ASK SILICON CHIP - CTD FROM PAGE 101
Advertising Index
Altronics .............................. 52-53
ing Feedback with Equalisation",
p106, August 1990). I have decided
to take your advice on frequency shifting the whole signal slightly with a
"Howl Round Stabiliser", though the
pitch shifting chips (MC1495) are
rather hard to find. (S. P., Melville,
WA).
• We have not considered doing an
expander although the circuit is not
much different from that of the compressor. We'll put it on the list of
projects for 1991. How about that?
The Motorola MC1495 should be
available from VSI Electronics (Australia) Pty Ltd in Perth. Try them on
(09) 328 8499.
Volume control needs
better matching
I have built two Studio 200 Stereo
Control Units, as described in the June
and July 1988 issues of SILICON CHIP.
Both work well but they both have
the same problem. When I want to
listen at very low levels, when the
rest of my family is asleep, I find that
one channel is louder than the other.
Is there a design fault in the circuit or
is there a modification I can make to
improve the problem? (M. K., Stanmore, NSW).
• What you are experiencing is not a
design fault but the normal lack of
matching between sections of the
volume control when it is set at very
low levels. Just about all controls on
stereo amplifiers have the same problem unless a higher cost, specially
matched vo lume control has been
install ed.
Japanese firms such as Alps do
manufacture closely matched dual
ganged volume controls but they.are
not cheap or readily available. It might
also be possible to purchase such a
volume control as a replacement part
for a Japanese amplifier.
One other way around the problem
would be to put in an extra switch to
reduce the gain for low level listening, similar to a Mute switch. That
way, you could listen at low levels
but have the volume contro l set to
say, 9 or 10 o' clock, where the control matching is reasonable. This
could be achieved by switching a
22kQ resistor in series with each section of the Balance control.
Another way could be to wire one
pair of the Source inputs for lower
gain. If you listen to CD most of the
time, connect a 120kQ resistor from
the CD input to the Aux 2 input, in
each channel. Then when you select
Aux 2, you can listen to CDs with a
higher setting on the volume control.
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PC Boards
Printed circuit boards for SILICON
CHIP projects are made by:
• Electronic Toy Services, 2/111
Glynville Drive, Hackham West, SA
5163. Phone (08) 382 8919.
• Jemal Products , 5 Forge St,
Welshpool, WA 6106. Phone (09)
350 5555.
• Marday Services, PO Box 19-189,
Avondale, Auckland, NZ. Phone 88
5730.
• RCS Radio Pty Ltd, 651 Forest
Rd, Bexley, NSW 2207. Phone (02)
587 3491.