Fast Class A Amp

[destroyer X]

He turned all of us "on"

This is good, some emotions in our lives.... the amplifier cannot be so good as he is saying...but we are interested.

To the ones believe specification sounds, this one may be the "voice of God"

Good Nico!

regards,

Carlos

[lineup]

I believe!
Now I will be quiet and maybe hear our God .. finally
If I may guess it is one no-global-feedback design
I can not imagine such a fast amplifier can work with FB

[jam]

.........so what happened to Nico?

Jam

[fab]

Originally posted by lineup
...If I may guess it is one no-global-feedback design
I can not imagine such a fast amplifier can work with FB

...and how can a no-global-feedback design do THD of 0.000012% ...

[Sorr]

Sounds like a very interesting design!

[Nico Ras]

Originally posted by AKSA
Nico,

With those measurements, and particularly with that sound as you describe, I doubt more needs to be done.

Are those measurements made empirically, or using PSpice?

Except perhaps that you should have it made in China and sold worldwide for $1k!!

Hugh

PS: Your graph measurements indicate 520V/uS, in fact, and you should specify a particular frequency if you quote group delay in degrees......

Hi Hugh and other replying,

We are assembling revision 13 PCBs which took us roughly 14 months to develop to this point and is what will be delivered.

Hugh the company we are making it for has its own large automated production line and it would be earmarked for the USA market. (Guess the current economic climate is not great for a new product launch).

To answer your question phase delay is measured across the band by sweeping the frequency 2 Hz to 200kHz (one decade above and below the audio spectrum) and measuring using a network analyzer capable of 10 pico second resolution. All these specs where design requirements, not achievements let me assure you.

With the kind of feedback here I wish I could share it on line, maybe one day we could. Thank you all.

Nico

[Nico Ras]

Originally posted by darkfenriz
Nico

You are either a genius or a clown.

Hi Darkenfritz,

It was a contract design that utilised several engineers over a period of 14 months this was not DIY.

[Nico Ras]

Originally posted by Steve Dunlap
If those specs are from a real unit no wonder you are SHOUTING about it. What distortion analyzer were you using? Mine doesn't go that high in frequency or that low in distortion measurement.

Our standard test equipment are Hewlett Packard Anritzu and Rohde & Schwartz, but you are absolutely correct, some test equipment was part of the development.

[AKSA]

Thank you Nico,

I wish you every success in this endeavour; the measurements are sensational, I hope you can achieve the contract requirements, this has the potential to sound absolutely supernatural.

I have studied most of your DIY designs on the website, and can see that you have built and tested many amps over the years. Significantly, you do not appear to be constrained by convention. I take my hat off to you (along with several others here!); progress depends upon unreasonable men......

Every non-linear process in amp operation has the potential to convincingly damage the sound quality; this is not, in my experience, such a problem with speakers. Thus attempts to progress the art of amp design are both necessary and inevitable, and the effects are clearly audible even by non-audiophiles in AB testing. We all routinely put up with (and adjust to!) lousy amplifiers as we move through our lives.

Cheers,

Hugh

[darkfenriz]

From the waveform one can see very little slew rate limitation, it is rather a first order filter limitation.

If that is really 250kHz, the waveform indicates a bandwidth of around 2-3 MHz (-3dB). It looks really like a square passing through RC.

Guys, could imagine this waveform compressed in time by 10 times, will that still be a nice square? It would be "only" 2,5 Mhz.

Nico, you might have designed a great amplifier, but the -1dB at 7,4Mhz is simply unbelievable to me, sorry.