NO! You wrote the Mullard 5-10 is not optimum. If you upload a precise schematic I can understand if you are talking in general you are wrong. Anyway, nowadays Mullard 5-10 refers essentially to the front end just like the Williamson where you can have triode or UL for the output stage typically, regardless of the original output stage.
The fact that the first amplifier had a certain configuration doesn't mean it hasn't evolved in several variants.....
Then you should explain on which basis a cheap 60 years old amplifier is not optimum. That frequency response is very much dependent on the transfomer they used.
However, does a frequency response limited to 20-25 KHz discriminate between optimum and non optimum? If you think this you still have to walk a loooooog way, IMHO.
I understand your HiFi concept is the one back in the eighties where awful sounding amplifiers with 0.00001% THD and 200 KHz bandwidth where the "best".....
I usually do not upload schematics because I don't use softwares and simulations....if you know how it works you don't need schematics and simulations.
The original circuit where I started from is this:
ECL82 PP1
I have modified quite a number of things, including the coupling between the input stage and the LTP, the LTP tail and the bias of the ouput stage, however the amplifier type is still a Mullard type circuit where I have a SE high mu triode or a pentode as input device followed by an LTP made of high gain devices.
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I wrote:"Mullard 5-10 is not optimum" and referred to this schematic:
http://www.r-type.org/articles/5-10-b1.jpg
I don't care what you (nowadays) understand as Mullard 5-10, but to me it is the above schematic and that is what I have referred.
No it is not, if original schematic with original component values are used.
But - as I said - with a good OPT, it can be improved.
Then it is not original Mullard 5-10 anymore.
Yes. When heavy GNFB (20 dB) is used the -1 dB frequency response should be up to 50 kHz if the design can be treated as optimum. (including many other features)
IMHO, you are simply wrong.
This statement tells me the essentials. I understand the background of your comments better now. I recommend you to update your design methods. It is eye-opening in many respects.
This - especially after your large modifications - is far from Mullard 5-10, what I have been talking about.
http://www.r-type.org/articles/5-10-b1.jpg
I don't care what you (nowadays) understand as Mullard 5-10, but to me it is the above schematic and that is what I have referred.
No it is not, if original schematic with original component values are used.
But - as I said - with a good OPT, it can be improved.
Then it is not original Mullard 5-10 anymore.
Yes. When heavy GNFB (20 dB) is used the -1 dB frequency response should be up to 50 kHz if the design can be treated as optimum. (including many other features)
IMHO, you are simply wrong.
This statement tells me the essentials. I understand the background of your comments better now. I recommend you to update your design methods. It is eye-opening in many respects.
This - especially after your large modifications - is far from Mullard 5-10, what I have been talking about.
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Back to the original topic?
Why do you need to put that pot in at all? (P1)
In most cases, you want the cathodyne (concertina) to have matched plate and cathode load resistors. Then at least that stage of the amp is balanced. (One problem down.) Then, if the output tubes are unbalanced, fix that problem. The bias network in the Williamson paper addressed that problem. R21 in this schematic:
Was that an inadequate way of doing it? Is P1 in that Sound Valves amp a better way of balancing the amp, or just cheaper and easier?
Why do you need to put that pot in at all? (P1)
In most cases, you want the cathodyne (concertina) to have matched plate and cathode load resistors. Then at least that stage of the amp is balanced. (One problem down.) Then, if the output tubes are unbalanced, fix that problem. The bias network in the Williamson paper addressed that problem. R21 in this schematic:
Was that an inadequate way of doing it? Is P1 in that Sound Valves amp a better way of balancing the amp, or just cheaper and easier?
The truth is that you didn't know that a Mullard 5-10 can be both UL and Pentode. If you can reproduce in practice exaclty the same amplifier then you are right if you cannot it is all HOT AIR. Still have to see an amp I build with that frequency response. It was like that 60 years ago, not today! The famous Olson amplifier made with 4 triode-connected 6F6GT's had a similar frequency response and this was surely because of the transformer. If sometime you build these amps you would find quite different results in terms of frequency response (using decent transaformers)! In the case of the Olson is pretty straightfroward as there is no feedback!
The PCL82 amp I built had 36 KHz at -1dB and 51 KHz at -3dB without any feedback and using a reasonably good but cheap transformer. That's something we can bet on, even all the money you have in your bank account!
Bla bla bla.....
For once you should talk about what you know. Unfortunately your supposition is wrong again. The PCL82 amp was a just a cheap amp made on request and surely works better than your 6SL7 concertina driving EL34's that is one of the worst solutions ever.....I have much better stuff to play with. I recommend you to check your auditory system!
That's a consenquence of your limited mind. I understand that as you paly a lot with simulations if you change the value of one resistor you have created a new design! Happy you.
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I think the best way to know is: try it! It also depends on what you have in hands....
You might not need any adjustement if the reistors are checked, the output tubes are reasonably matched and the OT can work fine with some DC unbalance.
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