howardnair
New member
if one could -what 2a3 would one buy?
if one could?
- Thread starter howardnair
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Grainger49
New member
RCA Blackplates, TJ Mesh Plates, Sophia Mesh Plates.
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
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
New member
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
New member
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
New member
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.
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.
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
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
New member
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.
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
Moderator
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!)
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
New member
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).
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).
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.
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 said:
I don't know that what I think is relevant to what EML's policies are about capacitors. Clearly the pages of boilerplate on the EML site indicate that there are a lot of parts and circuits out there that the EML management feels are incompatible with their product. If something bad happens the tube guy is maybe gonna say it's the amp maker's fault. The amp maker is maybe gonna say it's the tube maker's fault. Whatever. The bottom line is the all the amp maker needs to do is supply someone else's tube that works in his amp in order to play it safe. The tube maker either has to come up with a solution or generate a list of warranty violations. I'd rather be the amp maker than the tube maker in that situation.
Once again, I think the EML tubes can sound very, very nice. For ten years the only tubes that arc over on startup in our DC amps have been the AVVT and EML tubes. It appears by now that this tube maker is not going to make changes to try to achieve the same level of compatibility with our direct coupled amps that other tube makers already have. So we simply sell a bunch of 2A3 amps with someone else's tubes. Even though we can just continue to do that and say "using EML tubes in our amps will violate your warranty with EML (note here that the warranty on our amp is not voided, but we will not replace your EML tubes if they go poof)" we have come up with a circuit that should make the EML 2A3 usable in our amp - assuming that the research that the manufacturer sent us and the conclusions he has drawn are correct. I don't have any problem with doing that, and I want to try to help our customers who are otherwise caught in a standoff.
My experience in the industry is that we have the greatest success when we work with suppliers who are equally willing to adjust and adapt their product to work with ours as we are with theirs. A great example of this would be Mike LaFevre of MagneQuest.
Paul Joppa
Moderator
The problem seems to occur when there is a positive grid voltage an/or grid current during the warm-up of the filament in EML tubes. Even a tiny leakage current in the coupling cap can create a hefty grid voltage before the filament gets hot enough to allow grid current, which I assume is why they ban any cap that can have significant leakage. Also, large-value coupling caps in combination with high grid to ground resistance makes a long time constant, and the charging current of the coupling cap can cause this high grid voltage for enough time to occur during the filament heating. I don't think there is a problem with 0.1uF and 250K ohms, which is what we usually use - but some amps use 0.47uF or even greater coupling caps.
In my humble opinion, EML is taking their best practical line here. Their tubes sound really good, and there is a high probability that is partly because of the cathode they use. So changing their tube's design would risk damaging the sonics, and the tube works well with many - probably most - amplifiers. They are up front about not using the tube in amps that can damage it.
You could say the the esoteric tubes are find in normal amps, and normal tubes are fin in esoteric amps, and of course normal tubes are fine in normal amps. It's the combination of esoteric tubes in esoteric amps where unexpected problems sometimes develop.
In my humble opinion, EML is taking their best practical line here. Their tubes sound really good, and there is a high probability that is partly because of the cathode they use. So changing their tube's design would risk damaging the sonics, and the tube works well with many - probably most - amplifiers. They are up front about not using the tube in amps that can damage it.
You could say the the esoteric tubes are find in normal amps, and normal tubes are fin in esoteric amps, and of course normal tubes are fine in normal amps. It's the combination of esoteric tubes in esoteric amps where unexpected problems sometimes develop.
howardnair
New member
if one could?-- i would!! and did-sooooo!! i ordered the sophia princess 300B 2.5--why? well pure and unadulterated curiosity--whether i chose the sophia 300B 2.5 or the princess 2a3 -a pair of rca blackplates-or even the emission labs--what i will have is music!--i worried about caps and resistors , speaker terminals ,goldpoint selector or stock -alps or stock-wiring layout-and on and on--before i built --then the wooden chassis-[i had to make quite a few prototype pieces]-the finish on the chassis-then consternation about upgrading the tubes--yikes--i would not have done it any other way--very enjoyable--so i will put the sophia's in the stereomour--and sit back and enjoy-i still say that the stereomour is more than a improvement over my cayin 860 modded mono blocks which are still resigned to the basement system and most likely will stay there until i sell them and build another something or other--howie
