Sophia Electric 300B 2.5V tubes work in Stereomour?

rbc3 · 9353

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Offline rbc3

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on: April 25, 2015, 03:18:41 AM
Sophia Electric has these 300B tubes that are 2.5V which they claim are for use in 2A3 amps.  Will these work in a Stereomour?

http://www.sophiaelectric.com/pages/se/carbon_300b_25v.htm
http://www.sophiaelectric.com/pages/se/300b-25v-spec.htm

Robert C

Paramount 1.1 300B, Tekton Design Seas Pendragon, Stereomour 2A3, Omega Hemptone 8, Acoustic Signature Challenger Mk3, JMW 9T, Dynavector XX2mkII, Clearaudio Balance, Quickie 1.1, Schiit Bifrost Uber, Mainline, Audeze LCD2.2, AKG K1000, HiFiman HE-500, Sennheiser HD650, AK120


Offline rbc3

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Reply #1 on: April 25, 2015, 05:40:25 AM
Just in case, maybe I should ask about whether or not the Sophia 2A3 Mesh Plate will work in a Stereomour.

http://www.sophiaelectric.com/pages/se/2a3-specification.htm

Robert C

Paramount 1.1 300B, Tekton Design Seas Pendragon, Stereomour 2A3, Omega Hemptone 8, Acoustic Signature Challenger Mk3, JMW 9T, Dynavector XX2mkII, Clearaudio Balance, Quickie 1.1, Schiit Bifrost Uber, Mainline, Audeze LCD2.2, AKG K1000, HiFiman HE-500, Sennheiser HD650, AK120


Offline Paul Birkeland

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Reply #2 on: April 25, 2015, 08:07:35 AM
I don't trust the datasheet at all.  2.5V/1.2A can't be a correct specification.

In any case, these are specified as 2A3's, I can't figure out why these wouldn't work.

-PB

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline rbc3

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Reply #3 on: April 25, 2015, 09:08:28 AM
Yeah that is interesting. The second post with a link to their mesh plate 2A3 looks more like the standard 2A3 at 2.5V and 2.5amp filament current.
« Last Edit: April 25, 2015, 09:15:28 AM by rbc3 »

Robert C

Paramount 1.1 300B, Tekton Design Seas Pendragon, Stereomour 2A3, Omega Hemptone 8, Acoustic Signature Challenger Mk3, JMW 9T, Dynavector XX2mkII, Clearaudio Balance, Quickie 1.1, Schiit Bifrost Uber, Mainline, Audeze LCD2.2, AKG K1000, HiFiman HE-500, Sennheiser HD650, AK120


Offline rbc3

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Reply #4 on: April 27, 2015, 06:02:02 AM
I was comparing the specs of their 2.5V 300B to the standard 300B.  The standard  300B is 5V at 1.2A filament current.  I'm no tube expert, but my guess is that the filament design of the 300B is why the filament current is 1.2A even when running at 2.5V.

Robert C

Paramount 1.1 300B, Tekton Design Seas Pendragon, Stereomour 2A3, Omega Hemptone 8, Acoustic Signature Challenger Mk3, JMW 9T, Dynavector XX2mkII, Clearaudio Balance, Quickie 1.1, Schiit Bifrost Uber, Mainline, Audeze LCD2.2, AKG K1000, HiFiman HE-500, Sennheiser HD650, AK120


Offline braubeat

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Reply #5 on: April 27, 2015, 08:09:57 AM
I have been using that tube in my paramours for years. Sounds great. I am fairly sure it draws 2.5 amps.

Michael



Offline rbc3

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Reply #6 on: April 27, 2015, 11:19:53 PM
Michael,

You have your Paramours wired for 2A3 tubes and you're running the Sophia 300B 2.5V tubes in them?  Have you tube rolled other tubes for comparison?  If so, what are your thoughts about the differences between the different 2A3 tubes in Bottlehead amps?

Robert C

Paramount 1.1 300B, Tekton Design Seas Pendragon, Stereomour 2A3, Omega Hemptone 8, Acoustic Signature Challenger Mk3, JMW 9T, Dynavector XX2mkII, Clearaudio Balance, Quickie 1.1, Schiit Bifrost Uber, Mainline, Audeze LCD2.2, AKG K1000, HiFiman HE-500, Sennheiser HD650, AK120


Offline RPMac

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Reply #7 on: April 29, 2015, 04:26:11 AM
I use them in my Stereomour...no problems.

