Revintage,
I am afraid that you have let the smoke out.
You asked the question, now you have the answer.
Your mystery triode is no more liner than any other. They all follow Child’s law.
If you want linier stay off the knee of the curve.
DT
File:ChildLangmuirLawGraph1.png - Wikipedia, the free encyclopedia
I am afraid that you have let the smoke out.
You asked the question, now you have the answer.
Your mystery triode is no more liner than any other. They all follow Child’s law.
If you want linier stay off the knee of the curve.
DT
File:ChildLangmuirLawGraph1.png - Wikipedia, the free encyclopedia
EL82 in triode
Good evening,
may i suggest an EL82 in triode.
Reason:
- an EL82 does sound nice;
- EL82's don't cost a fortune;
- EL82's are easy to drive and do have a very normal load .....no extreme tranny !
As i was looking for a smaller amplifier ( the main amplifier is more than 300 kgs....) i came up with this set up: input transformer - PP 6C45 - interstage - PP EL82 (in triode) - output transformer. The 6C45 does give enough gain and power combined with a nice low load......the EL82 "triode" PP-pair gives a nice 7 ~ 8 Watt. And very good Watts indeed ! I am more than happy with the amplifiers.
Of course you have to invest in your power supply....but that does apply to all (tube) audio-gear.
I've made 2 monoblocks with fixed (but seperate !) power supplies. The powerlines are inside the connectors that hold the power supply fixed to the adui-part itself.
Enclosed some pictures. And i found a datasheet on internet; maybe of use (copyrigth).
So my suggestion....EL82 in triode.
Regards,
Reinout
Good evening,
may i suggest an EL82 in triode.
Reason:
- an EL82 does sound nice;
- EL82's don't cost a fortune;
- EL82's are easy to drive and do have a very normal load .....no extreme tranny !
As i was looking for a smaller amplifier ( the main amplifier is more than 300 kgs....) i came up with this set up: input transformer - PP 6C45 - interstage - PP EL82 (in triode) - output transformer. The 6C45 does give enough gain and power combined with a nice low load......the EL82 "triode" PP-pair gives a nice 7 ~ 8 Watt. And very good Watts indeed ! I am more than happy with the amplifiers.
Of course you have to invest in your power supply....but that does apply to all (tube) audio-gear.
I've made 2 monoblocks with fixed (but seperate !) power supplies. The powerlines are inside the connectors that hold the power supply fixed to the adui-part itself.
Enclosed some pictures. And i found a datasheet on internet; maybe of use (copyrigth).
So my suggestion....EL82 in triode.
Regards,
Reinout
Attachments
E130L triode
I have got good results using E130L in triode mode (SET) with a pentode driver hooked to a mosfet source follower. Just by adjusting the screen resistor of the pentode driver a fair amount of harmonic cancellation can be achieved. I have measured distortion as low as 0.2%/1W or about 0.5%/4W using EF37A as a driver. And the harmonic spectra is good as well (2nd higher than 3rd and low higher order components). Using a linear triode driver with mosfet source follower resulted in a much higher distortion (>0.5%/1W).
E130L tubes vary quite a lot. Tubes originating from Tungsram have higher distortion compared to e.g Mullard or Amperex tubes. And Tungsram tubes are more prone to oscillation which can be seen on the distortion spectra.
regards
Martti
I have got good results using E130L in triode mode (SET) with a pentode driver hooked to a mosfet source follower. Just by adjusting the screen resistor of the pentode driver a fair amount of harmonic cancellation can be achieved. I have measured distortion as low as 0.2%/1W or about 0.5%/4W using EF37A as a driver. And the harmonic spectra is good as well (2nd higher than 3rd and low higher order components). Using a linear triode driver with mosfet source follower resulted in a much higher distortion (>0.5%/1W).
E130L tubes vary quite a lot. Tubes originating from Tungsram have higher distortion compared to e.g Mullard or Amperex tubes. And Tungsram tubes are more prone to oscillation which can be seen on the distortion spectra.
regards
Martti
Hey Reinout,
E82 is a nice tube but is a little to small for my needs in SE. So the most interesting sofar is the Pamax=50w pentode I mentioned above.
Also have used 6C45 in a few designs and have a substantial stock of them. Really good tube! But this time I need a output tube with higher senstivity as the driver has quite low mu.
DualTriode,
Did you even bother to check the curves before complaining? If I understand your post right, you mean that all triodes have the same linearity
.
E82 is a nice tube but is a little to small for my needs in SE. So the most interesting sofar is the Pamax=50w pentode I mentioned above.
