Why does my system now have shrill top end.

@uberwaltz  pardon me for saying so but now you’re the one doing it. Walk a mile in my shoes. 👣

Regarding the exchange Jim (Jea48) and I had a few posts back about the "Ortofon Black" cartridge listed in the OP, and the possibility of trying the phono stage connected directly to the power amp:

In addition to the high output 2M Black moving magnet cartridge, which as I indicated would be unsuitable for use with the non-adjustable loading of the Linto phono stage, Ortofon has two low output moving coil models having the word "Black" in their name. Those are the Cadenza Black and the Quintet Black (or Quintet Black S). Both have rated outputs under the standard test conditions of about 0.3 mv.

I assume the OP’s cartridge is one of those two models, and if so I assume he is using the high gain (64 db) setting of the phono stage. 64 db would boost 0.3 mv to about 0.48 volts, which is about 2/3 of the voltage that would drive the amp to full power. So while performing an experiment with the preamp removed from the signal path is probably within reason, especially if a recording known to have low volume is used, and if care is taken to avoid a large transient when the stylus makes contact with the record, personally I would still feel somewhat uncomfortable about doing that.

Reducing the gain of this phono stage to its low gain (54 db) setting, btw, apparently involves cutting a wire internally, so that wouldn’t seem to be a good way of performing the experiment.

Regards,
-- Al

SPEAKERS ! After trying another amp and/or cables I'd try another set of speakers that a friend can bring over. The tweets may've gotten damaged somehow - if that's the case there's nothing you can do to get sweet music back. Find out.