Best way to switch output?

[feeench]

I believe it's been around 10 years, I've been using the S.E.X. 2.1 every day at my computer. Thank you guys for the awesome kit. It's been upgraded with the C4S, and the output impedance switch kit. I've been powering a pair of Blumenstein Orca Mini's and a pair of Sennheiser HD650's with a balanced cable... I built a little powered sub to go along with the speakers that takes the signal from the full output of the amp. It's pure bliss in this small room.

Here's my issue... I've modified the chassis by simply adding a 4 pole switch and a 4 pin XLR connector in place of the 1/4" TRS - I want to be able to switch between the speakers on my desk, and my headphones. Of course, despite turning the volume all the way down each time I switch the output (I imagine to help prevent arcing of the contacts), the switch always degrades over time. I lose fidelity, and eventually, entire channels will cut out...

I've tried a few different switches over the years, but I'd like a solution that is as long lasting as this amplifier has been...

What would you guys do?

Can I modify the circuit around the switch to make it last longer?

I've thought of using "patch cables" (ie. hook output of amp direct to a 4 pin XLR, then connect another 4 pin XLR to speaker outputs at back of amp. Plug headphones into output, or connect a "patch cable" from the output to the speaker output...?) - At least this way I could clean the contacts if they corrode.

I could build another amp if that's necessary, it would be nice to have a little more power for driving the Orca Mini's - and switch the output from my DAC into each amp? How would I do that? Could I just connect both amps to the output of the DAC? (I'm using the 1.4vrms output of a soekris 1021 ladder dac, i believe output impedance is around 625ohms (i don't understand impedance, however))

I'm open to any and all suggestions. I'm surely missing something obvious but just need to be shown a few paths to look down.

Thank you so much and Happy Holidays!

[Paul Birkeland]

Of course, despite turning the volume all the way down each time I switch the output (I imagine to help prevent arcing of the contacts), the switch always degrades over time. I lose fidelity, and eventually, entire channels will cut out...

Can you show us the switches you're using?  The voltage/current present where this switching is done is so small that any switch that's rated for 1A or so of current and 6V of AC voltage should last longer than anyone alive today.

Can you also show us the bottom of your amp?  There is one version of the SEX that's autoformer wired, and I could see that causing some potential switching issues.

[feeench]

Can you show us the switches you're using?  The voltage/current present where this switching is done is so small that any switch that's rated for 1A or so of current and 6V of AC voltage should last longer than anyone alive today.

Can you also show us the bottom of your amp?  There is one version of the SEX that's autoformer wired, and I could see that causing some potential switching issues.

Well, some good news. Taking a picture of the bottom of my amp, I had moved it a little bit while it was playing music and heard some strange things that changed my guess that the switch was bad. Funnily enough, a few of the solder tabs on the bottom of the switch move a little if you put lateral pressure on the switch. This is what I had to do to "get connection" at times... Turns out there was a solder joint that completely failed (was hard to get to when I soldered this switch in) and the wire was just hanging and barely making contact with the solder leg.. hence my intermittent issues. --Currently testing the amp now, no issues so far... It's good to know that you feel a switch is a perfectly fine solution for my use case.

I have a rather large switch in there right now. Just something I had laying around. (https://www.digikey.ca/en/products/detail/nkk-switches/S42/1007150)
I've put at least two of these in over the years as well, possibly three (https://www.be-electronics.com/product_p/41-253-1.htm) - I feel like they are perhaps just garbage quality... and that's why they failed? I also found that I would hang my headphones on the XLR jack, and coincidentally sometimes it would put lateral pressure on the switch - perhaps causing premature failure...

Attached picture of the bottom of my amp if you'd like to have a look.

While I was under there, I noticed some heat damage to the C4S board where the two large resistors are in the middle. I suspect I should raise the resistors from touching the surface of the board.

It's really interesting to look back at all my soldering from when I had practically started around 10 years ago.

Thanks

[Paul Birkeland]

That switch is certainly overkill. 

If you remove the 150K/2W resistors on your C4S board, feel free to replace them with 270K/3W PR-03 resistors and you won't have any discoloration.

[feeench]

That switch is certainly overkill. 

If you remove the 150K/2W resistors on your C4S board, feel free to replace them with 270K/3W PR-03 resistors and you won't have any discoloration.

Will do, thx PB.