Is the purpose of this book to judge "tube sound" better than "solid state sound"?
But I desire to have "accurate sound"
.Btw, thank you for the link.
I am not so sure. In addition, there is a nickel (feromagnetic) barrier between the copper and gold. Bad thing for non-magnetic resistors fans.
And to add insult to injury, they are not alone in such beliefs. Even local manufacturers do it, for example, Karan Acoustics - all boards fully gold plated over copper. Milan's reasinong is about the same as yours - I want it fully functional to specs 30 years from now, only caps have to be changed.
By all means, please do! If it's half as good as you suggest, I'll be buying one for sure.
How many have you built so far?
Yes, that kind of bandwidth does make me worry about RF breakthrough as well.
But I also worry about phase shifts.
So I do what others have done (e.g. reVox/Studer, Sony, etc). First I get it going up to say 500 kHz, and once that is achieved, I add a first order filter to the input, limiting the bandwidth to abour 200 kHz.
This method has served me well so far, and never once did I experience any RF breakthrough (so far). Of course, there's always a first time.
200 kHz is an arbitrary limit point, I don't think anything bad would happen if that point was lower, say 150 kHz or so.
Thst's exactly how Karan does it - gold plated traces, copper solder joints. And he's no novice, he's been at it for over 20 years and at his prices, he can't afford to be wrong.
On another topic, I just bought some zinc and ingested it. Let's see what happens.
You are surprising me. I have made all the electronic in my system for my own use. I hope you have done the same, I know that you designed and built first rate commercial headphone amplifier. Adapt it to line preamp and you will have something of Spectral level.
My best equipment are designed by Borbely, very underestimated designer.
His designs, even the old ones are the best possible-phono,line and power amps.ClassA, high working voltage, low noise ,DC servo , cascoded input etc.
I made PCB myself since I liked to use specific high quality material.
Combine it with good connectors , selector switch and pots and will get the highest quality units. Many snobs prefer of course famous brands to show their status and to sell later easier as a second hand. Audio equipment should serve to listening to the music, it is not part of the furniture.
He`s been building top quality power amps for at least 20 years (in his simulator). Ask him to send you a picture
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Fine, but we are supposed to know that - how? You certainly never mentioned it.
Thank you, yes, they are rather good, however, I have a nagging feeling that I can do better. Still, it was time well spent, since in the process I did make some good PSUs and additional circuits in line with my views, all of which can also be used for a proper preamp.
But I cannot know how they compare with Spectral, not until I get to audition a Spectral unit. No idea where I can find one locally.
On the current listening front, at this time the most neutral power amplifier I have ever heard is Harman/Kardon's Citation 24, which I own and enjoy very much. The above comment is related to my system, my room and my local acoustics. I find it very hard to beat that one, and frankly, I'm not sure I can do it. But I will try, of course, just for the hell of it.
In fact, I am trying it right now, with my Centurion project. It is my attempt at trying to make a reasonably priced HOME power amplifier, suitable for home listening. Once I am satisfied with it, it will be placed where it is publically available, that was the idea from the start. Much has been done already, but serious health problems have slowed me down because I need time for medical checkups, x rays, etc, unfortunately with meagre results so far.
But, all in good time.
Can't argue with that.
However, there seems to be a difference between us. From what you wrote, I gather that you have used Borbely's work for most part; I went down another route, I didn't use anybody's specific work, although of course I did use what is public knowledge, such as well known and understood circuit topologies, parts, etc. It's about as much mine as is most of what goes on today. This simply means I have to dedicate much time to testing, experimenting, making versions of the same thing, and so forth. Not complaining, mind you, I enjoy doing that.
And, truth be told, I did have help with some of it from forum members here and some not here, which in the end turned up some very interesting results and even a few ideas. I will investigate some of them when I have the time.
Actually, that was prototype No. ?, I can't remember them all. Its value today is twofold: first, it is proof of my own work, not one circuit was copie from anyone, although I am sure many have made similar circuits, and some are probably better than the ones I used, and second, it sure plays some good music.
It also an example of the worth of listening to others. Originally, I wanted to bias it at around 40 mA, which should be enough for pure class A operation with most headphones with an impedance of 30 Ohms or more- But, somewhere along the way, my favorite German told me I shuld try biasing it at 80 mA, and that while theoretically it should make little difference, if any, in real life it WILL sound better. I did try it and I do agree it sounds just that little bit better at a higher bias level. That cost me redoing the PCBs to accomodate larger heat sinks, but I feel it was worth it.
The same man suggested a FET input, MOSFET output version, so I made one of those as well. Then I friend suggested an all tube version, I said no because I know next to nothing about tubes, but he knows a lot more than I probably ever will, so he designed it.
To my mind, the best overall presentation was offered by the BJT version, which uses Motorola/ON Semi's MJE 15030/15031 devices in a SEPP configuration. The whole ciruit uses a fully complementary topology. The tube version has a better midrange presentation, but is lacking in force and sheer "oomph!". The FET/MOSFET vresions is all rigght, but not much more than that; I used IRF MOSFETS, my favorite German sayas I should have used other devices, and since he has always been right so far, I will have to try that as well.
But this is the core of my work, the power line filters. This is model Quintet, which has one Super Filter (handles 20 Amps at 220 VAC) and four standard filters (only 10 Amps each at 220 VAC), providing for full protection of each device both from the grid and from each other.
