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
Try taking out your Silver i/cs and put in a Generic pair of Wallyworld specials ( plastic stuff ) ..and see if it might be the Silver being the culprit.....If so you may have tog oto another makeup of cable.........
I own this preamp for years and have 2 friends that own this peamp as well. None of is ever experienced what you are describing. Either the preamp is defective or your problem lies elswhere. When you retubed the preamp did you poace the tubes correctly? Also what is the preamp yoy replaced aqnd what is the rest of your system?
Harsh mids and extreme sibilance you are experiencing is most likely a distortion somewhere. You have to find the component in the chain that creates it. 1) make sure the tubes in the CJ are fresh. 2) make sure the CJ pre matches well with your power amp as far as impedance is concerned. Phone CJ and give all the specs to a tech support person to evaluate may be the pre and amp are not an optimal match.
Does it sound too loud when the volume on CJ is relatively low?
Also, try taking the Silver ICs out of the equation, as Thorman suggested.
I don't think rolling tubes or changing cables will do anything major unless the tubes and cables you use now are broken.
If everything was ok until you put in this preamp then, duh, it' the preamp. Check the tubes. In my opinion, EH's arn't the best in CJ's. Try to get hold of some box plate Mullard's. Also, make sure the polarity of the AC cord is correct. Try reversing it. The warmest sound is the correct polarity. If all else fails, send it in to CJ.
oh, and by the way, there is nothing stange about CJ using EH tubes. That's a normal tube of choice for supplied tubes. Either EH or Sovtek in most cases. Some manufactures pack Chinese tubes with their equipment. Don't be expecting CJ to give you a nice set of NOS vintage Mullards. :)
Please keep us posted on how it goes with the sibilance issue.
Hi Guys, Thanks for some of the comments and suggestions thus far. I agree Soundwatts, This preamp should rock. Regarding the tubes, this set is brand new and provided by Conrad Johnson. The set, RT11 was $175.00 plush $17 shipping. That's why I was suprised by them using EH tubes. They placed the tubes, but come to think of it, I will check their placemnt. All the tubes have dual tube damping rings in place as well. I have removed the silver IC's and tried other cables, but so far no change. My IC's are from 18" to 3 feet depending on their purpose. Rebalancing the system has helped some, but the mids are still harsh. I will try the plug thing tomorrow and talk with CJ regarding my amps impedance match. Regarding your comment Audiophile 1, you are correct I do not have to turn the CJ up very loud to get a good volume, but it is not much different than my previous amp. typically 10 to 10:30 position on the dial now and was about 10:30 to 11 max on the prior. I will have to dig to find my amps input impedance. The manufacture did not specify it. Thanks, Dale.
Also, if I am not mistaking, some CJ preamps invert phase. Double-check if the PV11 does and take appropriate action to invert phase. Do the phase correction at the amplifier end by switching speaker cables "-" and "+" and see if this helps....only if the PV11 inverts and your amp does not.
When I've played with CJ, they always used US made tubes (GE). With 5751's for the final gain tubes instead of 12ax7's. What it in yours? A 5751 is capable of much more current. This may make a difference when you are pushing it hard??? Personally, I like NOS european tubes even though CJ always pushes much drier, hardier tubes. 1 Telefunken or Mullard for the CD tube and a pair of GE 5751's for the gain tubes will make a difference (yes, in my opinion). Keep in mind that I've never had a PV-11, only a 5, 10 & 12.
The PV11 uses 12au7's for the line stage and 1 5751 1 12au7 and 2 12ax7 for the phono stage.
What components are in the rest of your setup and why an equalizer?
audphile1 is correct this preamp inverts phase and you need to swap your speaker connections pos to negative. I dont think you would get a harsh mid but a suckout in the bass.
Hello Gentlemen, Thanks again for your responses. In answer to some more questions, I have replaced the silver IC's with generic IC's and no difference was noted. Pertaining to phase, I have phase inverted the speakers as recomended by CJ and stated in the manual. The bass is definately not suffering so I think the phase is correct. I did speak with CJ today and they informed me that they do indeed use EH tubes that have been hand selected and tested to their standards. One tube is infact a 5751. They felt that the tubes may need to burn in for awhile, but that what I am experincing is not the usual for this product. They also recomended removing the EQ for a test period. I will do so tonight, as well as try flipping the electrical plugs. As for my system I am using several types of amps (tube based) and some solid state. The present configuration consists of a professional series BSR 4000 EQ and a Carver M1.5t magnetic field amp. I have not tried my Audio Symphony tube amps as of yet. More later. Dale.
