Re: Newbie with RCA basket cases seeks guidance

Patrick Turner wrote:

Unless there are 8 x 6L6 in the output stage the power out won't be anything
like 235W.

235W is the input wattage.

Well maybe you will electrocute yourself with ease if you only have a vague
idea,
ie, no idea.

VALVE AMPS ARE LETHAL TO THE UNSKILLED PERSON!!!

So are transistor amps. Ever see how much juice the
power supply in some of those big honkin' transistor
amps can put out?
People can and have been killed by 48 volt telephone
battery supplies.
All kinds have connections to mains voltage, which in
Oz is even more deadly than here, being roughly twice the
voltage.

Expect to replace ALL the transformers, both power and output.
If one power T is shot then the other may be close to it.

Huh? Why would the outputs be shot? Plenty of ancient
output transformers work just fine. If he'd dug up
a pair of Marantz 5's or Leaks, would you suggest he
replace the outputs?

I bet that the OPTs have 100V output lines for the multiple speakers in the
store from where the
amp came,

The US does not have 100 volt constant-voltage speaker lines,
they're 25 or 70 volts.

ie, the cirrect load for the amps is way higher than the normal
speaker loads of
between 4 and 8 ohms.

Your schematic should give some indication of the load needed at the output to
match the tubes.
And if you ignore the loading and connect 6 ohm speakers anyway, then expect
clouds of smoke and very poor sound and not much power.

Most 8 ohm speakers have impedance dips to 6 ohms or
even below (depends on the cabinet), some have "real"
nominal impedances in the 6 ohm range. Why would
putting a 6 ohm speaker on an 8 ohm tap do anything but
possibly cause the amp to clip at a slightly lower output?
Depending on the plate load RCA chose, one might
actually get MORE power with a 6 ohm load on an 8 ohm
tap!

I have had a few old Phillips PA amps given to me and they were all useless.

What's THAT got to do with an RCA amp?

Lastly, I have to ask one more time: are ALL you Aussies
out of your gourds? I mean, the ones that post on MTUT
(misc.transport.urban-transport) are mostly nuts, too,
this is not just a RAT thing. I mean, they're practically
talking armed rebellion over uniforms worn by Sydney
CityRail employees. Could you guys just calm down, back
off the lager, maybe do some yoga? Pancho Villa practically
looks like a modern Buddha in comparison.

If I ever go on a real long-distance vacation, I'm going
to New Zealand, Hong Kong or Singapore. I might scratch
Kiwiland off the list if I think there's too
Tolkein-based tourists there. I mean, if I just want to see
someplace that *looks* like Middle Earth, I can go to
Oaxaca, which is a lot cheaper and has better mezcal.

--
Ned Carlson
SW side of Chicago, USA
www.tubezone.net
.

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