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How does the Stereomour compare to other 2a3/45 designs? Nt

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Posted on June 3, 2020 at 09:11:06
BenE
Audiophile

Posts: 368
Location: midwest
Joined: March 18, 2012
As above just wondering how this bottlehead stacks up against say fi, Yamamoto and others?
Thanks

 

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Could be very good..., posted on June 3, 2020 at 19:57:24
Ivan303
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Posts: 40969
Location: Cadiere d'azur FRANCE - Santa Fe, NM
Joined: February 26, 2001
Don't know where Doc. Bottlehead is getting his iron from these days?

I'm thinking on building the MonAmour mono-blocks as I like the driver tube (5670/2C51/WE396A) and I have a mess of them around here some place and I hate the sound of the 12AT7.

Granted, the 12AT7 as used with active loading in the StereoMour is likely fine, but still.






 

RE: Could be very good..., posted on June 4, 2020 at 08:01:32
Paul Joppa
Industry Professional

Posts: 6987
Location: Seattle, WA
Joined: April 23, 2001
The iron in current Stereomour and other Bottlehead amps is custom made for us; they are my designs.

 

Do tell..., posted on June 6, 2020 at 06:25:38
Ivan303
Audiophile

Posts: 40969
Location: Cadiere d'azur FRANCE - Santa Fe, NM
Joined: February 26, 2001
Or don't if you're not comfortable telling...

Lived in San Francisco from 1970 until just a couple years ago and knew a lot of the audio folks Northern California over the years. Be curious who's making them for you.





 

RE: Do tell..., posted on June 6, 2020 at 22:17:29
Paul Joppa
Industry Professional

Posts: 6987
Location: Seattle, WA
Joined: April 23, 2001
No, we consider that proprietary. But you would not likely have heard of them - nothing fancy, just a small-town American factory that happens to do really good, reliable custom work for us.

 

RE: why not outsource overseas to increase margin ?, posted on June 10, 2020 at 08:02:45
deathtube 667
Audiophile

Posts: 1989
Joined: November 25, 2010
Made in America usually means increase in cost.

Have you considered outsourcing magnetics manufacturing to increase margins?

Of course, "Made in USA" can be a selling point with some buyers.

DT 667

 

RE: why not outsource overseas to increase margin ?, posted on June 10, 2020 at 09:54:30
Paul Joppa
Industry Professional

Posts: 6987
Location: Seattle, WA
Joined: April 23, 2001
Reliability and responsiveness are the main reasons. The ability to work closely together is especially important when doing a non-standard custom design. And as many small manufacturers have found, outsourcing overseas has many ancillary costs that make it actually less costly to use a reasonably local domestic source.

 

RE: why not outsource overseas to increase margin ?, posted on June 11, 2020 at 03:12:30
deathtube 667
Audiophile

Posts: 1989
Joined: November 25, 2010
Product quality often takes a backseat to increased EBITDA, cash ROI and organic growth $$$.

Engineering is compromised by the finance department and executive leaders who have ZERO engineering experience.

The company I work for is constantly looking at cheaper materials and vendors (mostly non-US) in order to increase margin.

This wastes time that could be invested into new product development. Instead our lab is spending time on qualifying new vendors.

Common sense is a relic of the past.


 

RE: Stereomour vs other 2a3/45 designs? , posted on June 11, 2020 at 14:27:58
Frank Mena
Audiophile

Posts: 274
Location: S Western Ontario
Joined: May 28, 2006
Could the question be changed to Parallel Feed (parafeed) vs Series Feed output for SET amps? and are you asking about circuit design or sound quality/traits or cost? .... not sure what you are after when you say "stacks-up".

Lots of stuff out on the web about each and like many things it's all about the implementation, starting with a good circuit.

If it's about sound quality/traits you are interested in between the two, then my suggestion is to audition each design cause your likes/dislikes are most likely not going to be found reading the web.

Cheers
FM

 

RE: why not outsource overseas to increase margin ?, posted on June 13, 2020 at 15:19:15
GEO
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Posts: 4214
Joined: April 7, 2000
Contributor
  Since:
September 9, 2000
You owned by private equity?

