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Message |
    
Johnhenre
Member
Username: Johnhenre
Post Number: 71
Registered: 1-2004
| | Posted on Tuesday, March 15, 2005 - 10:24 am: | 
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I'VE PURCHASE A BIG HOMEBREW AMP. AND NEED INFORMATION ON METER HOOK UP? IT HAS A WESTON DC. MILLIAMPERES METER .0 TO 1 IN THAT IS NOT HOOKED UP SO HOW AND WERE DO I CONNECT THE TERMINALS? IT ALSO HAS A SEPERATE 3200 VOLT DC POWER SUPPLY IT'S METER IS 1 TO 4 KILOVOLTS THAT IS ALSO DISCONNECTED SO IF ANY TECH IS THAT HAS KNOWLEDGE IF THESE CONNECTIONS WOULD BE APPERCIATED,POWER SUPPLY HAS BLEND DOWN THAT IS WORKING. THANK'S BOB |
2600
Intermediate Member
Username: 2600
Post Number: 496
Registered: 7-2002
| | Posted on Wednesday, March 16, 2005 - 2:17 am: |
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Bob, you gotta be suicidal to poke around in there with neither a diagram nor safety training.
Hooking up loose parts with no diagram is no big deal in a 4 Watt radio. Not enough energy there to destroy more than just the radio if you get it wrong.
A box with a 3200-Volt power supply might just as well be a live grenade if you apply power with something hooked up wrong. It is definitely large enough to hurt MORE than just itself.
An "old hand" with lots of experience has the general circuit diagram in his head, and can interpret where things should go. But only if you put the thing physically in front of him.
A factory-made amplifier will normally contain sufficient safety devices to keep the damage to a minimum if you wire something wrong. With a home-brew, all bets are off in that department.
A factory-made unit will have a published diagram that somebody out here can consult and make suggestions. No such luck with your home-brew.
There are at least two "generic" places that milliamp meter could be hooked, depending on the designer's preference. It could be inserted in the positive side of the high voltage, leading to the plate choke. Or, more commonly it will be hooked between the negative side of the high voltage and the relay that connects to the center-tap of the tube's filament supply transformer.
A fella who has a "generic" diagram of grounded-grid amplifiers "burned" into his brain can work from a description like that.
What you really need is someone who has that "generic" diagram in his head from years of experience, since you don't have a printed diagram to work from that way.
The skill level needed to follow the diagram for a "factory" unit is a lot less than what's needed to dig into a homebrew and expect any success.
And then there's the question of tools. A "Variac", or variable-voltage AC power supply is a real asset in keeping the "smoke" to a minimum when performing a "smoke test", hooking something up for the first time. Just flipping the power switch to "ON" and hoping for the best is risky, to say the least.
To work on one of those you just about have to be qualified to design and build it in the first place. From the sound of it, that's what you're doing is "finishing" the construction of the thing.
73
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