Looking for a Beta 22 Builder - Page 2

Just remember that if using 4-pin XLR connectors that you'll need to use the shield as ground for connections that want to share a ground (anything and everything except for headphones).

Quote:

Originally Posted by nikongod 

 

Not this. 

 

This

Care to elaborate a bit?  I'd like to understand why instead of just have you point it out to me.
 

Each headphone driver has only two terminals.  When being driven in a balanced manner (i.e., differentially), the terminals are connected to the hot "+" and cold "-" signals, respectively.  "Ground" is not used.  2 terminals per channel x 2-channels = 4 wires.  Thus a 4-pin connector is enough.

EDIT: by the way, dual 3-pin XLRs for balanced headphones is something that HeadRoom came up with and became popular, with many aftermarket headphone cables made in that configuration.  The 4-pin XLR is used on the AKG K1000 headphone.  If you want maximum compatibility with all types of headphones (including those with aftermarket or DIY cables) then it would make sense to have all of those connectors on the front panel.  But if no one else will ever plug another headphone into your amp, then choose whichever method you like.

Quote:

Originally Posted by amb 

Each headphone driver has only two terminals.  When being driven in a balanced manner (i.e., differentially), the terminals are connected to the hot "+" and cold "-" signals, respectively.  "Ground" is not used.  2 terminals per channel x 2-channels = 4 wires.  Thus a 4-pin connector is enough.

 

I guess that makes sense, but its weird and a bit counter-intuitive to not want to connect to ground.
 

Nothing weird about it... it's exactly the same as a "bridged" power amplifier driving speakers.  Some home and pro amps are bridged and virtually all "high power" car amps too.

Check with Lee at CryoParts. He was looking into having some 4 pin inserts made for these very nice looking XLR's that he sells:

If he hasn't got the 4 pin inserts yet, you can still buy the plug and replace the 3 pin insert with a Switchcraft 4 pin insert, part number QG4M.

You can also replace the insert in the female XLR with a Swtichcraft 4 pin female insert, part number QG4F.

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Quote:

Originally Posted by FallenAngel 

Just remember that if using 4-pin XLR connectors that you'll need to use the shield as ground for connections that want to share a ground (anything and everything except for headphones).

What connections are you referring to here? I cannot think of anything that needs +,- and also ground at the same time.

 

Pre-amps would like to keep a ground reference, so connection between the DAC and preamp, just as connection between preamp and poweramp.

Quote:

Originally Posted by tranhieu 

What connections are you referring to here? I cannot think of anything that needs +,- and also ground at the same time.

 

Consumer gear (pre and power amplifiers, eq's) without transformer coupled connections often requires this. 

Transformer coupled gear generally does not.

If you do need a ground connection you should just use 3-pin XLR.

If your amp supports single ended operation the builder should provide outputs on dedicated connectors rather than providing adapter cables that can be used wrong. 

You guys are mixing two very different topics:

1. Connection from source or preamp to amp

2. Connection from amp to headphones

For 1., the industry standard for balanced interconnection is two 3-pin XLRs, one per channel, male on the source side and female on the amp side.  The pin-out is 1=ground, 2=hot, 3=cold.  Whether the ground connection is needed (i.e., transformer coupled vs. not) is gear-dependent but at the very least pin 1 should be used for shield and chassis ground.

For 2., there is no standard so either you go with the HeadRoom convention or the AKG K1000 convention, or both.