You can't be serious about that ...
Dead serious. There are many aspects of good sound and there is no one single amp that excel in all aspects. At least this darlington amp excel in displaying low level details in low frequency. May be only ACA#1 that can do better at that.
We have thousands of clients that will not agree with that ...
Rotel HT 5Ch and hifi RA RB series amplifier often come to shop for service They have minor issues, mostly cleaning,some capacitors may mostly as a precaution , some hardware issues like switches or a broken RCA Hardly ever you will find one that is toasted .
We do like 50 a year
In all of them we noticed that bias is lower than specified in the manual and in most of them nobody has been messing around.
When you find this in 50 amplifiers cannot be a mistake ...to my ears at the factory they tuned them lower in order to have less thermal stress.
At the service beyond others we restore them to original bias as specified in the manual and most of our clients notice the difference.
That is only one example i have thousands more ...In the Greek hifier percentage of listeners that enjoy class B operation should be no more than 1-2% and aged over 60 All the rest prefer other things ...
Out of blue how old are you ?
Rotel HT 5Ch and hifi RA RB series amplifier often come to shop for service They have minor issues, mostly cleaning,some capacitors may mostly as a precaution , some hardware issues like switches or a broken RCA Hardly ever you will find one that is toasted .
We do like 50 a year
In all of them we noticed that bias is lower than specified in the manual and in most of them nobody has been messing around.
When you find this in 50 amplifiers cannot be a mistake ...to my ears at the factory they tuned them lower in order to have less thermal stress.
At the service beyond others we restore them to original bias as specified in the manual and most of our clients notice the difference.
That is only one example i have thousands more ...In the Greek hifier percentage of listeners that enjoy class B operation should be no more than 1-2% and aged over 60 All the rest prefer other things ...
Out of blue how old are you ?
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Front panel finished - it still needed few varnish layers and some polishing - work with a maple tree is not easy - I prefer soldering and PCB etching
Ahaha love it - it very cute indeed !
I think one day you will find out that quantity is not a substitute for quality and others.
From thousands of amps you heard, how many is LIN topology? How many is LTP based?? (And how many is a Soulution?)
Yes, older people have in general dark electronic age. But that may include you when you still use those old amps as reference. Nowadays people can design low bias amp that can outperform most of class A of the past.
Start messing with it and it will never be a Pass Design
There was never a question or a consideration about the input stage I have actually never been looking at it ...Imagine only yesterday i noticed that there is no RF filtering
All considerations is about the multi vibrator output stage running free and nothing else
What? After that comment I really started messing with it. It started as a Pass design, now it's totally mine, my first all-bipolar design in 20 years. If I build it, it will get due diligence with gain-phase analyzer and all the usual tools of the trade. You'll likely never see one.
class B / low bias operation
I will totally agree with that and i will add that there is no pefect amplifier .Each and every one is suitable to a taste.Correctly a low bias one might be well designed and reliefed from a variety of distortions regardless if the result will be too clinical Often non tech clients of this style claim that their amplifiers have a "character" next to others that are totally flat.
I can imagine a client in his 60's obviously with classic rock backgorund interested on the tune and the distortions of an electric quitar . I take that tune of class B might be adding a tone or being more suitable for a content like that while crystal krisp highs is not a primary target or punchy bass either .
Ask me though at 51 yesterday i am more in to house music than ever to see how easily a music content of 124 bpm can dry out a PSU or OPS where you need the high to be crystal clear and krisp when bass needs to be arranged, descrete, punchy most sounds are electronic and distortions is not injected in the signal like in electric quitars and middle is not that important like is in vocals ,rockmusic. and classic music . There high speed , good bias , and wide bandwidth is simply a must .
Simulation ...
Who was the guy i was arguing with about simulation ?
take an amplifier of your own , the one you know very well and inside out ...Listen to it with the variants of 2.2 MKT in the input , Electrolytic 2.2uf in the input , and 2.2uf bipolar in the input.I bet you that all 3 varinats will sound different .
Can your simulator predict that ? NO and NO big time . WHY ?????
because all 2.2uf capacitors for the simulator are the same...meaning that if it was possible to add the data of each capacitor then obviously the simulator will have an opinion about that also .
In our case though no one is talking about a small detail in the sound performance we are taliking about stabilty So YES your simulation is as good as the data entry you feed your simulator where all 8 output transistors are totally the same and behave thermally accordingly .