Different tube, different flavor...all good
Only your ears can decide which might be better



Offline Paul Birkeland

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Reply #8 on: April 29, 2015, 09:17:36 AM
I was comparing the specs of their 2.5V 300B to the standard 300B.  The standard  300B is 5V at 1.2A filament current.  I'm no tube expert, but my guess is that the filament design of the 300B is why the filament current is 1.2A even when running at 2.5V.
5V at 1.2A is 6W of filament power.  2.5V at 2.5A is 6.25W of filament power (about the same)

I'm sure it's a typo in the datasheets, and I wouldn't worry about anything strange happening in the Stereomour. 

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline rbc3

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Reply #9 on: May 06, 2015, 01:12:04 PM
I decided to get a pair of Sophia Princess Mesh Plate 2A3 tubes.  They are an improvement over the Sovteks, mainly in the clarity of treble, and some improved detailing.  But the're not as significant as tube rolling 300B tubes in Paramounts.

Robert C

Paramount 1.1 300B, Tekton Design Seas Pendragon, Stereomour 2A3, Omega Hemptone 8, Acoustic Signature Challenger Mk3, JMW 9T, Dynavector XX2mkII, Clearaudio Balance, Quickie 1.1, Schiit Bifrost Uber, Mainline, Audeze LCD2.2, AKG K1000, HiFiman HE-500, Sennheiser HD650, AK120


Offline rbc3

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Reply #10 on: May 08, 2015, 09:02:52 PM
By the way, another interesting observation to me anyway, is that the lowest voltage I can get with my multimeter when adjusting the hum balance with the Sophia Mesh Plate is that the lowest I can get it is 1.3mV.  The Sovteks can get down to .7mV.  The champs are my AVVT 32B in my Paramounts that measure 0mV through the whole hum balance adjustment except at the end.

Robert C

Paramount 1.1 300B, Tekton Design Seas Pendragon, Stereomour 2A3, Omega Hemptone 8, Acoustic Signature Challenger Mk3, JMW 9T, Dynavector XX2mkII, Clearaudio Balance, Quickie 1.1, Schiit Bifrost Uber, Mainline, Audeze LCD2.2, AKG K1000, HiFiman HE-500, Sennheiser HD650, AK120


Offline Paul Birkeland

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Reply #11 on: May 10, 2015, 08:57:56 AM
The champs are my AVVT 32B in my Paramounts that measure 0mV through the whole hum balance adjustment except at the end.
DC powered filaments in the Paramounts make this data point a little irrelevant in evaluating 2A3's in the AC heated Stereomuor.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline rbc3

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Reply #12 on: May 10, 2015, 05:18:51 PM
I completely admit I don't have enough knowledge to explain why the AVVT 32B measure almost no mV when adjusting the hum balance in the Paramount.

Back to the Stereomour and the 2A3 though, I spoke a little soon on the sonic differences between the Sophia Mesh Plate 2A3 vs Sovtek 2A3.  I invited a friend over today to listen through my tubes and amps.  I started with Stereomour with Sovtek 2A3 driving Omega Hemptone 8 monitors and then switched to the Sophia Mesh Plate 2A3.  He was blown away by the differences.  Then I played him the same music through the Paramount 1.1 with Sophia Mesh Plate 300B and Tekton Design Seas Pendragon and his brain melted.  Point being that he heard a much more definite improvement over the Sovtek 2A3 and Sophia Mesh Plate 2A3 in the Stereomour.  So much that his exact words were, "I can't believe all you changed were the tubes!"  I do agree that the Sophia Mesh Plate 2A3 tubes give much higher highs with more detail and clarity to the point of delivering more dimensional and airy sound than the Sovtek 2A3.  The Sophia Mesh Plate 2A3 are an amazing paring with the Stereomour and do a fantastic job driving even the 95dbn 1W@1M Seas Pendragon to volumes loud enough for the neighbors to hear.

Robert C

Paramount 1.1 300B, Tekton Design Seas Pendragon, Stereomour 2A3, Omega Hemptone 8, Acoustic Signature Challenger Mk3, JMW 9T, Dynavector XX2mkII, Clearaudio Balance, Quickie 1.1, Schiit Bifrost Uber, Mainline, Audeze LCD2.2, AKG K1000, HiFiman HE-500, Sennheiser HD650, AK120