Stan Curtis' 60W Class A Amp

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Thank you everyone for your replies. I am very new to DIY Electronics, electronics in general actually. Some of my questions may reflect this so please bear with me.

Nelson, thanks for the input, I am definitely looking closer at the Zen Amps, mainly because of the level of support you and others give. I have been known to be a little ambitious at times though, hence the Curtis' amp.

Shadow, I plan on using the amps as is. Actually my ultimate goal is quite extensive. This is only the first step. My completed set up, as I plan it now will be:

2 Mono 60W Class A - 2 Channel Stereo Music Only
6 Mono ESP Project 3A Amps - Multi channel Home Theatre

All of this will be run from my HTPC (in progress of being built)
Using this as my pre-amp, all digital decoding being done via software allowing it to be upgraded anytime plus ability to try different things in the never ending search for the best you can get. I know this statement may start a fight but it is what I have, so maybe it should be stated as "the best you gan get with what you have".

I may look at bi-amping and active crossovers down the line but they are not planned as of yet. I am going to wait and see how difficult it is to build and how much it costs before I look at bi-amping.

Needless to say I have alot of learning yet to do.

Any help is verrry welcome. Thanks everyone

No comments on the Stan Curtiss design yet.
But, if you really want Class A and don't want to try any Zen or X stuff, I would really strongly recommend taking a look at Nelson's 20W Class A amp from 1977 (don't be concerned about the date!):

For those of use with vast collections of nice bipolar output devices that are begging for a project to be used in, to my mind this is the one. I still think it is a stellar performer. I know folks who have built these, still use 'em and won't trade for anything.

Who knows all the tweaks and mods you could do to this design!


Audiofng said:
....I am interested in looking at building a Class A amp for my system. Let me know what you think. All suggestions welcome. QUOTE]
I remember the Stan Curtis amp project from when it was first published. It was, as I recall, very well regarded by many. At least two companies were selling the project as a kit of parts for several years.

Even considered it myself, but being a penniless student at the time....I do still have the original article though.


Hi Audiofng

Wrong link !

As far I know and remember :
The input stage was a Curtis's creation, it's an inverting circuit.
The Curtis class A vas described in magazine Electronics Today International. Commerciallised quite similar, but maybe class B, were the first Mission and (maybe again) Lecson amplifiers. John Watkinson had kind comments on the Lecson saying it was much better than a Quad 405.
I have the ETI and Mission schematics.

~~~~ Forr

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