Hot enough to burn you is too hot. The thing that kills electronics is
heat. Most components are rated for use for a specified number of hours
(mean-time between failure or MTBF) at 85C... there are some rated at 105C
but consumer-grade equipment manufacturers are generally too cheap to use
them.
I have no knowledge of this particular amp, but I'd guess the bias of at
least one channel is way off if the amp runs that hot at idle (no signal).
Biasing of the output transistors sets the idle current... on some amps it's
adjustable with a trimpot on the amp PCB (one per channel) and on some amps
it's fixed and can only be changed by swapping out a resistor with one of a
different value.
Dave
"FrankMeng" <meng....@gmail.com> wrote in message
news:667b4203-87b1-413d...@q35g2000hsg.googlegroups.com...
If it gets that hot with no other symptoms it's possible that the bias is
not adjusted properly. This needs to be done by a technician, ideally by an
authorized Onkyo servicer, especially if it's under factory warranty. If
under warranty, checking / adjusting in this situation should be at no
charge.
Mark Z.
I'm thinking that a good class ab is going to bias for some double
digit percentage of it's rated power. That can be a lot of watts at
idle for some of them. Plus the higher idle biasing also means it is
operating in class a mode for longer as well, right?
<yangxia...@sina.com> wrote in message
news:f44a55fc-fc9b-4b5b...@p10g2000prf.googlegroups.com...
Modern digital receivers require a lot of ventilation. They should not
be enclosed, there should be flow-through ventilation, and there
should be several inches of clear air above them.
That said, Onkyo's recent receivers have a reputation for running
hotter than other brands, and many owners are adding forced-air
ventilation to their installations. There is a way to display an
internal temperature readout on Onkyos, which may help determine if
yours is unusually hot. See the FAQ here:
http://www.avsforum.com/avs-vb/showthread.php?t=935808
This is for the TX-SR705, but the procedure is the same:
How do I see the Temperature readout on this receiver?
1) Turn on Receiver
2) HOLD down the "Display" button and press "Standby" button once.
3) Release the "Display" button.
4) Now press the "Tone" button once
5) The temperature in Celsius and Fahrenheit will be displayed. These
temperatures are being displayed in real time so you can leave this
info on display for as long as you want to monitor the receivers temp.
"rdclark" <rdcl...@gmail.com> wrote in message
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Even if the TX-SR606 were rated for 4-ohm loads (which it isn't) or
had such a switch setting (which it doesn't), this would still be the
dumbest thing I ever heard.
If the receiver did have a 4-ohm setting and you used it with 8 ohm
speakers, all you would do is reduce the dynamic range of the
amplifiers by limiting the available current. This would make no
difference (either in heat or sound) at normal listening levels, but
it would compromise the sound quality needlessly when the system was
operating near its limits.
Actually, if a receiver has a 8/4 - ohm switch, when in the
4 - ohm position the rail voltage is dropped on the output
stage devices. The does actually result in less heat at no
load (for a constant bias current) and also for low level
listening.
David
> If the receiver did have a 4-ohm setting and you used it
> with 8 ohm speakers, all you would do is reduce the
> dynamic range of the amplifiers by limiting the available
> current.
That's not what the switch does. What it does is reduce the supply rails to
the output stage.
That naturally reduces heat dissipation under both quiescent and active
operation. IOW it will run a little cooler, whether you are playing music or
not.
> This would make no difference (either in heat or
> sound) at normal listening levels, but it would
> compromise the sound quality needlessly when the system
> was operating near its limits.
Yes, this will reduce the maximum voltage that is available, but most modern
home audio power amplifiers are rarely if ever used anywhere their maximum
ratings.
"Arny Krueger" <ar...@hotpop.com> wrote in message
news:nYSdnaGSycIVPWHV...@comcast.com...