let us not forget that so many of the claimed results are only simulated in real life expect them to be worst ...( which makes implementation +pcb and peripherals a difficult task to do when the target is to achieve the simulated results ) this is something not to forget !
I will confirm that bootstrap sound more musical and listeners that go for high efficiency low power ( relatively+-60W ) prefer bootstrap over current source .
On the other side where higher powers (>60W) and accuracy is needed seems that people prefer the current source while it seems to offer better control .
Kind regards
Sakis
I will confirm that bootstrap sound more musical and listeners that go for high efficiency low power ( relatively+-60W ) prefer bootstrap over current source .
On the other side where higher powers (>60W) and accuracy is needed seems that people prefer the current source while it seems to offer better control .
Kind regards
Sakis
Not quite. The amplifier power rating is often limited by the maximum voltage swing between the VAS and CCS collectors. This is more true with CFP output stages that are more efficient. If a bootstrapped capacitor is used, the voltage can rise well abve the rail voltage, though pointless without corresponding extension to the lower rail voltage. All it means is that the amplifier can produce a little more power from the same voltage rails - nothing about short term power reservoirs, though. The cap would behave badly indeed if it was used to supply power according to variable demand.
I will restate my question.
Is it possible to find any evidence that replacing the bootstrap with a ccs will "only make it sound clinical"?
I suspect not, because in my mind "clinical" only exists in one's head.
It may be possible to find evidence that with the CCS replacing the bootstrap in some implementations can make the amplifier more accurate or more linear.
Well of course, we all know that very well, don't we? I mean, I prefer to use my own amp than those from famous designers on the net. Then it must be easy, or I have seen many times the effect of CCS. That's what I meant with "technicality".
But the non-technical side, that's what I like to share, even tho it is subjective, because at some point I often think that nothing is really subjective. So my opinion and subjective feeling that ccs in P3A is clinical is still only my opinion, but it IS an information (I have built it of course, as I was definitely referring to P3A, not to ANY arbitrary amps).
But if you ask, what measurements or physical parameters correspond or responsible for this "clinicality", I still don't think it is important enough for me to find out. It is me who should ask the question. But yes, I like to observe "numbers" and find correlation with sound perception (and I learned a lot of things that I prefer to keep as a secret or out of discussion) but for some other phenomena, I prefer the "build and listen" approach.
An example, my passive crossover skill may outperform my active crossover skill such that none of other people's designs and my own is preferable or can stay in my system. So my hypothesis is that it is not good. But it is not at conclusion state, in that, I will always try to proof that my hypothesis is wrong whenever possible (Besides, I have hundreds of high quality opamps, what should I do with them anyway?)
When I think that A will not work, then when there is someone telling me that A will work, I will be more challenged to proof to myself (that I'm not wrong) than if I agree that A will work.
But this could be interesting: nothing is really subjective.
With respect, I don't think this is quite right. Even though a) #1 is true, and b) you DO need more power for good bass response, I am not sure it is necessarily the case that bootstrapping gives you better performance in the bass frequency range. If this were true, you could switch to a higher voltage supply with the same circuit, and bass would immediately improve.
You could test this with a variac. First lower the voltage 10~15% and listen to a sample track, then raise it back up, and listen again. Easy to do as a blind test, all you need is someone to turn the variac knob behind your back...
It was (partially) a question to confirm Ian's answer, and Ian has explained further. Actually this is an issue example where I don't want to experiment with.
Yes, for some (obvious?) reasons, a separate higher voltage always (ime) bring positive impact. It is just too complicated (and expensive?)
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There are so many subtle issues that are just being missed altogether. For example, the use of bootstrap affects compensation, slightly, due to the changes in VAS load impedance at higher frequencies when using certain electro's for the bootstrap. There are interactions between the VAS stage and the input stage too. Many of these subtle effects are missing from simulations - and I can't reveal IP of others here but I will say that I feel there is a case here to give credence to listening tests rather than rely on Spice and O'scopes.
And if cost is no object, you may want to widen your horizon and listen to a SET with high sensitivity speakers - but that's OT for this thread
And if cost is no object, you may want to widen your horizon and listen to a SET with high sensitivity speakers - but that's OT for this thread
There are so many subtle issues that are just being missed altogether. For example, the use of bootstrap affects compensation, slightly, due to the changes in VAS load impedance at higher frequencies when using certain electro's for the bootstrap. There are interactions between the VAS stage and the input stage too. Many of these subtle effects are missing from simulations - and I can't reveal IP of others here but I will say that I feel there is a case here to give credence to listening tests rather than rely on Spice and O'scopes.
