RE: [Harp-L] AFB chain of effects?

["John Balding" <John.Balding@xxxxxxxxx>]

Jason Ricci wrote:

"I've been running mine first???? Mp told me he ran his last so I tried
it
and the little blue light that's supposed to flash occasionally as you
blow
hard never appeared???? I think John Kinder told me to run it FIRST and
I
think he wants nothing before OR after it I'm probably wrong and I have
been
having amp issues anyway lately so I'm just as interested in getting to
the
bottom of this as anyone else!!!!
Help Jason"

The little blue light - This is the microphone calibration indicator. In
the initial set-up of the AFB+, you are supposed to, as you say, blow a
note hard, (i.e. - as if you were attacking the first note of a solo).
The idea is to adjust the middle knob until the light only activates on
the highest volume peaks. This process adapts the AFB+ to the input
signal which it is receiving. 
If you place the AFB+ after an effects pedal, the input signal to the
AFB+ will be whatever is coming out of the pedal. If the light on your
AFB+ is not coming on, it simply means that the signal coming from the
pedals/effects in the chain is not strong enough to cause the light to
activate. 
Some effects pedals/units have a level (volume, etc.) control, some
don't. If it does, you should place the AFB+ after the pedal, turn your
mic volume all the way up, and use the pedal's level control to
calibrate the AFB+. This will insure that the AFB+ is receiving the best
signal possible. You can still use the mic volume control as you
normally would after the initial set-up.
If the pedal does not have a level control, you would still place the
AFB+ at the end of the chain, due to the manner in which the AFB+
affects the signal. The AFB+ adds odd and even order harmonics to the
original signal. This is what kills feedback. If The AFB+ is placed
before, say, a distortion pedal, which also alters harmonics, the
pedal's manipulation of the input signal (in this case, the signal
coming from the AFB+) could be compromised. If the odd and even order
harmonics are altered by the subsequent pedal(s) in the chain, then,
theoretically, the essence of the AFB+'s feedback-fighting capabilities
could be cancelled out. Not always, but definitely possible.
Although it was never written in the AFB+ instruction brochure, or told
to me by John Kinder, I get the impression, by the nature of the AFB+'s
design, that you are correct when you state that it was not "really"
intended to be used in conjunction with other effects in a classic chain
situation. 
However, I have seen Rod Piazza and Rick Estrin using effects pedals
with their Harp King amps, which employ the same anti-feedback circuit
as the AFB+. (Same UB and AFB knobs) By virtue of that, one could
surmise that it is possible to use the AFB+ with additional effects
satisfactorily; but that the effects should be placed before the AFB
circuit. 

Hope this helps,

John Balding