CJ PV-12 mods & upgrades by Bob & Gary Backert

I recently shipped my 15 year old CJ PV-12 preamp to Bob & Gary Backert of RHB Sound Design to have a few modifications and upgrades installed on the CJ.

My very first conversation I had with Bob was very enlighten to say the least. I informed Bob, I would be using the CJ PV-12 preamp for my phono stage only with the VTL 7.5 preamp. To make a long story short Bob & Gary completed their modifications on the line stage, phono stage, caps, gold/silver wire, power supply & IEC conversion.

Father & son went further to build a custom head amp stage, to increase the gain so I would have the ability to use a Dynavector 0.3mV. The technical construction completed by Gary is flawless and his soldering skills are impeccable. Gary’s workmanship is actually beautiful to look at. This is one heck of a father and son team.

Bob suggested that I listen to the CJ’s line stage before strictly using it as my phone stage only. So agreed to listen and it was magical.

If I could only use one word to describe the performance of my CJ PV-12 with RHB Sound Dezign’s modifications that word would be “Heavenly.”

The bass the highs the lows the midrange the vocals the sound stage the imaging have all vastly improved and it’s so much more transparent, liquid. and dynamic.

For the record I have not listen to the VTL since I setup the CJ, simply because the CJ is blowing it away. I know some of you may find this hard to believe but if I didn’t hear it for myself I would not believe it. The CJ’s dynamic linearity is stellar in all aspects. Well I guess I’ll be boxing up the VTL getting it ready for RHB Sound Dezign modifications and upgrades.

The CJ will be performing constantly for the next week or so to allow the V-Caps, wiring and all modifications to break-in nice & smooth for my musical enjoyment.
Bob & Gary, keep up the great work you are truly the man.
After 72 hours of constant breaking in the CJ PV-12 with the RHB Sound Dezign mods & upgrades it's sounding better & better everyday. My VTL 7.5 preamp isn't getting any playing time he lost his starting position... I have him sitting on the end of the bench with a clipboard taking notes. It's basically like having a overpaid young superstar riding the pine watching the old seasoned pro deliver when the game is on the line.

Don't get me wrong I know when the VTL 7.5 goes to training camp in RHB Sound Dezign's lab Bob & Gary will send him home with a new and improved attitude, better shape, great legs and ready to take over the game again.

The RHB Sound Dezign modifications & upgrades are well worth the investment.
With the setup of my new turntable this past Saturday I've been listening to vinyl all weekend long. I must admit the phono stage on the CJ PV-12 is so sweet with the mods & upgrades by Bob & Gary Backert and it's only going to get better once everything breaks in.

I went back and played some of my old classics such as:

1. John Coltrane & Johnny Hartman
2. Doug Carn, Infant Eyes
3. Miles Davis, Kind of Blue
4. Billy Cobham, Crosswinds
5. Norman Connors, Love From The Sun
6. Teruo Nakamura, Rising Sun
7. Return To Forever, Romantic Worrier
8. Wynton Marsallis, Hot House Flowers
9. Chick Corea, Friends

I had one hell of a weekend just sitting back and listening to very nice music and cleaning vinyl with the VPI Typhoon... Moments like these are priceless. :O)
Thanks, JMO for passing along your experience. I just got off the phone with Bob. Nice guy. Here is where I am on this, help me out.

By the time I pay for an upgraded PV12, I can save money by buying a current model, PV 15L that is listed on AudiogoN. (I, by the way, don't use vinyl). So I asked Bob about the comparison. His reply was that they would upgrade even brand new models because they can offer (I paraphrase here) a better circuitry design and parts. Now, I am a newbie and not very smart when it comes to the technical side of audio, but it sounds like the reasoning is that "my design is better than Conrad Johnson's design - even if it is a brand new model." Now it certainly could be, and I may go through with the mods. But what about your thought process? Why did you choose to mod an old unit rather than going with CJ's new equipment using its proprietary designs? Did you have that much confidence in the mods? Again, I hope I have paraphased my understanding reasonably well.

