stereomour 11 question

Wayne100 · 1897

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Offline Wayne100

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on: December 15, 2022, 10:31:26 AM
So I built it a few months ago. Had KEF LS50 speakers, not the best. Talked with Doc and he said alot of guys where using older Klipsch, so I picked up some Heresy 2 speakers. Mids are pushed forward and no bass, not low bass, I have a powered sub for that so I decided to install the shunt regulator, broke a transistor on c4s board and ordered a new one. In the meantime I hooked up my old system a Bryston .5B pre and 2BLP 50wpc ss rig.
Bam, the bass is there and it hits hard. I can only turn it up 1/4 turn till its way too loud. Anything I can do to get more bass from the stereomour?

Offline Tom-s

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Reply #1 on: December 15, 2022, 10:45:18 AM
You could try looking into wiring the transformer outputs for 2 or 4 ohm speakers.

Offline Paul Birkeland

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Reply #2 on: December 15, 2022, 10:59:24 AM
The Heresy does seem to be pretty lean on SET amps.  I have heard probably ten pairs in my lifetime and this is always the impression that I get.  There's a lot of love here for Cornwalls and Lascalas, though those can get rather expensive.  There are plenty of newer Klipsch Reference models that are adequately sensitive and a bit more reasonable on the bottom end.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man

Offline Paul Joppa

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Reply #3 on: December 15, 2022, 06:53:43 PM
I did a little Google "research" on the Heresy II. Didn't find very much, but did learn the woofer impedance is low enough (and the midrange is high enough) to depress the bass (and enhance the mirange) a few dB with moderate-damping SET amps. It is specified to be a nominal 8-ohm speaker, but will do better on a 4-ohm amp output. So I support Tom-s's idea - it will get you closer to the Bryston tonal character, though not all the way.

Even with high-damping amps like the Bryston the Heresy II is a little weak in the bass, based on the measurements I've seen. It's a compromise design, to get the box small without losing midband efficiency. So  you might want a greater adjustment range. An equalization similar to a baffle step corrector, tuned to match the 700Hz crossover, would allow greater boost. You could implement it at the input of the Stereomour, (crude but effective) or in an external box (more elegant but more work). It's only a couple of small caps and resistors.  If you are interested, I'll work up some circuit ideas.

Paul Joppa

Offline IndyNate

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Reply #4 on: January 26, 2023, 07:06:36 AM
My experience with acoustic reflex/sealed enclosures like the Heresy is that they need some major current to make bass. Sadly, in my experiences, this only comes from SS, not my beloved SETs. Also, I've experienced the need for EQ with sealed enclosure cabinets. Not that any of this helps!

Final thought, I modified a pair of Klipsch KG 4.5 by replacing their woofers with Faital Pro (96dB with accordian surround) and swapping titanium diaphragms into the tractrix. Oh yeah, also designed a 6db crossover at 4500 Hz with some impedance correction for the woofer and an L-pad on the tweet for tuning. ANYWAY, they absolutely marvel me with my 45/2a3 SETs. Again, LOTS of work LOL. But, that's what it took to find a speaker for my flea amps. YMMV.