Wiring resistor-less 2.0 headphone jack to short speakers?

Dr. Toobz · 2110

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Offline Dr. Toobz

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The new 2.1 kit supposedly cuts sound to the speakers when headphones are plugged into the amp, whereas the 2.0 did not. I had ordered one of the shorting jack kits back in 2009 or so, but that jack has become unreliable and I don't need/want the 120 ohm series resistors in the circuit. My  thinking is that I can use the original Neutrik part as a shorting jack, but I'm not exactly sure how to accomplish that. How is the jack wired from the speakers in the 2.1 kit?



Offline Paul Birkeland

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Reply #1 on: November 16, 2013, 03:02:49 PM
Right now, you have two 120 Ohm resistors across the jack (I'm assuming you have the black Neutrik jack, not the silver one).  When you plug headphones in, the short that the jack creates across these resistors opens, and the level is attenuated a bit. 

To alter this scenario, you can start by cutting out the 120 Ohm resistors.  Now, when you plug your headphones in, you'll get no sound.  Logically, one would then need to flip the output transformer connections over to the empty side of the jack, and leave the speaker connections as they are.

-PB

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline Dr. Toobz

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Reply #2 on: November 17, 2013, 03:15:08 AM
Thanks! I actually do not have the black Neutrik jack in there right now - its the silver-colored, shorting replacement - so I was having a bit of trouble picturing what this should look like without having the stock jack in front of me.

I'm planning to either a) bring the 2.0 amp up to 2.1 standards (e.g., with the new iron upgrade and impedance boards) and give it to my father as a gift, or b) keep it for myself and give him my Stereomour, as he does not have terribly sensitive speakers and will likely not use headphones, whereas I mostly listen to headphones and have 99dbW speakers. Is the SEX amp that good - that I would actually want to keep it over a 2A3 amp? That, or perhaps I've just grown too attached to the thing.....