That's the hurdle ... the majority of systems, the majority of the time, you are listening to the equipment - you are always being distracted by the gear not quite getting it totally right, and that is like little mosquitoes constantly bzz'ng around the place, keeping you on edge.
Three basic levels of listening: very ordinary, cheap gear, which blurs so much of the finer detail that only the overall flow of the music and feel of the sound elements registers - this works beautifully, it's how we all fell in love with this music, listening on transistor radios, etc; next level, where the audiophiles usually are, the gear really exposes all that underlying detail, shines a very strong light on that stuff - but gets it somewhat wrong, just enough to really bug the listener at times; and then the last level, the best one, where you still hear all the finer detail but it all works, it all makes sense. At this final stage you are only listening to the music again, just like it was at the basic level - trouble is, a huge number of people get stuck in the middle level and don't know how to get themselves out of there, it becomes a predicament.
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Panasonic M are low esr caps since you have a lot of them I would say use them . Sillmic II and Muse measure better in esr department but by what is a small amount . higher voltage of those two also measure better than lower voltage. They do fall in the range that is small enough that they have to be very close to the devise or it not worth talking about the esr it is that low below .050 ohms at 100khz . Regards
Oh, rest assured, I do use them whenever possible, their 50V rating permitting. I got them when a German supplier was going bust and had a must-sell-everything sales, for something like €1.50 per piece, about 1/3 or 1/4 of their regular price. I couldn't help myself, I bought 50 pieces. 
Now 42 pcs left.
Now 42 pcs left.Exactly the point - the system should disappear sonically and leave just you and the music.
At the very worst, only room funnies should be left over, in case there's nothing you can do about them any more, having tried everything.
However, some mild effects will always be there, there are things about electronics we can do little about. For example, my Marantz 170 DC power amp always sounds a little warmer than my say H/K PA 2400, fr from being intrusively so, but that is its nature. The PA 2400 on the other hand is surgically precise and has an immediacy like few others I have ever heard, and its bass lines are second to none. It's lightning fast and that bodes well for fast and very dynamic music, you just can't catch it sleeping on its job no matter what you throw at it.
To be sure, these are subtle differences, but listen hard enough and you will hear thme. Yet, neither amp has a clearly outlined personality of its own and both tend to disappear as such. They both sound just right.
The system I use pulls everything apart. Beatles was never meant to sound this way. And yet it is better.
Out of laziness and wanting to know more I am forcing a Quad 33/303 to do the duties. Having worked out that the DL 110 MC might suit it the recent tweak has been phono gain. It was 2 mV and now about double. It is very nice but is swings and roundabouts. The ideal would be some options of gain to suit each record. This shows a design working at it's limit. This reminds me of my of Triumph motorcycles. The basic version became favourite in time. The stunning finding is the Quad is very,very quiet. The maths say it should be. More so than most op amps I would say. Single input device of < 1 nV noise. The Quad has two resitors in series to gain set. The upper one for a higher output PU like Shure M44. 470 and 220 R. If this is made 560 and 130 R it is about right ( R105/107 106/108, 107 108 = 130R ) . This doesn't give excessive gain and will just get there on DGG recordings. My speakers need every drop of power. No bad thing as it keeps crossover distortion away from the ears. The sound has lost something. Most logical is that the input cap at 100 uF ( C301/2 ) is too small. It now needs to be 220 uF to win back the losses. Not least as Quad do not think bass below 30 Hz worth the trouble it brings, the phono has a sharp cut on a graph I saw. This might be worth looking at. My speakers say 55 Hz - 3dB. The system is far from bass light although seldoms nicks in the ribs. Before now bass was never an issue. Now it is. With some people this would be enough to say get rid of it. That is stupid as the fix is almost certainly $1.
Quad always showed about + 2 dB on the bass control on publicity. I was told this would be the ideal setting if owning a transcription tunrntable. The simple reason to not offer full phono bass was that it was said it damaged the ESL 57's if it was rumble. Warps more likely I suspect.
The Quad 33 has less transitors per side than the majority of transistor radios and yet offers < 0.02% THD up to 10 kHz at 500 mV the power amp clipping point. It has by Gramphone tests 26 dB overload margin. This might be changed to 28 dB by changing a zener diode and PSU caps. It also needs many tweaks of resistors so not worth it. It has 0.1% THD below 5 V pk to pk.
