# Class "A" Single Ended S S Amp



## greco (Jul 15, 2007)

A friend of mine is an EE and has built several tube amps and other electronic devices. 

He was telling me about the John Linsley-Hood (JLH) Class A amp he recently built (~15 watts output) for use with guitar.
He is extremely impressed with the tone of this amp.....and he has several tube amps (his own and a Traynor, etc)to compare it to.

I looked up the schematic on the internet and this seems like a very interesting concept for a good quality SS build, especially for a beginner. 

I don't want to start a tube'ites VS Solid State'ites debate here, I'm just interested in comments from anyone familiar with the JLH amp, particularly anyonre who has built one.

Cheers

Dave


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## greco (Jul 15, 2007)

34 views....no bites

...Was it something I said? ...LOL

Cheers

Dave


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## fraser (Feb 24, 2007)

a couple of those views were me-
but as ive never heard of a JLH amp, it didnt make sense to say anything lol


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## greco (Jul 15, 2007)

From what I understand, the amp was developed in about 1969 by JLH for HiFi. 

I think he is an amateur builder/hobbiest and he designed this amp that has been copied by many and has withstood the test of time as an admired single ended SS amp.

Cheers

Dave


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## dtsaudio (Apr 15, 2009)

JLH was a professional designer. I believe he was an electrical engineer (i could be mistaken). His class A design is the basis for a number of modern designs. Today it's textbook stuff.
He passed away a few years ago. There's a number of websites devoted to his work.

The amp you're looking at should give very good sound. However it is a hifi amp with extended frequency response and can become unstable if not carefully built. The output transistors need a good sized heatsink as well. They will become very warm. So watch for thermal runaway. If you get this up and running check the current draw periodically when you're testing it.


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## greco (Jul 15, 2007)

dtsaudio....... Thanks for all the additional, and corrected, information. 

My friend certainly emphasized the need for a very beefy heat sink.

Cheers

Dave


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