Related topic: I think I'd like to have my preamp modify to use different power chords. Good or bad idea - any experience? (I use Von Schweikert VR2s, CJ MV60 SE amp and a Rega Saturn Cd player). Thanks for your thoughts.
Hi Lenkevy,

The reason for my upgrades are I was planning to use the CJ PV-12 as my "phono stage only". I have a VTL 7.5 preamp and it doesn't have a phono stage. The VTL is a reference preamp and there was no need to purchase another preamp when I have two.

After Bob & Gary upgraded my CJ, that I paid $2500.00 for 15 years ago it sounds better then my $16,500.00 reference preamp. He's using better components then what the Mfg. use that's way the sound quality is better. Bob, takes what they have and makes it better with his custom designs.

Purchasing the current model will not sound as good as having your CJ PV-12 modified. The money I invested on mods & upgrades is well worth every dollar. Actually I think that some of the older products were built better anyway.

If you don't listen to vinyl just have them modify the line stage and power supply. You don't have to go crazy all at once. I'm just crazy like that. :O) After taking the ball to the goal line I didn't want to come out of the game so we stop I went for the TD.

The IEC upgrade is a must do for the use of different power cords. I highly recommend the Synergistic Research Tesla T2 power cord it's killer in preamps I use T2's with both preamps.

I'll second Jmo's enthusiasm for the work of RHB Sound Dezign. I had Bob and Gary work on my $9000 current production tube amplifier, and I'm very happy with the results. They do some of their own original work, which Bob can explain better than I can, but it's also interesting to see how much of a difference you can make just by inserting top shelf components like V-Caps. You'd be surprised at some of the 'shortcuts' that some manufacturers take. I also had Bob & Gary take out the stock 2 feet of Belden cable on the inputs and replace it with gold plated silver input wire. I mean why bother spending big $$$ on interconnects if you're just going to run it through Belden wire inside the chassis.

Viva la difference,

You hit the nail right on the head some manufactures take short cuts. How much more would it cost them to use the better components right from the start? Pennies on a dollar.

I have a 16 year old Conrad Johnson Motif MS 2001 amp their entry into SS back in the early 90's... They used high-end caps and components, it's very well made piece of equipment. I still use it till this day the amp is bullet proof. I plan on shipping it to Bob & Gary to have power supply, IEC upgraded and gold silver wire installed. If I could get another Motif MS 2001 I would use them as mono blocks. That's how much I like that amp. The good it's going to be much improved when I send it to RHB Sound Dezign.
Appreciate the input very much. I'll probably make the investment sometime soon.
With the addition of the Mullard NOS tubes Bob & Gary Backert's modifications are that much better. "Wow"
Yup, G.& B.Backert......are Bob mods overrated ???
Absolutly not. Worht it ??? Yep. Would I do it again ???
Yes I would. Will I hear the difference ??? You will not only hear it but you will also feel it.
After Bob's modifications, my Consonance Cyber 800 turn into the monster and it is one of my favorite components in my system and I doubt that I will ever put it up for sell. It became the conversation piece and those who heard them agree that it is on par with the best.......whatever that means. I believe that it would be impossible for me to find a better amp for less the 10K......or even more. There is nothing that I can think of that could possibly improve the sound of Cybers except PC and tubes.......like Mullards for exemple.
Hi everyone,
I'm currently waiting to take delivery of vintage conrad johnson Premier V mono blocks to replace a cj Premier 11a. While I'm confident the gain in power will out way any deficiencies of an older cj design, I'm very interested in modification options that will improve speed, detail and performance at the frequency extremes without interfering with conrad johnsons house sound or unique virtues. In other words, I guess I'm looking for the Premier V that conrad johnson might make today. I'm particularly interested in an upgraded power supply and V-Caps, but I've been informed that V-Caps are hideously expensive. Any comments will be appreciated, except the most obvious one: At least wait until you hear the amps before you start talking about modifications idiot.
Good gravy! I really am an idiot - Of course I meant to write "outweigh" instead of "out way". Let this be a lesson to all you kids out there: Stay in school!
My best advise would be to wait .......then listen....and listen some more. Roll tubes, play around with cables to tune CJ to your taste. Only then and only if.......there is area that you feel needs attention and no matter what you do - you can not achive that last refindment and magic , give Bob a call. I should also mention that Bob is very, very knowlodgable when it comes to CJ gear and no need to worry about lost of signature house sound characteristics.......just explain what are you looking for with this mod and let Bob do what he does best.......- puts smaile on his costumers face. If you decide to do it be prepare to spend some extra money for wiring upgrade with his silver/gold plated wire, I did not opt. for that upgrade but I keep hearing from others that it is a worthy move.

