Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Toxophilite on September 23, 2015, 02:11:45 am
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Picked up these 2 'test point adapters' today for $7 (that's like 50 cents US)
I might solder a 1 ohm resistor to the cathode of the Octal unit so I can use it for bias testing...mostly thought they were cute!
Could come in handy though
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Cool Stuff :thumbsup:
Franco
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I might solder a 1 ohm resistor to the cathode of the Octal unit so I can use it for bias testing...mostly thought they were cute!
how's that going to work?
the test pins are test points that are in parallel to the socket pins. those are designed to allow you to measure pins without the need for access to or expose the solder pin side of the socket.
--pete
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Yes I would just have the resistor on the tube sockets cathode, then I could check it as usual, like having bias points built in
I wouldn't need a resistor on the unit..I got it bass ackwards :icon_biggrin:
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You have to be careful grabbing those thing to put them into the sockets or pull them out with power on in the amp!! Bzzzzt!!!
I have owned those for octal and 9 pin for thirty years and for all of those thirty years I have always thought "Wow, those should be very, very useful!" I've used them maybe five times in thirty years. They are expensive to buy unless you find them as junk somewhere.
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Funny!!
that's why I only wanted to pay a few bucks for them
I though "If I'm at the point where I want to check voltages, usually the amps out of the cab and upside down on the bench"
However I did think the octal one might be useful
As they were cheapish i could bend over the other tabs and wrap it with Electricians tape except for the cathode pin and use it for biasing on the one amp I have that doesn't have bias points in the chassis
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> solder a 1 ohm resistor to the cathode
You need to bust it open and break the connection inside.
And the shock hazard.
It really makes more sense to buy an octal socket, bust a dead octal tube for its base, and wire it yerself.
Leave exposed-lug adapters for reading Voltages (not currents).
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I might solder a 1 ohm resistor to the cathode of the Octal unit so I can use it for bias testing...
See Hoffman's "Very old bias checker" (http://el34world.com/charts/biascurrent.htm) to see why others are questioning whether you could make the adapter readily indicate tube current.
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HI
i think I already mentioned that that was a mistake
"Yes I would just have the resistor on the tube sockets cathode, then I could check it as usual, like having bias points built inI wouldn't need a resistor on the unit..I got it bass ackwards "
THanks!
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I see; I didn't understand you were talking about adding the resistor permanently inside the amp. Sorry! :BangHead:
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Originally I wasn't thinking too clearly :icon_biggrin: