"Andre Jute" wrote in message
On Sep 9, 6:59 am, "Iain Churches"
wrote:
"Andre Jute" wrote in message
...
Time to return to tech-talk.
In a modest-sized room (by horn standards anyway) I
want to rig up a singleton of my modded semi-Fidelio
bicor horns for Lowther PM6A. I thought I'd do the
monoing in a specially made 1 metre cable between the
CD player and the power amp.
The QUAD CD expects to see at least 10K impedance on
its outputs. Output of the CD player is 2Vrms and about
0.5Vrms of that is required to drive the amp to enough
power to handle the horns, so high value resistors can
be used in the monomaker if there is any advantage to
be gained.
However, the sound is NOT intended to be reprocessed as
stereo downstream (home installation, not studio); if I
want stereo again, i'll just plug in a stereo cable.
The pot on the integrated amp is probably (the board
won't be here until Tuesday and i can't read the spec
on the piccie) 50K Alps but I can replace it with a
DACT of which I have a good selection of values.
So what value resistors would you use for monoing?
How many? Only two, or three?
With your choice of values, what can I expect to lose
from the monoing in bandwidth as distinct from gain?
Andre Jute
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Hello Andre.
Good to see you posting again.
I would try three R's arranged as a Y, with the
top two arms (R=10K each) connected at the sources,
and the bottom leg (R=2k2) to ground,
with the mono output taken from the junction of
the three resistors.
I don't get this, Iain. You and David both want a low
value resistor shunted to ground. But it seems to me
you're looking backward to the series resistors whereas
the important direction is forwards to the unknown pot,
with which the shunt resistor will be in parallel. If the
shunt resistor is low, the parallel combination will be
grotesquely
low.
If you knew anything about circuit theory Andre, you'd know that resistor
networks are linear circuits which are bi-directional. The source impedance
at the output node of the 3-resistor network is the equivalent parallel
resistance of all three resistors.