So this is no longer a design aspect issue This is a question of what your simulator is capable to do .
Inetersting excersize will be to have the output transistor models messed up plus or minus 5% in some parameters which is farely low next to a beta 1000 transistor can do and then simulate .
I will totally agree with that and i will add that there is no pefect amplifier .Each and every one is suitable to a taste.Correctly a low bias one might be well designed and reliefed from a variety of distortions regardless if the result will be too clinical Often non tech clients of this style claim that their amplifiers have a "character" next to others that are totally flat.
I can imagine a client in his 60's obviously with classic rock backgorund interested on the tune and the distortions of an electric quitar . I take that tune of class B might be adding a tone or being more suitable for a content like that while crystal krisp highs is not a primary target or punchy bass either .
Ask me though at 51 yesterday i am more in to house music than ever to see how easily a music content of 124 bpm can dry out a PSU or OPS where you need the high to be crystal clear and krisp when bass needs to be arranged, descrete, punchy most sounds are electronic and distortions is not injected in the signal like in electric quitars and middle is not that important like is in vocals ,rockmusic. and classic music . There high speed , good bias , and wide bandwidth is simply a must .
Simulation ...
Who was the guy i was arguing with about simulation ?
take an amplifier of your own , the one you know very well and inside out ...Listen to it with the variants of 2.2 MKT in the input , Electrolytic 2.2uf in the input , and 2.2uf bipolar in the input.I bet you that all 3 varinats will sound different .
Can your simulator predict that ? NO and NO big time . WHY ?????
because all 2.2uf capacitors for the simulator are the same...meaning that if it was possible to add the data of each capacitor then obviously the simulator will have an opinion about that also .
In our case though no one is talking about a small detail in the sound performance we are taliking about stabilty So YES your simulation is as good as the data entry you feed your simulator where all 8 output transistors are totally the same and behave thermally accordingly .
So this is no longer a design aspect issue This is a question of what your simulator is capable to do .
Inetersting excersize will be to have the output transistor models messed up plus or minus 5% in some parameters which is farely low next to a beta 1000 transistor can do and then simulate .
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Happy birthday for yesterday, Sakis!
One good thing about being older is you have another year of experience and experience beats opinion every time.
Yes. Not just taste but more important is that sound quality comprises of several many aspects. Thats why it is understandable that i still like my low biased darlington amp. I cannot imagine an amp with latfet output can be made to easily control the speaker like that darlington amp
Many different aspects of sound quality can be understood and related with measurement. Caps have their sound but it is in no way similar to other sound related with variables you can see in simulator. And cap sound is more about taste. As long as the quality is very good i can live with either mkp, elyt or even mkt.
Simulator can do a lot more than a cro. Known good simulators are almost blameless. It is the users who make mistakes. The key is that the simulator should be the slave for the designer, not the designer being the slave for the simulator.
Thats a rough example of treating the simulator as a slave
Happy birthday!
Sakis,
I agree 100% with your points in #252, particularly long wires to output devices and changing the emitter resistors. I'd add that base/gate stoppers are often essential to stability, because output device commutate, and this brings on a base region of negative impedance, which leads to oscillation. I'd add that a mosfet is far more reliabile with a snubber, a small resistor in series and a small cap strung between gate and drain.
HD
I agree 100% with your points in #252, particularly long wires to output devices and changing the emitter resistors. I'd add that base/gate stoppers are often essential to stability, because output device commutate, and this brings on a base region of negative impedance, which leads to oscillation. I'd add that a mosfet is far more reliabile with a snubber, a small resistor in series and a small cap strung between gate and drain.
HD
Thank you all for birthday wishes
Good also to see some good old friends here ...
I'd like to summarize this
Supporting my opinion takes a lot of writing. Seems also that other solid state ppl do not want to share their opinion or mess up with a Pass design. I take it that will be easier to construct and finding out will be easier than trying to explain some people that i am not an elephant .
I am willing to construct to find out
I will only have a question for Nelson
What is the suggested replacement of the ZTX types?
Good also to see some good old friends here ...
I'd like to summarize this
Supporting my opinion takes a lot of writing. Seems also that other solid state ppl do not want to share their opinion or mess up with a Pass design. I take it that will be easier to construct and finding out will be easier than trying to explain some people that i am not an elephant .
I am willing to construct to find out
I will only have a question for Nelson
What is the suggested replacement of the ZTX types?