20 years ago if you said I would do this and be pleased I would have said no way.
Out of laziness and wanting to know more I am forcing a Quad 33/303 to do the duties. Having worked out that the DL 110 MC might suit it the recent tweak has been phono gain. It was 2 mV and now about double. It is very nice but is swings and roundabouts. The ideal would be some options of gain to suit each record. This shows a design working at it's limit. This reminds me of my of Triumph motorcycles. The basic version became favourite in time. The stunning finding is the Quad is very,very quiet. The maths say it should be. More so than most op amps I would say. Single input device of < 1 nV noise. The Quad has two resitors in series to gain set. The upper one for a higher output PU like Shure M44. 470 and 220 R. If this is made 560 and 130 R it is about right ( R105/107 106/108, 107 108 = 130R ) . This doesn't give excessive gain and will just get there on DGG recordings. My speakers need every drop of power. No bad thing as it keeps crossover distortion away from the ears. The sound has lost something. Most logical is that the input cap at 100 uF ( C301/2 ) is too small. It now needs to be 220 uF to win back the losses. Not least as Quad do not think bass below 30 Hz worth the trouble it brings, the phono has a sharp cut on a graph I saw. This might be worth looking at. My speakers say 55 Hz - 3dB. The system is far from bass light although seldoms nicks in the ribs. Before now bass was never an issue. Now it is. With some people this would be enough to say get rid of it. That is stupid as the fix is almost certainly $1.
Quad always showed about + 2 dB on the bass control on publicity. I was told this would be the ideal setting if owning a transcription tunrntable. The simple reason to not offer full phono bass was that it was said it damaged the ESL 57's if it was rumble. Warps more likely I suspect.
The Quad 33 has less transitors per side than the majority of transistor radios and yet offers < 0.02% THD up to 10 kHz at 500 mV the power amp clipping point. It has by Gramphone tests 26 dB overload margin. This might be changed to 28 dB by changing a zener diode and PSU caps. It also needs many tweaks of resistors so not worth it. It has 0.1% THD below 5 V pk to pk.
20 years ago if you said I would do this and be pleased I would have said no way.
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Listening to the recording means that you listen to the personal preferences of the recording engineer. I have a demo CD with recordings of just one particular piece of music, but recorded at once with different microphone placement, say, "philosophies". These recordings are, subjectively,emotionally, different pieces of music. Even when you liste to again the same performance in a concert hall, you also listen to the ideas on perfect acoustics of the respective architect of that respective concert hall. In terms of objective acoustics, the degree of space filling - how many people are the audience - has a considerable influence, if the audience came all naked, the impression of the music will be very different even if you have your eyes closed. Acoustics, as a consistent theory, is mathematically not less difficult than say quantum mechanics, perhaps even more difficult.
Actually Nige, some auncient models of integrated amps did have the gain choice, such as Sansui AU-9900, etc. There was a side slide switch to raise the sensitivity to the phono cartridge from 2 mV to 4 mV to 6 mV, with correspondingly high overload margins of (if memroy serves) 300 mV, 600 mV and 900 mV. Plus similar slider switch for capacitance adjustment.
They knew a thing or two, the ancients, eh?
Others followed suit, people like Pioneer, Kenwood at al. Of course, these features were reserved for their high end of the portfolio models, and especially their separates, preamps and amps.
Nige, I don't understand why do you insist on wasting your time and money on models which were never great performers, such as Quad 33.
I am quite sure that you could design and make your own amp which would do better to much better, which would allow you to put a stop to tinkering and get down to some serious music listening instead.
I know that starting from scratch is more complicated than modifying a ready made model, but on the other hand you do get to keep full control over each and every aspect of it and get the chance to do it properly right stratight off the bat. While at it, you can correct all the shortcomings of old designs.
I am quite sure that you could design and make your own amp which would do better to much better, which would allow you to put a stop to tinkering and get down to some serious music listening instead.
I know that starting from scratch is more complicated than modifying a ready made model, but on the other hand you do get to keep full control over each and every aspect of it and get the chance to do it properly right stratight off the bat. While at it, you can correct all the shortcomings of old designs.
