Re: Audio Amplifier Problems

Sounds like an overload is causing the amps to shut down. Are all of the
speakers working before it shuts down? Any chance there is a short on the
secondary side of one of the circuits?

70.7 volt systems only produce that voltage at maximum output power. How
are calculating power? Are you measuring voltage and current? Also, what
is the test signal (waveform and frequency). The meter might not be
adequate.

yeah, i does sound like an overload, except that it is inconsistent.
too inconsistent to be able to say for sure. all speakers seem to be
working fine, though with the quantities involved, i can't be sure. by
short on the secondary side, you mean on the secondary of the
transformers for the speakers? each speaker has its own transformer and
each is tapped at 1/2 watt.

yes, i'm measuring voltage and current. the test signal is a speech &
tone. the tone seems to be around 1Khz, though i don't know the
waveform. the meter has a min-max function which i've been using to
capture peak levels. the actual voltage on the circuit is more like 50.
what kind of meter do i need? or will a meter at all even be
adequate... do i need an O-scope?

...If the system doesn't work, test the amp into a
good dummy load, or check the wiring for a short to the building's
ground system. The whole idea of constant voltage sound systems is to
make it dirt simple to install and maintain. If the OP has 100
speakers, the taps should be set to 1 watt per speaker. He mentions
"Amplifiers", implying more than one amp...

what is a good dummy load? there are actually more than 100 speakers,
i'm just trying to get an idea for how to fix this and was therfore
giving an idea for 1 amp and its approximate load, i'm also learning a
lot as i go. the reality of it is more like >1000 speakers divided
across 10 amplifiers that are all separate from each other except for a
shared pre-amp input. though not all amps are causing a problem,
currently only 2 are, so the rest of it i should be able to ignore. i
think the main problem circuit is around 175 1/2 watt speakers. that
means by my calcs, i should have about 87.5 watts of speakers and
should then be well within the amps capacity. any more help is greatly
appreciated.

.

Relevant Pages

  • Re: a single output transformerstereo tube amp ??
    ... the two tweeters and woofer are arranged in a series-parallel circuit with a capacitor stuck in there to act as a poor man's cross over circuit to separate the high and low frequencies going to the speakers. ... This amp has STEREO input, STEREO volume control, STEREO tone controls and two sets of speakers, left and right. ... Now, take a look at the output of the output transformer, follow the wires going to the speakers, one wire goes to the left side of one of the speakers, the other goes to the right hand side of the other speaker. ...
    (sci.electronics.repair)
  • Re: Distortion on right channel
    ... with any set of speakers; ... replacing electronic components in circuit boards (when I say me I ... it's the same as the other channel, make a mental note, and move on to ... One can be made easily with a single computer speaker and suitable probes, which can be simple as attaching wire with an alligator clip to the ring of the 3.5mm stereo plug, attaching that to the signal ground of the unit and using the tip of the plug as a crude probe...although something longer and sharper would be superior. ...
    (rec.audio.tech)
  • Re: Pioneer SX-8
    ... this is part of the output protection circuit. ... Sound is present, just extremely low. ... I thought of that and attached different speakers and same result. ...
    (sci.electronics.repair)
  • Re: Audio Amplifier Problems
    ... speakers working before it shuts down? ... Are you measuring voltage and current? ... The meter might not be ... think the main problem circuit is around 175 1/2 watt speakers. ...
    (sci.electronics.basics)
  • Re: Audio Amplifier Problems
    ... speakers working before it shuts down? ... "Amplifiers", ... think the main problem circuit is around 175 1/2 watt speakers. ... problem moves, the amp needs repaired. ...
    (sci.electronics.basics)