Preamp PT

[Smokebreak]

Mark's preamp enclosure has got my wheels a spinnin..
What sort of PT have you guys used for a standalone preamp?
I'm thinking 4 stages.

[Leo_Gnardo]

What sort of PT have you guys used for a standalone preamp?

I didn't build it, hardly, buy my Alembic F2B IIRC has a nice lil PT, 6.3V 2A plus 125V at maybe 50 mA. Uses a voltage doubler on the hi voltage supply and filaments are run straight no tricks. It may have been a Stancor, not likelyyou'll find the same from them now. I'd scan the toroids for something along these lines, and an easier fit in a single rack space if that's what you're planning. More filament V and I if you're going to go DC regulate it.

[Regan]

This could be a nice little transformer for that!
I been keeping it in the back of my mind for awhile
http://ca-en.alliedelec.com/search/prod ... #tab=specs

Regan

[sluckey]

The Weber WRVBPT is a good choice also. It will fit inside a 2.5" high chassis. 260V/100mA and 6.3V CT/3A.

https://taweber.powweb.com/store/wrvbptsch.jpg

[M Fowler]

Single preamp tube transformer fits 2" chassis. I haven't used it yet.

https://www.tubedepot.com/products/sing ... ransformer

[Smokebreak]

Thanks everyone! Lots of good options here. I also came accross the Hammond 229 series, at around $12 a piece, but I'd need 1 for filament and 1 for power. They are "low profile", as well.
Leo, I'm considering regulating 12.6V DC heaters, and I'm thinking I would like to try some PCB work, as well. I'm starting to run out of room for big amps around here. Perhaps a run of small preamps is in my future

[M Fowler]

Yes I have a set of those 229 series going into a preamp too.

[ubxf]

The Alembic is using a Stancor PS-8415

[ampgeek]

Smokebreak,
Don't hesitate to give me a shout if you get a hankering to do some DIY PCBs for regulated DC filament power supplies. I have a couple of approaches and layouts that are working quite well so far.
Cheers,
Dave O.

[Smokebreak]

Thanks Dave. OK let's start at the top, selecting a filament xformer for regulated DC heaters. I've got to place an order with Mouser anyways so I'm going with these : http://www.mouser.com/ds/2/177/5c0013-48724.pdf

The way I see it, I'll be running 3 12ax7s, so would need at least 900mA for 6.3VAC operation. I'm going to wire the heaters in series with 12VDC, so I'll need 450mA .
Of course I'll need to rectify the secondaries, and I'll also need about 3V on top of the 12V, for the regulator to work. Also, Let's assume I won't need 5V for relays, for now, and that I can elevate the regular with a diode or 2 to get that extra .6V..

So I need around 15VDC. This is where I'm getting turned around with choosing the correct Xformer. Would I go with the 229B12? I mean, I understand I'll need to rectify ~12V to get to ~15, but I'm confused about whether to look at the parallel or series voltage to get there.

EDIT: I should say that I'm planning Bancika's MKIIC+, and just got the trace printed onto acetate, as I plan on using this method of etching: http://makezine.com/projects/cheap-frie ... b-etching/

[TUBEDUDE]

Smokebreak, you'll want to use thicker traces than the examples in that PCB tutorial.

[John_P_WI]

Without reinventing the wheel:

http://www.londonpower.com/power-supply ... wer-supply

[Smokebreak]

Yes, that PS kit hipped me to the 229 series, but I was thinking I'd fabricate my own and save a couple bucks...still an option though. I don't think he sells just the boards.

Tubedude this is the trace mask: http://diy-fever.com/wordpress/wp-conte ... ce_v11.pdf[/url]

[ampgeek]

I have used this PT a couple of times in DC filament applications with good success. But....I was doing 6.3 volt parallel configurations.

http://www.mouser.com/Search/ProductDet ... 546-187D10

Any chance that you have a schematic for that etching trace? I suspect that it has multiple regulators but would like to confirm it.

Two 12A*7s off of a single LM type regulator is a piece of cake. Three pushed me into thermal management concern territory big time which complicated things significantly.

Rock on!
Dave O.

[Smokebreak]

Here's the schematic : http://diy-fever.com/wordpress/wp-conte ... _schem.png
He used 6.3V in parallel , so the regulators were for for the relays and the B+, so I'm kinda goin off page here.

Check out my question above concerning how to select a filament tranny for my application. I'd like to get that process under my belt. That datasheet is throwing me for a loop.

That said, as I'm already gonna be over my head with the main PCB, as this is my first time going through any of that process, the KOC PS kit John linked to is looking more and more appealing. I'm relying on interweb traces as it is, and if I used the Hammond 229s, I'd have to come up with another board, and deal with mounting those PCB mounted trannies.
The one Regan linked to is looking good, too. I could bolt it down and coming up with a board for just the regulator circuit seems less daunting. I could always PTP that too, I guess.
Just trying to extend myself here a bit, but not sure how over my head I wanna go