Michael Gerzon's Sound Field Microphone allows repositioning of the microphone years later. As far as I know Sky football use it mostly. Michael showed how Dolby surround makes stereo worse. By use of the Gerzon matrix all of that is resolved. You can sit where you like inside the normal layout and revolve the image to suit. Even if the daftest way it works, that is sideways on. Michael used the Quad 57's. I am sure if it had been made as a commersial system only the middle panels required and sub woofer. Meridian who hold the patents ( I assume ) never seem to have done much with it. They did much with his lossless compression. I remember when Michael told me digital losses are so much easiler to live with. I went out of my way to challenge that. I could see he was not saying he heard it differently. He was hearing the future as maths. Michael was another who could walk on water I don't doubt.
Michael and Percy Wilson lived about 200 metres apart. I can only guess they knew each other, I never asked Michael. I read much of Percy's writtings and made a record cleaning machine to his recipe ( nearly 1500 in fact ) . Never once did he seem to use maths. One day I found out it was not because he couldn't!!! I suspect it was because he could he didn't as the end result is for ears. No amount of maths will get arround tin ears. The maths can always be learnt, the listening is a gift I feel. For Michael it was said to be almost a curse. I never knew him to have had a bath. Late in life that changed as he got a carer ( I read ). Alas too late. I wish he had been my friend, I made no effort.
Michael did an analysis of filters and sound problems ( studio use ). What seems the same filter sounds different. Michael called this flutter echo I seem to remember? Any power amp has these filters if you like it or not. My best guess is that and poor matching of stages in the story ( not enough current ). Seeing as the 19 year old Williamson in 1947 was talking about this it is not new in feedback amps. As Michael worked at the Institute of Mathamatics he could not be brow beaten by the likes of some I could name. For all that the maths was his friend and not an interlectual weapon.
To repeat what I said a year or so ago. I asked Michael what he thought about negative feedback to which he said ". I never have, but if I had I might have said this. Some amplifiers need very little and some a lot ". Then a long pause after which near hysterical laughter " You can be sure of one thing, nearly all will have the wrong amount ".
Michael and Percy Wilson lived about 200 metres apart. I can only guess they knew each other, I never asked Michael. I read much of Percy's writtings and made a record cleaning machine to his recipe ( nearly 1500 in fact ) . Never once did he seem to use maths. One day I found out it was not because he couldn't!!! I suspect it was because he could he didn't as the end result is for ears. No amount of maths will get arround tin ears. The maths can always be learnt, the listening is a gift I feel. For Michael it was said to be almost a curse. I never knew him to have had a bath. Late in life that changed as he got a carer ( I read ). Alas too late. I wish he had been my friend, I made no effort.
Michael did an analysis of filters and sound problems ( studio use ). What seems the same filter sounds different. Michael called this flutter echo I seem to remember? Any power amp has these filters if you like it or not. My best guess is that and poor matching of stages in the story ( not enough current ). Seeing as the 19 year old Williamson in 1947 was talking about this it is not new in feedback amps. As Michael worked at the Institute of Mathamatics he could not be brow beaten by the likes of some I could name. For all that the maths was his friend and not an interlectual weapon.
To repeat what I said a year or so ago. I asked Michael what he thought about negative feedback to which he said ". I never have, but if I had I might have said this. Some amplifiers need very little and some a lot ". Then a long pause after which near hysterical laughter " You can be sure of one thing, nearly all will have the wrong amount ".
I worked a lot on engines in my time. If the workings were strong anything might be possible. Yes I am wasting my time. In two days I could brush this aside. However my stupidity level would not have improved as I would be holding predudice over fact. Any twit can throw money at a problem. It takes courage to see a job through. None of that aimed at anyone except me.
The Quad has two strong commings. Low noise and adaptability.
That is well known but not at all undisputed as acoustical hologram. Btw. mathematics is not a tool of description, as it describes only itself. It is the physicist who ascribes meaning to mathematics which by itself it does not have.
No more courage than to say nay, ye nitwits, ye shall not corrupt me with bad sound, for I have God's grace in me to make my own. Assuming stupidity to be the Dark Side of the Force, true, that would not have gone up, but in fact it would have gone down. Nothing like the pudding to prove its existence. Although a pint or two of Zomerzet zider would no doubt provide for more inspiration. Don't take my word for it, ask Coleen. If I was over there, I'd get you to it over an excellent roast, quality light ale and an apple pie, all areas in which Britain still shines, or exert some international pressure on you using traditional Serbian beans, made here as nowhere else. In short, I'd play dirty as hell.
