Does the heat an amp puts out have any effect on the sound quality ?

Does how hot an amp runs have any effect on sound quality ?

A definitive answer can’t be provided without knowing if how hot the amp is running is normal or abnormal for the specific design. If it is running abnormally hot for some reason, in other words hotter than it was designed to run, then yes, its sound quality may be affected. By both whatever is causing the abnormal temperature and by the abnormal temperature itself.

The others have made very commendable attempts to answer your question as thoroughly as possible, especially in the post just above, but we might be able to provide answers that are more focused if you would tell us what the model number of the amp is.

Regards,
-- Al

Don, the relevant specs on your equipment are:

Speaker impedance:  6 ohms nominal, described as "easy to drive."

Amplifier:

Rated Continuous Average Output Power (both channels operating simultaneously, 20 - 20,000 Hz):
150 W/ch 1-ohm load (1-ohm operation possible with music signals only)
120 W/ch 2-ohm load
60 W/ch 4-ohm load
30 W/ch 8-ohm load

Power Consumption:
160 watts idle
260 watts in accordance with IEC 60065
200 watts for rated output into 8 ohms

Maximum Dimensions:

Width 465 mm (18.31”)
Height 191 mm (7.52”)
Depth 428 mm (16.85”)

Weight:

24.7 kg (54.5 lbs) net

Consistent with what you have found, I would not expect an amp having size and weight as substantial as the E-600 and dissipating (consuming) roughly 200 watts to get particularly hot.  The same dissipation in a much smaller package would be a different story, though.

Regards,
-- Al
  

Bombaywalla, here are internal photos of the Yamaha CA-2010 and the Accuphase E-600:

CA-2010 internal view

E-600 internal view: On page 3 here.

There may be somewhat more heatsinking on the E-600, which perhaps contributes to the weight differential, but it’s hard to tell for sure (in part because the height of its heatsinks isn’t apparent in the photo).

Perhaps more significantly, though, I see that the CA-2010 is specified here as being capable of providing:

2x 120W (Class B, 8 Ohm, 20Hz...20Khz, 0,03% THD)
2x 130W (Class B, 8 Ohm, 1Khz, 0,03% THD)
2x 140W (Class B, 4 Ohm, 20Hz...20Khz, 0,03% THD)
2x 180W (Class B, 4 Ohm, 1Khz, 0,03% THD)
2x 30W (Class A, 8 Ohm, 20Hz...20Khz, 0,03% THD)

And has having power consumption as follows:

600W / 700VA (USA / Canada)
900W (EU)

I see three relevant implications in those numbers:

1)Although the test conditions upon which the CA-2010 power consumption numbers are based are not explicitly specified, all of those numbers are far greater than the numbers for the E-600.

2)The relatively small increase in the power capability of the CA-2010 into 4 ohms vs. 8 ohms would seem to indicate that it is not designed in an especially robust manner, which would seem consistent with a greater rise in internal temperatures compared to a more conservative design.

3)The fact that the CA-2010 is specified to operate in class B at much higher power levels than in class A would seem to suggest that its internal B+ and B- voltages are likely to be much higher than in the E-600. Which in turn would seem consistent with its much higher specified power consumption.

Best regards,
-- Al