A Rant About DC Heater Supplies

[kg]

I should have been clearer- i've done a brake job on my suby,

hold on a minute here...

what kind of scoob?

[R.G.]

Simplicity is simple, and that's why it is undervalued. RG asks why we don't have certain features-individual biasing of power tubes, circuit protection in the event of a power tube failure-these are all things that could be done at a price which (I think) the makers of consumer grade amps believe the market will not support. Consumer grade electronics is a much different sort of enterprise than craft type work.

I'm sure that the makers of consumer grade amps do *believe* that the market won't support that. On the other hand I designed and sold guitar amplifier production runs which were small (and therefore more expensive per unit) compared to the big guys, and sold them for at or under the comparable amplifier if there was one. The BOM cost of individually biased power tubes is trivial. I spent about $2.50 per amp putting in the red-light/green-light biasing indicators and about $0.35 for the adjuster pots. We made a profit on the amps and sold all we made. It can be done. But you have to want to.

[Rhodesplyr]

Competent engineers who speak English almost never design power supplies these days. If you're a good EE, you can make a lot more bucks and respect doing something else in the EE spectrum of stuff, English speaking or not.

I've restored two combo organs and two guitar amps for a client who *is* an EE. He told me that his degree program emphasized digital electronics to the practical exclusion of everything else and that, as far as he can tell, I know more about analog circuits than he does.

Then again, he probably makes more money with the ones and zeros than I do with all the shades in-between.

[R.G.]

I've restored two combo organs and two guitar amps for a client who *is* an EE. He told me that his degree program emphasized digital electronics to the practical exclusion of everything else and that, as far as he can tell, I know more about analog circuits than he does.

I'm sure that's true. The EE curriculum has been crowded with stuff for at least half a century. It can only get worse. To stuff in more courses in anything, you have to pull stuff off the bottom. The "simple" stuff gets ignored, by necessity. Analog design is a rare skill. There was a frenzy in the industry a few years back, maybe even still. Seems that all those guys who became ham radio operators before they went to college retired. People who understood anything about RF as opposed to high speed digital were suddenly being wined and dined.

Then again, he probably makes more money with the ones and zeros than I do with all the shades in-between.

Probably more than me, too.

[diagrammatiks]

hey R.G... maybe you can help me out...

let's assume that in an amp the original plan was to have an auxiliary transformer with multiple 6.3v taps for the heater runs..

and it turns out that it won't fit... so you're left with 1 6.3v tap on the power transformer for the tap...

now if the power tubes are run from 6.3vac and then that is rectified and regulated for the preamp...

is it possible to ground reference the ac filaments and then lift the dc filaments even though they are on a single winding?

put it another way would the ground reference of the supply after rectification mess with the supply prior to rectification?

[NorCalTuna]

KG: 03 Bugeye Wagon (GIGMOBILE!!!) VF34 COBB Etc., 269/285 bhp/t (roughly 375 redneck crank hp) v5 sti wheels, and a 2.5/6 speed/hubs/brakes swap getting ready (thanksgiving?) Are you subaruud too?

Incidentally, BACK on the subject of DC heaters, I'm thinking about building a amp for the car, not for reproduction- it has 1kw of JL amps for that- but so I can plug my guitar in and play! Yah, I wanna go play guitar at lunch at work. If I use a 12k5, like the sopht, and get 35 mw, I should still get about 85db out of a ragin cajun or some other HE speaker, which is enough to drown out the Dynomometer in the building 50 feet away, but not disturb anybody. If I use a quartet, I might break 90db! I'd put it in the dash where the dual din radio was (now an iphone holder and a silver blank plexi plate) behind a metal (silvered) grille and it'd look pretty sick, at least to nerds! I wonder how the 12k5 would work in push-pull (I might get 93db!!), hey, here's a scheme! trails been blazed! it'll be a simple build, I don't think heater or rectifier hum will be much of an issue. ; )

Hot rodding AA5 radios

BTW, the WRX was the last hurrah of the meathead hick speed mechanic, like how the GTi was the first last hurrah. Once you could build a low 13 car in your driveway with off the shelf maps (mine was tuned at FLI here in nor cal, they found power and mpg over trey's map) and go walk on camaros etc. the writing was on the wall for edelbrock, holley, et al. and their proponents.

[kg]

KG: 03 Bugeye Wagon (GIGMOBILE!!!) VF34 COBB Etc., 269/285 bhp/t (roughly 375 redneck crank hp) v5 sti wheels, and a 2.5/6 speed/hubs/brakes swap getting ready (thanksgiving?) Are you subaruud too?

no shit! midnight black pearl 03 wagon here too...



vf23 (got it for $100 lol)
probably around the same chp/whp
no 2.5 or 6mt though... still running on the originals!
self-tuned with utec, tuner pro wideband, enginuity/rom raider

modlist here Ken’s Subaru Impreza WRX | ken-gilbert.com

Once you could build a low 13 car in your driveway with off the shelf maps (mine was tuned at FLI here in nor cal, they found power and mpg over trey's map) and go walk on camaros etc. the writing was on the wall for edelbrock, holley, et al. and their proponents.

good stuff, for sure! only been dragging once, but once i got into the 12s i was ! only turbo cars for me from here on out... so easy to squeeze another 20% more power from them with minimal $!

ken
(ride5000 on nasioc.com, iwsti, iclub, romraider, etc)