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Audioexpress/Class A SS [message #2459]

Tue, 22 November 2005 19:28

Manualblock
Messages: 4973
Registered: May 2009

Illuminati (13th Degree)

Nelson Pass has a real nice SS class A amp design in this months issue.
It is an old John Lindsey Hood design using "three gain stages with the middle stage consisting of a NPN transistor used as a phase splitter driving the positive half of the output stage and the negative half with symmetric signals of opposite phase." (NP)
Real simple looking but very high performance according to Nelson.
Which brings up a point I wish to make concerning older,( from the 60's) transistor amps in that they sometimes have a real nice presentation if you don't push them too hard.
I use an old Fisher that I swear sounds like a tube amp. Nice and smooth. So; does anyone know if that is a consequence of design or parts choices?
Another thing nice is the very last sentence of the article he says he will no longer critique the sound of his designs; you must build it and see for yourself. Thats a good position to take.

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Re: Audioexpress/Class A SS [message #2460 is a reply to message #2459]

Wed, 23 November 2005 21:24

MWG
Messages: 344
Registered: May 2009

Grand Master

I started out with a Fisher 500T and it was pretty hard to tell it was a SS receiver. I've been told that the first generation Mac gear was designed to sound as close to tube as was possible in it's day. Because McIntosh figured it would be a uphill battle to win tube folks over to SS so they wanted it to sound as close as possible. I have first generation SS Mac stuff and it doesn't have any of the harshness that used to be associated with early SS gear. Or maybe I've just had it so long I don't hear it

I have compared it with a MC-275 and while not as full sounding as the tube amp it doesn't give much up to the 275. Except 25 WPC.

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Re: Audioexpress/Class A SS [message #2461 is a reply to message #2460]

Thu, 24 November 2005 06:58

Manualblock
Messages: 4973
Registered: May 2009

Illuminati (13th Degree)

Yeah; I have the 500T also. Sweet but just recently I am getting a bad pop on turn-on. It's a pretty reciever though isn't it. I like the sound it has a smooth and more organic tone that is nice to hear.
That is the point Nelson makes in his excellent article; makes you want to build it. I am gaining a great respect for his personal philosophy. He really has his head on straight. Not afraid to explore anything in the way of sound without prejudice. And never talks in absolutes.

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Re: Audioexpress/Class A SS [message #2469 is a reply to message #2461]

Thu, 24 November 2005 10:08

MWG
Messages: 344
Registered: May 2009

Grand Master

Gee I thought that was what audio was all about.....absolutes......Mine is absolutely bigger than yours

Seriously though I wish I had the knowledge to build a tube amp. I could probably follow the directions in a kit form but would rather like to know the whys and where fors on design selection and so forth. I missed out on a 500T a while back and will look for another soon. I still have the speakers I started with so I'd like to get back where it all began for a listen

I've since developed a magnetic like attraction to KLH 17's. I now have 4 and would get more if they came along. I figure one of these days my boys are going to give up the X-box and want to hear music. So I'll have something decent to start them out with.

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Re: Audioexpress/Class A SS [message #2472 is a reply to message #2469]

Thu, 24 November 2005 11:22

Manualblock
Messages: 4973
Registered: May 2009

Illuminati (13th Degree)

Boy; funny how the path leads ehh? I have a pair of KLH 23's I use with a Sonic T-amp; what a nice sound. How did they do it back then without all these high powered technological testing apparati?
Let's hope the younguns' get to hear some of the good stuff some day.

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