Just finished my S.E.X. build; hotdog!

timindq · 1539

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Offline timindq

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on: February 01, 2018, 10:46:51 AM
I had built a couple Cracks and a Quickie previously and found the S.E.X. to be quite a bit more involved. Not harder, just more pieces.
When I went through the resistance checks upon build completion, everything was spot on. Then when I went through the voltage checks, all voltages were very close until I got to H2, H4, H5 and H7. The problem was a large blob of solder providing contact with one lead of the 5W resistor and the mounting nut sitting 1/8 inch from it. Easy to diagnose as I noticed it when I soldered in the resistor, but thought I had removed the blob.

Now that that's taken care of, the amp sounds fantastic. Zero noise of any kind with headphones, even at max volume (no signal applied). So I hooked the amp to my KEF LS50s and it sounds great. Not trying to shake the house, but Norah Jones sounds wonderful.

Now for my recommendation. Solder the .1 ohm 5 Watt resistor to the terminal strip before installing the terminal strip. It may be out of sequence, but if I built another S.E.X. amp, that's what I would do. Couldn't hurt.

Source: Lumin D2 with SBooster power supply, 2tb SSD attached to Lumin, Pre: Moreplay, Amp: Bryston 2bSST, Speakers: Joseph Audio RM22XL. Setup in large, well treated dedicated listening space.


Offline Paul Birkeland

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Reply #1 on: February 01, 2018, 12:24:10 PM
That's some good advice, especially for checking that solder joint when no voltage is present on the heater terminals.

I'm quite happy that the low voltage diodes tolerated that abuse without popping!

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline timindq

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Reply #2 on: February 01, 2018, 03:45:33 PM

I'm quite happy that the low voltage diodes tolerated that abuse without popping!

Me too.

I'm surprised at how quiet this amp is. Also surprised at how well it drives my LS50s. I listened for an hour and a half this evening to mostly pretty tame music with my phone's db meter peaking at 70db. This is fairly normal for me. I heard no distortion at this level. :)

Source: Lumin D2 with SBooster power supply, 2tb SSD attached to Lumin, Pre: Moreplay, Amp: Bryston 2bSST, Speakers: Joseph Audio RM22XL. Setup in large, well treated dedicated listening space.