Hello Johan,
I have the greatest respect for you and your theoretical position and the care with which you formulate your arguments. None of this changes my belief that coupling caps are audible. I've been a professional musician most of my life (as a psychologist I specialise in musicians) and I've learned to trust my ears since this is how I made my living. I may not be able to satisfy your theoretical stance that hearing is subjective and therefore to be dismissed when it appears to contradict various laws of physics, but in practice this doesn't represent what actually happens. If I repeatedly hear a discernable difference between component A and componant B and am in a situation where I have to choose one or the other, I will make a choice based on what my ears tell me. The alternative would be to make a random choice of either A or B by, for instance flipping a coin. Put yourself in this situation and ask yourself what you would do - go with what sounded better or flip a coin. I mean this quite seriously! Your theoretical position would require you to flip a coin even if you subjectively heard a difference, because in theory such a difference could not occur. Do you see what I mean? Even if you auditioned an infinite number of coupling caps and irrespective of what your ears told you, you would be required at the end of the day to flip a coin.
Andy
I have the greatest respect for you and your theoretical position and the care with which you formulate your arguments. None of this changes my belief that coupling caps are audible. I've been a professional musician most of my life (as a psychologist I specialise in musicians) and I've learned to trust my ears since this is how I made my living. I may not be able to satisfy your theoretical stance that hearing is subjective and therefore to be dismissed when it appears to contradict various laws of physics, but in practice this doesn't represent what actually happens. If I repeatedly hear a discernable difference between component A and componant B and am in a situation where I have to choose one or the other, I will make a choice based on what my ears tell me. The alternative would be to make a random choice of either A or B by, for instance flipping a coin. Put yourself in this situation and ask yourself what you would do - go with what sounded better or flip a coin. I mean this quite seriously! Your theoretical position would require you to flip a coin even if you subjectively heard a difference, because in theory such a difference could not occur. Do you see what I mean? Even if you auditioned an infinite number of coupling caps and irrespective of what your ears told you, you would be required at the end of the day to flip a coin.
Andy
Last edited:
Might be able to grab some pointers from my quad II restoration bolg: Quad II Restoration
I've long since finished the restoration, just need to update the blog one day!
Cheers
I've long since finished the restoration, just need to update the blog one day!
Cheers
Andy,
I envy you your field! A lot of experience there that I would like to have! Also my thanks for your respectful tone - likewise.
But you have me at a disadvantage. We cannot continue this discussion without hi-jacking/being seriously OT. If it would serve any purpose a new thread could be opened. (My conscience accuses me; I am a moderator on our more local forum AVForums South Africa - Index, where I have to enforce similar rules!)
Thus, if Clintek will allow a definitely last comment on the subject of sensual experience vs. basic science: The position you sketch above cannot arise - yes, I follow your logic for you. But I need not describe what the consequences will be if proven science can be dismissed every time our senses say diffferent. There are still those who believe the earth is flat; ergo, it is no longer a question of logic.
Both you, I and everybody else have the advantage of rigid science (where proved, that is) in our daily lives. We cannot enter a position where, say, 3 + 5 = 8 is open to dispute. That is what I mean. Often that is to my disadvantage - I earned my living in research and believe me how often I would have liked certain basics not to have been so! Yet I could always succeed in the end without having to concede that 3 + 5 = 9 or whatever else my senses told me. As said, unfortunately we do not have the luxury of making science democratic.
Regarding the "sound' of components a multitude of acceptable tests have been done following good statistical procedure - see the internet. They all made the point. Some unbelievable outcomes, mystified test subjects (including myself on occasion!) but repeatable every time.
It is a pleasure to have discussion with you, but frankly better people than myself have not found solutions following that route. If it sounds like an easy way out so be it, but please accept that I cannot abuse the rules any further with this discussion; we are hi-jacking.
Thanks Clintek; back to Quad II restoration.
I envy you your field! A lot of experience there that I would like to have! Also my thanks for your respectful tone - likewise.
But you have me at a disadvantage. We cannot continue this discussion without hi-jacking/being seriously OT. If it would serve any purpose a new thread could be opened. (My conscience accuses me; I am a moderator on our more local forum AVForums South Africa - Index, where I have to enforce similar rules!)
Thus, if Clintek will allow a definitely last comment on the subject of sensual experience vs. basic science: The position you sketch above cannot arise - yes, I follow your logic for you. But I need not describe what the consequences will be if proven science can be dismissed every time our senses say diffferent. There are still those who believe the earth is flat; ergo, it is no longer a question of logic.
Both you, I and everybody else have the advantage of rigid science (where proved, that is) in our daily lives. We cannot enter a position where, say, 3 + 5 = 8 is open to dispute. That is what I mean. Often that is to my disadvantage - I earned my living in research and believe me how often I would have liked certain basics not to have been so! Yet I could always succeed in the end without having to concede that 3 + 5 = 9 or whatever else my senses told me. As said, unfortunately we do not have the luxury of making science democratic.
Regarding the "sound' of components a multitude of acceptable tests have been done following good statistical procedure - see the internet. They all made the point. Some unbelievable outcomes, mystified test subjects (including myself on occasion!) but repeatable every time.
It is a pleasure to have discussion with you, but frankly better people than myself have not found solutions following that route. If it sounds like an easy way out so be it, but please accept that I cannot abuse the rules any further with this discussion; we are hi-jacking.
Thanks Clintek; back to Quad II restoration.
Pointy,
A very nifty and pleasing result indeed!
