if one could?

[howardnair]

if one could -what 2a3 would one buy? 

[Grainger49]

RCA Blackplates, TJ Mesh Plates, Sophia Mesh Plates.

[Jim R.]

Well, not having heard the stereomour yet, but having owned and currently owning a couple of superb 2a3 amps, I'd say that the NOS american valves have their appeal for their fairly laid-back presentation and classic "tube" sound.  The absolute best 2a3 I've yet heard is the Shuguang 2a3z black bottle treasure series.  They take forever and a day to break-in (typically recommend 300 hours), but once there are wonderful.  Not quite as smooth, but less than half the price, and with very good bass/mid bass is the JJ 2a3-40s.

I have yet to hear two others on my short-list -- the EML solid plate 2a3s, and the sophia 2.5v filament 300Bs -- these were recommended to me by Jon Verhalen of Lowther America, who aside from his new GM-70s, has a pretty extensive collection of 2a3 amps and told me he likes these tubes best of all.

IMO, most of the upper echelon new production 2a3s -- those I just mentioned. leave the NOS americans in the dust, unless you happen to be looking for that classic sound.  Also, the only 2a3s I've tried and could not take are the shuguang 2a3cs -- they are very thin and brittle sounding on my fi 2a3 monos, and sounded only slightly better on the tektron 2a3 reference integrated that I used to have.  I'll take thesovteks over these anyday.

All just my opinion of course.

-- Jim

[shelby1420]

Have tried the Sophia mesh plates 2A3 and the K&R 2A3 and both were spanked ( pretty hard I might add) by the RCA Black Plates I have in my Stereomour now!!! Not big on all the audiophile talk but I can tell you my feet are tapping now and the music has come alive whereas with the aforementioned tubes feet were still and music was kinda dull, YMMV of course.

[howardnair]

jim-grainger and shelby-you give me food for thought-i currently have the shuaguang 2a3c's in my stereomour-i am looking at the rca's ,shuaguang treasure's ,TJ''s and sophia's in no particular order-emission labs has a no go for bottlehead-i do not know what that is about-there is also the sophia princess mesh and the regular sophia to consider-what is the difference?  jim you mentioned the sophia 300  2.5v for filament which  i noticed  on their site --what are the benefits and thought behind them-it seems a odd thing -a 300 where a 2a3 should be--thanks howie

[Grainger49]

I have a couple of pair of old RCAs, one black plate one gray plate.  I also bought Shuguang 2A3Cs a year ago.  I thought they were amazing but only had the worn out Sovteks to compare with.  I still think the 2A3Cs have a huge bang-for-the-buck.  

I suggested the mesh plates since they were all the rage on the last board with the guys who owned highly modded Paramours and its predecessors.

The No-Go from Emission Labs has been discussed here.  Search for it and you will find Paul Joppa's explanation.  It has to do with the voltage they will see at startup.

[Jim R.]

Howie,

The EML problem is constrained to the Paramounts because they are a direct coupled amp, and as Grainger says, it may be that the startup spike is too much for the tubes, but this is a special case.

Like the JJ 2a3-40 (*which is essentially a 300b with a 2.5v filament) the sophia is also a 300b with a 2.5 v filament (instead of the 5v that's normal for a 300b).  Just a different sound -- typically with a bit more midbass/lower mid energy and less aggressive top end, though the sophias are said to have a wonderful top end.

HTH,

Jim

[Grainger49]

Thank you Jim,

I remember that the thread mentioned that the new soft start board, coming soon to a Bottlehead site near you, would ameliorate the problem.

[Paul Joppa]

I personally believe the new board will treat the EML gently enough in a Paramount, and the EML should be no problem in a Stereomour or other cap-coupled amp. However, I don't guarantee anything - I am not going to invest that much $$$ in an attempt to see if my designs can destroy the tube, nor am I going to run a 10,000 hour test switching the amp on and off every hour to determine if the tubes will survive long enough to be satisfactory.

Please understand, everyone, that the new board has some limitations. If you shut it off and turn it back on without waiting 30 minutes, the soft start won't work as well as it does from a cold start, and the EML could be damaged. The main purpose of the new board is to accommodate heat sinks more easily, and to allow an adjustable bias on the driver to set the driver plate voltage. The soft start was easy to implement, and it cures a grid-cathode spark that occurs with a few other new-design tubes, so we included it. These things, along with a small reduction in the regulated voltage, should increase the reliability of the board under severe conditions, especially excess power line voltage - which is becoming more and more common.

Also, I should mention that the 2.5v 300Bs run as 2A3s will run much more conservatively than regular 2A3s and should last much longer, even though they don't produce any more power. To my mind, that's their main advantage in a 2A3 amp. To get more power from them, you have to run them as 300Bs in a 300B amp which happens to have an available 2.5v/2.5A filament power supply. (Such as the Paramount, of course!)

[Thoburn]

I

[Thoburn]

In addition to the 300B for 2A3 tube offering, Sophia has a 2A3 for 2A3 offering that is an alternative that they seem to have more confidence in:

Princess 2A3 Mesh Plate Tubes for 2A3 Amplifiers
Option 1: $375 per premium matched pair with one year warranty (ceramic base).
Option 2: $325 per premium matched pair with 30 days warranty (ceramic base).

[Jim R.]

Just curious why you say it appears they have more confidence in the 2a3 offerings than the 2.5v 300b?

-- Jim

[Doc B.]

I think the EMLs are great sounding tubes. I find the EML 45 particularly nice. My guess is that there is apparently some difference in the way the emissive coatings are formulated and/or applied to the EML filaments vs. those of other 2A3s. The Paramour was never a problem for the EML tubes and neither will the Stereomour be a problem. They are both capacitor coupled between the driver tube and the 2A3, and thus the EML tube is protected at startup.

The EML tube cannot handle the startup cycle of the present, no soft start ParaMOUNT 2A3 amp (or the now retired Afterglow/Paraglow), which is direct coupled between stages. Other brands of 2A3s handle the startup cycle of the present Paramount without any trouble, but we have seen this incompatibility issue with the EML and it's AVVT 2A3 predecessors and direct coupled amps with solid state power supplies since around 2001.

[Thoburn]

Just curious why you say it appears they have more confidence in the 2a3 offerings than the 2.5v 300b?

-- Jim

Because of the large difference in what they charge for a one year warranty. That is just my gut reaction.

[Thoburn]

The Paramour was never a problem for the EML tubes and neither will the Stereomour be a problem. They are both capacitor coupled between the driver tube and the 2A3, and thus the EML tube is protected at startup.

Hi Doc,

What do you make of the EML ban on paper and oil coupling capacitors? (I have Jupiters for instance, which are beeswax and paper (oil??) )

On the EML site I think I ban on 'Large' coupling capacitors as well.