Will The Stereomour Make My Speakers Happy?

[JimOfOakCreek]

I am building Full Range speakers using the Tang Band W8-1772 which is rated at 95 dB 1W/1m. From the specs, the Stereomour produces 3.5 Watts/channel. Would the Stereomour be a good match for my full range speakers?

I listen to jazz and rock at moderate levels in an 20'X24'X8' room. Would the Stereomour have enough juice to make me happy?

[Paul Joppa]

It will probably be adequate, based on my rule of thumb.

Some years ago I gathered a large number of Stereophile speaker reviews, and discovered that their minimum power almost always corresponded to 102dB - in your case, 95dB per watt, plus 6dB above 1 watt (i.e. 4 watts available) equals 101dB. Tube amps overload more gracefully on transient peaks, so this gives a margin of a few dB for tubes, probably 3 to 6dB (or 2 to 5dB in your case)

I have interpreted this analysis as being satisfying for "most audiophiles, most of the time." It works out to about 5dB louder than what studio engineers use when making recordings. There are many variables that can change this number by several dB. In your case your room is fairly large, and you mentioned rock music. Jazz won't be difficult to reproduce, but if you like your rock extra loud, and if your room is fairly absorbant, you could stretch the limits of the combination. If you like it REALLY REALLY LOUD, like rock concert level, forget it - neither the speaker nor the amp would come close!

[Grainger49]

I listen to the same power, Paramours, in a 14' X 24' X 8' room with 94dBW speakers.  It plays much louder than I want to listen to without distortion.  I just don't want to listen that loud.

[JimOfOakCreek]

I still haven't made up my mind on the Stereomour. My gut tells me that it would be plenty loud with my 95db speakers. I live with a wife and daughter and have learned to listen to moderate volume.

Thanks for your help.

[Grainger49]

Jim,

If your wife and daughter don't tell you you are playing the TV or radio too loud then you should be happy with the sound level of the Stereomour.

[InfernoSTi]

Perhaps it might be useful to hear what your goals are for your amplifier?  Volume level was perhaps number four or five on my list of criteria....but that was because my speakers are 96db speakers and I have several 2-5 watt amps so I knew what I was getting. 

For me, I was looking for a classic SET amp sound and knew it would be a 2A3, 45, or 300B.  Since then, the GM-70 has caught my attention but at the time I didn't consider it. The sound I was looking for was a smooth, detailed, and with a emphasis on midrange and highs (I bi-amp bass augmenters with my OB speakers so bass was less of a concern to me). I wanted a clean/clear sound quality with minimal background noise/hum.  I wanted an amp I would be happy with for a number of years, one that I could tweak if I wanted from time to time.  And I wanted an amp that I could build myself for a very reasonable price and that would have the support of a reputable company and forum.  I selected Bottlehead and ordered the Stereomour before it was released, so I did it on reputation of their previous body of work and forum alone.  And I couldn't be happier with the choice!

Good luck with your selection process, but please look to the other reasons to select one amp over another besides volume...I think you will be happy with the volume levels but these other areas will be what determines your longterm satisfaction.

John

[JimOfOakCreek]

Perhaps it might be useful to hear what your goals are for your amplifier?  Volume level was perhaps number four or five on my list of criteria....but that was because my speakers are 96db speakers and I have several 2-5 watt amps so I knew what I was getting. 

For me, I was looking for a classic SET amp sound and knew it would be a 2A3, 45, or 300B.
John

I need adequate volume in order to enjoy the music. Like you I want a classic SET amp, i.e. 2A3, 45, or 300B. Unlike you, I've never heard my 95db/watt speakers driven by just 3 or 4 watts. I don't know what that sounds like. My goal is to get down to the most basic and simple means of amplification as possible. But the amp must deliver adequate power, detail and bass response to drive my FR speakers to satisfying listening levels. My DIY Tang Band W8-1772 full range speakers have no BSC nor any other equilization circuitry. I compensate for their bright presentation by listening off axis.....simple solution with no compensation circuitry!

My audio philosophy is 'less is better than more'.

[Grainger49]

To get the lowest response from Bottlehead amps I suggest upgraded iron very strongly.  The kits are built to a price point.  Paul has designed custom output transformers for the Stereomour and Paramount.  These are considerably improved over the generic transformers previously used.  But.. there is always a but isn't there, MagneQuest iron is a step up from Paul's designs.  Their site mentions Paramour transformers that would be appropriate.

http://www.magnequest.com/products.htm

Yes, that increases the kit price and sound quality appropriately.

