Stereomour II (in progress)

D

denti alligator

New member
Well, I'm still waiting for it to ship, but I thought I'd start a thread anyway, since I want to ask about ohms. I'm using a pair of Klipsch Forte II horn speakers. I'm assuming I would want to wire the Stereomour for 8 ohms. Is that right?

This will be my first major upgrade since getting the S.E.X. 2.0 back in 2010 or so. I'm pretty excited. I think I will continue to use the S.E.X. as a headphone amp until I get some old B&W speakers set up upstairs, then I'll probably swap it out with my Crack in the main listening room. My plan is to use the Steremour switching capabilities and output to the Crack with a separate set of RCAs.
 
Apparently:

99dB sensitivity, 8 ohm nominal impedance, 4 ohm minimum

Then there's this file, which I don't quite know how to read:
https://community.klipsch.com/index.php?app=core&module=attach&section=attach&attach_id=97104
 
The dip to ~3.8 ohms in the deep bass worries me a little. I suggest you try it at 4 ohms as well as 8 ohms, and compare them.
 
It's the damping factor. Most speakers are designed to operate best with an amp that has a very high damping factor; SETs usually have a DF between 2 and 4. This makes the response sensitive to variations in speaker impedance. Peaks when the impedance is high are limited, but notches when the impedance is low are unbounded.

In the Forte II graph, the biggest dropout would be in the bass where it drops below half of the nominal 8 ohms. There will be a smaller peak in the upper midrange where the impedance is high. Room acoustics are significant, especially in the bass, so sometimes just moving the speaker around will adequately compensate. That's why I suggested trying both options and listening.
 
I'm terrible with a drill, and even though I marked where I wanted the extra RCA jacks, they ended up elsewhere. Oh well, they'll be mostly hidden anyway.

116nqqu.jpg


Made a little more progress. Slowly building. Using Danish Oil on base. More of that later.

21cf7k1.jpg
 
Ok, thanks. One more question ... I'm waiting for a replacement of the 3.3uF cap, one of which came damaged. Is there a voltage range that is acceptable if I wanted to use another 3.3uF cap in the meantime?
 
You will be amazed at how good it sounds with the Solens.The design of the circuit is more important than the parts that go into it.
 
There is nothing wrong with Solen capacitors, i have used them in amps and speaker crossovers and they always work well.  Boutique caps can sound different / better, but i would try the Solens first and go from there as it may better inform you of what characteristics you would prefer in a replacement capacitor.
 
Alright, I've used the extra leads (orange/blue) and wired them to an additional pair of RCAs, which I want to use to output to a headphone amp, while still using the inputs and switch of the Stereomour.

right RCA: orange solid (ground tab), orange striped (center lug)
left RCA: blue solid (ground tab), blue striped (center lug)

The other ends of these wires need to go to the center lugs A, B, C, and D of the selector switch, right? My question is: which goes to which? My guess: striped orange to A, solid orange to B, striped blue to D, and solid blue to C.  But I'd like confirmation before I do this.
Thanks.
 
mcandmar said:
There is nothing wrong with Solen capacitors, i have used them in amps and speaker crossovers and they always work well.  Boutique caps can sound different / better, but i would try the Solens first and go from there as it may better inform you of what characteristics you would prefer in a replacement capacitor.
Click to expand...

I concur. The stock Solen caps in the parafeed position are pretty nice. It is however worthwhile upgrading the stock interstage cap which is also in the signal path. Its the one that is .1uf 630v and is brown in color. You dont have to spend a lot of money either. I've used these with very good results.
http://www.parts-express.com/audiocap-ppt-theta-010uf-600v-film-foil-capacitor--027-710
 
I was never a fan of those poly gum drop caps, i think they are Panasonics.  The russian FT-3's are an interesting cap to try as they are great for detail, and very cheap.  Money no object i would highly recommend the Jupiter wax caps, both for inter stage and output as i am yet to find another cap i like better.
 
denti alligator said:
Alright, I've used the extra leads (orange/blue) and wired them to an additional pair of RCAs, which I want to use to output to a headphone amp, while still using the inputs and switch of the Stereomour.

right RCA: orange solid (ground tab), orange striped (center lug)
left RCA: blue solid (ground tab), blue striped (center lug)

The other ends of these wires need to go to the center lugs A, B, C, and D of the selector switch, right? My question is: which goes to which? My guess: striped orange to A, solid orange to B, striped blue to D, and solid blue to C.  But I'd like confirmation before I do this.
Thanks.
Click to expand...

Bumping this question. Anyone know how to wire these rotary switches?
 
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