New Tube Amp Use EQ or not


I've been using my new amp for about 2 weeks now and have been very happy with the more "rounded" edges and richness in the mids. My main reason for the switch away from SS is my age related sensitivity to certain frequencies, especially if they have a percussive source. I used to think these offending frequencies were in the high frequency range and experimented with several types of tweeters to no avail. After using test equipment I discovered that the problem actually occurred in the 1000 to 1400 KHz range. I bought a decent EQ (Behringer DEQ2496) in an attempt to tame these and, to some extent, it worked.

Switching to the Cary Audio Design 808R (Rocket 88R) amp made a difference that even I could tell. The sound was richer with no loss of detail that I could discern. I just received a new Ralph Towner CD, though, with Xylophone accompaniment that brought back the discomfort at approx 1000Hz. I'm not looking for perfection but the idea of putting the Equalizer back in service to tame this frequency range crosses my mind. I know I can selectively attenuate these frequencies but my concern is that by doing so to selectively diminish these frequencies that are so uncomfortable as a percussive source, will result in some loss of the richness or fullness that those frequencies contribute otherwise. My gut says it would have to but I'd like to hear from the experts.

FYI, I switched from Peachtree Audio Nova Pre, Peachtree Audio 220, Martin Logan Ethos TO Peachtree Nova pre, Cary Rocket 88R amp, Reference 3A MMC Serie Speakers. The EQ has not been in the system for months.
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OK, I installed the EL34's, biased them to 165 mA and started listening. With only about 15 hrs on them, though, I didn't expect much and, sure enough, they sounded pretty bad and the only way to get them to sound nearly as good as the 88's was to switch from triode mode to UL. A friend, though, traded me a set of 34's that he had in his PrimaLuna for mine and, what a difference. This amp, then, is definitely a keeper and the EL34 tubes will remain at least until I try the 6L6's that also came with the amp. 

Lowrider, in regard to your suggestion that I look into the front end tubes,  I spoke with Mark at Cary who suggested that I try 12AX7 in place of the BZ7's.  I haven't tried it yet but I do have some spare ones that I keep for the DACs that I have so will try it later. I don't, though, like making multiple changes at the same time for obvious reasons. 

Atmasphere, re your last comment, you ALWAYS give me plenty to think about especially as regards the importance of feedback and harmonics and how they influence sound quality. I'm using the Cary Rocket 88R which I thought did not incorporate loop feedback. I don't know where I got that info or if it's even true.  

Anyway the progress I'm making is very satisfying and even fun. 
Behringer also sold a parametric Equalizer that you may benefit from in your situation. It has adjustable notch filters that could be adjusted to the offending frequency. Also the Parametrics are not locked into a set number of frequencies that are adjustable, it is variable from top to bottom broken up into bands. The frequency and bandwidth of the frequency are adjustable as well as the gain or attenuation for the frequency. I have a pair of these and found them more useful than the DEQ2496.