Hi, audiowize and arnoldc.
I can see the post by Gordon Rankin where he sees the 5687 to not fit very well in this position (too low impedance for EF86). I will be using 310A for input, but I guess the same problem will be there. Rankin also point at the size of the choke. I have had commented that the choke sholuld have had a lower DCR than the one used in Lux, an active current source has been suggested in stead of the choke ... As I see from the description Thorstein L. and Brian C. gives, the choke seems part of a "concept" that makes this the "reactive driver" it is - and helps the cathode follower get a different impact on the sound (not giving the "ss" coloration).
Regards Aril
I can see the post by Gordon Rankin where he sees the 5687 to not fit very well in this position (too low impedance for EF86). I will be using 310A for input, but I guess the same problem will be there. Rankin also point at the size of the choke. I have had commented that the choke sholuld have had a lower DCR than the one used in Lux, an active current source has been suggested in stead of the choke ... As I see from the description Thorstein L. and Brian C. gives, the choke seems part of a "concept" that makes this the "reactive driver" it is - and helps the cathode follower get a different impact on the sound (not giving the "ss" coloration).
Regards Aril
In general, if you wish to hear the true sound 300B, you need to do the scheme original WE amplifier.
As yours nick))
Schemes on this tube with call in grid currents, i.e. with mode A2, belittle that big air, for what this tube is appreciated.
And to not use at all cascades in a mode of cathodic repeaters!
As yours nick))
Schemes on this tube with call in grid currents, i.e. with mode A2, belittle that big air, for what this tube is appreciated.
And to not use at all cascades in a mode of cathodic repeaters!
Thank you, Vlauga! I have been "warned" a bit on the MQ "audi-asylum" page as well as here! Thank you for pointing me in the direction of the original WE91 again. I felt I perhaps needed the few more watts in the Lux, as m loudspeakers are "only" 90dB/1w/1m freefield sensitivity. They are quite easy to drive though. I will do some calculations and find out what to do.
Regards Aril
Regards Aril
well, with 450V plate and a 2K OPT you can get 15W or so right? Thats from old WE data. Maybe they are figuring in some positive grid region swing because of the driver. (but realistically, i don't think the 300b grid is designed for that and it will probably melt down if run flat open too long).
Hi again all.
Thank you very much for your offer of sharing your SE 300B schematic with us, Vlauga! I would appreciate it very much!
Thank you all for your input on OPTs and the Lux. I still believe there to be a very good reason for Thorsten to design the Lux this way (as I have the highest respect for him as a designer).
Best Regards Aril
Thank you very much for your offer of sharing your SE 300B schematic with us, Vlauga! I would appreciate it very much!
Thank you all for your input on OPTs and the Lux. I still believe there to be a very good reason for Thorsten to design the Lux this way (as I have the highest respect for him as a designer).
Best Regards Aril
Hello WE91:
I just finished building my version of a WE91 clone and have been looking into adding that cathode follower RE the “LUX”. I have the “LUX” schematic without any values which is kind of useless. I can’t understand how the cathode follower can work with just the choke on the cathode.
So if anyone can share a schematic of a cathode follower with a choke on the cathode directly coupled to a DHT and some real numbers (voltage and resistance) I would be interested.
Now on the other hand, I have been tweaking values of the bypass caps and the operating point of the pentode and my WE91 clone is starting to sound really fine.
Some where on another WE91 related thread, a comment was made that if you want a WE91 amp, just build it as close to the original design as possible. Right now I leaning that way.
Then the other side of the brain wonders if this CF directly coupled to the DHT really is an improvement?
Hi for all!
WE91
In the limited range of frequencies a choke behaves as usual resistance.
The scheme with choke loading are usual for electronics. In them there is nothing unusual.
In sound application any CF stage has not proved musical. It is well-known experience. Therefore such cascade is applied there where other stages are impossible. In the given concrete case with 300B such stage only will worsen sound quality 300B.
WE91
In the limited range of frequencies a choke behaves as usual resistance.
The scheme with choke loading are usual for electronics. In them there is nothing unusual.
In sound application any CF stage has not proved musical. It is well-known experience. Therefore such cascade is applied there where other stages are impossible. In the given concrete case with 300B such stage only will worsen sound quality 300B.
Hi again, WE91!
As to you promised, a scheme on 300B on which I have stopped in the researches.
