What gives? A Revelation?!

ScottAstroNut · 672

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Offline ScottAstroNut

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on: April 30, 2020, 09:51:59 AM
I just did a little experiment with my fairly newly constructed S.E.X. 3.0. On a whim I hooked them up to my Dynaudio Excite X38 speakers, which are 4 ohms with a sensitivity of only 88 dB. I wasn't expecting anything. To my amazement, they sounded great in my small listening room! And they played much louder than I thought they would, as loud as I usually listen at.

What gives? I didn't think that the S.E.X. was supposed to work well with such low efficiency speakers? I am quite blown away, actually, that the S.E.X. sounds so good with those speakers!

Scott Burgess

BeePre 2, Kaiju, Eros 2, Rega P6, Rega Apollo CD player, Bryston BDA-1 DAC, Bryston BDP-1 streamer, Jager speakers, Mainline and Crack for headphones.


Offline Paul Birkeland

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Reply #1 on: April 30, 2020, 09:56:55 AM
We err on the side of caution when it comes to recommendations like this.  For small rooms, nearfield setups, and desktop listening, the SEX amp works nicely with a far wider variety of speakers, especially if you don't listen loudly.  I bet you can push the amp to clipping without it being all that loud. 


Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline ScottAstroNut

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Reply #2 on: April 30, 2020, 10:07:45 AM
How can I tell when clipping occurs? I don't usually listen to any of stereo gear at high volumes.

Scott Burgess

BeePre 2, Kaiju, Eros 2, Rega P6, Rega Apollo CD player, Bryston BDA-1 DAC, Bryston BDP-1 streamer, Jager speakers, Mainline and Crack for headphones.


Offline Paul Birkeland

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Reply #3 on: April 30, 2020, 11:00:12 AM
You will hear distortion.  What you could do is play a 60Hz tone into the SEX amp and slowly turn it up until what you hear starts to change dramatically.  That will give you a sense for what a clipping tube amp sounds like. 

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline bmkuter

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Reply #4 on: April 30, 2020, 02:29:51 PM
What's the max wattage output for 4ohms vs 8ohms? I cant remember the math right now. I want to try this with my LS50s when my kit is assembled this weekend.



Offline Paul Birkeland

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Reply #5 on: April 30, 2020, 03:31:08 PM
You can wire the output transformers for 4 or 8 ohms, and there will be about 2W available from either configuration, assuming the nominal speaker impedance is matched to how you have the output transformers wired.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man