Balanced XLR issues THX AAA 789
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My THX AAA 789 when I plug in a 4 pin XLR to RCA adapter to go into my electrostatic headphones energizer (I know unneeded and unnecessary considering the energizer operates as a perfectly decent amp itself designed to run the headphones) the 789 starts cutting out switching from orange to white back to orange. This however doesn't happen on the Cavalli tube hybrid amp that I own when I used the adapter on that amp (yes I know this amp isn't balanced so that technically makes a difference). I bought the 4 pin XLR adapter because I wanted to see how my electrostatics sounded on while also connected to my other amps and see if I liked the sound any more, not necessary but I like sound what can I say. Currently I do not own any balanced headphones to test if the 789 works properly on those but I wanted to know the communities thoughts on whether the issue is with the adapter I used which works perfectly on my hybrid amp, or if it is the fact that it's a unbalanced connection on a balanced port, or if the issue is the amp itself which I would then exchange for a new one if that was the issue. Honestly if it's either of the first two issues I'm not concerned at all because I really only wanted to hear my electrostatics on my tube amp anyway cause it colors the sound. The only issue I have is that I will be picking up a pair of balanced headphones in the near future and I don't want to be running into an issue where the amp doesn't work with those.
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Running an XLR to SE adapter on a headphone output is not recommended, you are most likely tripping the short circuit protection on the 789 as the vast majority of those just short the unneeded pins. If you don't own a "balanced" connected non-estat headphones I genuinely don't understand why you own either of those HP amps. Both are at their best via the XLR output, something like the SMSL SP200 would be a better fit for your uses, and just use the TRS output, the XLR on that one is just for convenience. You could damage your gear, your headphones or start a fire with what you are currently trying to do. Edit: Wait I looked up your purchase history, are you talking about the Koss 95X? Because you seriously don't need either of those HP amps for that, just run a set of RCA from the bypass of the 789 to the input of the Koss Energizer if you use the amp for other things. All that requires is a source, adding something in between will only degrade the sound, not improve it. 2nd Edit: You have the CTH, that amp is single-ended through and through, the XLR output is no different than the TRS output... that is why your adapter works on one amp and not the other. There is NOTHING wrong with your amp, just you doing things that you should not be doing.
(Edited)
DwarfWight
50
Sep 24, 2020
Thanks for the explanation. I figured that was the case anyway. I have tons of headphones with true balanced connectors inculuding the sennheiser hd800 (got a balanced connector for it) the audeze lcd-1 (also got a balanced connector for them) and the beyerdynamic t1 (once again got a balanced connector for them too). Having come from an electrical engineering background I was simply confused as to why a strictly output port would be shorting due to the connection that is plugged into it. The idea behind putting the koss energizer into the 789 was curiosity because the koss energizer is on the crappy side of electrostatic amplifiers and the 789 is a pretty good amplifier. I was curious if I took some of the strain off the amplification of the koss amplifier and put it towards the 789 would it improve the sound. In general I really wasn't so incredibly curious because I simply gave up the idea of it and decided to eventually buy a really nice amplifier for the koss 95x and solder the 5 pin probias connector onto the extension myself. I also picked up the darkvoice amplifier and couldn't be happier with it for my t1 and my hd800. Thanks for all the advice and taking the time.
ds60
54
Jun 29, 2020
Make sure your adapter is wired correctly, it sounds like maybe the protection circuit is preventing a short. Hopefully an electricity wizard (which I am not) can better answer your question.
DwarfWight
50
Jun 29, 2020
Yeah like I said. My adapter works perfectly on a non balanced amp with no issues at all so I don’t believe that it is an issue with the wiring of the adapter.
ds60
54
Jun 29, 2020
Sorry, I read that but it didn't click. That does sound like it could be an issue with the amp then, or maybe the Cavalli is just more tolerant to some potential disparate voltage over ground the adapter is allowing. That's a common issue with balanced to unbalanced adapters. Again, not an electricity wizard, so I could be wrong.