Output level inexplicably reduced- help

I have an Volume output level problem with my system. My electronics are Audio Research:
Reference 150 amp
Reference 3 preamp
Reference 2 phono preamp

Lyra Atlas cartridge

This system was running great for three years. Nothing has changed. Now, my highest output level is inexplicably reduced. I cannot get a volume level greater that about 90db. I just re-tubed my amplifier and expected that to solve my output level problem, but it didn't happen.

I have always run the pre-phono on low gain, load 50k. The sound was warm, detailed, great soundstage - everything was great.

Now, the only way I can higher output volume is to switch to high gain on the pre phono, keeping the load at 50, or 100k, it doesn't seem to matter much. I can get the big volume, but, the sound loses its smoothness and warmth. It has an edge if I switch to high gain.

Can anyone provide me advice? I would surely appreciate it.


PS I'm not losing my hearing.
For starters, do you have a CDP, DVD, or blu-ray player you could hook up to the Reference 3 preamp? If so I would start there. If you have plenty of volume output playing a CD then that will rule out everything downstream of the line level inputs of the preamp.

It is more likely either the Ref 3 or Ref Phono 2. Do you have another source you can try? Even a cheap DVD player so that you can see if the Ref 3 is working properly. It sounds like it is a problem with one of the tubes. Are all the tubes in both preamps lit? How old are the tubes in the Ref 3 and phono 2, especially the 6550 in the power supply? It could be a very week power supply tube in one of them.
It may be the famous ARC "blown resister". I traded in my ARC Classic 60 (for a VT-100) and the proprietor informed me that I had a "blown resister" on one of the tubes
(I had no idea there was a problem).

Now when there are 3 good tubes, the volume drop may not stand out (on a given channel). But in a power supply role, it may make a big difference.

Also, have you switched IC's lately? Going from RCA to XLR?
If so, there will be a drop in volume (at your regular volume setting).
Make sure you set whatever input your phono pre is on to balanced. The setting may have been lost because your preamp was unplugged for so long.
check tubes on both preamps especially ref3.
Does this problem show up on all functions or only phono?
Oops! Got that backwards... XLR has a higher output than RCA.
Sorry 'bout that...