requirements for power

for the DIY ST35, the Dynakit and every other PP EL84

requirements for power

Postby birkeland » Tue Aug 05, 2003 11:31 am

I want to use three of these finished boards in my car (don't laugh too hard). There is a DC-DC power supply I've found online that will put out 38vdc, but that's all. What are the power requirements for these boards?
Paul
birkeland
 

You require much more!

Postby Thermion » Tue Aug 05, 2003 4:28 pm

I think it is a great idea to use tube amps in car stereo. I have wanted to give this a try, but never followed through. :?

Your best bet is to use a power inverter. These are sold commonly in various power output ratings. What the inverter does is convert the 12 volt DC to 120 volt ac. This way you can put TVs and DVD/VCR players in your minivans for the kids to watch on long trips, or camping, or whatever. I once had a 10 channel strain gage conditioning unit and a data logging computer powered with one at a remote site and had no problems. The lower wattage models plug into the cigarette lighter, but bigger ones need to be wired directly to the battery posts.

This way you can just build the amps without worrying about designing some kind of brute force power supply to give you the 400 dc volts for the amps. It also keeps the high voltage safely tucked inside whatever chassis you are planning to house the boards in. :sunny:

JT
Thermion
 
Posts: 181
Joined: Mon Jul 07, 2003 6:04 pm
Location: Fisher, IL

Tubes to go.

Postby EWBrown » Wed Aug 06, 2003 5:15 am

I did something to this effect back in the early '70s. Used one of the "hockey puck" toroid transformers for a 12VDC to 300 VDC converter, used some huge round germanium transistors to drive it. I doubt these are still available in this age of silicon, but a possible soure is old "retired" two way radios, they have this kind of power converter.
It "switched" at around 2 KHz, so it was relatively easy to filter the DC.
It did have a little bit of mechanically generated whine, but keeping it in the trunk pretty well muffled it.

This drove a mono P-P 6V6 amp, about 10 watts out, into one of those ubiquitous Jensen 6x9 inch oval speakers that fit so well into the rear deck
of most cars back then (as in '68 Pontiac Tempest) . Audio source was an AM/FM mono car radio, and an 8-track player. which had previously blown it's (crappy) amplifier.

Filaments were series connected for 12V the 300V (approx) converter supplied the B+.

It wasn't elegant, but it was fun...

In later years, this same 12 to 300V converter powered my first attempt at a crystal controlled single channel 144 MHz FM ham radio transmitter, using the transmitter deck from a WWII vintage SCR-522, using a couple of 832A tubes on the RF output.

/ed B in NH
Real Radios Glow in the Dark
User avatar
EWBrown
Insulator & Iron Magnate
 
Posts: 6389
Joined: Wed Mar 19, 2003 6:03 am
Location: Now located in Clay County, NC !

Re: requirements for power

Postby Shannon Parks » Wed Aug 06, 2003 7:04 am

birkeland wrote:I want to use three of these finished boards in my car (don't laugh too hard).


There's a Simpsons episode where Bart visits his favorite daredevil, Captain Lance Murdoch, in the hospital, with Marge hoping that the visit will make him rethink his skateboard jumping ways. The daredevil asks to be alone with Bart, appearing to set the boy straight, only to further encourage his dangerous hobby.

OK - I'm not a car stereo guy, and things have changed mightily since I had a pair of 6x9's cranked up in my '66 Fury III. Part of me says this is crazy, don't do it, the power isn't enough, etc. But the Lance Murdoch in me says, go for it - this is what makes America great!!
Some notes:
-Therm's comments about using an EL34 based amp make sense as I don't think 17 1/2W may cut it
-I know car speakers have very low impedances; are these paralleled or run in series or just multiple-amped?

Shannon
User avatar
Shannon Parks
Site Admin
 
Posts: 3762
Joined: Tue Mar 18, 2003 5:40 pm
Location: Poulsbo, Washington

Big Blue Board on E-bay

Postby EWBrown » Wed Aug 06, 2003 12:30 pm

Here's a chance for a new unused / unbuilt one:

http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... gory=39783

Up to $51, 9 hours left on it.

