Thanks guys, that helps me out quite a bit.

Lost the auction for the 24k gold plated tube socket on ebay (must have been fer how much it went for!)

Project delayed but still coming.
Re: 10V Filament Transformer for 833 dilemna
Brett Miller, Sun May 06 2007, 07:01PM

Dan,

I tried to tell you this on the phone last night...but RF parts has the ideal socket for the 833 series triodes. It's ceramic, but unlike the 90 degree mounts made by RCA etc. it allows for vertical mounting of the tube, straight to the top of the chassis. Follow this link and scroll down to the SK13 socket:

http://www.rfparts.com/sockets.html

It costs less than the ebay socket went for, and I'm pretty sure it's the same socket Chris Hooper used in his dual 833C (and quad) coils.

Now that we've gone from the filament transformer to the filament socket, we are beginning to stray off topic. You may want to start a project thread regarding your impending 833A vttc.

-Brett
Re: 10V Filament Transformer for 833 dilemna
Vaxian, Mon May 07 2007, 12:56AM

Yes, saw that mount, probably going in that direction.

going for a small footprint on this one.

And yes, I need to start a project thread.
Re: 10V Filament Transformer for 833 dilemna
Fessenden, Wed May 16 2007, 12:15PM

When I was building my dual 803 VTTC I had the same dilemma. I ended up using an old 12V transformer (I think its was removed from a UPS or a car battery charger) with a few of secondary turns removed. It was not very difficult to do, and I am pleased with the results.
Re: 10V Filament Transformer for 833 dilemna
Vaxian, Fri May 18 2007, 01:23AM

I ended up using an old 12V transformer (I think its was removed from a UPS or a car battery charger) with a few of secondary turns removed. It was not very difficult to do, and I am pleased with the results.


Never even thought of that! Thanks!
Re: 10V Filament Transformer for 833 dilemna
teravolt, Fri May 18 2007, 03:42AM

If what EVR is saying is true you could use 2 5v switching power supplies in series. you get them surplus in many current ranges