[sdiy] ARP2601 question

[Dave Manley]

On 2/25/2011 9:12 PM, Bob Weigel wrote:
> I just have the 2600 downloads of course on this. I have an odd thing that might be just something not configured right etc. Both speakers make good sound..but
>
> 1) pan to the right and all sound pans to zero.
>
> 2) You can put a plug in the left in, tap and get a buzz..not so in the right in
>
> 3) neither reverb works at the moment..it appears there is reverb amount to right and left or am I misunderstanding those controls?

What you're describing is weird - if both left and right speakers work
then there shouldn't be any way panning to the right causes both left
and right speakers off.

If you drive the 'pan input', with pan slider centered, and turn both left
and right reverb sliders off, do you get output on both left and right
speakers?  If so, if you then pan left/right does the pan work smoothly?

The panner feeds the left and right preamp opamp inverting input, while the
left and right input jacks feed the non-inverting input.

The 'right input' not working could just be a jack problem, not related to
the pan issue, since it bypasses everything else and goes straight to the
non-inverting input.

The reverb pickup amp feeds the left and right reverb level controls, which
then feed the left/right preamp outputs, so you have it right.

If there's no reverb anywhere, unmount the reverb and verify the internal
connections from the RCA jacks to the coil assemblies are not broken.
The small wires are easily broken.  If reverb works on left but not right,
it's probably the 'reverb output' jack.

Take look at the schematic for the '4-2 Bd'.  All of the above is on the
right side of the sheet.

-Dave