Powering tubes in a car...

[KatieandDad]

The simple TL497 Buck regulator will do the job.

The components to the right of L1 simply need to be scaled to produce the voltage required.

You are sampling the output so you want 1.2V across R5.

TR1 needs to have sufficient Vce rating for output voltage as does D1 and C4.

Other than that the extra voltage comes from the collapsing field of L1 so L1 will need to have sufficient inductance to produce the voltage required.

In my experience just wind as many turn as you can on an RM type pot core with wire that can sustain the current required.

The circuit becomes more complex at higher currents but for low current use this will do the trick.

[speaker]

Originally Posted by Doz

This is a power amp, I can't see a 6DJ8 producing much in the way of output power. OK if you want to drive a pair of headphones I suppose, or just have a pre-amp

From the OP -

"It'll probably be a line stage amp with 12AU7's or such. But, the real challenge here is getting a B+ voltage from 12Vdc."

[Doz]

Originally Posted by speaker

From the OP -

"It'll probably be a line stage amp with 12AU7's or such. But, the real challenge here is getting a B+ voltage from 12Vdc."

My Bad

[speaker]

Originally Posted by Doz

My Bad

Usually it's me doing that.

[DJNUBZ]

Originally Posted by Doz

I've just completed a tube amp for my car. It uses a butchered "cheapo" car inverter, designed to give 230 V "Pseudo sine wave" at 50Hz. I've tapped the rectified HT off from the switched mode before the H-bridge, and filtered it, gives about +320V under load.
This feeds 4 6550 beam tetrodes, suspended on little rubber mounts (think CD player transport here), driven by 6N6P phase splitters and a 6N6P input tube. Really pleased with it. Getting round the problem of the cars electrically noisy environment involved the use of input transformers to isolate the grounds. 6N6P are Russian NOS, and I've had no microphony problems so far.
The bias supply is derived from a tiny mains transformer off the output from the H-bridge, rectified and filtered to give -50 volts. The design is loosely based on Triodedick's Mono Bill.... any why? ... because I can !

Could you post up some pics of this? I bet that would sound amazing on my hlcd setup.

I personally looked into tubes for the mobile environment a long time ago and gave up. The idea is great but there are just to many drawbacks imo. I have a plan to build a F5 for my car one day and use it on my compression horns. I just havent had the time to find a PS to use in the setup though.

[Doz]

Some pics here: Anybody using a tube amp in their car?