As already spoke, I experimented with this tube much long. As a result of experiments as much as possible to open potential 300B it was possible by means of here such circuitry. I am sorry, it is figure from the working writing-book, not prepared to the publication. Resistor Rx it is possible to change character of sounding in some limits. Output power up to 12 watt. This scheme extremely demanding. Accessories of the highest quality are necessary for it.
Also I shall repeat again, that the original scheme of amplifier WE very well opens sound character of 300B.
As to you promised, a scheme on 300B on which I have stopped in the researches.
As already spoke, I experimented with this tube much long. As a result of experiments as much as possible to open potential 300B it was possible by means of here such circuitry. I am sorry, it is figure from the working writing-book, not prepared to the publication. Resistor Rx it is possible to change character of sounding in some limits. Output power up to 12 watt. This scheme extremely demanding. Accessories of the highest quality are necessary for it.
An externally hosted image should be here but it was not working when we last tested it.
Also I shall repeat again, that the original scheme of amplifier WE very well opens sound character of 300B.
reply
Contrary views are fine with me as diversity is a good thing and who knows what invention can come of it.
But 'fraud' is a nasty word even when it's paired with 'borderline'
I posted the circuit diagram so anyone can see there is no transformer. Interstage means 'between stage' and could be any device that could work as such, RC, LC, transformer or whatever. I knew that as soon as that little wire from the cathode connected to the input of the following tube was noted some would cry 'cathode follower' and see nothing else.
Is it OK to use terms to conceptualize? What else are words good for? Reactive interstage: both L and C function together within this stage in passing the signal from the input stage to the output stage. Choke on the cathode is not common but it's been done 50+ years ago. We tried and really like the result.
300B: 12watts: perhaps a read of the 300b data sheet will help on this point.
Regards
Brian
Contrary views are fine with me as diversity is a good thing and who knows what invention can come of it.
But 'fraud' is a nasty word even when it's paired with 'borderline'
I posted the circuit diagram so anyone can see there is no transformer. Interstage means 'between stage' and could be any device that could work as such, RC, LC, transformer or whatever. I knew that as soon as that little wire from the cathode connected to the input of the following tube was noted some would cry 'cathode follower' and see nothing else.
Is it OK to use terms to conceptualize? What else are words good for? Reactive interstage: both L and C function together within this stage in passing the signal from the input stage to the output stage. Choke on the cathode is not common but it's been done 50+ years ago. We tried and really like the result.
300B: 12watts: perhaps a read of the 300b data sheet will help on this point.
Regards
Brian
Thank you very much for describing this for us, Brian Cherry.
A pity if critics are made without the right understanding of how the circuit in question actually works. I know I've mentioned CF, but then again I am not a very technically knowledgeable person in regards to circuitdesign, and I have made this clear in my postings. I hope those who read this thread can see that they actually must give Lux a real chance. It really seems to be a very well designed circuit that get the most out of your 300B. I'm only saying that please do not judge the Lux negatively based on criticism in this thread, as this is given out of a mis-conception that this is a CF, which it isn't.
Well, what OPT to upgrade the Lux with ...
If you want the best, well - Tamura F-7002 seems to me to be the choice if a Hirata Tango of the better ones can't be found!
For best bargain ...
Have a look at James or Silk ...
I'm still wondering where to actually place the MQ, Electra Print and Sowter here, but I feel pretty shure about the Tamura and Silk/James ...
Best Regards.
A pity if critics are made without the right understanding of how the circuit in question actually works. I know I've mentioned CF, but then again I am not a very technically knowledgeable person in regards to circuitdesign, and I have made this clear in my postings. I hope those who read this thread can see that they actually must give Lux a real chance. It really seems to be a very well designed circuit that get the most out of your 300B. I'm only saying that please do not judge the Lux negatively based on criticism in this thread, as this is given out of a mis-conception that this is a CF, which it isn't.
Well, what OPT to upgrade the Lux with ...
If you want the best, well - Tamura F-7002 seems to me to be the choice if a Hirata Tango of the better ones can't be found!
For best bargain ...
Have a look at James or Silk ...
I'm still wondering where to actually place the MQ, Electra Print and Sowter here, but I feel pretty shure about the Tamura and Silk/James ...
Best Regards.
WE91 said:
The Japanese auction with TANGO XE60-3.5S by HIRATA!
http://page.auctions.yahoo.co.jp/jp/auction/109974343
Price today ~ 500 USD
The similar transformer used Herb Reichert in known amplifier Flesh and Blood 300B
http://www.enjoythemusic.com/magazine/equipment/0801/fleshandblood.htm
It is your chance!
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