I guess I'm an audio slob, I just like chuck in a CD and sit back and enjoy and have no interest in joining you guys on an audio treadmill.
I have no interest in dragging out my old TD 124/II or TD 125 to re- discover vinyl and the charms of brushing and flipping every 20 minutes.
My Quad II tube outfit will remain where they have sat for over 30 years, I'm more in awe of what can be crammed onto a little chip and the pleasing sound it produces when connected to a good pair of speakers.
Modern integrated circuit technology and nimble Chinese fingers has made quality sound almost free.
Slobbery has nothing to do with it,
... 30 years ago I was content with fiddling with audio in the same way most do it, I was not aspiring to anything special, just trying to eliminate the last annoying audio gremlins in the normal hifi sound I was getting at the time. Then, one day, I fell off my chair - I was getting 'miraculous' sound, I fluked having enough in good order to lift the quality to a whole new level - which quickly faded back to the "normal" standard, .That was it ... no going back now, I knew what was possible so I had no alternative from then on, except to keep chasing that elusive quality, working out how to produce it, and maintain it, whenever I wanted to ...
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Dejan, no hard and fast rules, or technique - what I've done over the years has varied depending upon my knowledge at the time, or interest in learning something new; and to be perfectly honest, I'm a lazy bugger - sometimes close enough is good enough, I wear out quickly these days, ...
Everything I do is based upon what feedback I get from listening to the amp playing tracks, I don't do measurements, or guesstimate an approach from looking at the internals - my attitude is that of a troubleshooter: I listen for what the amplifier is doing wrong, pick the subjectively most offensive misbehaviour and proceed to do what I believe will be most effective in improving things ... in one sense asking me how I go about things is like asking a mechanic how he fixes a car - in most cases I reckon the answer he'll give is, "Well, depends on what's wrong with it ...!!",.
Okay, I listen for the naturalness of the sound it produces, and how loud it can go before it loses its composure ... "naturalness"? This is a subjective measure of how much of a smell it has of that typical "hifi" sound, the artificial quality which makes vocals, for example, sound nothing like a real human voice. The ability to go loud is pretty obvious, which has to track along with the ability to remain "natural".
What I then do depends totally on what I hear, I don't bother fiddling with anything unless I believe it will have a direct impact on the problems I heard from the listening.
So sorry, this is probably not what you were after ... I don't work from a menu of "things to do" - I listen, and then let the results of that guide me ...
...Everything I do is based upon what feedback I get from listening to the amp playing tracks, I don't do measurements, or guesstimate an approach from looking at the internals - my attitude is that of a troubleshooter: I listen for what the amplifier is doing wrong, pick the subjectively most offensive misbehaviour and proceed to do what I believe will be most effective in improving things ... in one sense asking me how I go about things is like asking a mechanic how he fixes a car - in most cases I reckon the answer he'll give is, "Well, depends on what's wrong with it ...!!",
.Okay, I listen for the naturalness of the sound it produces, and how loud it can go before it loses its composure ... "naturalness"? This is a subjective measure of how much of a smell it has of that typical "hifi" sound, the artificial quality which makes vocals, for example, sound nothing like a real human voice. The ability to go loud is pretty obvious, which has to track along with the ability to remain "natural".
What I then do depends totally on what I hear, I don't bother fiddling with anything unless I believe it will have a direct impact on the problems I heard from the listening.
So sorry, this is probably not what you were after ... I don't work from a menu of "things to do" - I listen, and then let the results of that guide me ...
You had to know the man and the context to say that. John Curl might say, Bob Stewart also. That would be like saying about Einstein and maths. Einstein himself used maths. Friends assisted. Michael would talk maths all day long which meant he never got his PHD as far as I know. If I am right the need passed. He could teach well above that level. I asked my friend Hubert why Michael was so distracted even by his standards. Hubert said that Michael was close to solving very big problems in maths that linked subjects. I suspect he found answers and decided not to publish. Maybe he saw danger. The British Library has Michael's collection of Ambiophonic recordings.