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.
Hi, I have a CJ PV12. I swapped out the Silver ICs with Zu Oxys which tamed some of the forwardness (lat a cost of a bit of detail) and I also use older tubes including Holland manufactured (my favorite sound), Mullard/Brimar, RCA clear tops, and Tungsrum. 1950/60s Sylvanias are nice also, they may fatten the base but does not provide that rich mid range that many look for in a tube preamp like the CJ. As was said, Mullard (& the Brimar 13D) is probably your best bet to help tame the harshness and sweeten up the mids. Forget 12AU7 telefunkens, cold sound. Hope this helps. Dave
Thanks aagian for the further input. Sorry I have not been able to give too much in further results... been sick with an abcessed tooth..Ouch! Anyway, I have rebalanced my system with the B&K Mic and RTA and achieved some better results as of late last night. Tried to remove the EQ, but did not like the room effects. Bass was overwhelming with slight high absorbtion in the 16 to 20K range. Sill only about 2 db of loss here. In addition, I may have some further info and perhaps I am now experiencing some poor quality tubes in another component shinging through. As I said, I use a modified Jolida JA100 CD player which is tube based. Part of the mods called for changing the original Chinese tube set for New Svetlanna 12AX7's. Talking with Dr. Tube, says he believes the Svetlanna tube to be very poor quality, so much so that he has discontinued selling them or supporting them. He says, only about a 30% yield was the norm and that 30% was mediocre at best. This is confusing to me as several High end places are doing the CD mod with the Svetlanna. Something I researched before i had it done..Oh well, Cest la vie. This may be part of the problem, since the CJ is a very revealing preamp. Perhaps it is emphisizing what these tubes are doing. They are still very new with perhaps only 10 to 15 hours use on them. Still I have some problems with other input devices producing the same type of effect, i.e. tunner, or TV audio. Though these are not that important to me, as I use the CD or Phono most. I guess I have much to do with trying different tubes and combinations. I will post with further results. Good listening. Dale.
Sorry to be slow here. I'd put WXT's against Mullards any day. I have owned both. Don't care for most Amperex (except the ones made by mullard...), Telefunkens are always the best all around tube, Golden Dragons are the premium Chinese and are what I'm currently using along with Telefunkens and NOS Groove Tubes.
Sorry I haven't posted any further info gentlemen, I have been out of town on a family emergency. Regarding the original problem... I have rebalanced the room acoustics using the spectrum analyzer and put a lot more hours on the tubes. Probably 75 hours + now. It does seem to be somewhat better, but the original problem still exists. I went to cheaper interconects and OFHC 10 ga. copper speaker cable as well. Seems the silver is a little too bright. Still I would love to find a real solution. So, I intend to do some tube rolling with older tubes and experimentation here and there. Finally, I might just return the preamp to CJ and have it gone over throughly, so at least I can have peace of mind. Interesting on the WXT tubes. I also have two sets of mono block tube amps that I am rebuilding and I intend to use some of the new issue matched quads of Gold Lion KT88's and 6550's. Hope these live up to expectations. Thanks, Dale.
If you don't mine me expressing my personal opinion: if you don't like how it sounds now, no amount of tweaking and tube rolling will make you to like it. Any component's basic sonic signature represents approx. 90% of it's sound and the remain. 10% can potentially be changed, and not necesssarily improved by tweaking. Do not waste your time and money, move onto something else, you'd like from the beginning. The choices are abundant. Just a thought.
Dale, I suggest you either borrow a different preamp same in class as the CJ or take the CJ to check in another system to see if the sibilance problem is there as well.
I agree with Maril555 about tube rolling. Applies to cable changes as well. The sonic foundation of the unit will always prevail does not matter the tubes or cables. Especially with a sibilance problem. I doubt you will get rid of it completely by rolling tubes or changing cables. Also, I think sending the pre back to CJ may be a waste. If it is working, not making any strange noises but just does not sound right to you, sending it back to the factory won't do a thing. Most likely it is fine.
just I said before, I believe the only way to check the pre is to either insert it into another system or borrow another hi-rez preamp to try in your system.
Also, is the sibilance problem you get on particular recordings or is it on every recording?
