1st Quickie! With small problem.

jake111 · 5786

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Offline mcandmar

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Reply #15 on: April 27, 2014, 04:38:19 AM
There is also a 5th connection which is the metal casing of the USB plug/socket which is not the same thing as the - line. In some devices that shield isn't actually connected to anything at all and left floating, and on others its connected to the metal enclosure.  I always found this rather puzzling and its different from device to device.

M.McCandless

Offline jake111

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Reply #16 on: April 27, 2014, 09:03:50 PM
I still would like to know about how to short the RCA jack.
I think I posted a pic. Would this short the RCA jack?


Offline Grainger49

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Reply #17 on: April 28, 2014, 02:06:27 AM
Ok, you can build a shorting plug as Dan describes here:

http://bottlehead.com/smf/index.php/topic,586.0.html

Or go to Radio Shack and buy a pack of jumpers.  They are wires with alligator clips on each end.  Put one end of a jumper on the center pin of the RCA jack then the other end clips on the wire soldered to the outer conductor of the RCA jack.


Offline jake111

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Reply #18 on: April 28, 2014, 06:07:05 PM
Thanks Grainger, just what I needed.
Jess


Offline Grainger49

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Reply #19 on: April 28, 2014, 10:57:04 PM
Jumpers are just too handy not to have a bunch of them.  I use them when trying out bypass caps.  It allows me to add them and remove them until I make the decision if they need to be soldered in.

The shorting plugs come in handy any time I put in different output tubes in my Paramours.  You need to adjust the hum balance pot with the input shorted.


Offline jake111

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Reply #20 on: May 02, 2014, 11:44:35 PM
Yeah, the hum balance is what I've been trying to set. Turns out my meter was the problem. It wouldn't read that low.
Got a good one and hum is balanced.  :)
Thanks, Jess


Offline Grainger49

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Reply #21 on: May 03, 2014, 12:53:54 AM
The "hum balance" is a pot on Directly Heated Triode (DHT) amps that lowers hum caused by the AC heated cathodes.  In a DHT the cathode itself is the heater.  I have Paramours, they are monoblock versions of the Stereomour.  To adjust the hum balance I need to short the inputs of the amps and adjust for the lowest voltage at the speaker outputs.  It is necessary every time I swap tubes.

Don't get me wrong, I have only worn out one set of tubes but have several flavors of tubes I use.


Offline jake111

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Reply #22 on: May 03, 2014, 08:06:14 PM
I've combined two issues/devices on this thread, sorry. Y'all still have been a lot of help. The hum balance was for a Stereomour.
Thanks, Jesse
   


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