As I said before this was a man who could not be brow beaten when maths. However Michael used maths to make things easier. Others use them to exclude. The mathamatical statement Michael made about negative feedback seems simple. It is not because it in a nutshell describes the lack of vision of people. How many times have I read the voyage of slewing rates without a clear idea of why do it. The Quad 303 is a low slew rate amplifer that has no obvious slewing problems and isn't excesssively dull sounding . Many high slew rate amps obviously do have a problem. That is because somewhere along the line sceince overtook from commonsense. Sceince of that type is pholosophers stone rather than reality.
BTW. I read in a 1955 Wireless World published a 3 verses 4 valve circuit of hi fi performance. The designer infered that the transconductance said it should be possible to make them equal. Positive feedback used to get the last drop of gain ( sorry no dia ). The two amplifers were as near as 1955 could tell identical.The best part was the maths, whilst simple it asked every question. It was delightful to read. I recenly made a similar amp by chance. 2 valves , 8 watts, 0.6 V in . 1 % THD. 0.2% 1 watt ( typical is >3% 5 watts ). With 3 valves it was easilly hi fi. That maths stayed in my head from reading the old WW. Transconductance is a difficult subject in transistor amps. The ghosts in the machine are not ghosts. Some say if it is not in the current waveform then the job is done. Not so. Also as I read the other day to use the VAS distortion to say what the crossover distortion really is. Very good and logical.
I will be repairing some Spendor BC1's today. First time ever with the Quad. I suspect it will be a very boring sound? Will be interesting to see if the Dynaco A25 is bettered. They almost were the two to buy 30 years ago ( KEF would dispute that and a host of others ). They were from slightly different schools of thought. Dynaco being the more modern way to me. I knew Spencer. He often worked on production so perhaps he built these? When I built a turntable Spencer's words helped about resonance and the impossibility of people's vision. Again very simple maths from his work at the BBC. In a nut shell people push the ridgidity of speakers. This chanages the problem from 500 Hz to 4 kHz if very lucky. Spencer said they should try for 40 kHz which is impossible. Why don't they aim for 14 Hz ? Then deal with the problems they caused. Lockwood knew this and Klipsche. Lockwood will not work with Theile and Small analysis. Some turn that around and say T& S doesn't work. T&S is if you like is to design a workable product arround assumptions. That is like designing a motorcar arround assumptions. You will never arrive at the E type Jaguar. That car is far more advanced than 90% of anything. I totally mean that. It can be made safer, use less fuel and be warmer/colder. I strongly doubt it can be bettered as a blue print. Enzo knew this, what of the rest of the world? If you doubt this just look at the suspension ( how many dampers and where placed ), brakes and where they are ,semi FI constrution and not least the engine. Even SU carbs are a work of art , get vacuum the same and the job is done. No one has ever said this to me, nearest thing to injection without any mysteries ( Needle, spring, jet and adjustment, don't forget the SAE20 damping oil) . Honda copied them ( Keihin ) . What do you really know guys? Certainly even less if J Clarkson gets involved. If I had a E type I would fit the later smaller 6 and save a bit of fuel. 120 MPH is fine if so. 1964 S type is even better in some ways. Drophead is nicest ( white ? ). I met one of the designers in Cyprus. He thought I was steeling a car. He went back to Cyprus in his old age. Sorry to talk cars. These seem to get the message over better. The rub is the Jag was slightly more exspensive than a familly car( mostly tax at that ). No one today can do that. And often hi fi is the same. WW2 trained good engineers. That training is dead. We survive on the secondhand knowledge.
Quad sold 70% power amps in the middle years. They needed the flexibility. Active speakers are the worse example. Logically right and a sales disaster. The hi fi industy is so good at selling up grades that people need to be able to choose. Choosing wrongly very often. The NAD 3020 is a perfect concept. Alas the customer will not buy that when the better products. The customer is always right which takes us to where we are.
I know the tweaking side of hi fi. It is horrible to know what people will buy. They will ignore the speakers that would be ideal to have one friends approve of. They will spend more than a good 911 seconhand on speaker cables. Guess what guys. My system uses 0.6 mm cable and my system sounds better. They always say to me " good sound, my wife wouldn't allow those". My version of T&S woutld see the wife as the room problem.
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