JFET input, MOSFET VAS, LATERAL output = Perfect!!

[lineup]

Originally Posted by Rudi_Ratlos

I am thinking about this, LineUp:



http://www.abload.de/img/varianteiiy76z.png

But I wonder:

1) if it makes sense
2) if anybody likes this concept
3) if the price for a big PCB like this (best quality, that you can imagine, about 30€ incl. shipping) is tolerable

Best regards - Rudi_Ratlos

Rudi_Ratlos
1. Personally I like 1 channel per PCB. So called Dual Mono.
2. Probably there are those who likes such a concept
3. If high quality I think people would pay €30 incl shipping

AndrewT
You should click the links - not the thumbs.

[mikelm]

I'm begining to really like this amp ( in this system )

Today I connected to a heavily modded B&W 602 speaker.
Also added 50% attenuation at the amp i/p so I can turn the computer digital volume louder.
At present both filters in place - Hugh, I'll do that check for you later tonight.

I think the easiest way to summarise is that if I had to live with the system I just heard for the rest of my life I wouldn't be that disgruntled - actually I really like this sound - very listenable indeed and there is still so much room for improvements !

This is using my macbook as a source via headphone socket - actually those guys at apple do audio pretty well - it will be interesting to get a comparison when all my normal audio gear arrives.

Building these boards by hand is a real trip so I've been working on a board to make my second pair of prototypes - I'll post it later to see what people think of it.

Greg, you can relax, in my opinion, your high opinion of this amp is well justified.

mike

[lineup]

mikelm
Good to hear your positive 2nd report.
So comparatively simple and yet so good amplifier.

Sound and listening is something that needs a real amplifier.
No spice sim can replace this.

[mikelm]

addendum:

I think that when reading my comments above you should bear in mind that I have been starved of a good audio system since early January this year - it was so great to hear something pretty good again - upon further listening this evening I did notice that I was missing the refinement of my buffalo DAC and because there are too many variables here this does mean that my subjective assessment is even less reliable than usual subjective assessments.

Despite this I still do think little amp is pretty good and perhaps extremely good - just can't say anything for certain just yet.

Hugh, I tried testing with & without the VAS filter and I think I marginally preferred it with but I have to say that 1) I'm not a big fan of A/B testing and 2) I think I would need a better digital source to really notice differences - if there is noise in the signal it's not easy to notice the presence or absence of PSU noise but my opinion, for what it's worth is that, is that it's best to have at least the option of a filter in each rail.

[AKSA]

Thanks muchly Mike,

Terrific news, really heartening!

We are a bit stalled for Greg's response; he will be in your neck of the woods by end weekend (assuming the Icelandic Black Cloud has left the Oz continent by then) for two weeks but will hopefully remain in touch via email and the forum.

I'm standing by, with or without filter, to accommodate whichever sounds best on the pcb.

On my forum, the Aspen forum, I now have tentative orders for ten boards, so there is palpable interest in this circuit and I think it shows signs of being one of the more popular projects I've seen on this board in ten years.

Hats off, this is terrific. It is a real shot in the arm to see something tangible arising from our dialogues, so much more constructive than intergalactic urinary competitions......

Cheers,

Hugh

[jkeny]

Originally Posted by AKSA

.......
Hats off, this is terrific. It is a real shot in the arm to see something tangible arising from our dialogues, so much more constructive than intergalactic urinary competitions......

Cheers,

Hugh

Yes, absolutely fantastic that this collaboration would give rise to such a result in a record time. Love your turn of phrase, Hugh

[AKSA]

John, welcome to our nightmare...!

Hugh

[MiiB]

Hugh... I do hope that you in spirit of all that has contributed release the schematic for your final take..(the one you use for the PC board)... As I would have a hard time seeing common ideas going into your business...without at least shearing your ideas and final adjustments...which I in turn have the greatest respect and admiration for as you seem to take circuits in your own specific direction..

The foundation of this little circuit came from this thread...

One JFET poweramp looking for THE FET SOUND

The circuit was a development of lineups one rail circuit posted in this forum a long time ago...where I suggested to make it dual rail... I attached the mother of this fine circuit in post 10...

[GregH2]

Great mikelm,

Very glad it's at least listenable for you! This is the 9610 version you're talking about right?

Hugh, why not make provision for the filter on the boards? Then if people want them they can use them and if they don't they can simply omit the capacitors and bridge the resistor gap with a wire jumper.

I think any simple modification using only passive devices that improves noise performance can't be a bad thing.

This is all good stuff - the real icing on the cake.

I can imagine you must be quite sick of modifying the board design - my apologies.

[AKSA]

Mike,

I will attempt to get the schemat together, with Greg's permission of course, but I don't have the model for the ZVP.... or at least, can't get it to work (sub-routine aspects).

Not sure what you are saying about sharing my ideas.... some I will not, of course, because they are commercial, but this amp is a public domain circuit a la NP's excellent designs, so I have no problem with that at all.

Greg, can I publish the circuit on your behalf? I will indeed include decoupling for the voltage stages.

Cheers,

Hugh