Other than buying a preamp with such a switch, it would seem a
relatively easy device to design. Needs to be completely inaudible, and
avoid switching "pops". My ears are very sensitive to correct polarity
(in some recordings) but my pre-amp does not have a switch, and its a
royal pain to reverse the speaker leads.


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uson wrote:
Other than buying a preamp with such a switch, it would seem a
relatively easy device to design. Needs to be completely inaudible, and
avoid switching "pops".

The actual device need be nothing more complex than a double-pole,
double-throw switch for each channel.

However, your desire for it to be "completely inaudible and
avoid[ing] switch pops" is an impossibility. Only if you switch
during absolute silnce is this possible. At any point where there
is signal voltage, no matter HOW you do it, there MUST be an
abrupt change in the signal, and and the result WILL be a
switching transient of some level. The degree of audibility is
dependent, of course, on the instantaneous signal at the moment
of the switch and the spectral density of the music. It'd be harder
to hear it on thrash metal than it would on a recorder solo, for
example, because any switching transient is going to cause a
fairly wide-band, spectrally dense signal, and already having a
lot of energy throughout the spectrum is likely to mask it.

It's certainly possible, given sufficient sophistication, to build
a curcuit with soft switching: instead of the transition happening
at a specific instant, it's xpread out over a few milliseconds with
a "fade" between the two states: that'll reduce substantially the
potential audible impact of switching but has some costs, the
major one being that, technically, it's far more complicated than
a simple switch. There are, undoubtedly, also those that might
argue that such sophistication MUST have deleterious audio
impact, though, as an a priori argument, this is simply speculation.


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On 22 Apr 2006 15:43:18 GMT, uson wrote:

Other than buying a preamp with such a switch, it would seem a
relatively easy device to design. Needs to be completely inaudible, and
avoid switching "pops". My ears are very sensitive to correct polarity
(in some recordings) but my pre-amp does not have a switch, and its a
royal pain to reverse the speaker leads.

The gadget can be a simple but good quality switch IF your
preamp-to-power amp connections are balanced. If not, you need a way
to invert polarity, either an active circuit or a transformer.

Kal


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In article , uson
wrote:

Other than buying a preamp with such a switch, it would seem a
relatively easy device to design. Needs to be completely inaudible, and
avoid switching "pops". My ears are very sensitive to correct polarity
(in some recordings) but my pre-amp does not have a switch, and its a
royal pain to reverse the speaker leads.


--

Why not put a reversing switch in the speaker leads?

Isaac


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"uson" wrote in message
...
Other than buying a preamp with such a switch, it would seem a relatively
easy device to design. Needs to be completely inaudible, and avoid
switching "pops". My ears are very sensitive to correct polarity (in some
recordings) but my pre-amp does not have a switch, and its a royal pain to
reverse the speaker leads.

If you want to swap the leads at most points in the circuit, you have a
problem with grounding. Speaker leads are a good point at which to do the
swapping. Simply use an SPDT switch, as follows:

Middle 2 terminals: Output to the speaker.
Left 2 terminals: Red and black.
Right 2 terminals: Black and red.
That is, the switch connects the speaker to its cable with the wires in
either of the 2 orientations.


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Absolute polarity would not be a consideration unless a recording was
made with only two microphones. When multi-microphones are used, any
polarity considerations are destroyed. Proper polarity between speakers
is altogether different however.

---MIKE---
In the White Mountains of New Hampshire
(44=B0 15' N - Elevation 1580')



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Kalman Rubinson wrote:
On 22 Apr 2006 15:43:18 GMT, uson wrote:

Other than buying a preamp with such a switch, it would seem a
relatively easy device to design. Needs to be completely inaudible, and
avoid switching "pops". My ears are very sensitive to correct polarity
(in some recordings) but my pre-amp does not have a switch, and its a
royal pain to reverse the speaker leads.

The gadget can be a simple but good quality switch IF your
preamp-to-power amp connections are balanced. If not, you need a way
to invert polarity, either an active circuit or a transformer.

Kal


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Or switch at the loudspeaker inputs (assuming you don't have active
speakers) using a pair of two-input to one-output relays or mechanical
switches. This requires very low on-resistance in the switch/relay, but
it is possible.


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