Holton N-Channel Amplifier Questions

[mrfeedback]

Hello All, I have tried emailing Anthony, but like some other members here, so far no response.
Maybe someone here can help answer these questions.

This is a copy of what I sent.....

"Anthony, Hello from Perth.
I have read with interest, discussions on Diyaudio and your website regarding your amplifier designs.
I am curious of your statement in the pdf plans for the N-channel amplifier, that
"There just seems to be something about amplifiers that use N-channel MOSFETS in their O/P stage."

Can you elaborate on this observation for me please, ie subjective opinion, and do you know the reasons ?.
Also have you tried and compared a P-channel version of this amp ?.
Also, I am not able to find a link to schematic for your 1000W amp module ?."

Re your N-channel amp - with an appropriate PSU stage, is the driver stage happy driving enough parallel
output transistors to drive down to 2 ohms load (ie 4 paralleled 8 ohm drivers) or less ?
Or recomended mods/enhancement to enable this ?.
Is it beneficial to provide seperate supplies for input/driver stages and output transistors, and of differing voltages ?.

Many thanks for your assistance,
Regards, Eric.

http://www.aussieamplifiers.com/poweramp.htm
http://www.aussieamplifiers.com/download.htm

Can anybody answer these questions for me (and Anthony) ?.

Also, in the IRF range of mosfets, can anybody tell me what the typical dopant element is ?

Thanks and regards, Eric.

 

[GRollins]

I once raised the question of possible sonic differences between N & P MOSFETs to Nelson. He said he wasn't aware of any difference and couldn't see why why there would be any. Yet my curiosity remains: Since N-channel devices are--for lack of a better word--more 'natural' in the manufacturing sense, meaning lower on resistance, higher current, etc. etc. etc. than comparable P-channel devices, would there be a consistent, identifiable difference in sound between the two after other variables are taken into account?
(Note for the record that tubes are 'N' devices and are pretty decent in sound quality.)
By extension, I suppose the same question could be raised in reference to bipolar transistors.
I will be testing this, as the question dogs me. I figure the easiest way will be a SOZ (or BOSOZ, perhaps), as that will remove as many variables as possible. However, for the time being, my workbench is tied up with a few other things...
Perhaps one of the headphone crowd could take a whack at this, as a simple MOSFET power follower would be quite easy to arrange, and a good set of headphones might be sufficient to answer the question. All I have on hand is an antique pair of second-hand Yamaha HP-1s, so I'd have to do something on the big system and that raises questions of scale. In my case it would be easier to go for a preamp circuit, I guess.
All in good time.

Grey

 

[mrfeedback]

Dopey Question ?.

Hello Gray, yes I'm intrigued also.
I have repaired amps that are npn ouputs only, and there does seem to be a subtle sonic difference to complimentary opst, IMHO.
According to my getting hazy theory lessons memories,
P material runs on holes transmission, and N material on electrons transmission, and tubes electrons transmission.
Also that PNP bipolars are inherantly 1/f noisier than NPN, but I don't think this the effect we are talking about.

I'm also interested to know what element is used to 'poison' the silicon crystal in N-type fet.

Thanks, Eric.

 

[jleaman]

He's a bussy Guy

Anthony is a bussy guy i have called him he is hardly home as you can tell his webpage is lacking updates and needs some.. i almost have mine compleeted just need time to get to the machine shop to get my case welded..

ill be postin pics soon..

Jason

 

[mrfeedback]

Thanks Jason, I figured such reasons are likely for Anthony.
I'm not intending to sledge him, I just thought this might be an interesting topic and that I might get some quicker answers this way.
And of course, we are waiting to hear of your results - good luck.

Eric.