Enjoy your amps .......and call Bob for advise and recommendations.



The silver/gold wiring modification/upgrade is well worth it, that was one of the many upgrades I had Bob complete on the CJ PV-12. Phaelon, the V-Caps were another dollar well spent. I'll be sending Bob & Gary my amp for the following modifications..

1. IEC Upgrade
2. Power Supply
3. Gold/Silver Wire
4. (1) Internal 1/2 amp FB HiFi turning fuse I have already replaced the other (5) HiFi tuning fuse.
Father & son have done it again, modifying a very good amp and transforming it into a totally awesome killer amp that will rival the so called best. I recently had the following modifactions/upgrades completed on my 16 year old CJ Motif MS 2001 amp by Bob & Gary Backert.

IEC with silver wire to PCB
Two new Vampire input jacks
Gold/silver wire from input jacks to PCB w/shielding
Dual power supply mod’s
Gold HiFi tuning fuse

The Motif MS 2001 was CJ’s intro to Solid State. CJ cut no corners with the components they used to build this amp and put together one hell of an amp. The Backert’s have made it better in every way possible. Upon completion of the break-in period I will give you a full report.

I can tell you this I have put my Ayre mono blocks on hold...
After 3 weeks of listening on & off due to the fact that I've been hitting the roads on the HOG. I have to admit I'm very pleased with the mods & upgrades completed by Bob & Gary Backert. It was money very well spent. Lastly there's no need for me to purchase new Ayre mono blocks now my amp is cooking with gas. Bob & Gary job well done...
I started with a Tube Audio Design TAD 150 Signature as a starting point because I love the remote volume control function. I have a second one so I have an absolute perfect comparison. Bob and Gary took my TAD and did their latest rhbackert preamp mods and all I can say is compared to a host of $10K major league preamps i have had through my system I have never heard anything like it.
(And a growing number of guys in the Phila Audio Society have had the same experience.) My amps are a pair of Conrad Johnson Premier 8A monoblocs with NOS GE 6550 tubes. After Bob did his mod upgrades to them including his power supply mods, and his dynamic linearity circuit changes to the main system plus V-Caps and gold/silver wiring changes I have never in my 35 years of Audio heard anything to get even remotely close!! FYI, The rhb preamp and amp are driving Magnepan 20Rs. A final comment, I never knew how magnificant the 20Rs were until I heard them with the rhb moded equip.
I own a CJ PV-12 with "Black Gate" caps for the electrolytics; as good as it sounds, I am sure additional mods would make it better.
Thats nice to hear Bbro, Bob and Gary have my CJ PV-14L right now doing their magic on it. Dynamic linearity circuit and the V-caps also, plus they are adding a second pair of output jacks. I can't wait to get it back in my system and hear how it sounds. Everyone I have talked to about RHB has said the same thing you just did
Hey Everyone,

I’m thinking of bringing my CJ PV12 and Premier 11 to Backert for modifications. I’m NOT looking to change their sound to something more modern (modern CJ or solid state). How would you describe the sound of the mods (line / phone stage and power supply)? Would you say that your modified CJ pieces retained the romanticism and big sound but were improved, or did the modifications take the sound in a bit of a different direction?