'Apologies for interrupting your present train of thought but below is a link to a lab. demo procedure from Analog Devices that shows how the key voltages in a class B (or AB) audio output stage change with the signal. The output devices and drivers are represented by single transistors in such a simple circuit but overall, a compound transistor of 2 or more devices in an emitter follower (EF) or Sziklai (CFP) pair, as in P3A, amounts to the same thing. Activity: Amplifier Output Stages [Analog Devices Wiki]
I hope some DIYs who usually shy away from theory and learning, do try the teaching rigs for themselves with a breadboard or whatever universal board you have, even with junkbox bits and pieces. An oscilloscope with a decent size display or a PC 'scope, does make a nice, visual presentation but a voltmeter and hand-drawn graph is much cheaper and can at least be used for static voltage measurement points.
I hope some DIYs who usually shy away from theory and learning, do try the teaching rigs for themselves with a breadboard or whatever universal board you have, even with junkbox bits and pieces. An oscilloscope with a decent size display or a PC 'scope, does make a nice, visual presentation but a voltmeter and hand-drawn graph is much cheaper and can at least be used for static voltage measurement points.
I will just tell a story ..... rather than a listening test .....
I have made a few P3A for friends
Story goes : one had his amp for service in my shop so he wanted to have a replacement amplifier ....So i gave him a P3a ....
a few days later my friend oredered a P3A made at his specs which was dual mono on spacific enclosure and specific bias ....
all fine pared it with chario speakers used it for a long time with no issues .... Understanding how P3a works, related pre also ,he realised that sources was lower fi than the amp ....
one at a time he had to upgrade his sources also .....
Brake
At the shop we have authorised service for a few brands ...hegel is one of them .... Sad for us good for clients in a period of 5 years we have serviced 3 hegel amps and none of them had an issue that is factory related .... 3 problems and all three was client related ...one conected the wrong source had an op amp destroyed ....one his kid was playing with power on off up to the point that recticfier was doomed ....
The local distributor though adressed other service requests of his shop to our service shop .... beyond that Antony is a real decent person very service minted and a real gendleman in his relations with clients .
Back to the original story
when my friend wanted a DAC i sugested hegel of course prise range 3K and also said that Antony is a nice guy and you can probably get a demo ....
so indeed my friend contacts Antony scedjule a Sunday morning apointment to have a demo Hegel delivered in to his home from Antony in person ....
Bottom line was that the local distributor of Hegel spent the all day there listening to the P3A with or without the DAC
Session ended something like 7.30 in the afternoon after they had dinner there.
After that Antony stop sending service requests to our shop ....still we remain good friends but we make no money out of this story ....
I dont have an explanation for that but with my mind i think that Antony after that see us as competition since If a P3a dual mono plays 9/10 next to a hegel with only diference that a P3A will cost tops 1500 Euro to be made in the finest enclosure and beats the crap out of an amp that costs 4.000 euro
makes sense ?
I have made a few P3A for friends
Story goes : one had his amp for service in my shop so he wanted to have a replacement amplifier ....So i gave him a P3a ....
a few days later my friend oredered a P3A made at his specs which was dual mono on spacific enclosure and specific bias ....
all fine pared it with chario speakers used it for a long time with no issues .... Understanding how P3a works, related pre also ,he realised that sources was lower fi than the amp ....
one at a time he had to upgrade his sources also .....
Brake
At the shop we have authorised service for a few brands ...hegel is one of them .... Sad for us good for clients in a period of 5 years we have serviced 3 hegel amps and none of them had an issue that is factory related .... 3 problems and all three was client related ...one conected the wrong source had an op amp destroyed ....one his kid was playing with power on off up to the point that recticfier was doomed ....
The local distributor though adressed other service requests of his shop to our service shop .... beyond that Antony is a real decent person very service minted and a real gendleman in his relations with clients .
Back to the original story
when my friend wanted a DAC i sugested hegel of course prise range 3K and also said that Antony is a nice guy and you can probably get a demo ....
so indeed my friend contacts Antony scedjule a Sunday morning apointment to have a demo Hegel delivered in to his home from Antony in person ....
Bottom line was that the local distributor of Hegel spent the all day there listening to the P3A with or without the DAC
Session ended something like 7.30 in the afternoon after they had dinner there.
After that Antony stop sending service requests to our shop ....still we remain good friends but we make no money out of this story ....
I dont have an explanation for that but with my mind i think that Antony after that see us as competition since If a P3a dual mono plays 9/10 next to a hegel with only diference that a P3A will cost tops 1500 Euro to be made in the finest enclosure and beats the crap out of an amp that costs 4.000 euro
makes sense ?
Thanks for sharing, Sakis.
I'm also curious if you ever try P3B with lower current than the original article but still higher idle current than P3A (say, 200-300ma) to get a few more watts running in class A. Is that better for low level/near field listening like in your case?
Yes, please.
I'm also curious if you ever try P3B with lower current than the original article but still higher idle current than P3A (say, 200-300ma) to get a few more watts running in class A. Is that better for low level/near field listening like in your case?
Yes, please.
Yes, but one needs to be careful in a service agency or any other support role agreement in business. The written agreements I have seen are mostly about the manufacturer's quality requirements, confidentiality of technical details, parts sourcing and procedures. However, if you appear to be steering a customer away from the retailer's product line, he sees you as a threat to his business and income.
It is good that a retailer also recognises the sound quality of your P3a builds but this Antony fellow will only see the bad side which could hurt him. Inside, he's not happy at all so you may need to look around for another service agency or three, because he may also discuss the matter with other retailers.
Ok lets have fun !!!
Client and old good friend comes in .... musician, bassist player and maestro , at his 60's, actually a musician that formed in the late 60's the band that Vagelis Papathanasiou started to play, a world class musician Chariots of fire and many more .
Jim is holding a Quad set one 403 amplifier and one 303 prepamp ....to be repaired ...
I say to him what is exactly that you want ?
I need to repair my system cause is not working ....
I say why bother with rubish ?
Now Jim is getting ungry with me and starts telling me stories about the parties he made with this amp and sounded so well and so on and on ...
I say Jim my friend , your are talking to me about very nice memories , of an era that equiment was hard to get , cost a fortune ,and few people had the ability to have and make party with
On my side i am only talking about technical facts and the bottom line is that my job is to fix your system not to judge it ...So i will do ...
Now jim is asking what is about to be done ...
I explain that most of the capacitors will need to be rerplaced, both aged and horrible brand to begin with , pots and switches need to be cleaned deeply , there is some upgrades to be done in the input IC of the amp trimers to be replaced some cpacitors also and so on ...
Ok fine Jim said
how much time ...he asked
I said most of parts i have but some others i have t order give or take 10 days
Jim said
you are killing me ...i am dead without music for 10 days ...
ha ! No problemo i said you can have one of my amplifiers to work with and when you are ready we swap them back .....
----------------------------------------------------------------------------------------------------------------------------------------
At the time Jim is getting from me a P3A made as integrated amp together with a P37 that features all the usual goodies
P37 has an extremely low noise dedicated power supply and trafo, Pot is set to the input of the pre and yet remains dead quiet, gain set X6 ....input and output capacitors are Wima MKS bypassed ,transistors are closely matched all precision resistors
Amplifier was alike since integrated no input capacitor, fast drivers, 1302-3281 combo, Vbe multiplier my style , huge sinks , 100 ma biased , 500VA trafo and 40.000 uf capacitance .... ( few other tweaks as described in the long thread )
Input selector made with relays + shunt topology =ultra quiet even with 3 active sources on it
all made in one pcb
---------------------------------------------------------------------------------------------------------------------------------------
so 10 days passed i made all the repairs as described and the system was up running operating according to specs i called Jim to pick them up ....
Jim is comming to the shop ( without my amp ,looking at me in a weird way )
How much he said ?
I said to him 90 euros .... To explain that 90 euro was almost the cost of the parts before VAT i didn't charge any labour since Jim was a friend ....
can i have a receipt ? he said
that was odd because if i issued a receipt i had 24% tax and my intention was to do the job black between friends ... If i was about to issue a receipt means that from this i was going to actually loose money instead of making any ....
I thought that this was understood from my friend's side and there is no place in the world that you can have this level of service for 2 machines for 90 euro ....
So i go to the register issue a receipt of 90 euro in total i hand him and he places the exact amount of money on my desk .
After that Jim is picking the receipt placed it against light and start looking at it or better said examine as one would do if checking a fake bank note ....
i look at him trying to understand where this is going ....
few minutes later Jim is asking if we are even ? ...he said i gave you the money you gave me a receipt are we even ? are we ok ?
I look at him very surprised said " yes Jim all is fine ""
Then Jim is picking up the set from the bench smashing it on the flor and beyond that he started to step on the broken pieces of the to make sure that nothing is left working ...
I look at him breathless dont know what to do and what to say ....
After all pieces was totally destoyed Jim put his hand in pocket and brings out a pack of cash money ....
Now tell me how much is your amp ...
He pay cash for my amp without bargainig about the cost ....
8 years of use till today no probs at all ....
Client and old good friend comes in .... musician, bassist player and maestro , at his 60's, actually a musician that formed in the late 60's the band that Vagelis Papathanasiou started to play, a world class musician Chariots of fire and many more .
Jim is holding a Quad set one 403 amplifier and one 303 prepamp ....to be repaired ...
I say to him what is exactly that you want ?
I need to repair my system cause is not working ....
I say why bother with rubish ?
Now Jim is getting ungry with me and starts telling me stories about the parties he made with this amp and sounded so well and so on and on ...
I say Jim my friend , your are talking to me about very nice memories , of an era that equiment was hard to get , cost a fortune ,and few people had the ability to have and make party with
On my side i am only talking about technical facts and the bottom line is that my job is to fix your system not to judge it ...So i will do ...
Now jim is asking what is about to be done ...
I explain that most of the capacitors will need to be rerplaced, both aged and horrible brand to begin with , pots and switches need to be cleaned deeply , there is some upgrades to be done in the input IC of the amp trimers to be replaced some cpacitors also and so on ...
Ok fine Jim said
how much time ...he asked
I said most of parts i have but some others i have t order give or take 10 days
Jim said
you are killing me ...i am dead without music for 10 days ...
ha ! No problemo i said you can have one of my amplifiers to work with and when you are ready we swap them back .....
----------------------------------------------------------------------------------------------------------------------------------------
At the time Jim is getting from me a P3A made as integrated amp together with a P37 that features all the usual goodies
P37 has an extremely low noise dedicated power supply and trafo, Pot is set to the input of the pre and yet remains dead quiet, gain set X6 ....input and output capacitors are Wima MKS bypassed ,transistors are closely matched all precision resistors
Amplifier was alike since integrated no input capacitor, fast drivers, 1302-3281 combo, Vbe multiplier my style , huge sinks , 100 ma biased , 500VA trafo and 40.000 uf capacitance .... ( few other tweaks as described in the long thread )
Input selector made with relays + shunt topology =ultra quiet even with 3 active sources on it
all made in one pcb
---------------------------------------------------------------------------------------------------------------------------------------
so 10 days passed i made all the repairs as described and the system was up running operating according to specs i called Jim to pick them up ....
Jim is comming to the shop ( without my amp ,looking at me in a weird way )
How much he said ?
I said to him 90 euros .... To explain that 90 euro was almost the cost of the parts before VAT i didn't charge any labour since Jim was a friend ....
can i have a receipt ? he said
that was odd because if i issued a receipt i had 24% tax and my intention was to do the job black between friends ... If i was about to issue a receipt means that from this i was going to actually loose money instead of making any ....
I thought that this was understood from my friend's side and there is no place in the world that you can have this level of service for 2 machines for 90 euro ....
So i go to the register issue a receipt of 90 euro in total i hand him and he places the exact amount of money on my desk .
After that Jim is picking the receipt placed it against light and start looking at it or better said examine as one would do if checking a fake bank note ....
i look at him trying to understand where this is going ....
few minutes later Jim is asking if we are even ? ...he said i gave you the money you gave me a receipt are we even ? are we ok ?
I look at him very surprised said " yes Jim all is fine ""
Then Jim is picking up the set from the bench smashing it on the flor and beyond that he started to step on the broken pieces of the to make sure that nothing is left working ...
I look at him breathless dont know what to do and what to say ....
After all pieces was totally destoyed Jim put his hand in pocket and brings out a pack of cash money ....
Now tell me how much is your amp ...
He pay cash for my amp without bargainig about the cost ....
8 years of use till today no probs at all ....
Last edited:
P3A is more than 15 years with me .
