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
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
Attachments
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
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
Attachments
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
reagards, L
limono said:
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.
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
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
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.
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.
Setting my bias on my new 300b set?
hi everyone,
This is a silly question im sure but I have just purchased a 300b set amp and bought some tj mesh plate 300b,s. I want to set the bias for them. Is that that the plate current .80mA or filament current 1.2 A. Can someone help this beginner ? I bought a multimeter.
hi everyone,
This is a silly question im sure but I have just purchased a 300b set amp and bought some tj mesh plate 300b,s. I want to set the bias for them. Is that that the plate current .80mA or filament current 1.2 A. Can someone help this beginner ? I bought a multimeter.
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
The funny thing is that guy very often speaks about the differences between the old Tesla's and new JJ's and how the former tubes used better materials and bla bla bla....
Actually JJ's are excellent! Maybe they don't use the best materials available but at least they are accessible very good tubes and are reliable. Considering their share of the market the failures are minimal.
I have handled a good number of 2A3-40's - which are 2.5V 300B's, nothing more nothing less - and 6L6GC's and never got a problem.
I find the 2A3-40 superior to 5V 300B's. The low voltage filament gives you a clear advantage.
Cheers,
45
There's a lot of imprecise terms used and that will definitely confuse a beginner. The bias is the negative grid voltage (or positive cathode/filament voltage with respect to ground) which sets the idle current (cathode-to-plate) through the tube. I don't know your amp, but from the numbers you mention here, 80 (not .80) milliamps is the idle current. There will either be a potentiometer which varies the negative voltage on the grid to control this or there will be a large variable resistor (probably bypassed) between the filament and ground that may be adjusted to set this current.
Filament current is a totally separate thing- it's the current that keeps the filament hot and is usually not adjustable.
The only info i have on my amp is:
I SPECIFICATIONS
■Power Output 2×8watts (RMS,8Ω)
■Frequency response 10Hz~20kHz -0.5dB
■THD 2%
■S/N ratio 85dB
■Input impedance 100kΩ
■Input sensitivity 300mV ( Input2, Integrated)
600mV ( Input1, Direct-in)
■Output impedance 4Ω,8Ω
■Power requirements 220VAC±5%, 50/60Hz
■Weight 21.3kg
■Dimension 350×410×190mm(W×L×H)
On the cards with the tubes it says: .80mA (plate current) and 1.2 A (filament current)
On the amps website it says:
1. Please prepare a "Multi-Meter" (or DC.V Meter), a flat-type screwdriver for bias adjustment use.
2. Before turning on the amplifier, please ensure all the power tubes (i.e. 300B in this case) are correctly plugged in the tube sockets of the amplifier.
3. Locate the testing pot which has been silk-printed as "Bias ADJ." on the amplifier cabinet as well as the bias pots [Note: Bias adjustment pot "V1" is for tuning the 300B tube marked beside the sign "V1 with an arrow" whilst "V2" pot is for adjusting another 300B tube marked beside the sign "V2 with an arrow"].
4. Prior to switching on the amplifier, please make sure the cables, including the speaker cables, are correctly connected. Yet, it is necessary to disconnect the signal cable, or alternatively to turn the volume to the lowest position in order to avoid any signal input that would in turn affect the accuracy of bias adjustment.
5. Switch your Multi-meter to the DC.V mode. Connect the "N" (i.e. negative testing lead) of the Multi-meter to the pot on the amplifier which is marked with the " - " sign whereas the "P" (i.e. positive testing lead) of the Multi-meter should be connected to the pot which is marked with the "+" sign. Since there are totally 2 pcs of 300B tubes to be adjusted by turns, please select either "V1" or "V2" bias pot first.
6. Now you can turn on the amplifier and let it operates for about 3 minutes before proceeding to the next step.
7. To adjust the bias value for the "V1" tube, connect the "+" testing lead of the Multi-meter (or DC.V. meter) to the "V1" bias pot and the " - " testing lead to ground (* test point cross 10ohm/resistor to ground). Using the screwdriver to adjust the bias until it measures the value at 0.6DCV (i.e. the static current is around 60mA for this vacuum tube). Repeat the same procedures for another 300B tubes (i.e. V2) accordingly.
8. Upon completion of the above steps, repeat Step. 8 after 10 minutes to make sure every bias pot measures the value at 0.6DCV.
9. Since bias adjustment involves much technical knowledge, should you require any technical assistance, please free feel to contact us.
Is the 0.6DCV for the tubes that came with the amp?
Thanks SY
Kind Regards
paul
I SPECIFICATIONS
■Power Output 2×8watts (RMS,8Ω)
■Frequency response 10Hz~20kHz -0.5dB
■THD 2%
■S/N ratio 85dB
■Input impedance 100kΩ
■Input sensitivity 300mV ( Input2, Integrated)
600mV ( Input1, Direct-in)
■Output impedance 4Ω,8Ω
■Power requirements 220VAC±5%, 50/60Hz
■Weight 21.3kg
■Dimension 350×410×190mm(W×L×H)
On the cards with the tubes it says: .80mA (plate current) and 1.2 A (filament current)
On the amps website it says:
1. Please prepare a "Multi-Meter" (or DC.V Meter), a flat-type screwdriver for bias adjustment use.
2. Before turning on the amplifier, please ensure all the power tubes (i.e. 300B in this case) are correctly plugged in the tube sockets of the amplifier.
