2. tech-talk
  3. 156996-104029

Weird problem noticed last several playings...

The system: CJ PV-10AR preamp, Emotiva XPA-2 Gen3 amplifier, Yamaha BD-1060 Disc Player, Bluesound Node 2i streamer, Maggie 17i speakers,  2 Emotiva BasX10 subs. 

Fairly suddenly , over last several listenings - especially with the female background vocals on "California Dreaming" there a lack of detail, a muffled sound, and it sounds like much of the detail, punch and soundstage has disappeared on all sources. 

I am hoping (even though they are only a couple years old) it's one of the CJ tubes but does anyone have any diagnostic ideas (aside from "your system sucks, replace this or that. This is particularly galling as I have been a budget audiophile for 40yrs and the system, when right, sounds amazing and just what I want.) 
jkf011
erik_squires
16,245 posts
 
If this was a tube or speaker issue it is rare they all fail at the same time.

Swapping speakers, or tubes should help diagnose, but if the problem is systemic, it's possible the regulator on the PV 10 has failed, or one of the cascaded diodes has. 
I like the PV 10, but the thing the later generations did well was to split up the voltage regulator into multiple sections so the chances of one regulator failing was rarer, not to mention offering better power supply isolation.
jkf011 OP
292 posts
 
CJ says it's definitely the tubes. They say I haven't replaced then since '14, but it seems sooner than that. So regardless, they are sending 2 new tubes I bought. So we'll see if that fixes it. If not I am going to send it to them for full upgrade. 
slaw's avatar
slaw
21,820 posts
 
Why didn't you contact CJ first?
jkf011 OP
292 posts
 
Because I wanted to see if people thought it was the preamp and what they thought if?t might be, duh. Why ask? 
jkf011 OP
292 posts
 
A follow-up that isn't good: as above, I called Conrad Johnson and they said the tubes were well past their expiration date. So I had to wait a  week for tubes to arrive. I got them in today and, while it sounded better, something still wasn't right. I finally thought of turning the balance knob and, sure enough, when I put it all the way left there was very little output from the Maggie on that side and what output there was was very muffled and constrained. So I switched the preamp outputs and the problem stayed on the left side - which to me tells me it's the speaker, right? Could an interconnect or speaker wire cause that? I should think that would be exceedingly unlikely, no? 
More to discover