One is constantly playing in my shop two more are installed in my house
through the years there have been loads of variations , various set ups and enlosures as integrated or as a pre and main combo
many pcb many power supplies small variations in the circuit and mixmatching of parts
Bottom line is that the basic circuit is the same as the original and outputs always 1302-3281....and most of the times with standard bias of 75ma
Latest version is dual mono amplifier not integrated it has a preamp P37 X6 gain behind ,Phono stage included (as described a few posts before that)
Driven of 43+43 rails it produces almost 85W at 8 R .....
IT drives a pair of VISATONS which are made with 2*8" Woofer 2*3.5" mIDS +one Tweeter front bass reflex obviously at 4R
Now i know very well that this trully on the risky side but since its for home use and hardly ever pushed hard i took my chance and for 2 years is working flawless ....
In my home there is two listening modes ...
One is night mode where the listening power is low and low will mean up to the point that the speaker can reproduce some music with all the units just a bit of bass just a bit of mid and high ...because my girlfriend is sleeping or any of my kids is sleeping ...
the other mode is 20-25 of standar and clean power so you can have a spread to allow dynamic peaks up to 85 W
Previous speaker was JBL at 8R ,2way one 9" and one tweeter obviously far easier to drive but i gave them away .... So i am now with two Visatons that play well bit better than the JBL but they are not the same sensitive and obvioulsy these are hungry for power ...85 W NO cannot drive them to there full potential (never needed though).
--------------------------------------------------------------------------------------------------------------------------------------------
So i was ordered to complete one LJM AUDIO L10 amplifier for a client configured as dual mono with 2* 500W 36+36 AC trafos 2*15.000uf per ch .
The schematic is well known, client got only PCB i had to install the parts All semis are original and measured and selected by hand for parameters and outputs was the Last version of 1302 and 3281 where the PNP is no longer green but black and i got them from qsc as standard transistor installed in the PLX amplifiers they made ... Drivers are 1930 and 5171....Miller compensation where ever needed according to the schematic are syroflex MIAL at 630V.
Project was completed client wanted 50ma per transistor ofset was 12 mv for one Ch 16 for the other
So i decided to keep it for a week in my house to listen to it to make a detailed listening
I listen to EFP amplifiers every day in my shop after those are finished repairs but for the latest 15 years my listening is P3A both in the shop and in my home ....In the shop amplifier plays from 10.00 in the morning till 9.00 in the night at home is 5-10 hours per week .
L 10 produced 200 clean Watt before clipping almost 3 times the power of my P3A...trully i never heard the my Visatons play like that ... Obviously those can handle the power easy and remain clean and with low distortion almost at any level....Very very impressive !!!!
The first impression of the the EFP is that things are in order ...meaning that instruments give impression that are descrete and the boundaries of each instrument is very sharp ... compared to a P3A i could say easilly 10-15% percent more sharpness.
The low and had a bit of punch more .... bass was at least 10-15% more tight than the P3A .... that in the beginning sounded diferent the punch was impressive to begin with, but after the first impression and a more detailed listening a realised that the bass was Less than the P3A.... Not especially less ( i dont know if i can describe that correctly remember English is not my native language )
If you have a song that has a kikc drum then yes the diference in kick/punch is imidiatelly noticable , but when the bass joins in in lower frequencies it seems there that L10 is not that live .... Indeed copaired to a P3A where the bass is far more rich and extensive to more lower frequencies but then the bass appears a bit wably and lets say that when very low frequencies flood the program it appears that you loose control .
In my very first tests many years ago i made a comparison test P3A next to a SANYO P 55 which is an amplifier that has avery bright middle area and i think that its an amp for listener that will value that and only that.
In my test i hopped that the P3A will have the same qualities in the middle area and yet remain superb at the edges ....
Obviously this never worked and P3A was linear as any amplifier should be while Sanyo P55 was only more shiny in the middle area .
So one might jump to the wrong conclusion that a P3A has in a way a poor middle area.... I was sad to realise that the middle area of the L10 was noticably worst ( can tell how much ) Then again middle area in the L10 is less bright and shiny it losses in ammount but remains sharp and descret ...
The tops had alike behavior with bass .. a detailed picture but far thiner than the P3A . It appeared less in amount and in volume of just a bit,
but i felt that high couldn't moove or vary in the frequncy area that was supposed to be .... Again i dont know if the description is placed correctly
if you expect the high to vary in frequencies from 4000-20.000 i feel that this window is smaller for the L10 that focus somewhere arround 10.000 and doesn't go down to 4000 with the same linearity.