Also have used 6C45 in a few designs and have a substantial stock of them. Really good tube! But this time I need a output tube with higher senstivity as the driver has quite low mu.
DualTriode,
Did you even bother to check the curves before complaining? If I understand your post right, you mean that all triodes have the same linearity
.Hey Martti,
Have tried the E130L and it was OK and have three Mullard lying around. Brute tube, but not so easy to find lowZ transformers. About distortion cancellation there is nothing wrong in trying to get ow distortion in the two tubes separatey. About triodes I have got the best results with triode-triode.
Have tried the E130L and it was OK and have three Mullard lying around. Brute tube, but not so easy to find lowZ transformers. About distortion cancellation there is nothing wrong in trying to get ow distortion in the two tubes separatey. About triodes I have got the best results with triode-triode.
I have used Lundahl 1664 output transformers at 100mA with 3k output impedance. Impedance is a bit high but works quite well in practise.
regards
Martti
Hey Spreadspectrum,
My driver is a triode at 10mA with not very much signal out due to low Ua and Mu. Because of that I mentioned the need for high sensitivity.
It is totally unsuitable( not even very clever) to use a triode as driver in a plate-grid/Schade. I really like the concept though. Earlier today I presented a suggestion for a cascode(E88CC) Schade(807) in the "UL cascode" thread.
I´m sure you´ve followed the discussions between me, MJK, kenpeter, Smokingamp and a whole lot of others. You must use something like E280F, D3a or other high Gm tubes if you wan´t a good result.
My driver is a triode at 10mA with not very much signal out due to low Ua and Mu. Because of that I mentioned the need for high sensitivity.
It is totally unsuitable( not even very clever) to use a triode as driver in a plate-grid/Schade. I really like the concept though. Earlier today I presented a suggestion for a cascode(E88CC) Schade(807) in the "UL cascode" thread.
I´m sure you´ve followed the discussions between me, MJK, kenpeter, Smokingamp and a whole lot of others. You must use something like E280F, D3a or other high Gm tubes if you wan´t a good result.
Guess a tube again, but this is simple
Maybe to linear for some of you. No probem to drive them anway. Have two of these beauties in my stash.
EL156 (in triode mode)
revintage,
If it is a game of name that triode, say so.
Yes I did check the curves.
The mystery plate curves increase in slope as the current and voltage increase. Depending on the selection of the operating point and load impedance you might get to 10 watts output before you get to 5% 2nd harmonic distortion. Is this more linear than a 12b4A outputting 1.2 watts?
DT
If it is a game of name that triode, say so.
Yes I did check the curves.
The mystery plate curves increase in slope as the current and voltage increase. Depending on the selection of the operating point and load impedance you might get to 10 watts output before you get to 5% 2nd harmonic distortion. Is this more linear than a 12b4A outputting 1.2 watts?
DT
You might consider the Tung-Sol 6AR6/6098. It is a linear tube with a decent mu in triode mode. For class A operation it biases nicely at around -30V. The datasheets with triode curves are here:
http://www.mif.pg.gda.pl/homepages/frank/sheets/087/6/6098.pdf
Plus, if you want, you can get radical with the Bendix 6384.
John
I know this is off topic for this thread, but I think my favorite implementation is with cathode feedback windings. You have to come up with a way to keep screen voltage constant relative to cathode, but there is not onerous schade network to drive.
Another inelegant idea would be to maybe have a mosfet buffer between triode and power tube that passes a lot of current to drive the schade network. I never see anyone do that. However, you may be looking to keep it simple here.
I think I'll start another thread some time soon. Hope you and the usual suspects will stop by.
Hey Spreadspectrum,
If I understand you right(but I´m not sure exactly how you mean) Michael Koster has quite recently showed a tubey solution at this forum.
Been there, done that. Think it was in the ECL86 PP thread. Unfortunately one has to rearrange the feedback network so sensitivity gets low.
Absolutely, like this subject.
If I understand you right(but I´m not sure exactly how you mean) Michael Koster has quite recently showed a tubey solution at this forum.
Been there, done that. Think it was in the ECL86 PP thread. Unfortunately one has to rearrange the feedback network so sensitivity gets low.
Absolutely, like this subject
.
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Hi Lars, I was looking at EL156 recently for a possible amplifier project. It is only available from one factory in China, but at least it is available, and now with an 8 pin base.
They have nice specifications with respect to anode characteristic curves, mu, and internal impedance.
Good luck with your project.
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