Bottlehead Forum
Bottlehead Kits => Stereomour II => Topic started by: Mucker on November 13, 2023, 03:22:53 PM
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I have been using a very powerful Emotiva XPA-2 Gen 2 stereo power amp to drive high efficiency Klipsch RF-7II speakers:
Frequency Response 30Hz-24KHz ± 3dB
Power Handling 250W RMS / 1000W Peak
Sensitivity 101dB @ 2.83V / 1m
Nominal Impedance 8 ohms compatible
High Frequency Horn 8†square 90° x 60° Tractrix® Horn
High Frequency Drivers 1.75†(4.45cm) Titanium diaphragm compression driver
Crossover Frequency 1200Hz
Low Refequency Drivers Two 10†(25.4cm) Cerametallic™ cone woofers
Inputs Dual binding posts / bi-wire / bi-amp
Enclosure Type Bass-reflex via dual rear-firing ports
Height 48.5†(123.3cm) with feet
Width 11.6†(29.5cm)
Depth 16.3†(41.5cm) with grille
Weight 87.1lbs (39.5kg)
I have no plans to change from these speakers but recently tried my S3X amp with them and was very happy with how it drives them.
My dilemma now is that I am really wondering how much better a Stereomour II would drive the Klipsch. From a volume standpoint, I don't need much more than the S3X provides. However, I would desire possibly a bit more weight in the sound, particularly with the bass. A few more dB power with slightly more bass would really nail my needs. Cost does come into play and I want to make sure the jump to Stereomour will get me to where I want to be. Any comments, and or suggestions, is greatly appreciated.
I have never heard a 2A3 or 300B amplifier before but would like to experience one if the leap is big enough. Thank you!
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The Stereomour might get you a little more bass weight than a S.E.X. amp, but the 2A3 is not a super weighty tube. The Kaiju would do more of what you are looking for. You could use the S.E.X. amp as a preamp to drive it.
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OK Doc, thank you for the feedback. Appreciated.
If using the S3X as a preamp, is it done from the headphone jack?
I am currently using a Topping E70V DAC @ 2.5V out of RCA into S3X.
The E70V can output 5V from it's balanced XLR.
EDIT: I didn't realize Kaiju was a power amp., but after looking at it, I will certainly be considering it. Thank you. And I also have a Moreplay which I assume would work great with Kaiju?
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Since you are looking for a little more weight in the sound, you might to look into adding the Moreplay preamp.
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Yup, Moreplay works great with a Kaiju.
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Thanks!
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Ordered the Stereomour + Shunt + DC. Thanks for the sale price Doc!
Plan is to use the Moreplay as a pre-amp to it. I am using the Moreplay to feed S3X now and into speakers and it's really good.
I read an earlier post about turning the volume on the Stereomour to max and controlling with the Moreplay. I've done this with the S3X and have also used a combo of different volume positions on both. Is there a technically optimal way for volume setting? Will the tubes output better at higher or lower volume on one device over the other?
With my solid state DAC's I always have the output at 0dB (max) when running into an amp with a volume control.
Anyway, thanks again. I am really looking forward to building and operating the Stereomour.
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With the volume pot all the way up and the balance pot centered, you will end up getting the best frequency response and the Stereomour is essentially operating as a power amp.
If you take the wire leaving the wiper (middle lug) of each level of the balance pot and move it over a terminal to where the 33K resistor lands on the balance pot, that takes the balance control out of the circuit and gives you true power amp type operation when the volume pot is turned all the way up.
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Ah interesting. I will definitely do that and will come back here when I am ready to do that. Thank you Paul.
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Hi Paul,
I ordered the MourQuiet today (thinking of the future and possibly wanting to use the amp as an integrated one), so I guess that means just running the Stereomour at max volume with Moreplay? Thank you!
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Yes, that's a good plan.
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I can't say enough about the subs I built; the "Bucket Subs". Very inexpensive to put together. With the various high efficiency speakers I've used them with, they really help immensely with bottom end weight. Using a 300 watt class d plate amp on the speaker outputs with my various amps. Something to consider...
Steve T
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Thanks for the feedback Steve! My Klipsch RF-7ii are rated 30Hz-24KHz ± 3dB. They do a really good job with all but the lowest bass frequency.
I have a pair of SVS PB-12NSD that are superb with music that extend linearly into deep territory. They were unreal with home theater too.
I did integrate them with the Klipsch speakers using Moreplay and a power amp but found that I was enjoying the speakers without the subs just as much. And hence what set me on the path to the Stereomour.
My interests have changed away from home theater and into stereo music listening. My days of thunder are being put to bed and now I enjoy the lower volume warmth and clarity. I clearly prefer tube amp listening and heavily use my Crack and SEX amplifiers. Using the SEX as a speaker amp was a revelation into just how little power is needed for wonderful full audio.
After more listening with the SEX/Klipsch setup, the bass was certainly not lacking. Maybe just a whisker shy with weight but far from being an issue. Everyone has been talking about the Harman curve in the headphone and IEM circles, but my personal opinion is that Harman bass is too much.
Anyway, I think I am going to be very pleased with Stereomour as I already am with the S3X.
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Stereomour II + Shunt + DC filament + Mourquiet has arrived. Thanks for the quick shipping!
Assuming all together stock first; and then what order is now recommended? Thank you!
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Definitely the basic build first and let it run for a week. The DC filament supply is the easiest to install and easiest to debug. Then I'd go with the attenuator upgrade, and lastly the shunt regulator.
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Excellent. Many thanks!
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Getting a good start on my build but have a question on determining the best wiring impedance for my Klipsch RF-7ii.
They spec at 8ohm and 101bB sensitivity but I've been reading across the web more realistic numbers of 4-8 ohm and 97bB.
What impedance would be best in your opinion? Thank you.
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I'm assuming you're referring to this? I don't know how to interpret that with respect to predicting the best impedance match. Maybe someone else can.
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Hi and thanks.
I'm not trying to be too technical about it but was curious if 4 or 8 would be a better when wiring the output transformers.
I've been using my S3X at 4 ohms and they seem to do OK. I will no longer use the S3X as a speaker amp once the Stereomour is built.
The setup will be near field with speakers pointed directly at my listening position from no more than 12 feet away.
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The answer to this question is always, "try both and see" but I would start with 8...John
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It may sound a little thin in the bass at 8 ohms due to the 3.5-ohm impedance dip - unless there is a room resonance around 150-200Hz to compensate. Normally, a dip below 5-6 ohms would indicate 4 ohms is likely to be best, but room acoustics plays such a big role, it's usually worth trying other impedances.
For what it's worth, Stereomour has a bit more damping than S.E.X.
If 4 ohms sounds better, you can even try 2 ohms!
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Thanks everyone and great information Paul. I definitely do not want thin bass. I think I'll start with 4ohm and go from there. Appreciate the feedback.
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I finished mine today.
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It's very handsome in mat black! A nice tidy build as well, I hope mine goes that well.