Notice that when the listening level is going down to night mode where the power low to the point of not enough, the above conditions get far worst for the L10 ...behind the amp is P37 as a preamp with times 6 configuration that has been more than enough to create superb dynamics at this system even at very low listening levels ....
Now i cannot tell if the L10 is more preamp hungry or its the way its made but yes the diference in very low listenng level could be described as HUGE .....
In the very beggining i described in general the P3A as a very musical thingy that provides revealing pleasure while similar EFP designs provide a click more accuracy but comes with the drawbacks as describe above .
Enjoy
Sakis
One is constantly playing in my shop two more are installed in my house
through the years there have been loads of variations , various set ups and enlosures as integrated or as a pre and main combo
many pcb many power supplies small variations in the circuit and mixmatching of parts
Bottom line is that the basic circuit is the same as the original and outputs always 1302-3281....and most of the times with standard bias of 75ma
Latest version is dual mono amplifier not integrated it has a preamp P37 X6 gain behind ,Phono stage included (as described a few posts before that)
Driven of 43+43 rails it produces almost 85W at 8 R .....
IT drives a pair of VISATONS which are made with 2*8" Woofer 2*3.5" mIDS +one Tweeter front bass reflex obviously at 4R
Now i know very well that this trully on the risky side but since its for home use and hardly ever pushed hard i took my chance and for 2 years is working flawless ....
In my home there is two listening modes ...
One is night mode where the listening power is low and low will mean up to the point that the speaker can reproduce some music with all the units just a bit of bass just a bit of mid and high ...because my girlfriend is sleeping or any of my kids is sleeping ...
the other mode is 20-25 of standar and clean power so you can have a spread to allow dynamic peaks up to 85 W
Previous speaker was JBL at 8R ,2way one 9" and one tweeter obviously far easier to drive but i gave them away .... So i am now with two Visatons that play well bit better than the JBL but they are not the same sensitive and obvioulsy these are hungry for power ...85 W NO cannot drive them to there full potential (never needed though).
--------------------------------------------------------------------------------------------------------------------------------------------
So i was ordered to complete one LJM AUDIO L10 amplifier for a client configured as dual mono with 2* 500W 36+36 AC trafos 2*15.000uf per ch .
The schematic is well known, client got only PCB i had to install the parts All semis are original and measured and selected by hand for parameters and outputs was the Last version of 1302 and 3281 where the PNP is no longer green but black and i got them from qsc as standard transistor installed in the PLX amplifiers they made ... Drivers are 1930 and 5171....Miller compensation where ever needed according to the schematic are syroflex MIAL at 630V.
Project was completed client wanted 50ma per transistor ofset was 12 mv for one Ch 16 for the other
So i decided to keep it for a week in my house to listen to it to make a detailed listening
I listen to EFP amplifiers every day in my shop after those are finished repairs but for the latest 15 years my listening is P3A both in the shop and in my home ....In the shop amplifier plays from 10.00 in the morning till 9.00 in the night at home is 5-10 hours per week .
L 10 produced 200 clean Watt before clipping almost 3 times the power of my P3A...trully i never heard the my Visatons play like that ... Obviously those can handle the power easy and remain clean and with low distortion almost at any level....Very very impressive !!!!
The first impression of the the EFP is that things are in order ...meaning that instruments give impression that are descrete and the boundaries of each instrument is very sharp ... compared to a P3A i could say easilly 10-15% percent more sharpness.
The low and had a bit of punch more .... bass was at least 10-15% more tight than the P3A .... that in the beginning sounded diferent the punch was impressive to begin with, but after the first impression and a more detailed listening a realised that the bass was Less than the P3A.... Not especially less ( i dont know if i can describe that correctly remember English is not my native language )
If you have a song that has a kikc drum then yes the diference in kick/punch is imidiatelly noticable , but when the bass joins in in lower frequencies it seems there that L10 is not that live .... Indeed copaired to a P3A where the bass is far more rich and extensive to more lower frequencies but then the bass appears a bit wably and lets say that when very low frequencies flood the program it appears that you loose control .
In my very first tests many years ago i made a comparison test P3A next to a SANYO P 55 which is an amplifier that has avery bright middle area and i think that its an amp for listener that will value that and only that.
In my test i hopped that the P3A will have the same qualities in the middle area and yet remain superb at the edges ....
Obviously this never worked and P3A was linear as any amplifier should be while Sanyo P55 was only more shiny in the middle area .
