X1 preamplifier circuit advice


2003-01-02 6:17 pm
I have the Pass X1 preamplifier but have no schematic of it.

Can anyone advise me if there are any capacitors in the signal path of it (I understand - so are the ones in the power supply, but for the sake of simplificity of information let us skip on those here...), and if they are, which value and part number, if you have access to this information.
I have modified the Xono phono amp by changing most of the caps in the signal path (and some in the PS) with good results, so I am curious if I can improve on the X1 preamp as well.


Nelson Pass

The one and only
Paid Member
2001-03-29 12:38 am
There are film input capacitors (1 or 2 uF depending on the rev #)
and 220 uF + film bypass on the outputs.

You may replace the caps with the parts of your choice, but of
course you bear the consequences of mistakes.

As the to 220 uF output caps, we are currently favoring the Elna
Silk capacitors, of which there is an inexpensive 220 uF at 16V

Nelson Pass

The one and only
Paid Member
2001-03-29 12:38 am
As a practical matter we don't want any offset (ever) at the output
of a preamp. Fearless DIYers can get away with that, but I don't
want to have the conversation with the customer in Sri Lanka about
adjusting DC offset.

(No insult meant to the many fine customers in Sri Lanka)