Oh, I have ambitions of doing some "high-end" things I guess, but as well it would be nice to be able to recommend parts to people and have some confidence that I'm giving out reliable information. I spent years designing the electronics for cheap powered speakers that shipped in the millions, and enjoyed providing the best quality that could be accomodated by the cost target. Been there, done that, but unfortunately behaved in my expenditures as if it would go on forever*. Now things, almost impossibly, have gotten not so much cheaper but a good deal poorer, as essentially no one seems to mind
The tide may turn in time. At least the nonsense that youth prefer MP3 over higher-resolution audio, put forth on the basis of very poorly-controlled experiments by some professor, has been debunked by Sean Olive in better tests. So I think there is some hope.
Brad
*so my ambitions are thwarted if they are to make a small fortune, since I don't have a large one to start with.
Will you go fully balanced ? All techno aside how much of a sonic difference is it over single ended. I'm asking because I have never done a side to side comparison in my own system and I can't say the systems I have heard which were fully balanced sounded superior in a aha way .....
Actually, I have nothing to say. My school, surprisingly named The Quan tock School, occupied the mansion of Lord Taunton, built in the late XIX century. His son gambled it away in the 1920, and until 1961, it was a sanatorium for lung deseas - again, hardly surprising. It's surrounded by grass fields on three sides, the forest on the back side, and the Bristol Channel is about 5 miles away - how much more perfect can it be?
I horse rode and bicycled all over the place, Bridgewater was some 12 miles away, Taunton was about 18 miles away and Birstol was 62 miles off. Farm country through and through, but the farmers are very friendly people, and once they know you, they stop even offering you the cider from the front yard, you get promoted to the back yard lot, where the family stuff is kept. That's how I got hooked on cider and let me tell you folks, the French version from Bretagne is dirty bath water compared to Somerset, The Apple County. NOBODY makes it like they do.
Exactly the same as home, only locally, it's plum brandy, or sliwowitz (only 86 proof, if you're lucky, usually more like 94 proof). Also front and back yard approach. A Virginia farmer first let my uncle, aunt and me light up a barbeque on his land, and then he offered us some of his own moonshine, as a gesture of pure and simple hospitality. Hot ding, them farmers is the same all over the world!
Nice people, down to earth, just what we city slickers need as therapy.I learnt how to ride horses, drive go carts, even some rally driving, while in the UK. No surprise then that I think of those three years (August 1967-July 1970) as some of the best in my life. It would not be overstating it to say that I do have some UK in my blood by now.
From my school yard, I could just barely see Watchet. And, across the Bristol Channel, Swansea.
But if you want something really impressive, do go see Ilfracombe. It sits on top of a gigantic boulder, very surreal. When I was there, there were dark storm clouds gathering, which made it even more surreal.
Imagine 30 mph on that .......
Kudos to Wayne - it was a Carlton indeed. Borrowed from a Canadian friend.
And doing 30 mph with it downhill is really rather easy.
Even if you did do a side by side comparison, it would only show which of the specific two you had was better, not which topology is better.
Frankly, I've heard The Good, The Bad and The Ugly in any topology you care to name, with transistors, FETs, MOSFETs, IGBTs, tubes, you name it. There are too many other aspects you'd need to examine as well to make any single topology a clear cut winner.
That said, I admit to having a strong preference for a fully complementary topology in the mould of James Bongiorno, who invented it. Somehow, it makes me feel the best, the accent being on the word "feel" rather than "hear".
You may as well ask which output trannies will Brad use. In that respect, I am MOST partial, I'll take Motorola/ON Semi MJ 21195/21196 over and above all others, old style as they may be. In the very unpractical metal TO-3 package. I routinely use them as replacements for no longer available Japanese transistors, and risking my life here, I will say that not once have they failed to sound better, more natural and certainly more at ease than nominally faster and more whizz bang Japanese transistors. Of which I am fond of only Toshiba's 2SC5200/2SA1943, with which I also have excellent experience.
And how many pairs per channel.
That's funny the Bryston I was going to restore has those transistors. I have three sets, maybe I should take a second look at them, see what I can do with them.