/ed B in NH
Last edited by EWBrown on Mon Aug 11, 2003 6:15 am, edited 1 time in total.
Real Radios Glow in the Dark
User avatar
EWBrown
Insulator & Iron Magnate
 
Posts: 6389
Joined: Wed Mar 19, 2003 6:03 am
Location: Now located in Clay County, NC !

Question to birkeland about dc to dc convertors

Postby glassaudio » Sun Aug 10, 2003 12:58 am

Hey birkeland!

Please tell me where you found the power supply that gives you 38 volts output with 12 volts input. I just bought a diytube board off ebay but I also plan to put a high voltage amp in my car and bought a true sine wave invertor for that. I might have some ideas for you if you need some info about using your new DIYTUBE amp in a car.

Please contact me at brad@earles.ws if you care to contact me.

Thank You,

Brad Earles
glassaudio
 

Postby DG » Thu Aug 14, 2003 2:24 pm

Cool idea guys ..... some info

There are some tube amps built for the mobile audio industry. US AMPS, Butler, Hollywood Sound and a couple others make them .... they are all hybrids .... either a tube pre-amp section or buffer.

There is one exception, Milbert . Milbert makes all tube amps for the car .... very expensive.

Something to consider ...... will you really hear the difference with the vehicle moving and a resulting 50 - 70 db noise floor from road and wind noise?
You'd need alot of tube power to completely overcome the road noise to even begin to honestly know whether you can hear the tube benefit in a moving car.

Still, if you are willing to try it, more power to you ... I'm with ya 8)
DG
 

Tubes to go

Postby EWBrown » Fri Aug 15, 2003 6:00 am

My first car was a 1955 Plymouth Savoy, got it when I was in Monterey Cal back around 1970-71. Flathead straight 6, and 6V positive ground enectrical system. The car radio was interesting, AM only, on two chassis, the "tuner" had 5 or 6 tubes, and the separate amplifier had 4 or 5 tubes,
including a push-pull 6AQ5 output. The 6V ws turned into the required higher voltages by means of a vibrator, which had two sets of contacts, the first switched the 6VDC back and forth at 115 Cycles for the primary, the second set acted as a mechanical "rectifier". This radio fed a 6 1/2 inch round speaker located in the far right hand side of the dashboard. sounded great, lots of volume, and it had excellent sensitivity, but it was definitely a battery hog, if I left it running with the engine off, it would kill the batter in less than 2 hours.

Vibrator power supplies and dynamotors worked very well for the time, but they were battery killers... solid state inverters or converters are a lot more efficient.


/ed B in NH
Real Radios Glow in the Dark
User avatar
EWBrown
Insulator & Iron Magnate
 
Posts: 6389
Joined: Wed Mar 19, 2003 6:03 am
Location: Now located in Clay County, NC !

Re: You require much more!

Postby Gerard Courtenay » Sat Apr 26, 2014 8:04 am

Thermion wrote:I think it is a great idea to use tube amps in car stereo. I have wanted to give this a try, but never followed through. :?

Your best bet is to use a power inverter. These are sold commonly in various power output ratings. What the inverter does is convert the 12 volt DC to 120 volt ac. This way you can put TVs and DVD/VCR players in your minivans for the kids to watch on long trips, or camping, or whatever. I once had a 10 channel strain gage conditioning unit and a data logging computer powered with one at a remote site and had no problems. The lower wattage models plug into the cigarette lighter, but bigger ones need to be wired directly to the battery posts.

This way you can just build the amps without worrying about designing some kind of brute force power supply to give you the 400 dc volts for the amps. It also keeps the high voltage safely tucked inside whatever chassis you are planning to house the boards in. :sunny:

JT

Hello Thermion, I have designed mixture twice and still not operating so have taken to my Little store nowadays for them to kind as still under assurance. I am having issues discovering an adaptor that fits the smokeless huge I have three but nine fit? Can anyone let me know which kind of adaptor will fit the smokeless huge or offer me a weblink to where I can buy one?
Gerard Courtenay
 
Posts: 1
Joined: Fri Apr 25, 2014 9:28 am


Return to stereo 35

Who is online

Users browsing this forum: No registered users and 1 guest