Cary SLP-05 - rectifier tube questions

Hey All,

Several days ago, my 05 began to blow all the fuses (HiFi Tuning tweak ones too.. damn it!) and wouldn't power up. I found out that it was the rectifier tube that was blown and I swapped it out for a local 5AR4 tube that I found at my neighborhood Guitar Center.

Swapped it in and VOILA! Music again!

ONLY... this time, it sounded different - imaging wasn't as clear, there was a "dirty background" to it all, the voices didn't respond the way it used to from my memory when I turned the volume up, the stage was set further back behind speaker plane...

I am using Martin Logan Summits which are ruthlessly revealing of any upstream component.

So I began suspecting that there was a change and it might be because of the crappy rectifier tube that I just swapped in. A search on audiogon and many other forums seemed to validate my opinion and that rectifier tubes DO change the sound! I didn't know that! So I had NO bias going into this...

So now, I'm in search of the perfect 5AR4 rectifier tube.... a lot recommend the Mullards, but are there any other recommendation for tubes that are not so overly pricey?

The Cary 05 uses only 1 5AR4, so in that sense, I'm lucky I won't have to buy a pair...

Help me out, thanks!