And if cost is no object, you may want to widen your horizon and listen to a SET with high sensitivity speakers - but that's OT for this thread
That was very correct Bigun and that second questions AndrewT's opinion about the subject since his opinion is not valid coming from simulations only.
Sorry for that Andrew but if you need your opinion to have some validity in issues like that people are waiting for your pictures ..
still i have to say once more that half of the forum including me should bend on its knees in front of you for the theoretical support that you kindly provide all these years and the mistakes you uncovered in teh schematics we post .
Thanks
Sakis
Hi Sakis, If I read you correctly and you said calculation or textbook, you might be right but I don't think AndrewT uses simulations as a basis of his posts. You get straight theory from AndrewT, no SPICE.
http://sound.westhost.com/project3a.htm
'Not sure whether you were talking about the P3a design or about trying out a CCS in it as an experiment, because P3, P3a have always been boostrapped capacitor VAS designs. There's no need to argue about the type of VAS there unless you are comparing different amplifiers altogether. That would probably end up as a different topic. One big problem with taking one design's features and stitching them into a different design, then listening to the results and concluding the circuit is no good or whatever, is that we usually have no clue whether the modifications are still valid circuits and operating in the appropriate way. Simulators will likely tell you no more than a real experiment can but they can be faster and at least show what an absolute mess we can make of circuit when we only have our "ears" to design with.
BTW, I'm reminding myself here of how I used to go about design in my schooldays and early working years, so don't think I'm just being harsh on others here.
http://sound.westhost.com/project3a.htm
'Not sure whether you were talking about the P3a design or about trying out a CCS in it as an experiment, because P3, P3a have always been boostrapped capacitor VAS designs. There's no need to argue about the type of VAS there unless you are comparing different amplifiers altogether. That would probably end up as a different topic. One big problem with taking one design's features and stitching them into a different design, then listening to the results and concluding the circuit is no good or whatever, is that we usually have no clue whether the modifications are still valid circuits and operating in the appropriate way. Simulators will likely tell you no more than a real experiment can but they can be faster and at least show what an absolute mess we can make of circuit when we only have our "ears" to design with.
BTW, I'm reminding myself here of how I used to go about design in my schooldays and early working years, so don't think I'm just being harsh on others here.
Yes, I see such comments but you may also have seen him admit that he has problems with digital gadgetry, like settings for the PC, managing images and settings etc. This is not unusual at our age as many retired guys never touched modern PCs, laptops, tablets MP3, media players and last time they took pics was with a 35mm camera.
Who is going to retrain us in the latest digital technologies unless we actively seek specialised assistance? I think we have to live and let live as the benefits of AndrewT's contributions far outweigh having our curiosity satisfied about what he's currently working on, if it is audio anyway, as I think he also has other interests and concerns.
ooops ... talk about your self here Ian ...I am only 47 and i am
learning new things every day including computers also !
Correct said a P3A with a diamond in the input or an EFP output stage will be no longer a P3A.
As combination of semis produced slightly different results which is an issue that cannot be simulated ,
As the opinion of many ( also personally confirmed ) that the 1503X series drivers eventhough extremely rugged device sounds quite hard which also is not a thing that simulators may tell
Also in simulation the term decoupling does not exist which in a circuit with poor pssr in real life will be needed while the simulator will assume that the power is clean 100% all the way through
Similar to the above will be the difference between the CCs and bootstrap
So beyond simulation implementation pcb and related hardware will play some role to the listening and measuring real life results
Kind regards
Sakis
learning new things every day including computers also !
Correct said a P3A with a diamond in the input or an EFP output stage will be no longer a P3A.
As combination of semis produced slightly different results which is an issue that cannot be simulated ,
As the opinion of many ( also personally confirmed ) that the 1503X series drivers eventhough extremely rugged device sounds quite hard which also is not a thing that simulators may tell
Also in simulation the term decoupling does not exist which in a circuit with poor pssr in real life will be needed while the simulator will assume that the power is clean 100% all the way through
Similar to the above will be the difference between the CCs and bootstrap
So beyond simulation implementation pcb and related hardware will play some role to the listening and measuring real life results
Kind regards
Sakis
Last edited:
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You are asking us if there is a sound difference, but it is you who have the amplifier just finished - so we are hoping to hear your opinion - we do not want to pollute your opinion by giving ours first - so please without thinking of others opinions listen to the amplifier and tell us all your thoughts and feelings about it.
If you don't mind me asking, where about in Malaysia are you, my wife is from Malaysia and I have visited several times. It is a wonderful country, the food is fantastic !
If you don't mind me asking, where about in Malaysia are you, my wife is from Malaysia and I have visited several times. It is a wonderful country, the food is fantastic !