Steremour power amp questions

[Audioclyde]

OK, I'm a newbie , and I'm considering a Stereomour build as follows:

1--I'd like it built as a power amp, and for 45's (I understand that with the 45 build, you can also roll in 2A3's without making modifications?); my tubed preamp is the Aesethix Calypso, which has an output impedance of 1k ohms for single ended--Aesethetix recommends an amp load of at least 10k ohms; any issues here?
2--I plan to use it primarily as a headphone amp; my can's are Audio Technica W-3000ANV's, which have an imput impedance of 40ohms; based on what I've read with regard to others driving LCD-2's (60 ohms impedance for these) from the speaker taps, I'm hoping that I should not have too much of a hum issue (I also have a Hifiman HE Adapter, which puts 25ohm resistors in series, which I've used to reduce hum when driving 'phones from other amp's speaker taps, that I could use if necessary)...any thoughts/potential issues with this plan?
3--I have relatively efficient speakers (96db with a fairly benign 6ohm impedance curve), and would like to sometimes use the Stereomour to drive the speakers as well...I don't listen at loud volumes, so I think the 45's output would be enough....
4--I welcome cap upgrade suggestions (i.e. Mundorf silver/gold/oil caps)...

Finally, I've never built much DIY (only a small bit of speaker wire soldering, etc., and at this point I'd say my soldering skills are not very good at all), and would definitely be willing to pay someone for a nice build if anyone has the time, experience and is interested.

Thanks in advance for any thoughts/suggestions, and I'm looking forward to joining the Bottlehead community!

Randy

[jimiclow]

Welcome!
The experts are probably busy at this time.
1. To build it as a power amp, you just need to omit the volume control and replace it with a resistor, omit the input selector. It has an input impedance of 270K so no issues. Yes, you can use a 2a3 in a 45 amp with reduced output.
2. I'm the one who use it with an LCD-2, no hum issue because the headphone has low sensitivity. On my Grado SR60, the hum is very audible. It may lower with a 120-ohm series resistor. Even with a Schiit Lyr, I can hear hum thru the Grado. You can further lower the hum (?) by wiring the output as balanced.
3. Corect. I have a quad of 97db Hoyt Bedford (Omega) Type I's and they can get pretty loud with a 1.5WPC.
4. I'm using a V-cap coupling and a Mundorf silver/oil parafeed caps. Nice combo for me.

[Jim R.]

Hi Randy,

Funny meeting you here :-).  No problem to all your questions except that I don't know the efficiency of the cans you are referring to, and that will make the most difference as to how well they will work in terms of background noise.  My guess is that they'll be fine unless they're super efficient.

There are a few other tweaks and tricks like power supply chokes, possibly grid chokes, and more that could be useful down the road.

I *could* build it for you, but I don't want to commit at this point as I have a lot of my own projects to get done first and the timeframe I could offer would be far longer than any sane person would want to wait, plus my health is so variable that I really couldn't do it in good conscience.  If you don't  have what you want by late summer and I've somehow managed to make it through my other projects and am feeling energetic, then I could entertain the possibility.

Only caveat I see with your preamp is that you'll want to keep the interconnects to probably 1.5m at most and shorter would be better, and shielded as well.

You may also want to consider starting with the s.e.x. amp -- a good quiet amp with very nice sonics (though not the true DHT sound), designed for headphones and speakers and is said to be really nice with Orthos like the Hifiman, the LCD2/3 and even the AKG K1000s.  And overall, a great place to start and get your feet wet with construction, parts rolling, etc, and it will fit nicely on the nightstand too :-).

Glad to see you dipping a toe in the bottlehead stream.

-- Jim

[Audioclyde]

Thanks fellas; hey Jim, I'd read some of your posts from the past, hope things are going well.

My cans are 102db/1mW, so the Stereomour may be problematic from that standpoint.

[Doc B.]

The S.E.X. amp would pretty much exactly fill your needs.

[kgoss]

And if you really don't want to build the amp yourself you can ask the folks at Bottlehead to build it for you.  I'm not sure how much that costs, but it is a service they offer.

[Doc B.]

Actually we have stopped building amps for customers. They guys working here these days are actually here for R&D and it is just not feasible for us to try to fit building kits into their already busy schedule. Thinking about the thousands of people who have never built anything before who have successfully completed our kits, I have confidence that no one needs to feel like they couldn't handle it themselves. That's half of the pleasure of owning a Bottlehead kit.

[Grainger49]

Randy,

Most kits start soldering with the power supply.  As the Stereomour has one circuit board it might start there.  To build your confidence you can skip the board, possibly the hardest soldering, and leave the board build till the board is called for.

[Audioclyde]

Again, I appreciate the thoughts & input.  I was pretty sure I had read that Bottlehead was no longer offering to complete kits due to their time constraints.

I feel like I can probably do the build; I have a digi multimeter and would of course acquire a decent soldering station.

I've looked at the S.E.X. amp and might go that way, but really wanted to try a 45 based amp...

Thanks,

Randy

[Grainger49]

The manuals include a very good photograph on every step as you assemble the components and solder.  If you follow the instructions you will get everything in the right place.