john curl said:
Mr Curl as soon as you mentioned Naim audio and aligned yourself with its creator your credibility just sunk into the ground.
Those Naim amps are your common or garden variety quasi complementary output stages from the 60's that no serious designer would ever contemplate on using these days or even referring to as a credible design.
And like someone else said you had to use special cables with those amps otherwise the damn things would take off and self destruct.
Sounds like they could of done with a bit of L on the output stage 
As I said, not having one I can't comments authoritatively, however its possible that just eliminating such marketing driven details as speaker switches and streamlining the connections from the output transistors to the speaker with as few things in the way may alone make a big difference. Also there may be tricks in the power supplies that make a difference. Its possible that modifying a Japanese amp with the same type of tweaks could yield similar results. I don't know but I suspect that everything from resistor choice to obsessively fanatic layout are all a part of the process. All things that turn out to be far more expensive than they look to be.
And just because the transistors are arranged the same way as another product doesn't mean they are used the same. Alter the gain at the individual stages and you can get a very different result. This should be obvious to anyone who has been reading this thread for the last few months.
I agree that the Naim stuff looks overpriced and not very special but that should not presuppose the performance it delivers. It can be very hard to separate ones initial reaction to the presentation from the actual performance delivered. Looks can be very deceiving.
And just because the transistors are arranged the same way as another product doesn't mean they are used the same. Alter the gain at the individual stages and you can get a very different result. This should be obvious to anyone who has been reading this thread for the last few months.
I agree that the Naim stuff looks overpriced and not very special but that should not presuppose the performance it delivers. It can be very hard to separate ones initial reaction to the presentation from the actual performance delivered. Looks can be very deceiving.
1audio said:
There is an old saying. You can't turn a "sows ear into a silk purse" which applies to Naim equipment
There is nothing special about the way Naim used semiconductors in their equipment nor did they have a monopoly over better silicon than other manufacturers. It was very mediocre by anyones standards.
You sound like your trying to say that by some fluke of magic that can only be explained by paranormal science that only Naim used the appropriate parts in the appropriate combinations to get an infinitely better result than anyone else who used them
If that is the case then we all should own and be using this old equipment. Somehow it's just not happening 
Snoopy, you are overreaching and do Naim a disservice. I KNOW that the output devices were special for the time, I saw the spec sheet. This made the amplifier better, yet powerful enough for people's needs. Remember, Bob's amp is only 50W. My JC-3 amp (designed the same time as Naim's) is only 20W. Naim was making much bigger amps in the 1970's as a commercial product. This is where Glen is coming from, today. He found a quality N channel only power mosfet and is now doing much like Naim did, long ago, with his output stage.
john curl said:
John I don't think so. I remember years ago someone having a Naim amp. Looking at the back of it, it didn't even have decent heatsinks and it used Philips BDY-20 or BDY something TO-3 metal can transistors. Like I said nothing special. It's something you'd find in a Mullard application note.
There is nothing special about a quasi complimentary design no matter what quality output devices are used
john curl said:
The 'secret' of using quasi-complementaries because NPN's have better SOA has never been a secret to anyone half-witted about audio design.
Naims may have been SOTA half a century ago. Two weeks ago I attended a Naim demo at the local hifi club. The week after I demo-ed my 'diy' amp. 28 out of 30 attendants stated that after the Naim demo, it was good to hear some good equipment again.
Maybe you should review your standards, John.
Jan Didden
stoolpigeon said:
The Japs were using advanced power semiconductor devices decades before Naim ever did
The proof is in the eating of the pudding. See how many of those so called rubbish "Japanese" designs are snapped on ebay these days and then see how much demand there is for old Naim amps. Naim doesn't even get into the starting gate anymore Paying big dollars for a quasi complimentary output stage using mediocre semiconductor devices
LOL It's comical really There is a sucker born every minute in the HiFi fraternity and the ones that bought Naim got taken for one hell of a ride
Sorry to break the bad news to you 
What is the problem with Quasi-complementary?
This have nothing to do with the Blowtortch but here it goes.
Have mostly been reading on this thread but i think i need to defend the quasi-complementary design a bit. First of all Snoopy, are you mostly dismissing QP because of its age and theoretical shortcommings? On paper it might not look so hot but in practice it can be realy good, both tecnically and above all, sonically. I urge everyone who have never heard an old Dynaco st-120 with some bias on the output stage on a pair of not to power hungry speakers to give it a listen. It is a bit rough around the edges if you push it but it has a drive and dynamic flow that really gets me going. I am not saying it is the best amp i have heard (far from it) but it certanly beats alot of modern amps.
BR and thanks for charing JC!
Anders
This have nothing to do with the Blowtortch but here it goes.
