[slowburn]

my humble homebrew octal cornet has been playing great for five years now. even impresses the inlaws.  thanks again, jim!  great circuit.

(by the way, what happened to the DIY'er of the Month? it sure put a spring in my step a few winters back)

I'd like to add a switchable rumble filter.  now and again, particularly on older pressings that otherwise sound fab, I get some rowdy woofer excursion from subsonic groove info.  it seems to me that simply switching in a lower output cap value--shifting the 6db filter's elbow a little north--will not diminish the subsonic junk's amplitude an order of magnitude or more, which is what I think should probably occur.

does anyone have a circuit elegant enough to suit the cornet?  and where's the best place to implement it?  on a scott integrated amp, I see both rumble and scratch filters placed at the input.

Herr Hagerman, what thoughts have you?  Thank you.

[hagtech]

The component to change is C5 is the CORNET or C203 in the CORNET2.  The 100nF gives a rolloff at about 15Hz.  You may want to drop that to 47nF or 22nF to eliminate woofer pumping.  Yes, the bottom end will go with it, but sometimes that is exactly what you need.  This is not the greatest place to put a switch, as it is super easy to inject noise.  It is possible.  I would suggest a metal toggle switch mounted on the top cover right above the cap.  The chassis with ground the external portion and hopefully keep the hum out.  Then run short wires to the board.  Install the 22nF or 33nF on the board, and switch in the 100nF in parallel.  That should keep the "thump" a bit lower.  Turn volume way down before switching.  If you want to do one better, add a resistor (470k or 1M) to ground on the output of the switched cap.  Then at least it will have a proper dc bias after power is applied.

I would have loved to keep up the DIYer of the month, but it was a lot of work keeping up...

jh