EML 300B XLS and Mesh comparison - diyAudio
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Old 7th July 2008, 08:45 AM   #1
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Default EML 300B XLS and Mesh comparison

Hello all,

for my amplifier i use the 300B as a driver (for a TB 3/1000 triode). I have seen quite some 300B's last years:
- Tanjin Meshplate (perforated mesh);
- Golden Dragon 300B;
- Svetlana 300B;
- Sovtek 300B;
- Valve Art 300B and 300B-98C (perforated mesh)

No....i haven't tried the Sophia, the JJ, EAT, and the WE.....sorry.....

EML always attracted me; the build quality is amazing. Prices are somewhat prohibitive.....but WE's and Sophia's are even more expensive.....

So last year i ordered a pair of EML 300B-mesh and 300B-XLS. First to find out what the nicest combination was. Second to have an alternative. Tube rolling with input tubes (like the used 6SN7) is done a lot; but you don't see that so much with power tubes.

So the tubes arrived........a couple of weeks AFTER i was send to Afghanistan for 5 months. So the goodies were simply gathering dust here. But now i'm back and the 300B-XLS is already glowing nicely.

I'll keep you posted on the progression. And eventually the "outcome" of the listening session between the XLS and the mesh version. And this mesh version is NOT perforated sheet metal but really intertwined wire.

First impression of the build quality: as expected.....SERIOUS ! These tubes are of high quality; thick glass; sturdy build; attention to detail.

Be carefull with older style Johnson Sockets with collar. The ceramic tubebase is somewhat thicker than expected (maybe due to the extraordinary thick lacquer on the base ?). Normally an UX-4 tube base fits snugly in the socket.........these EML's required a bit pushing. This will leave scratch-marks on the tube base.

Some data on the used (home made) amplifier:
signal-path: input transformer (nickel)- 6SN7 - interstage (permalloy) - 300B - interstage (armco) - TB3/1000 - output transformer (armco).

300B:
grid voltage: -75 V
plate voltage: 350 V
plate current: variable (with the XLS on 70 mA). The mesh will be on 60 mA for the total plate dissipation is at 28 Watts (0,06 ampere x 350 V = 21 Watts. Plus the filament heath wich also must be taken into consideration: 5 V x 1,4 A = 7 Watt. So in total 28 Watt). With the XLS there is no problem.....these tubes can dissipate 55 Watts.

Included some photo's of my current 300B's. Just see the size difference.

Regards,
Reinout
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Old 7th July 2008, 08:47 AM   #2
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Default picture of EML 300B-XLS in use

The XLS is situated IN the socket which is mounted under the topplate. And even now the EML is bigger than the Valve Art which i placed there for comparison.
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Old 7th July 2008, 08:49 AM   #3
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Default used amplifier

And a picture of the used amplifier.

Tonight i'll make some night pictures of the EML. Happily i can switch on/off every single voltage/power supply. For as long as the TB3/1000 glows (with it's 12 V / 8 A filament) it will be too bright for the 300B.

Reinout
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Old 9th July 2008, 05:45 AM   #4
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Default First impressions

Hello all,

the EML-300B-XLS took serious time to reach listenability. Normally a tube is settled after an hour of 2. After that it will only change in details. The XLS took half a day !

Result of the long waiting: a very well presented soundstage. Clean but not over-analytical. A bass-line to die for: again clean and punchy. Very glad that this tube is not over-analytical (as most transistors are); it simply does it's job without adding or distracting something to the signal. So.....neutral. I i mean that very positive !
Power.........oodles of it !
If you have a (too) warm sounding hifi-set this XLS can be the trick. And you have REALLY a power booster at your disposal. For me the essence of neutrality.

The Mesh-variant is a totally different story. Within the hour it did it's job more than adequate. Today we'll continue with the listening session. But the differences are HUGE:
- great soundstage. You can pinpoint musicians. Also in heigth.
- again a fantastic bass-line. BUT.......with a musical twist. There is joy in this triode. And the good part is that it is not overly warm or tries to cover something. It is simply a musician-triode....it wants to play.
- voices.......here's the tube you want.

Session to be continued. But as you can read i'm impressed by the quality of both tubes. The XLS is a beast.......power, bass, definition. It really delivers.
The Mesh.......musical delight.
And as my set is certainly not a warm cuddly affair.......the Mesh will continue.

But it is very difficult to take a picture of it during the night. Again a beautifull tube: you can see the filament-wires and blue glow (no worries).

Grtz,
Reinout
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Old 9th July 2008, 06:05 AM   #5
Cappy is offline Cappy  United States
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I'm enjoying your listening notes.