I listened to one channel of the 3B vs one channel of the LM3875. I decided to peruse the chip amp project, go figure.
Maybe there is still potential with those parts for another project. I could use 2 pair and one of the transformers.
I listened to one channel of the 3B vs one channel of the LM3875. I decided to peruse the chip amp project, go figure.
Maybe there is still potential with those parts for another project. I could use 2 pair and one of the transformers.
There's absolutely nothing funny about that. Those transistors will be found in most professional amplifiers from many sources.
The reason is simple - to do them any harm, you generally need a sledgehammer. 250V, 250 Watts, continuous 15A, impulse 30A of current. I swear by them, and at all times maintain a healthy stock of them.
There is no other singular semiconductor manufacturer in the world who has anything like Motorola's 40+ years of experience in power transistors. At other times, there were RCA and Fairchild, but they dropped out a long time ago. Thordarsen-Meistner tried for a while, but ended up repackaging Japanese offerings.
Hi,
Are you sure they are not called Toshirola?
Ciao T
I know one. It is called Motoshiba.
Are you sure they are not called Toshirola?
Ciao T
For 10 years in the 80's our family went every year to the summer school at Taunton School. I led a walking group across every which-way of the Quantocks, from the Black Hills to the Blue Ball.
I have just googled the summer school - all gone
So is my old school - from 1692, but it's gone now.
All that's left is a forum of ex-students.
Ah yes I remember that cross-licensing with Moto and Tosh. I actually did advise on a discrete power amp and initially wanted the slightly larger devices (3281 etc.) but the Chinese manufacturer pleaded for the next size down. As I was attempting to make incremental changes to a not-entirely-excremental design, so as to not wholly alienate said manufacturer, I didn't do a complete tearup. The design already had complementary bipolar pairs at the input. I think I enhanced the second stages, used "better" output devices, but otherwise did not implement a whole host of ideas I might have considered.
The overall product, a home theater system, was a critical success and a complete flop commercially, owing much to the stupidly poor AV preamp/DVD player sourced from a famously terrible vendor (can you say 41% defects in initial shipments?), but also due to the economic collapse. Either people had money for a 99 dollar Whizzio, or >50k for a full-fledged room. But at the ~6k price "point" as they say, there were few customers. The system included, besides the bad apple piece, a 5.1 channel amp system in the subwoofer, a motorized screen with LCR speakers, a top-line LCD projector for ceiling mounting flanked with rear channel speakers, a universal remote that communicated through a receiver/controller in the screen. The sub electronics cried out for a good DSP-based programmable EQ, but at that point it represented too much of a sea change for the managers, and instead there were five switch-selectable complex EQs for different positions of the screen relative to the wall and ceiling, all done in the analog domain with a sea of modified state-variable biquads. The boards are something to behold.
Oh well, it paid the bills for a while.
As far as high end semantics, I guess my definition is do the best you know how to do. To say simply to "do the best" might presume one knows all and sees all, and I make no such claims. Indeed I am undergoing a huge shift and cascading series of revelations that are quite bracing and challenging. I read part two of the Rees pieces last night and thanked myself for my background in philosophy I can understand SY's impatience with it. But there is something going on, and I don't want to risk violating the Geneva conventions by airing some of the woolier things that could be considered. 
Oh these smilies. Who thinks of this stuff?
The first product I'm considering is "yet another" phono preamp, which will employ among other things synthetic "cooled" terminations as at least an option for the cartridge damping resistor, done in a somewhat new way. There's little advantage with MC cartridges with very low inductance, but substantial noise reduction for highish inductance ones. I'd also like to provide variable input capacitance loading, including negative capacitance, very high overload margins with however the option of a very clean symmetrical clipping function, to prevent downstream overload. Fully balanced might be an option, despite the ~fourfold increase in silicon area (or other device proliferation!) for the same noise performance, and despite the very few tonearms etc. that are wired for balanced operation.
Just some thoughts. Actually I've been working on aspects of this for some years now. How the time flies.