 

If I were going to ask the question..., posted on June 13, 2020 at 15:39:55
Ivan303
Audiophile

Posts: 40969
Location: Cadiere d'azur FRANCE - Santa Fe, NM
Joined: February 26, 2001
I'd ask how it compared to the original Paramour with similar upgrades (Constant Current Source, etc.).

Which reqresented good value for $$$ back in the day.

Preferred the sound of the Paramount and would wonder how much better (if at all) the new MonAmour is when compared to the original Paramount




 

RE: If I were going to ask the question..., posted on June 13, 2020 at 20:37:48
Paul Joppa
Industry Professional

Posts: 6987
Location: Seattle, WA
Joined: April 23, 2001
MonAmour has DC filaments, better iron, and a more linear driver tube, compared to the original Paramount. It is not direct coupled, which the 2A3 version of Paramount was.

I am limited in what I should say on this forum; best to post on the Bottlehead Forum if you want details.

 

RE: "a more linear driver tube"..., posted on June 15, 2020 at 06:24:01
Ivan303
Audiophile

Posts: 40969
Location: Cadiere d'azur FRANCE - Santa Fe, NM
Joined: February 26, 2001
Sorry, thought both the Paramount and the MonAmour used the 5670 series of tube as a driver (good!). Maybe only later Paramounts? Maybe the tube is the same but the circuit is different?

Also, I am very sure that answering a couple technical questions about products one designs is allowed my the management as is well within the prescribed rules of behavior by a manufacturer.







 

RE: "a more linear driver tube"..., posted on June 15, 2020 at 08:55:37
Paul Joppa
Industry Professional

Posts: 6987
Location: Seattle, WA
Joined: April 23, 2001
Yes, answering questions is OK - and I am happy to do it.

You used the term "original Paramount" - that used a 12AT7. There were some issues in certain specific cases which led to a revision incorporating a slow-start driver power supply and a few other tweaks. We switched to the 5670 at that time. There was an upgrade kit for earlier amps.

Incidentally, we did do a few before-and-after distortion measurements. I was pleased to find that both drivers produced essentially the same distortion harmonic spectrum at the output, suggesting to me that the distortion was dominated by the output tube - the current source plate load made the 12AT7 more linear than a [Sovtek] 2A3.

 

Only heard the 5670 version..., posted on June 15, 2020 at 16:35:45
Ivan303
Audiophile

Posts: 40969
Location: Cadiere d'azur FRANCE - Santa Fe, NM
Joined: February 26, 2001
and that with a WE tube of some sort.

Sounded very good, IIRC it was a 2A3 version of the amp driving Cain & Cain Abbys. Might have been a 300B version but do remember the WE tube,

Long time ago.





 

RE: Only heard the 5670 version..., posted on June 15, 2020 at 21:22:40
Paul Joppa
Industry Professional

Posts: 6987
Location: Seattle, WA
Joined: April 23, 2001
That's the 396A.

 

RE: "a more linear driver tube"..., posted on June 16, 2020 at 06:05:11
Deke609
Audiophile

Posts: 8
Location: Toronto
Joined: January 11, 2019
Like Ivan303, I also think there's something special going on with the 5670. I am probably one of the few outside of Bottlehead who has heard the Stereomour with the premium iron that comes with BH's Kaiju 300B and Monomour 2A3 amps. I installed my Kajiu iron in a Stereomour. It appreciably improved the sound (to my ears), but the Stereomour still fell considerably short of the Kaiju. Other than the driver tubes (12AT7 in the Stereomour, 5670 in the Kaiju), the amps were essentially identical (besides the output tubes -- but I used very nice EML tubes in both). In fact, the Stereomour with Kaiju iron arguably had an advantage: installed in the Stereomour, the Kaiju plate choke could be used full winding (I think 60H?), whereas in the Kaiju only a partial winding is used (40H?).

Which leads me to think that it's the 5670 that makes (much of) the difference. The only other potential explanation I can think of is the spacious layout of the Kaiju - perhaps greater distances between iron and other components is a contributing factor.