So one might jump to the wrong conclusion that a P3A has in a way a poor middle area.... I was sad to realise that the middle area of the L10 was noticably worst ( can tell how much ) Then again middle area in the L10 is less bright and shiny it losses in ammount but remains sharp and descret ...
The tops had alike behavior with bass .. a detailed picture but far thiner than the P3A . It appeared less in amount and in volume of just a bit,
but i felt that high couldn't moove or vary in the frequncy area that was supposed to be .... Again i dont know if the description is placed correctly
if you expect the high to vary in frequencies from 4000-20.000 i feel that this window is smaller for the L10 that focus somewhere arround 10.000 and doesn't go down to 4000 with the same linearity.
Notice that when the listening level is going down to night mode where the power low to the point of not enough, the above conditions get far worst for the L10 ...behind the amp is P37 as a preamp with times 6 configuration that has been more than enough to create superb dynamics at this system even at very low listening levels ....
Now i cannot tell if the L10 is more preamp hungry or its the way its made but yes the diference in very low listenng level could be described as HUGE .....
In the very beggining i described in general the P3A as a very musical thingy that provides revealing pleasure while similar EFP designs provide a click more accuracy but comes with the drawbacks as describe above .
Enjoy
Sakis
I think your command of English is excellent!
“…a shiny mid range…” is a first for me. That is a different yet eloquent way to describe an amp attribute.
Last distraction from the fine contribution you make every day to the DIY world: your likes and dislikes on Rotel’s RB 980BX & 981 amps.
I own & like several of both models. All are due for maintenance. I’m considering some tweaks from another DIYer VERY familiar w/Rotels. I have capacitor and a few resistor replacement/upgrades in the plan.
I hope google translate did my closing correctly…
χίλια ευχαριστώ
Tony
“…a shiny mid range…” is a first for me. That is a different yet eloquent way to describe an amp attribute.
Last distraction from the fine contribution you make every day to the DIY world: your likes and dislikes on Rotel’s RB 980BX & 981 amps.
I own & like several of both models. All are due for maintenance. I’m considering some tweaks from another DIYer VERY familiar w/Rotels. I have capacitor and a few resistor replacement/upgrades in the plan.
I hope google translate did my closing correctly…
χίλια ευχαριστώ
Tony
Tank made machines ...I actually like them a lot ... For a machine that is made in Taiwan i think its machine that is 9/10 close to a Japanese made machine and i think that its the most honnest machine that is ever made ....Both regarding construction and sound ...
Indeed though i found their sound flat up to the point that have no character which can be a very good think and will reveal all the preamp speakers and sources can give without messing with it at all ...
I could use a joyful preamp form CJ PVseries behind them or a Luxman C02 if repaired and upgraded correctly ..... I would never use a rotel prepamp , I would never use a passive preamp behind them
speaker also ...something that has a bit of juice ....B&W is bad choice Pmc could be one option AR could be one other
Small tip :
most Rotels have one capacitor C611 for 980 model which is 330pf to ground on bias scheme .
There have been some cases that this capacitor fails /shorts
in the upgrade replace those ...
Origiallly these are styroflex capacitors with excellent characteristics and absolutely switable to the task but then they do suffer from temperature while at soldering and present failure modes aout of the blue and without obvious reasons .
Best option with the same characteristics is silver Mica capacitors
Last edited:
Thank for the upgrade tip. I’ll hafta see how my “mentors” covered the C611 in their refresh practices.
I’ve read repeatedly, their preamps or preamp sections in their integrated* amps* are a system’s weak point. Further, better to replace and/or use a better external connected to the amp’s* power section inputs.
In closing, Rotel RB-981s made my Home Theater speakers disappear and blend better w/the other channels over different brands but otherwise similar amps. Looking forward to post cap refresh listening and viewing.
again humble thanks. Tony
Member
Joined 2009
Paid Member
It was indeed these stories from Sakis that pointed me towards the p3a. In the end I did modify the circuit a bit (I call it TGM8) but it became my 'last amplifier' without any desire to design another. After a decade in the hobby I didn't feel that there were any possible further improvements that I could make which would be audible to my years and there were no attributes of the amplifier that would ask for any improvement.
We learned at a young age at school that ancient Greeks tell very good stories, why not also modern Greeks?
p.s. Gabor tells a good story about his Darlington output amplifier but I didn't try this one yet.