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Conrad Johnson PV-7 phono stage any good?

I just acquired a very nice CJ PV-7 preamp. It sounds really nice, but I am a little confused about the phono stage. I am using a MM cartridge with an output of 5.2 mV. I need to turn the volume up to about 1-2 o'clock to achieve a normal listening level, which isn't earth shaking by any means. In comparison, my CD player commands only about 10-11 o'clock on the volume knob to reach the same listening level. There is no noise or distortion of any sort when listening to the phono, it just seems a little odd that I need to turn up the volume that much. Will this cause any damage to the preamp? Is this normal for a tube phono stage? Has anyone experienced a similar phenomenon? One other oddity is that the volume knob and listening level were at about the same position (1-2 o'clock) with a 3.0mV and a 5.2mV output cartridge. I thought the higher output cartridge would play a bit louder. Does the preamp have some circuit that makes the phono output the same no matter what the cartridge output is? Will different tubes make a difference. I'm not sure what is in there now, they have no brand, they just say made in west Germany.
Thanks for any help,
The skipper
skipper320
mechans
3,048 posts
 
As the others have said and explained, the difference in volume is normal.
The tubes are either Telefunken (highly probable) or much less likely Valvo or Siemens. The Telefunken are very long lasting and should serve you well. A simple way to find out is to remove one and look at the base between the pins. If a diamond extruded mark is present, its a Telefunken. (at least for now until someone figures out how to counterfeit them.)
skipper320 OP
89 posts
 
I was told by the previous owner that the tubes said made in west Germany when I asked which tubes the preamp had. Turns out, they actually say made in Hungary. I have no idea what brand these might be. What brand tubes do you recommend without breaking the bank?
tls49's avatar
tls49
1,351 posts
 
What brand tubes do you recommend without breaking the bank?
Since there are so many choices for the 12AX7's and 12AT7's used in this preamp, it might be helpful to say how you would like to change the sound you have currently.

Also, I suggest changing the line stage tubes first, unless you are completely happy with the sound of the CD player, as these change sound on all inputs. Then change the tubes in the phono stage.

Here is a tube layout diagram. V1, V2, V3 are in the phono stage, and V4, V5 are in the line stage.
maxima95
294 posts
 
I was advised by a gentleman named Bill Thalmann that V4
was the more important of the 2. I have changed V5 also (in addition to V4) and noticed a difference.

My PV-7 linestage is very noisy for some reason (not the tubes). I am keeping it for it's phono stage. One day I used it that way and was surprised at how good it sounded.
schubert
7,386 posts
 
Skipper320, Tungsram were only tubes I ever heard of from Hungary.
They have a good reputation, I've owned a least a dozen and they were all fine.
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