Quasi-complimentary; pro / cons?

[kASD]

Hi Kanwar

How you doing mate😉

Its true properly implemented N-channel output stage amplifiers
are very rugged, more so than BJT designs.
dispite the intrinsic low linearity of HEXFETs or NVMOS devices
very low distortion figures can be achieved and excellent performance in terms of efficency are realised.

The new n-channel design I am working on has a R2R performance of around 1 volt rail loss.
allowing well over 500 watts RMS into 4 Ohms with only +-70 volt rails
under load the supply drops to 66 volts

The sonic performance is also very good, of cause this is only my opinion.

But you will get to hear this design yourself when it is released onto the world market....

Thermal management of N-channel Mosfets is tricky, but once mastered, works very well in deed.

Hi Anthony Eric Holton,

I am pretty much fine....brother

Nice to hear about your R2R designing NVMOS amps....very good power supply loading..Quasi-amps always load the supplies much Symmetric than full complementary...

The Sonic performance must be good because the amp is designed by the very best mosfet designer in Tasmania...ANTHONY...

I have recently designed another Quasi N-channel with R2R loss below 0.5Volts @ 1KHZ when loaded with 2 Ohmsresitive ....Comprising 5 Pairs of APT20M18BVR in parallel ...with rails at +-90VDC
Full Power Bandwidth is 5 Hz to 100Khz .....

Keep up the good work.....

best regards,
K a n w a r

 

[GEirin]

Hi.

What do you think about the n- channel mosfet power output, driven by a p channel mosfet phase splitter of the Creek 4330?
Pros and cons?

Thanks

GEirin

 

[x-pro]

Hi.

What do you think about the n- channel mosfet power output, driven by a p channel mosfet phase splitter of the Creek 4330?
Pros and cons?

Thanks

GEirin

I personally think it is rather nice and good sounding circuit... .

Wait a minute! I would say that, wouldn't I?! I've designed it, after all

🙂

Cheers

x-pro

 

[anatech]

Hi x-pro,
Also (from experience), when people blow them up, they typically only take out an output or two. I always change them both.

I like a design that doesn't lay waste to everything from output to input when it goes. Beware older Yamaha's for that reason.

-Chris

 

[GEirin]

Hi Xpro.
Thanks for you reply.

Then, P- channel is better than N- channel? (phase splitter)

Geirin.

 

[GEirin]

Creek 4330

Hi X-pro

Another question.

Is possible to replace the output quasi n-channel for quasi-Bjt npn? Which is your opinion? Better sonic performance?

GEirin

 

[x-pro]

Re: Creek 4330

Then, P- channel is better than N- channel? (phase splitter)

With P-ch splitter transistor the output stage is a follower, providing for a low open loop output impedance, where with N-ch splitter the output stage has a gain and high open loop output impedance. I've started with N-ch splitter when I've first developed N-ch output stage in 1992 however very soon I've found that the P-ch splitter works better.

Another question.

Is possible to replace the output quasi n-channel for quasi-Bjt npn? Which is your opinion? Better sonic performance?

I personally prefer the sound of N-channel MOSFET output.

Cheers

x-pro

 

[GEirin]

Hi X-pro.

Thanks for you reply.

GEirin

 

[mikeks]

Re: Quasi vs Fully com

......Fets have much higher distortion than BJts and so masses of global feedback must be applied......

.......The same argument applies to quasi BJts. Fully comp BJts are so easy to work with and the various non linearities that exist are not that difficult to eliminate.

200% correct!

We built the last THX series of Citation amplifiers for Harman Indistries (5.1 and 7.1) and through carefull design the amplifiers sound superb.

I have these service manuals...interesting design philosophy (not perfect, mind)...

Goes back quite a while though...virtually identical to early marantz designs...

 

[Circlotron]

You have only two choices:

1/ Drive the same end of the load alternate directions.
2/ Drive alternate ends of the load the same direction.

If you have 2 output devices of the =same= polarity, the most logical approach is #2 IMHO Most of us here have seen a circlotron topology output stage though perhaps not many have actually built one and seen first hand just how well they work. They are every bit as as symmetrical as a complementary cct, just the line of symmetry is drawn vertical instead of horizontal. None of the difficult drive problems of the uper device in a quasi setup. Have a look at this thread --> Click They work just sooooo well and I think that more people don't play with them because they look strange on paper until you get used to the idea. But believe me, they work and they work well!