Aleph-X builder's thread.

[Nelson Pass]

Originally posted by noisefree
Only a resitor which connects the gates to ground?

That would do it. In our case, the output of the front end
is loaded by 10K to each rail, the equivalent of 5K to ground.

This results in outputs which float at about -4V or so (absolute,
not differential), if the front end is shut downand this is fine, but
for esthetic reasons we bleed enough current into the system to
raise it close to 0.

[Nelson Pass]

Originally posted by noisefree
I've drawn down the k2 und k3 components of a X-amp (have seen that in a magazin). Could you explain what happen with k3 @ 20W.
Why is it so low only for a short periode of outputpower?
It has something to do with the SE-bias, but I don't know what?

I assume that K2 and K3 represent 2nd and 3rd harmonic
distortion. If so, I don't recall having seen such a thing, that is
to say a short disappearance of 3rd harmonic on a swept
power curve. It might be an artifact of the test.

[EUVL]

> I assume that K2 and K3 represent 2nd and 3rd harmonic

K is Klirrfaktor in German, or distortion factor if translated directly.
So K2 is 2nd harmonic, etc.


Patrick

[gl]

Nelson,

Are you saying here that the SE bias in the output stage of the XA100.5 is supplied through a passive load and not an active CCS?

Cheers,
Graeme

[noisefree]

Many, many thanks to the master!!!

javascript:smilie('')
worship
(I'm doing something wrong with loading a smilie, sorry...)

Try to understand if this is done with the front end outputs (from p-ch and n-ch devices) connected together or with voltage bias between them....
I need a bit more time to think about it.........

The switch posibility (X.5) is done with the negativ front end voltage - only a resistor from there to the base. When front end is shut down SE bias is turned off - that's it :-)

Hi Graeme, I would say yes, CS not CCS....

Dirk

[zerohead_ak47]

ý can how make line input to balanced input ?

[Nelson Pass]

Originally posted by gl
Are you saying here that the SE bias in the output stage of the XA100.5 is supplied through a passive load and not an active CCS?

Yes.

[gl]

Thank you.

[gl]

Originally posted by Nelson Pass



1) The resistor trims the bias current, as the ZTX450 is used
to set the current source DC value

2) No, each side uses 20 parallel sets of complementary
follwowers. The resistors are for dissipation of the single-ended
bias.

3) Try a simple switch.

Nelson,

In 2) above I interpret your response as 2 (sides) x 20 (parallel sets) x 2 (MOSFETs per set). Should that be 2 x 10 x 2 for an XA100.5?

Graeme

[Nelson Pass]

Yes, 40 devices / ch