[Doc B.]

Couple of things -

First, the Stereomour uses a different output transformer (Bottlehead OT-2) than Paramour (Speco T-2010), and realtively few people have heard it. It is much closer to the MQ upgrade iron for the Paramour than the inexpensive little Speco we used in the stock Paramour. I would say the difference would be more akin to the stock and MQ iron for the Paramount, which seems to create a 50-50 split on what folks like.

Secondly, Mike is not taking any new orders for MQ iron at this time.

[InfernoSTi]

I need adequate volume in order to enjoy the music. Like you I want a classic SET amp, i.e. 2A3, 45, or 300B. Unlike you, I've never heard my 95db/watt speakers driven by just 3 or 4 watts. I don't know what that sounds like. My goal is to get down to the most basic and simple means of amplification as possible. But the amp must deliver adequate power, detail and bass response to drive my FR speakers to satisfying listening levels. My DIY Tang Band W8-1772 full range speakers have no BSC nor any other equilization circuitry. I compensate for their bright presentation by listening off axis.....simple solution with no compensation circuitry!

My audio philosophy is 'less is better than more'.

That sounds like a great philosophy, Jim. 

You are right, I had two major "givens" that you do not, and that made it much easier for me to decide.  I don't know if you like to get one amp and live with it for a long time or if you change amps a lot, like some folks do.  If you are more of the former, then a careful selection is even more critical.  There are so few of the Stereomours "out in the wild" that getting a good consensus is still tough.  I suppose there may be 12-24 out there currently?  Just a guess...but still not a large pool to sample from since this is a BRAND NEW design!

I think you are hearing that there is a high probability you will love a Stereomour in your setup.  However, if power is a thing for you, then a 300B or GM-70 SET may be an important consideration.  At that point, however, you are spending a lot of money on the amp and (in the case of the 300B) tubes. 

If you want big power, the you really need to look at the GM-70 (too expensive for me).  They say a GM-70 SET has the midrange of a nice 300B and the extension of a good 2A3.  I don't know first hand but folks who I respect have said good things about them.  The amps are hard to find and expensive to buy is the problem...so if you DIY, that is really the only affordable way to get there.  Although out of my league from a price point, this is the one that an audio friend has and calls his favorite SET amp:  SAC Tailand http://www.sacthailand.com/ GM-70 Mono Block Single Ended Class A Amplifier.  He is out of state and I haven't heard it myself so am simply passing it along for informational purposes.

(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Fwww.sacthailand.com%2FPic%2FAmpGM70MonoBlock-1.jpg&hash=1f428ddb8f3c72c2222d30d5d1939e9a12731aa5)
 
I love my Stereomour 2A3, so I'm certainly not trying to steer you away...just wanting you to make the best decision you can so you will be satisfied and have no buyers remorse.

Best of luck...

John

[JimOfOakCreek]

>>>>Best of luck...<<<<


Thanks John. I don't need a ton of power. What I am looking for is an SET amp that will deliver moderate volume from 40hz-15K in a 20X24X8 room. The Stereomour may be perfect for me. I just need a little time to work through this decision. Thanks everyone for all your help.

[Grainger49]

No one has said it yet, so I will give you my favorite suggestion.  Post in the General forum for someone who lives close to you to listen to his 2A3 based Bottlehead amp(s).  It doesn't have to be the Stereomour.  The Paramour II and Paramour predated the Stereomour and I don't remember what was before that.

The best scenario is to entice him to bring his amps to your house.  Offer beer and good music.

You have nothing to lose and might gain a buddy!

[Paul Joppa]

Just a quick note here - the Stereomour can be set up as a monoblock with twice the power, about equal to a 300B amp. (And it costs exactly half the Paramount, for what that's worth). The Paramount is still (IMHO) a better amp, but the difference is not huge and it does give you some flexibility.

Mike has not come up with an output transformer for the Stereomour yet, and the BH-5 transformer (Paramour II upgrade) does not fit the chassis exactly; some creating mounting would be needed. The BH-6 plate choke, and the similar BCP-15, would fit but they have exposed terminals at full high voltage (380vDC) which you DO NOT want on the top plate!!! unless you have some creating way to prevent accidental electrocution of friends and family.

The Stereomour choke and transformer have very similar bass performance specs to the Paramour upgrade products from Magnequest; it's the treble subtleties that will be different.