Perhaps the greatest compliment to Sir Peter is the degree of commitment so many put into restoration of his little amplifier. Much lies somewhere between wanting to preserve originality and making the best Quad possible today. In my own efforts I always tried to follow the owner's desire - not always easy.
I have made my contribution; perhaps a last remark. It is sometimes not realised that the output stage is not simply a tetrode with local feedback. It is actually an UL topology, although being with only 10% "screen taps". (With a 'tetrode with local feedback' the screens should have been decoupled to the respective cathodes.)
Good luck, Clintek!
A very nifty and pleasing result indeed!
Perhaps the greatest compliment to Sir Peter is the degree of commitment so many put into restoration of his little amplifier. Much lies somewhere between wanting to preserve originality and making the best Quad possible today. In my own efforts I always tried to follow the owner's desire - not always easy.
I have made my contribution; perhaps a last remark. It is sometimes not realised that the output stage is not simply a tetrode with local feedback. It is actually an UL topology, although being with only 10% "screen taps". (With a 'tetrode with local feedback' the screens should have been decoupled to the respective cathodes.)
Good luck, Clintek!
The power supply capacitor was always a 16 + 16µF 450V dual electrolytic capacitor. It was contained in a round can about 38mm dia x 65mm long. (In comparison a 8µF 700V paper-in-oil capacitor of the time was 123mm x 10mm x 60mm rectangular, far larger. The Quad could not have contained non-polarised caps in that small a place.) Although having occasionally worked on Quad IIs since 1958 I have never seen a different type power supply capacitor.
Electrolytic capacitors were recognisable by the annotation P and E at the 'live' terminals. The "E" capacitor had an etched + foil, thus having a quite bigger foil area and consequently higher capacity for the same physical size. It could however not handle the ripple current of the plain foil type. Thus the P terminal was the input capacitor (at the rectifier side) and the etched foil type the capacitor at the amplifier side of the filter. That arrangement does not appear to exist any longer.
Electrolytic capacitors were recognisable by the annotation P and E at the 'live' terminals. The "E" capacitor had an etched + foil, thus having a quite bigger foil area and consequently higher capacity for the same physical size. It could however not handle the ripple current of the plain foil type. Thus the P terminal was the input capacitor (at the rectifier side) and the etched foil type the capacitor at the amplifier side of the filter. That arrangement does not appear to exist any longer.
Great info guys and Ideas guys, I now feel the need to be clever and make the upgrades look original.
Have not been feeling up to playing for the last 2 days, but have been thinking a lot about how to make things look nice and stock; it may just be too much effort to achieve what I am after but I am going to give it a test and see what I can come up with.
Have not been feeling up to playing for the last 2 days, but have been thinking a lot about how to make things look nice and stock; it may just be too much effort to achieve what I am after but I am going to give it a test and see what I can come up with.
Perhaps useful: At an early stage sit down and make a list of what it is you are after. Then group the conflicting matters and consider objectively which you prefer, or fit in best with the whole.
If at the end this steers you too far away from the original Quad aims and characteristics/limitations .... rather build a new amplifier. Beware of the quick-sand of a stir-fry result. It is a contradiction that one can suddenly become aware of significant (audible) improvements in a classic circuit of that reputation.
If at the end this steers you too far away from the original Quad aims and characteristics/limitations .... rather build a new amplifier. Beware of the quick-sand of a stir-fry result. It is a contradiction that one can suddenly become aware of significant (audible) improvements in a classic circuit of that reputation.
I should just like to say that, as a total newbie and just beginning to learn from this forum, I have been really impressed by the debate between Andy and Johan. The quality of the discussion has been truly illuminating to me and conducted with clear mutual respect.
I learn so much from following such well informed arguments. Whilst I appreciate Johan's point about hi-jacking the thread, I for one would love it to continue if only for my own selfish pleasure of following the debate. Thanks guys; you offer hope to people like me that one day I may have a level of knowledge to contribute to the debate!
I learn so much from following such well informed arguments. Whilst I appreciate Johan's point about hi-jacking the thread, I for one would love it to continue if only for my own selfish pleasure of following the debate. Thanks guys; you offer hope to people like me that one day I may have a level of knowledge to contribute to the debate!
Here is a funny thing, well made me smile anyway;
I have been rather unwell over the last 2 years and have lost a fair bit of memory. Since the last 6 months I have been getting back on my feet and got a new workshop up and running a few weeks ago and started to unbox my old projects.
ooooh, a pair of dismantled Quad 2's! After going though and checking the parts were all there (1 bit missing) I decided to have a search around the internet for Quad 2 restorations, I stumbled across this thread and started to read. On page 2 I realised the author was me..... oh my.
Anyway I am back and will continue where I left off, I have done a little over the last week so will update the thread tomorrow with that !
I have been rather unwell over the last 2 years and have lost a fair bit of memory. Since the last 6 months I have been getting back on my feet and got a new workshop up and running a few weeks ago and started to unbox my old projects.
ooooh, a pair of dismantled Quad 2's! After going though and checking the parts were all there (1 bit missing) I decided to have a search around the internet for Quad 2 restorations, I stumbled across this thread and started to read. On page 2 I realised the author was me..... oh my.
Anyway I am back and will continue where I left off, I have done a little over the last week so will update the thread tomorrow with that !
Welcome back! Hope you're feeling better and ready to have at your Quads again! Will be following your restoration with interest. Done a couple myself and FWIW whether PIO, poly or electrolytic caps, the Quads will be just fine and sound great....I had three on the bench once all done to the different cap materials demanded by their owners and you couldn't distinguish the difference between any of them...either subjectively or on the scope.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.