The most important thing ignored with all Quatros, Fives, etc is when changing to the new 10 year Lithium Batteries or changing to a different amp like the OP did is to confidently confirm the amps input impedance spec for proper dip switch settings.
The high passes, when returned from Tech, could have had their vital corresponding dip switches moved.
Best way fix is Voltmeter probes attached to main power amps speaker binding posts Red to Plus Black to Minus
Set the meter to AC volts if your afraid get someone who can ya
studeren prick ya...
Play track 27 Vandertones CD adjust Pre amps volume control looking at Voltmeter slowly adjust preamp to 1 V AC close as possible.
Then play Track 30 if it’s .707 or close you are good, if not change settings and start above again track 27 confirm 1 V AC etc
If track 30 reads .79 V ac or above or .62 V ac below you are off the 100 HZ x over losing performance. Never assume the owners manual is correct most listed are off the mark with how these specs relate to 1000 and 100 hz
Best JohnnyR
The high passes, when returned from Tech, could have had their vital corresponding dip switches moved.
Best way fix is Voltmeter probes attached to main power amps speaker binding posts Red to Plus Black to Minus
Set the meter to AC volts if your afraid get someone who can ya
studeren prick ya...
Play track 27 Vandertones CD adjust Pre amps volume control looking at Voltmeter slowly adjust preamp to 1 V AC close as possible.
Then play Track 30 if it’s .707 or close you are good, if not change settings and start above again track 27 confirm 1 V AC etc
If track 30 reads .79 V ac or above or .62 V ac below you are off the 100 HZ x over losing performance. Never assume the owners manual is correct most listed are off the mark with how these specs relate to 1000 and 100 hz
Best JohnnyR