3. Locate the testing pot which has been silk-printed as "Bias ADJ." on the amplifier cabinet as well as the bias pots [Note: Bias adjustment pot "V1" is for tuning the 300B tube marked beside the sign "V1 with an arrow" whilst "V2" pot is for adjusting another 300B tube marked beside the sign "V2 with an arrow"].
4. Prior to switching on the amplifier, please make sure the cables, including the speaker cables, are correctly connected. Yet, it is necessary to disconnect the signal cable, or alternatively to turn the volume to the lowest position in order to avoid any signal input that would in turn affect the accuracy of bias adjustment.
5. Switch your Multi-meter to the DC.V mode. Connect the "N" (i.e. negative testing lead) of the Multi-meter to the pot on the amplifier which is marked with the " - " sign whereas the "P" (i.e. positive testing lead) of the Multi-meter should be connected to the pot which is marked with the "+" sign. Since there are totally 2 pcs of 300B tubes to be adjusted by turns, please select either "V1" or "V2" bias pot first.
6. Now you can turn on the amplifier and let it operates for about 3 minutes before proceeding to the next step.
7. To adjust the bias value for the "V1" tube, connect the "+" testing lead of the Multi-meter (or DC.V. meter) to the "V1" bias pot and the " - " testing lead to ground (* test point cross 10ohm/resistor to ground). Using the screwdriver to adjust the bias until it measures the value at 0.6DCV (i.e. the static current is around 60mA for this vacuum tube). Repeat the same procedures for another 300B tubes (i.e. V2) accordingly.
8. Upon completion of the above steps, repeat Step. 8 after 10 minutes to make sure every bias pot measures the value at 0.6DCV.
9. Since bias adjustment involves much technical knowledge, should you require any technical assistance, please free feel to contact us.
Is the 0.6DCV for the tubes that came with the amp?
Thanks SY
Kind Regards
paul
The 0.6Vdc listed relects the recommended operating point (60mA) for this amplifier - you should set the bias to the recommended value provided by the amplifier manufacturer, NOT the value listed with the tubes you purchased.
I've been using two pairs of the EML 300B for about 10 years and by now they must have several thousands hours on them. They are completely reliable and still test better than 90% of new. Most likely, there's some parameter in your amps that caused premature failure.
I've owned vintage WE 300B's (1940s and 1960s production) and only sold them when I found something better -- the EML 300B. FYI, the mesh plate version has an even better midrange and bass, similar to the Elrog, but more reliable for a much lower price.
I am using EML 20 AM tubes in my latest line stage design and have to say they perform quite well. The importer and factory are very helpful, and if you remember to register them when received a warranty extension to 5 years is offered on at least some types.
It pays to use the Yamamoto sockets that they recommend I have discovered from experience. The pins are perhaps minutely wider than standard and this can cause contact issues with inexpensive and moderately priced Chinese made knockoffs of the Yamamoto socket.
Their tubes offer some interesting possibilities for designers such as myself that are not generally found elsewhere. I plan to take advantage of that in the future.
The 20AM is extremely linear in measurements and also subjectively meets my criteria.
It pays to use the Yamamoto sockets that they recommend I have discovered from experience. The pins are perhaps minutely wider than standard and this can cause contact issues with inexpensive and moderately priced Chinese made knockoffs of the Yamamoto socket.
Their tubes offer some interesting possibilities for designers such as myself that are not generally found elsewhere. I plan to take advantage of that in the future.
The 20AM is extremely linear in measurements and also subjectively meets my criteria.
Or 10 years ago the reliability and consistency was an issue. There is nothing strange. The old tubes are typically reliable because they were produced for decades. This is a typical issue in industry. A new product comes out but reliability is not great and then the manufacturing process is adjusted until faliure rate is minimized.
Today EML's are really good. Unfortunately this problem is not really realated to the final user price. It happens with both cheap and expensive products.
Are there somemore experiences on Mesh vs. Non Mesh ?
I just did a little rectifier rolling....Telefunken rgn1064/2004/2504 mesh vs. non mesh. The Mesh add a 3D, a micro-resolution and micro dynamic which makes the sound-stage real. Very, very difficult to go back once you accepted this as the more realistic and holografic.
How are the Mesh triodes / 300Bs doing ? Same effect ?
I just did a little rectifier rolling....Telefunken rgn1064/2004/2504 mesh vs. non mesh. The Mesh add a 3D, a micro-resolution and micro dynamic which makes the sound-stage real. Very, very difficult to go back once you accepted this as the more realistic and holografic.
How are the Mesh triodes / 300Bs doing ? Same effect ?
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