NIGC Buffer

[Assesears]

G'Day

Been looking through the threads can't find anything on nigc buffers, does it not work out in the 'ni' setup or does it sound sh!7e. I thought the nigc setup is the latest craze, it seem's not many dudes are building buffers with them or am I totally wrong.


Cheers Bruce

[Sheldon]

I've done it. Details here: Any interest in GC input buffer and power supply regulator pcb's?

It's not quite as common, because the NIGC generally has higher input impedence and therefore, in theory, benefits less. I built Pedja's discreet jfet buffer and it sounds very nice to me. I haven't compared with non-buffered. No reason not to try if you are interested. Carlos's buffer should work too. I might try that one next time.

Sheldon

[Nuuk]

You can use a buffer with a NIGC just as you can with the inverted type.

Does it make the amp sound better? Only you can say by trying one.

[mikelm]

Originally posted by Sheldon
It's not quite as common, because the NIGC generally has higher input impedence and therefore, in theory, benefits less.
Sheldon

Mmm... I think it would be the other way round.

the inverting i/p GC always has the i/p resistor inbetween the amp i/p and the o/p of the buffer so the amp i/p sees just under 10K minimum

on the NIGC the low impedance of the buffer can be directly injected into the amp i/p so the amp sees a very low impedance which should reduce distortion and give a 'bigger' sound.

also on the NIGC this effect can augmented as well by reducing the values of the feedback resistors - but it will be a matter of taste as to wether this is desirable and low impedance FB will probably erode stability margins.

mike

[planet10]

The buffer has a theoretically greater benefit on the inverted gainclone because it removes whatever you have plugged into the input from the feebback loop.

dave

[Nuuk]

The buffer has a theoretically greater benefit on the inverted gainclone because it removes whatever you have plugged into the input from the feebback loop.

Dave, I think you meant 'input loop".

[planet10]

Originally posted by Nuuk
I think you meant 'input loop".

Maybe feedback circuit would be more correct ... in an unbuffered IGC, the cable, and at least part of the source device (ie CD player back to the eoutput buffer) are part of the feedback circuit.

dave

[mikelm]

Originally posted by planet10

Maybe feedback circuit would be more correct ... in an unbuffered IGC, the cable, and at least part of the source device (ie CD player back to the eoutput buffer) are part of the feedback circuit.
dave

Whatever we choose to call it there seem to be good auguments for having a buffer for all kinds of GC.

I have only tried a transformer volume control for this function. I wonder if anyone out there has compaired TVC, Valves, opa627 etc, and Jfets.

I would be interested to hear opinions of how they compare.

mike

[skyraider]

I used my NIGC with 2132/buf634 buffer.
I just like it better, even though its a bit noisier. I get tighter bass, and less harsh highs. I wouldnt say buffer is better, maybe its an overall combination.

[janneman]

Originally posted by planet10


Maybe feedback circuit would be more correct ... in an unbuffered IGC, the cable, and at least part of the source device (ie CD player back to the eoutput buffer) are part of the feedback circuit.

dave

Dave,

Good point for the IGC. On the other hand, any decent CD player or preamp has its own buffer (or at least low output impedance stage) so you end up buffering the buffer...
But, again, tube sources can be a different kettle of fish due to highish and/or non-linear output impedance.

Jan Didden