300Vdc from car battery(ies)?

[WJS]

I was thinking about this in the car

Radioshack makes a variable voltage regulator which goes up to +90. if you used 3 batteries and one regulator on each thats 270 volts. If you add another bat. you could easily get exactly 300 volts. I believe each is rated for enough current, but if not you could double them up.

good luck
Bill

 

[deanp920]

I've got my battery powered filaments going now.

I bought everything at wal-mart for about $80

Deep Cycle 115 AH Marine Battery

Plastic marine battery box

Cool toggle switch with red LED on the bat(mounted that directly on the plastic battery box)

in-line fuse

#14 hookup wire

Made my circuit dead quiet. But the weird thing is that the sound seems different, to...cleaner, sort of, with depth. Must just be the improved S/N.

Or is it?

Research on the 300V B+ shows that I could get 25 lead acid 12V, 5AH batteries for around $350...safe to charge indoors, according to the battery store. This would cover my phantom power too, as well as giving me a bunch of taps for powering various tube stages with different plate voltages.

I doubt it's worth it, though the curiosity about the possible improvement in sound quality nags at me.

Has anyone here listened to any tube preamps powered only on batteries?

 

[gyraf]

you could experiment with a pack of relatively inexpensive 9V batteries..

 

[bcarso]

That is wonderful that you followed through with this.

Oh but I would be very afraid of HV with that much energy behind it. I think for me it would sound different based on fear :roll:

 

[BYacey]

This seems like a really extreme endeavor at obtaining low noise. What is your application, and is it really necessary to go these lengths at gaining a few db lower noise?

 

[deanp920]

you could experiment with a pack of relatively inexpensive 9V batteries..

I looked into that, but the cost is still up there.

Oh but I would be very afraid of HV with that much energy behind it. I think for me it would sound different based on fear

Well, I'd be putting fuses on every battery, at the terminals, plus a master fuse. Then all of that in a plastic case, or maybe cases inside a case. Still hazardous, but with care and planning the idea doesn't bother me much.

This seems like a really extreme endeavor at obtaining low noise. What is your application, and is it really necessary to go these lengths at gaining a few db lower noise?

You're probably right. I have a home studio and I'm just curious to see what kind of sonic effects such a hard and clean power supply would have. I like the idea of having the best possible power supply for my circuits. Something unique. Well designed DC supplies are fairly involved, whereas this method really isn't that expensive and is superior to any rectifed/regulated DC supply. Am I wrong on that one?

We'll see. No mistakes.

 

[bcarso]

Is it better? Well...It's not regulated, and it can actually have higher noise than a really well-designed regulated supply. But it floats, except for its own capacitance to the rest of the Universe, so that is an advantage.

For some data on battery noise , see towards the end of:

http://www.tnt-audio.com/clinica/regulators_noise4_e.html

 

[emrr]

[quote author="deanp920"]I've got my battery powered filaments going now.
Made my circuit dead quiet. But the weird thing is that the sound seems different, to...cleaner, sort of, with depth. Must just be the improved S/N.
[/quote]

[quote author="bcarso"]Is it better? Well...It's not regulated, and it can actually have higher noise than a really well-designed regulated supply. But it floats, except for its own capacitance to the rest of the Universe, so that is an advantage.

For some data on battery noise , see towards the end of:

http://www.tnt-audio.com/clinica/regulators_noise4_e.html[/quote]

Nice to see some comparative plots bcarso!

I'm gonna throw this out to see what argument it starts, and then duck and cover since I can't speak from any experience at all.

I have heard several extreme antique (1920's-1930's) audio nuts swear to the 'cleaner with improved depth and imaging' thing with the direct heated tubes of that era. I've heard mention that many of those tubes were designed with battery supply as the rule for all voltages, and that they do indeed sound far better with batteries. This is with new amps built with new parts driven by 4 pin direct heated triodes, as well as your restored WE esoterica.

I can't address at all how much crack they may or may not have smoked before the listening tests, or whether or not they burned their houses down.

 

[recnsci]

A bit OT:

If lowest hum is goal, wouldn't fully differential ClassA pushpull design
be a way to go ? Since none of expert minds mentioned it, I guess there
are some serious problems with that aproach. I'm sandstate only person
due my tender age, so what do I know. One problem I do see is: two pairs
of triodes are more expensive than two triodes, two pairs of matched
triodes are more expensive that two pairs and two well matched pairs
are even more expensive (unless builder is doing all the matching).

And even more OT: only toob fully differential nonpoweramp circuit I've
seen is original Pultec makeup/driver, not counting VariMu's. Are there
more differential designs floating around (and is "fully differential" corect
english expression for that topology)?

And finaly: Bcarso, could you please give some details on exact mechanism
of that "common-mode coupling" you mentioned on first page of this thread?

cheerz
urosh

 

[CJ]

If low hum is the issue here, just use an external pwr supply with an octal connector.

Or are you going portable?

I have a rack full of stuff wired like that and all you here is the electrons bouncing around the plate resistors.

 

[mikeyB]

I'll try again! - didn't post last time for some reason?!
I've asked this one before. yeah - i've seen a student at uni make a ht supply with leadacid at 240V - I soon got the **** away from that one!
I was contemplating something like 12v battery-sine generator-poweramp chip(from car hifi booster etc)-12:240 transformer.
Anybody got more comments?