Re: [Harp-L] getting high gain... no feedback

[Rick Davis <bluesharpamps@xxxxxxxxx>]

Yep, that's the secret:  Turn down your microphone!  A hot mic can send more
than a volt of power to the amp on loud passages.  That is so much power
that the amp does not even need its first gain stage... the signal could
drive the second stage!

That big a signal overwhelms your input tube, beating it into square waves.
What you hear is your input tube fighting for its life.

Turn your mic down, exactly as Michael suggests.  Your tone will be more
musical and your feedback demons will retreat.

Custom harp amps such as the Mission Chicago and other fine amps are
designed to handle the hot signal and there is no need to necessarily
attenuate your mic.  But with most guitar amps it is a must.

-- 
-Rick Davis
The Blues Harp Amps Blog
http://www.bluesharpamps.blogspot.com/

On Fri, Oct 29, 2010 at 7:38 AM, Michael Easton <diachrome@xxxxxxxxxxx>wrote:

> I C/P'd  the message below from one I sent to the local harp players I
> network with.
> I played at our local blues jam last night using the house Deluxe Reverb
> bought for harp use. (still set up with 12ax7's)  The amp is set on top of
> the house Leslie speaker at ear level.
> Read on.
>
> "I tried something different with the Deluxe Reverb last night.  I don't
> know if it will work for the rest of you because of the polar pattern of
> your mics. Maybe with Bill's 545 and Daine's  Sennheiser.  I used the
> Heumann volume pot on my SM57 and a line transformer on the xlr cable.  I
> plugged into the 2nd input on the reverb channel and cranked the volume to
> 6. This drives the amp output to play hotter. The 2nd input has a lower
> gain, so while the amp was outputting hot the input was lowered so as not to
> force the signal through the amp.
>
>