Just wondering if anyone can help me, I've got a phillips IC based amplifier
circuit and I need to power 100v line speakers, am I right in thinking that
as long as I match the Impedance (4-8 Ohms) and chuck a couple of diodes in
I can use a 100v line transformer on the amplifiers outputs? any help is
greatly appreciated!
--
Charlie
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Charlie wrote:

Just wondering if anyone can help me, I've got a phillips IC based amplifier
circuit and I need to power 100v line speakers, am I right in thinking that
as long as I match the Impedance (4-8 Ohms) and chuck a couple of diodes in
I can use a 100v line transformer on the amplifiers outputs? any help is
greatly appreciated!

You forgetting what the circuit is actually doing. A distributed
commercial sound high Z amplifier puts out 70 or 100 volts at its full
output. Note this is VOLTs and not WATTS. So, a 1 watt amplifier could
have a 100 volt output as well as a 100 watt amplifier. Both have output
transformers. What's the difference? The turns ratio and wattage
capability. A 1 watt amp would have a higher step up turns ratio to make
its output swing compared to a 100 watt amplifier. SO to answer your
question, you cannot just use any old 8 ohm to 100 volt transformer and
expect it to work properly. The transformers wattage must match or be
close to what your amplifiers is. And hopefully the step up turns ratio
will be about the same if you do.

Also, some output stages don't like the reactive load of a output
transformer.

Bob


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On Fri, 29 Oct 2004 19:20:19 -0500, Bob Urz fought his
way into alt.electronics, paused briefly and let forth upon the unsuspecting
patrons the following literary masterpiece:

snip


You forgetting what the circuit is actually doing. A distributed
commercial sound high Z amplifier puts out 70 or 100 volts at its full
output. Note this is VOLTs and not WATTS. So, a 1 watt amplifier could
have a 100 volt output as well as a 100 watt amplifier. Both have output
transformers. What's the difference? The turns ratio and wattage
capability. A 1 watt amp would have a higher step up turns ratio to make
its output swing compared to a 100 watt amplifier. SO to answer your
question, you cannot just use any old 8 ohm to 100 volt transformer and
expect it to work properly. The transformers wattage must match or be
close to what your amplifiers is. And hopefully the step up turns ratio
will be about the same if you do.

Also, some output stages don't like the reactive load of a output
transformer.

Bob


Thanks for that Bob, I'm using a 50w amp based on a phillips chip and I've
got hold of a 100v transformer with a 4Ohm tap and a 30W output tap so I'm
going to just plug in and see what happens, I'll put diodes in to prevent
any back emf frying the chip, thanks again for the help!
Charlie
--
Charlie
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