The overall product, a home theater system, was a critical success and a complete flop commercially, owing much to the stupidly poor AV preamp/DVD player sourced from a famously terrible vendor (can you say 41% defects in initial shipments?), but also due to the economic collapse. Either people had money for a 99 dollar Whizzio, or >50k for a full-fledged room. But at the ~6k price "point" as they say, there were few customers. The system included, besides the bad apple piece, a 5.1 channel amp system in the subwoofer, a motorized screen with LCR speakers, a top-line LCD projector for ceiling mounting flanked with rear channel speakers, a universal remote that communicated through a receiver/controller in the screen. The sub electronics cried out for a good DSP-based programmable EQ, but at that point it represented too much of a sea change for the managers, and instead there were five switch-selectable complex EQs for different positions of the screen relative to the wall and ceiling, all done in the analog domain with a sea of modified state-variable biquads. The boards are something to behold.
Oh well, it paid the bills for a while.
As far as high end semantics, I guess my definition is do the best you know how to do. To say simply to "do the best" might presume one knows all and sees all, and I make no such claims. Indeed I am undergoing a huge shift and cascading series of revelations that are quite bracing and challenging. I read part two of the Rees pieces last night and thanked myself for my background in philosophy
I can understand SY's impatience with it. But there is something going on, and I don't want to risk violating the Geneva conventions by airing some of the woolier things that could be considered. Oh these smilies. Who thinks of this stuff?
The first product I'm considering is "yet another" phono preamp, which will employ among other things synthetic "cooled" terminations as at least an option for the cartridge damping resistor, done in a somewhat new way. There's little advantage with MC cartridges with very low inductance, but substantial noise reduction for highish inductance ones. I'd also like to provide variable input capacitance loading, including negative capacitance, very high overload margins with however the option of a very clean symmetrical clipping function, to prevent downstream overload. Fully balanced might be an option, despite the ~fourfold increase in silicon area (or other device proliferation!) for the same noise performance, and despite the very few tonearms etc. that are wired for balanced operation.
Just some thoughts. Actually I've been working on aspects of this for some years now. How the time flies.
Self describes it in his Small Signal Audio Design book - his example phono preamp app only gave 1.5 dB noise improvement
basically you use a quiet input op amp and a higher value resistor, with a fixed negative feedback loop gain reducing the effective value of the big R seen by the cart
basically you use a quiet input op amp and a higher value resistor, with a fixed negative feedback loop gain reducing the effective value of the big R seen by the cart
Sounds good Brad, just one question, what's a phono pre-amp ..... ?
Synthetic terminations (or more generally synthetic impedances), which "look" like an impedance with a resistive component but have less than a physical resistor's thermal noise over a limited (but usefully large) bandwidth, go way back.
Someone pointed me to a possibly-earliest reference in van der Ziel's classic book from 1954, simply titled Noise. The reference was to a considerably earlier article by Percival in Wireless Engineering, Vol. 16, 237, 1939, which was followed up with a scholarly paper with a whole bunch of other stuff in Physica by Strutt and van der Ziel (Vol. 9, 513, 1942). Oliver mentions impedances with less-than-thermal noise over a restricted bandwidth in his IRE tutorial paper Thermal and Quantum Noise. I saw it first in the Arbel book I like a lot, Analog Signal Processing, and his discussion is of its application to nuclear science instrumentation by the great instrumentation guy at Brookhaven, Veljko Radeka. Pease mentioned it in a column some years ago, and recently Self included the notion along with his particular realization for cartridge loading in his Small Signal Design (along with a remark that he doesn't like the "cooled" part --- but this is the "standard" terminology among the Nuc Sci brethren).
Brad
Thanks jcx. When applied to some high L low R cartridges that like to see 47k, done right it can yield a substantial improvement. Of course it will be argued that surface noise spoils all of this as soon as the needle is in the groove. But I still think, as does Self, that's it's worth doing. If one is going "all out". Self's particular example in the book is also woefully suboptimal. Good book though, although like much of his writing he's light on historical references. But filling those in is a whole lot of work.
Brad
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