Thanks for your comments guys. I tend to agree with you. Unfortunately, there is no one close by whom has a stereo with higher quality components to test the CJ in, so that is not an option. I also tend to agree regarding the checkout at CJ. They look for the obvious, such as complete malfunction or noise. As far as tube rolling, I would simply try other sets of tubes I already have here. I certainly wouldn't purchase any more. Finally, I just don't have the money to turn over the CJ and try something else. It took long enough just to save up and buy this one, let alone the WAF. I guess I will have to live with it for awhile, though I must admit it is a big disappointment.
I have had a PV 11 for 15 years and love it. I had to do some work on my PV 11 about 10 years ago and sent it to CJ. Call them and ask them, they are great to work with and can I think can still service the PV-11 or just advise you. could be tubes. ps bought a used ART-2 last year and in heaven.
Thanks, Jim. I appreciate that. A litttle update... the preamp is starting to sound much better since the tubes have burned in. The exagerated sibilance is softening and not nearly as extreme. I would say I have about 150 hours on the EH tube set now. Otherwise, little else has made much of a difference. Talked with CJ twice and they had little to offer except to return the preamp and check it out. Dale.
I figured this would be a good thread to hijack for a moment ;-) I have had a used PV-11 for a little over 2 years, and recently ordered new tubes from C-J. Although I do like the overall sound of the PV-11, I do find it a little on the bright side with all but the best source material. I guess this is just what you get with a very revealing, unforgiving preamp. However, two issues remain troubling:
1. Channel imbalance. As the PV-11 warms up, the center images seem to drift right. The balance control usually helps, but I really wish I didn't have to use it. I have tried new tubes, new ICs (from both CDP to PV11 and PV11 to amplifier), swapping L/R interconnects between CDP and PV11, a different CDP, all made no difference. I have yet to switch amplifier channels or speakers, which I will do when I have the time, but I am very frustrated. I fear it might be acoustical, yet when first powered up, the channel balance seems spot on.
2. Hiss (tube rush?). Until I added a PS Audio Quintet to my rig, I never thought of the PV11 as excessively noisy. Dead-quiet it never was, but because of a hum/buzz issue with my amplifier, the added noise I could hear when the PV11 came on was minimal. With Quintet, the amplifer noise has been vastly reduced (I now must place my ear within 2" of the speaker to hear it). When the PV11 comes on, the jump in background noise, even at lower volume settings, is quite large, and easily audible from the listening chair. Is this a normal amount of noise from a properly functioning PV11?
Any ideas on these issues would be greatly appreciated.
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.
If you are still having problems with your CJ PV-11 I highly recommend you contact Bob & Gary Backert of RHB Sound Dezign. They will make your CJ PV-11 sing...
I'm very pleased with the mods & upgrades they did on my CJ PV-12. Here's their contact info: www.rhbsounddezign.com 215-355-8529
Sorry I have not been on lately. I have been caught up in the whirl-wind we call life. I need to get back to the tunes.
Regarding some of the posts I missed. I have to say that my CJ PV-11 is now doing very well and apparently most of my original issue was simply tube break-in. It is now quite listenable and very, very quiet.
I also added a PS Audio Power Plant to my system, (I tried other products but none like the PS) and it made such an unbelievable difference it was beyond words. I like to call these my "Ah Ha!" light switch moments. Like someone flipped a switch and then there was magic. I really hate it when I have to strain and hem and haw...did that really make a difference? You all know what I mean.
Thank you JMO for the upgrade info too. I also found Bill Thallman of Music Technologies. 703-764-7005. They are an Apogee Ribbon dealer and specialize in upgrades for CJ and some other high end stuff.
Thanks again for all the interest and responses. Dale PS our new web site went on line last week. www.hhr-exoticspeakers.com
Glad to hear things are looking better. I retubed my PV11 (tubes from C-J). Still having channel balance issues, and I am beginning to suspect room acoustics or even my power amp.
However, even though I installed the new tubes with C-J's supplied dampers, I have been hearing a lot of microphonics (I think). Sounds like a very high frequency ringing or feedback-type noise. It comes and goes, and can be pretty annoying. Plus, the pre is pretty noisy. It got a tad quieter when I plugged it into my PS Audio Quintet, but I wonder if that's just a price to pay for a tubed pre, or perhaps my PV11 needs servicing?
Any thoughts on this would be very much appreciated.
You have nothing to lose contacting Bob & Gary Backart, my PV12 sounds much better then it did when it was brand spanking new... Current age 16 years of old. :O)
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