Have mostly been reading on this thread but i think i need to defend the quasi-complementary design a bit. First of all Snoopy, are you mostly dismissing QP because of its age and theoretical shortcommings? On paper it might not look so hot but in practice it can be realy good, both tecnically and above all, sonically. I urge everyone who have never heard an old Dynaco st-120 with some bias on the output stage on a pair of not to power hungry speakers to give it a listen. It is a bit rough around the edges if you push it but it has a drive and dynamic flow that really gets me going. I am not saying it is the best amp i have heard (far from it) but it certanly beats alot of modern amps.
BR and thanks for charing JC!
Anders
Re: What is the problem with Quasi-complementary?
No I'm dismissing it because with modern semiconductor devices it is no longer necessary or desirable to resort to this asymmetrical design practice.
I can understand your sentimental attachment to this old amp but can you please explain why you think it is better than most modern amps ??
bappe said:
No I'm dismissing it because with modern semiconductor devices it is no longer necessary or desirable to resort to this asymmetrical design practice.
I can understand your sentimental attachment to this old amp but can you please explain why you think it is better than most modern amps ??
Who said that the Naim power amp is better than many newer power amps? Julian has been dead for about 10 years, Naim is just another company now. However, it its day, Julian did some innovative things, like provide high peak current, not put in E-I protection, keep the circuit through-path simple, REMOVING the output coil, etc. He was very successful, as most POWERFUL amps at the time were quasi-comp. I worked on one, myself, in 1973, because only NPN power devices had enough safe area at that time. In order to get around that problem and use complementary output devices, we had to use more complex circuits, such as series connection (Borbely), or bridge connection (Gale) to REDUCE the working voltage across each output device, or else use constricting E-I protection, or both.
Crown and Phase Linear used quasi-comp in the '70's. Marantz and JBL used lower power, or multiple CHERRY PICKED complementary output devices, that the rest of us could not get, and often severe E-i protection.
If you can find a Marantz 500, go for it, but we found it compromised, sonically, as we did Phase Linear, and most other solid state amps at the time.
Now, what about the sound of Naim? I visited Julian at his home in 1976, and spent a few days. He was very proud of his hi fi system and demo'ed it with a popular song that included a chime like door bell. I told him that it did 'door bells' as good as any hi fi that I ever heard, but that other aspects could still use improvement. As you see, I am an 'equal opportunity' critic, and don't just criticize the rest of you.
Crown and Phase Linear used quasi-comp in the '70's. Marantz and JBL used lower power, or multiple CHERRY PICKED complementary output devices, that the rest of us could not get, and often severe E-i protection.
If you can find a Marantz 500, go for it, but we found it compromised, sonically, as we did Phase Linear, and most other solid state amps at the time.
Now, what about the sound of Naim? I visited Julian at his home in 1976, and spent a few days. He was very proud of his hi fi system and demo'ed it with a popular song that included a chime like door bell. I told him that it did 'door bells' as good as any hi fi that I ever heard, but that other aspects could still use improvement. As you see, I am an 'equal opportunity' critic, and don't just criticize the rest of you.
Re: Re: What is the problem with Quasi-complementary?
I tend to play music through it, if it did not do that in a way that i can tolerate it would go out the door asap. I am not saying that it is a superior topology, just that one can make a darn good amp with either technology, there is so much more to amp design than just the choice of basic topology. My line, dac I/V and riaa today are symmetrical designs, not JC but much inspired by his designs. For power i use a circlotron, hence symmetrical but not complementary.
BR,
Anders
snoopy said:
I tend to play music through it, if it did not do that in a way that i can tolerate it would go out the door asap. I am not saying that it is a superior topology, just that one can make a darn good amp with either technology, there is so much more to amp design than just the choice of basic topology. My line, dac I/V and riaa today are symmetrical designs, not JC but much inspired by his designs. For power i use a circlotron, hence symmetrical but not complementary.
BR,
Anders
john curl said:
For crying out a loud John, all of these so called "innovative" things made it an unreliable product and ready to blow up at a drop of a hat which it did in a lot of cases
Any of the other manufacturers could have remove the same elements from their design and made them an equally unreliable product. I wouldn't have called it innovative to make a product unreliable like that
It is NOT the topology that Naim uses, but the way that it is implemented. You know, no E-I protection, no output coil, etc. Yes, it makes it non-bulletproof. Julian owned the company, so he only had to answer to himself, and this gave him a sonic advantage. Can't you understand that what a lowly engineer must do to protect himself from being fired, IF something goes wrong with an amp, and he only had to restrict the peak current, and add a output coil, to remove the potential problem? Julian went for 'sound' first, absolute reliability second. Much like Lotus made race cars. Julian used to race cars, so maybe that is where he got that approach.
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