Class A amplifier Designs?

[blair]

Does/has anyone:

A) Built their own Class A transistor amplifier?

B) Know of any good TO-3 transistors that can put out a good amount of power and remain respectable from a distortion/linearity standpoint?

Here is a project called "Le Monstre" it looks very nice! I purchased some heatsinks planning to drill them for the 2SC5200/2SA1943, but they are really nice, and tapped already for a TO-3 package. One per heatsink, but that it fine since I was planning to put on per heatsink to help cool these beasts.

I am hoping to use this circuit to drive a decent TO-3 transistor to around 50W in class A. This design pushes 2SC5200/2SA1943 to 58w cleanly, so I am hoping to do the same with a TO-3 package transistor.

http://diyaudioprojects.com/Solid/Je...s-A-Amplifier/

Thanks for any reccomendations!

Blair

[HareBrained]

Re: Class A amplifier Designs?

You may already be aware of this, but you should post this in the amplifier forum on diyaudio. Nelson Pass is there quite often and I don't think there would be a person more qualified to answer your questions.

For those who are interested, Mr Pass has a very good DIY site found here:

http://www.passlabs.com/

[blair]

Re: Class A amplifier Designs?

Thanks,

I am aware of that forum, and Pass' as well as Curl's presence there. Most of their designs use multiple transistors though. My heatsinks are only tapped for one TO-3 each which is why I am interested in the design I linked to in my previous post. I did post there as well, but have yet to receive a response.

Thanks again!

Blair

[philiparcario]

Re: Class A amplifier Designs?

www.ska-audio.com I made 2 of these class a mono blocks

[blair]

Re: Class A amplifier Designs?

Thanks Phil,

These are nice, and believe it or not, I have a pair of SKA 300Ds ready to build in my closet including the entire BOM. I'm not sure why I have not built them yet. I keep avoiding it like the plague.

What I'm looking for is a single NPN TO-3 pair good for 50w to match my heatsinks. They are already tapped for a single TO-3 per heatsink.

Someday I'll get around to the SKAs!

Blair

[dickwest]

Re: Class A amplifier Designs?

You probably know one of the Pass ZEN designs might be suitable and uses only one power device. but, it only produces, as I recall, about 10 watts -- and a lot of heat.

A 50 watt class A amp will need huge heat sinks and will be good to heat your house this winter.

[ttan98]

Re: Class A amplifier Designs?

You probably know one of the Pass ZEN designs might be suitable and uses only one power device. but, it only produces, as I recall, about 10 watts -- and a lot of heat.

A 50 watt class A amp will need huge heat sinks and will be good to heat your house this winter.

Fully agreed, wasted energy detriment to global warming.

[AJ]

Re: Class A amplifier Designs?

MJ21193/MJ21194 is a good TO3 for high power amps. Make an account at Onsemi.com and you can get samples (up to five of each, free).

Have you seen the JLH class A amps? http://www.tcaas.btinternet.co.uk/index-1.htm

This seems to be the latest/most proven circuit http://www.tcaas.btinternet.co.uk/jlhupdate.htm

[blair]

Re: Class A amplifier Designs?

Thanks everyone! Including captain environmental holocaust!

Anyway, AJ, this amp looks perfect for my spare sinks and parts. Thanks for pointing me in this direction.

Blair

[AJ]

Re: Class A amplifier Designs?

If you need more info on building the JLH, there is at least one big thread on it at diyaudio.com. Are you going to make your own PCB?

As always, post pics of the build in progress and let us know how it goes :D

[blair]

Re: Class A amplifier Designs?

Hey AJ,

Have you ever done this with onsemi? How long does it take to get samples?

Thanks!

Blair

[AJ]

Re: Class A amplifier Designs?

Yes I have; I think they shipped them UPS ground. Took a week tops and cost me all of 11$. I don't suggest people make a major habit out of ordering just samples and take advantage of it but it's nice for testing out the random new product or to get a few extra parts for a project.

[blair]

Re: Class A amplifier Designs?

Thanks AJ! I'll post pics of my progress since it is SS and it seems to be of more interest here than tubes.

Blair

[AJ]

Re: Class A amplifier Designs?

Well, I've always enjoyed seeing your tube amp builds; please, continue posting those also. Good luck on your build!

[blair]

Re: Class A amplifier Designs?

It takes a little longer than it used to to get projects built, but here is a little progress on these amps. Overall, there is less than $200 in these, so that is not too bad at all if you consider the cost of a pair of 50w class A amps from audigon.

Blair