Your output tube is seriously wild!
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Old 10th July 2008, 04:27 AM   #6
limono is offline limono  United States
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I also have KR 300BXl and EML 300B . I hope that they won't send you to Afganistan again because EML tubes have poor shelf time . Mine lasted 500 Hrs before troubles started and after a 1.5 years on the shelf they were dead. KR 300Bxl is a very good tube; dynamic ,extended ,alive and quiet. EML has such a long, long record of poor reliabity that I'm surprised tha anyone buys those tubes.For me they are scam ,postcommunist manufacturer with shady work ethics. Instead of solving manufacturing problems first they kept pushing their junk to unaware public.
reagards, L
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Old 10th July 2008, 07:28 PM   #7
kevinkr is offline kevinkr  United States
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Quote:
Originally posted by limono
I also have KR 300BXl and EML 300B . I hope that they won't send you to Afganistan again because EML tubes have poor shelf time . Mine lasted 500 Hrs before troubles started and after a 1.5 years on the shelf they were dead. KR 300Bxl is a very good tube; dynamic ,extended ,alive and quiet. EML has such a long, long record of poor reliabity that I'm surprised tha anyone buys those tubes.For me they are scam ,postcommunist manufacturer with shady work ethics. Instead of solving manufacturing problems first they kept pushing their junk to unaware public.
reagards, L

Hi Limono

The term shelf life actually refers to the time they sit in storage (presumably on a shelf) prior to actual usage. I assume you meant service life or similar.

What went wrong with them at 500hrs, and at your reported end of life at 1500hrs?

Can you provide information on operating points, filament voltage, etc?

I've heard good things about their performance and if your experience is typical I will avoid them as I look around for other 300B to try..

Incidentally the experience you report is better than I had with a slew of SV300B, and even certain well regarded US made ones have had reliability and QC issues from time to time.
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Old 10th July 2008, 09:48 PM   #8
limono is offline limono  United States
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Kevin
I made a mistake and bought those tubes (regular EML 300B not mesh ) without warranty which was extremely stupid on my part because I paid only 15% less than retail. Original owner just kept them on the shelf for over a year in the box. I used them in REichert amp (flesh & blood) which admitedly run tubes hot -400V
70-80 mA . First I let them burn in my friend's amp (60mA) for a 50-100 hrs. Then put them in my amp. After another few hundred one of the tubes aparently started to lose emission and (both of the tube bases got loose too) degraded more than 20%. Filaments were 4.84V 4.9 (or close) . I contacted Jac and he is a cool guy. I did not expect exchange nor anything just information on possible cause. He said that it must have been "fatal occurence" and his files didn't indicate any excessive failure rate for this year. Besides, tubes were still operational .
After short invastigation on the web it was clear to me that a "fatal occurence" is rather a norm if it comes to EML tubes. I bought 300Bxl (which were quieter, and sounded better to my ears) and boxed EML 300B's for MF , HF section of my future Bi-amp system (and low operating point). Two years later a pair of AN Quest came along for repair /upgrade and I though I check out those EML how do they compare to AN stock (chinese??) Flashes and distorted sound in both channels. I put them in the tester and they (both) just lost emision sitting on the shelf .I've read somewhere that those tubes just have short shelf time and after a certain point "fatal occurence) might happen. Now, the tubes were manufactured in December 2002. I heard that they have improoved quality control ,but I'm not anxious at all to check it. And in my biased eyes 80% post on EML tubes are complains about poor reliabity and how people going trough several pairs to get one which work. And I thought I bought them for a lifetime since they are not only "as good as WE but an improvement" -yeah maybe in aesthetics .They do look nice.
The thing is t AFAIK EML as a manufacturer never officialy admited having any problem with quality.
OK .I will stop "bashing" EML from now on. Should let it go long time ago but it still hurts
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Old 10th July 2008, 10:14 PM   #9
kevinkr is offline kevinkr  United States
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Hi Limono,
Sounds like a very good reason to stay away from them. I too have had my share of bad experiences with other 300B, so far the JJs are working fine and continue to provide relatively consistent performance. I think emission in these has fallen slightly based on the recent need to touch up the bias settings - however they are >6 yrs old and have received a fair bit of use.

I'm thinking about the TJ and KR types as possibilities, I don't think the JJ will wear out soon, I'm just curious to try something else.

Thanks for the information.
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Old 11th July 2008, 01:00 AM   #10
Serge66 is offline Serge66  Switzerland
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Hi Reinout,

Love your amp. It looks very professional.

Serge
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