I suspect that there's something not captured by distortion measurements going on here. The Kaiju just sounded "bigger and better".

I would imagine that the Monomours, which take advantage of the full plate choke winding and use 5670 drivers, sound very good indeed.

cheers, Derek

Derek

 

Thanks..., posted on June 16, 2020 at 07:26:02
Ivan303
Audiophile

Posts: 40969
Location: Cadiere d'azur FRANCE - Santa Fe, NM
Joined: February 26, 2001
IIRC, I have a number of 5670 types somewhere in storage. Maybe even some WEs.

Also recall the weak link in the Paramour was the 'stock' choke? At the time the Paramour was a 'starter' kit ($500?) and a number of friends built them, later upgrading the 'iron' and even going so far as to change the 12AT7 driver tube.

My Edgar Hours would be perfectly happy with 3 measly watts, and yes, EML tubes are 'nice'!





 

RE: Thanks..., posted on June 16, 2020 at 08:35:13
Paul Joppa
Industry Professional

Posts: 6987
Location: Seattle, WA
Joined: April 23, 2001
Yes, the weak links in the original Paramour from 20 years ago were the plate chokes - and the output transformers. (That's a big part of what made it inexpensive, of course ...)

It's a long story, but the original Paramour had a 10H choke at 4K load, for 2.5H per kOhm (that's what counts). The original output transformers had limited bass power bandwidth, something like 3.5 watts above 50Hz, 1.75 watts at 35Hz. Current Stereomour is 20 henries, power band 3.5 watts at 22Hz.

Some customers (e.g. Deke609) have indeed experimented successfully with various mods to the iron and driver.

 

RE: why not outsource overseas to increase margin ?, posted on June 18, 2020 at 17:37:39
deathtube 667
Audiophile

Posts: 1989
Joined: November 25, 2010
You owned by private equity?

We are publicly traded, sir.

 

Sadly no 5670's in the tube stash..., posted on June 18, 2020 at 18:59:28
Ivan303
Audiophile

Posts: 40969
Location: Cadiere d'azur FRANCE - Santa Fe, NM
Joined: February 26, 2001
Only a bag full of 'tested' WE 417A's and a dozen or so Raytheon and Amperex 5842's. :-(







 

RE: why not outsource overseas to increase margin ?, posted on June 20, 2020 at 16:37:08
GEO
Audiophile

Posts: 4214
Joined: April 7, 2000
Contributor
  Since:
September 9, 2000
Ok. Thanks.

 

Not sure anyone answered your question., posted on June 21, 2020 at 05:18:51
jusbe
Audiophile

Posts: 5852
Location: North Island
Joined: April 4, 2000
I can't either! It's one I've asked myself and others over the years.

There's a lot going for para-feed designs, and Bottlehead are long practitioners of the art. But there are hardly any direct comparisons, or comparative reviews made, to more traditional and current designs, making buying choices harder than they should be. IIRC, there may have been a comparative review in Positive Feedback years and years ago, but that's guessing and the designs have evolved a substantial amount. I certainly liked reading about all the special inter-leaving methods using alternating core materials, for example. Not sure such upgrades are offered now?

BH have an enviable reputation - from what I can tell over the years - when it comes to a) customer service and b) community support. Their amps are highly though of, by those who use them. Maybe someone will chime in soon.
Big J

"... only a very few individuals understand as yet that personal salvation is a contradiction in terms."


 

RE: Not sure anyone answered your question., posted on June 23, 2020 at 10:05:43
BenE
Audiophile

Posts: 368
Location: midwest
Joined: March 18, 2012
Perhaps not, but interesting replies nonetheless and I appreciate it. Thank you
On another front I did recently receive an Alan Eaton 45 stereo amp that was written about in Glowinthedarkaudio. Uses old 1960's transformers and sounds very robust, quick and more powerful than I would have thought a 1.5 watt amp could. I've never owned a 45 amp. I did own some 2a3 mono blocks at one time.

 

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