Ultra-LD 100W

[gev]

links siliconchip

I removed the links as they are siliconchip copyrighted.

/Hugo

[AndrewT]

This looks like a Doug Self schematic with the option to replace the follower with a cascode to help the VAS that he shows in his published designs.

The frequency extremes could both do with about one octave wider bandwidth.

I don't like Self's use of LTP mirror and Miller comp cap (Cdom) that dominate all his designs.

[Greg Erskine]

I have redrawn the SC ULD class AB schematic, so can I post that because I believe it's the magazine that has copyright, not the actual schematic?

[Netlist]

Absolutely.
The posted links were images and schematics, copyrighted by siliconchip and from the paid section of that site.

/Hugo

[Greg Erskine]

Hi all,

Here is the schematic of the Silicon Chip Ultra Low Distortion class AB amp. (SCULD class AB). I hope this makes the thread a little more meaningful.

Only last Saturday I had an audition of a highly modified version of this amp and was impressed to say the least. So, I not sure what the standard ones sounds like, but I can say if you know what you are doing you can get one of these to really sing.

regards

[awpagan]

Looks very much like there 15W class A amp schematic!!


allan

[sandyK]

The one that Greg heard belonged to a friend who is using a CFP VAS and 30,000uF capacitance for each supply rail,plus another tweak or two..

SandyK

[destroyer X]

Depending on the simulator results....awfull the original into my simulator..this one modified is a little better...but not good.

I will continue to study this one.

Maybe it will turn the next Dx amplifier... maybe i said...i have to study for weeks into the simulator and ask a lot of friends about.

Also i will ask Graham to evaluate and to simulate it.

I will ask Michael Bittner and Hugh Dean too.

And then...maybe...not sure...if positive results of conversations, maybe a prototype....... if the prototype sound fine after tweakings it is possible that i will open a thread about.

For a while.... only to give a shot on it!

The original was already smashed, destroyed and it is in the garbage can (the box may be offended!)... the original Miller modified capacitor of 100 picofarads are triangulating the wave form after 60 kilohertz!!!!!....the enormous output filter were eating the high frequencies.... the zobel loading the amplifier...and low frequency drop was enormous...people may be kidding to publish those things!...not you Qev!....the magazine!

This complicated thing is simulating worst...many times worst than the simple and cheap Dx amplifier.

regards,

Carlos

[sandyK]

Carlos
The amplifier that Greg heard only has a passing resemblance to the original published design . The original design's HF response was deliberately rolled off to ensure repeatibility, without susceptibility to EMI. I raised this issue with the magazine. The original was NOT a bad sounding amplifier. I don't feel that it is helpful to rubbish the original design, or publicly attack the design's perceived shortcomings. Have you seen the full specifications of the original design , and the rest of the published article ?
I have heard Destroyer X AND the modified design that Greg refers to, but in fairness to everyone concerned, I decided not to post my findings in a forum with public access. Also , I did not want to place Greg in an untenable position.


Kind Regards
SandyK

[destroyer X]

And because i love Aussies, i will not post my findings anymore, with the exception if they were very good...rigth?

Agreement made!

regards,

Carlos