Hartke HA5500 sounds horrible

[Noot]

Hello, I'm hoping to get some advice beyond my comprehension.
They said they took the preamp of the worldwide successful HA3500 and replaced the 300W power amp with a 500W power amp. Awesome! Having played the HA3500 before, I was sold. So I buy the HA5500 and what do you know? The preamp sounds horrible. The tube channel sounds very muddy and indistinguishable, while the solid-state channel sounds thin and bitter. I'm struggling to find a barely acceptable sound with the EQ and Contour, but it still sounds terrible. I plug the bass in my ancient Peavey Mark III and it sounds ten times better with all settings flat. What's the story? Did they "optimize" (as in make it cheaper) the preamp on the HA5500? I've read it has to do with the valve itself. A friend told me the 12AX7 is a cheap ripoff of the ECC83, and that a good, low-noise ECC83 costs from 100$ up. Is this true? Do I really need to start modding the amp to make it sound?
FTR I'm using a MIA Fender P, and I've played many other amps before (Ampeg, SWR, Gallien-Krueger, Fender, Peavey, Laney, Line 6, etc.)

 

[kringle77]

Ecc83 and 12ax7 are the same type of tube. Your friend is wrong. As for the sound of your hartke, I don't know.

 

[eltonpereira]

I own a HA5500 and have some experience with Hartke HA series in older versions. For my ear they have the same sound and same EQ resources. In summary, they are very very similar. Regarding your amp, I would recommend send to some review with technician. I hope it helps

 

[twbassman]

I just bought a HA5500C. I was using an LH500, the difference is night and day. My tone with the LH was good, but the HA is so much clearer, punchy, the best amp I have owned. Used to have a GK RB400. I do play through both a Hydrive 115 and 410. Sweet!

Work with your settings, it's in there.

 

[Noot]

Thanks guys, I'll have it looked at.