It does NOT need the ground for operation at all, ground is used for display LEDs only. Therefore, it cannot be upset by sudden ground potential changes, nor can it introduce any itself. 100% symmetrical, it has no real "in" and "out" side, works the same both ways. This is version No. 11, the last thus far. It has completely reworked circuit layout, one sode of the two sided board being dedicated to ground to reduce interference. You can put it on top of a tuner, right above the front end, and you will experience zero disturbance. Bottom plate is made out of pure copper.
It does NOT need the ground for operation at all, ground is used for display LEDs only. Therefore, it cannot be upset by sudden ground potential changes, nor can it introduce any itself. 100% symmetrical, it has no real "in" and "out" side, works the same both ways. This is version No. 11, the last thus far. It has completely reworked circuit layout, one sode of the two sided board being dedicated to ground to reduce interference. You can put it on top of a tuner, right above the front end, and you will experience zero disturbance. Bottom plate is made out of pure copper.
Attachments
About gold leached into the solder alloy will embrittle the joint? Re-read your book on solders and soldering.
THx-RNMarsh
No, I am not sure that manufacturers tin plate components pads before gold plating PCB traces and groundplanes.
And, quite frankly, I am not at all sure about a lot of things.
Gold plated circuit boards. I am not convinced they offer any audible advantage over 70 micron, let alone 120 micron fibreglass boards. They will run circles around the usual commercial fare, 35 micron boards, to be sure, but so will 120 micron boards.
That said, I readily admit that if my Centurion turns out as I expect it to, I will dish out the dough for gold plating, and I know it - but not because I think it'll make all that much of a difference over my standard 70 micron boards, but because I like to drive things to the max, sensible or not, believe in it or not.
Or about DC servos. Yes, they do keep the DC offset very, very low, but more than half the amps I think of as excellent are AC coupled and that doesn't seem to bother them one bit. My point is, while it can help, it is not a prerequisite for good sound. My own reference, Citation 24, is an AC coupled design.
On the other hand, I do believe - very strongly - in quality materials, parts, bits and pieces. My view is that they do more for the sound than a say DC servo. MUCH more. I've seen good designs fail because they were made using cheap'n'cheerful materials. Right or wrong, I believe pure silver cabling is ideal for internal wiring, although I have come across a few excellent OFC cables as well.
And so forth. My point is, assuming quality materials, I think it's not what you use, but how you use it. A good deal depends on how well one's circuit board is laid out; I can do it, but I rarely do, I prefer to get Alex (from Romania) to do it, he's a professional who's been at it for over 30 years, and he has a flair, an artistic side to him, which I do not. I simply do the job, he gives the term "artwork" its true meaning. So far, second version was as far as it took, and that is DAMN good.
So, because of all this, Kamis, I think categorizing designs as "ancient" is a very slippery slope. Some of those "ancient" designs were in fact made much better and I daresay much more seriously than most current designs.
Do tell me, how would you rate the following specification for a power amplifier: THD is less than 0.05% at any power up to the rated output, IM distortion is 0.05% or less with any combination of frequencies up to 20 kHz, at any power level up to the rated output?
How many times have you even seen a specification this complex and comprehensive?
Gold plated circuit boards. I am not convinced they offer any audible advantage over 70 micron, let alone 120 micron fibreglass boards. They will run circles around the usual commercial fare, 35 micron boards, to be sure, but so will 120 micron boards.
That said, I readily admit that if my Centurion turns out as I expect it to, I will dish out the dough for gold plating, and I know it - but not because I think it'll make all that much of a difference over my standard 70 micron boards, but because I like to drive things to the max, sensible or not, believe in it or not.
Or about DC servos. Yes, they do keep the DC offset very, very low, but more than half the amps I think of as excellent are AC coupled and that doesn't seem to bother them one bit. My point is, while it can help, it is not a prerequisite for good sound. My own reference, Citation 24, is an AC coupled design.
On the other hand, I do believe - very strongly - in quality materials, parts, bits and pieces. My view is that they do more for the sound than a say DC servo. MUCH more. I've seen good designs fail because they were made using cheap'n'cheerful materials. Right or wrong, I believe pure silver cabling is ideal for internal wiring, although I have come across a few excellent OFC cables as well.
And so forth. My point is, assuming quality materials, I think it's not what you use, but how you use it. A good deal depends on how well one's circuit board is laid out; I can do it, but I rarely do, I prefer to get Alex (from Romania) to do it, he's a professional who's been at it for over 30 years, and he has a flair, an artistic side to him, which I do not. I simply do the job, he gives the term "artwork" its true meaning. So far, second version was as far as it took, and that is DAMN good.
So, because of all this, Kamis, I think categorizing designs as "ancient" is a very slippery slope. Some of those "ancient" designs were in fact made much better and I daresay much more seriously than most current designs.
Do tell me, how would you rate the following specification for a power amplifier: THD is less than 0.05% at any power up to the rated output, IM distortion is 0.05% or less with any combination of frequencies up to 20 kHz, at any power level up to the rated output?
How many times have you even seen a specification this complex and comprehensive?
Gold is very cheap for PCB's compared with expectations . In the past I was offered it instead of solder resit at the same price . I like it because 20 years from now it should be the same . Some think pure silver better . If so use maximum solder resist . There is a 4% gold 96% silver mix which is well regarded . A sort of stainless silver . In my experience the silver needs to be of the 99.99% + purity . We tried some standard quality silver as wiring . I supect it was 92% . It was not well liked .
Anyone want to offer any ideas about Devialet Analog Digital Hybrid ?
http://en.devialet.com/assets/Uploads/D-Premier-White-Paper-Munich.pdf
Anyone want to offer any ideas about Devialet Analog Digital Hybrid ?
http://en.devialet.com/assets/Uploads/D-Premier-White-Paper-Munich.pdf
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