[stan]

I know the Pioneer model SX-3800 uses a non-switching amplifier, but would
anyone know if the SX-3700 uses a Class A, B or A/B amplifier section? It
seems to run a bit warm for a receiver with its output power rating, leading
me to think it might be Class A, but there may be other reasons for the heat
being generated that are unrelated to the power amp section. Thanks in
advance for any insight.

[DaveW[_4_]]

No common consumer receiver uses a Class A ampifier section. Class A means
that the output transistors run at FULL OUTPUT POWER CONTINUOUSLY.
Obviously this means that the chasis must use MASSIVE Heat Sinks to
dissipate all that heat.
--
--DaveW

"stan" wrote in message
...
I know the Pioneer model SX-3800 uses a non-switching amplifier, but would
anyone know if the SX-3700 uses a Class A, B or A/B amplifier section? It
seems to run a bit warm for a receiver with its output power rating,
leading me to think it might be Class A, but there may be other reasons for
the heat being generated that are unrelated to the power amp section.
Thanks in advance for any insight.

[Mark D. Zacharias[_2_]]

"stan" wrote in message
...
I know the Pioneer model SX-3800 uses a non-switching amplifier, but would
anyone know if the SX-3700 uses a Class A, B or A/B amplifier section? It
seems to run a bit warm for a receiver with its output power rating,
leading me to think it might be Class A, but there may be other reasons for
the heat being generated that are unrelated to the power amp section.
Thanks in advance for any insight.


It would be a fairly typical AB design, I'm pretty sure, but the bias may
need readjusting. It's not uncommon to see bias out of spec 100% or more on
older units. Since power dissipation at idle is a product of the voltage
across the devices multiplied by the current through them, a lower bias
setting will result in substantially less heat.
Don't try to adjust it yourself unless you are a professional - these models
are flammable enough as it is. There may be two bias adjustments plus an
offset adjustment - I know the SX-3900 of that same series had two bias
adjustments for each channel. You adjusted for X millivolts with one, then Y
millivolts with the other.

Mark Z.