Conrad Johnson PV11...Extreme sibilance, harsh sou


Hello everyone,
I have an issue and was wondering if I might prevail upon the community to help me out. I am a seasoned audiophile, I would like to think, but I am sure this old dog can still learn a few tricks.
I have recently acquired a CJ PV11 preamp that is basically in mint condition and came with a brand new tube set from CJ. The tubes were installed around 7/10 and I received this amp on 7/28/07. (strange though, they used Electro-Harmonics tubes)
Anyway, After I installed the preamp, I now have very serious issues with harsh mid range and extreme Sibilance issues that I never had before.
My system is very revealing. I use NEW Walsh drivers based on the Ohm Acoustics design of the model "F" and "A". In fact I have both. These units I make and build myself.
I have not even attempted to use the phono section of this preamp yet. Just the line stage.
While I have never encountered this problem before, I have it now, so much so that I can barely stand to listen to my system. Nothing in my system has changed except the preamp. I intend to rebalance the room and speakers using my calibrated mic and high quality RTA. And even though I am a purist at heart, I do use a high quality graphic equalizer just to cope with some room acoustic issues, but it is set to a very low and flat curve and mainly compensates for low end reflections from my omnidirectional speakers.
I have read about the usual tube rolling, try different interconnects and ac conditioning, but most of that seems very subjective, even to those that suggested it.
I do use dedicated 30 amp lines and separate grounds for my system and even have an ac conditioner, but found the conditioner caused hum issues, strange as that might seem. So I took it out and run direct to the line.
My speaker cables unfortunately are long runs of 25 feet by necessity, but are high quality OFHC braided cables with a 10 ga. size. I also use silver interconnects that I have designed.
Does anyone have any ideas? I have put into CJ for help, but no response yet. (Holiday) and have also been in contact with Dr. Tube.
I would appreciate any help.
Thanks in advance.
Dale
dale_harder

Showing 2 responses by phd

I have owned the CJ PV11 & two of the things that struck me the most was the lack of bass but on the other hand it was a very revealing preamp. I think Audiophile1's comment on the lack of bass can make higher frequencies more prominent should apply here. On the other side of the coin, I don't remember the PV11 sounding harsh. You may want to remove the equalizer, if you are trying to increase the bass response try hooking up a sub to the preamp which will have the least effect on the preamp's sound.
If any of you feel adventurous I would look into the newer Eastern Electric Minimax preamp. I just recently picked one up and have walked away very impressed for a pre in this price range. Can on occasions be purchased used for around $550.00 or higher.

Soundstaging, transparency & depth are excellent providing your other components are up to the task. The Minimax is an all tube design with tube rectification, no circuit boards or transistors here, all point to point wiring and build quality is ridiculously good. Compact but heavy for a preamp in this class.

Tube types & interconnects make a "Dramatic" difference for tayloring the sound, creating an endless realm of possibilities. It delivers a nice full sound from top to bottom unlike some other compact designs and as one reviewer said the Minimax is mini in size but is max in performance. Many rave reviews from their website (Morningstar Audio). If I were to sell, it would only be for the necessity of a remote control.