After multi decades of using separates in my electronic repair work shop for all day playing back ground music, with first a early version of Crown IC-150 preamp driving a Crown D-150 power amp, that I picked up inexpensively a few yrs. before, when offered to me.
I reworked both enough to meet factory specs. before installing in a lightweight SKB brand 2 &1/2 ft. in height rack.
This provided reasonably decent SQ for that environment driving the pair of RS Minimus 7 speakers after being high pass fed from a Cerwin Vega 12" dual VC floor firing passive subwoofer`s crossover.
A few yrs. later I was inexpensively offered the later upgraded Crown IC-150A preamp, so reworked that unit before swapping out the older version, and that seem to upgrade the music`s SQ out in the shop.
About 20 yrs. later my self employed body shop friend down the street from me was given a Mc. MA-6100 integrated amp by one of his long time customers along with some speakers, and had no use for it (the MA-6100) as he already had some receiver driving his shop`s speakers.
I offered to purchase the 6100 from him, but he said he would rather give it to me instead, out of consideration for all the computer work that I had helped him with since I was introduced to him at no charge.
Anyway the MA-6100 was cosmetically perfect, but had some leaking outputs in one of it`s channels, so I replaced them and ran that integrated for 24 hrs. on the bench, and then fully checked it out on my bench.
It passed all the published specs, which greatly pleased me.
The shop`s separates (which in the meantime the Crown IC-150A preamp had been upgraded with a Mc. C-32 that I acquired at an attractive price a handful of yrs. prior) were removed and the MA-6100 installed in it`s place, with nothing else changed.
For whatever reason, that same output power as the 24/7/365 powered up Crown D-150, and well regarded Mc. C-32 preamp combination didn`t sound as full bodied good as the MA-6100, by a significant margin !
Ever since I installed the MA-6100, it has remained powered up 24/7/365 and has been playing very good sounding hard wire fed WAV. ripped music all day, as it currently doing.
I would have not really thought this would be the case changing from separates of very good quality to a fairly old non restored, and similar era integrated amp, and I was pleasantly surprised.