Bass leaves after amp warms up?

I admire all you kind people you have tried to help a brother out. Also, who doesn't love a good mystery.

Fishing, it would be great to test your system with the MF
M6PRX Power Amplifier. Once again, they give no power rating into 4 ohms; but state 260 wpc/8 ohms and claim it provides high current (around 140 amps), with a peak voltage output of 130 volts. This will drive those PSBs.

I keep thinking about the impedance curve of these speakers, and I think this has played a major factor in your problem. (or inconsistent line voltage).

Also, some advice...you should leave a SS amp powered-up 24/7. Those who don't always let the amp warm up one hour before any critical listening.

Good Luck.

My apology
Marantz CD Professional CD Recorder CD300

I absolutely leave the amp powered up much as possible including overnight..

My comments about the CDR420 also apply to the CD300. Looks like it has a front panel switch that selects between ALC, Manual, and Limiter. It should be set to manual, and the recording level set such that its volume meter never gets near the 0 db full scale reference point during any of the recordings. On the other hand, if you set the recording level too low, then noise levels will increase, relative to signal levels, which is why I suggested allowing a margin of perhaps 6 db or so, relative to the 0 db reference point.

Regards,
-- Al

Yes I see those parameters
I will record them again