Conrad Johnson PV10A Mods/upgrades

Hey everyone..

I'm looking to get both my CJ PV10a preamp and MF200 solid state amp refurbished and upgraded. I've read several recommendations for Bill Thalmann and Bob Backert... who both seem to do excellent work! I was hoping to reach out to you all and see if anyone could chime in and help me decide who to go with? I'm leaning towards Bill Thalmann as he was technical director for 25 years at Conrad Johnson.. Any advice would be greatly appreciated! Thanks!
Hi Joe,

I have to imagine both are excellent. I have spoken with Bob Backert, and the Pres of the Philadelphia Audiophile Society who spoke extremely highly of him. I have owned CJ for a dozen straight years now, and Bob seems like a very knowledgeable person to me.

Meanwhile, a 3rd alternative is to go back to CJ. They often will do 'custom upgrades'...i know someone had Teflon capacitors put into his Premier 8s!!!

Ed in Service at CJ is amazing.
Bob modded out my CJ MF2250 and it sounded much better. I'm still trying to decide whether or not to send my PV-15 to Bob or to CJ for the cap upgrades. Tough decision. Bob's version will no doubt be superior, but it will cost more as well.
I believe the 10A can be upgraded to a 10B by cj......

I haven't had any work done by Bill Thalmann, so I cannot speak for his work. I have had Bob Backert work on a BAT VK-75SE amp and the results were stunning to say the least. I would highly recommend his work.
i wonder what Bob Backert would do on a GAT?
I would hope that at $20k, there isn't anything that could or should be done to the GAT. :)

Years ago I had Bill Thalmann convert my PV-10AL to a 10A by adding the phonostage to the unit. He also upgraded the capacitors and RCA connections and it sounded much better at the frequency extremes and had better clarity as a result.

In communicating with Bill at the time, he said that he knew just where c-j had compromised the design in order to come in at its price point and therefore, where the most cost effective modifications should be made.
Lloydelee’s third alternative should be seriously considered if resale value is of concern. Even though Bill Thalmann and Bob Backert are both accomplished technicians whose cj mods are well reviewed, the amp can only be considered a pure cj if cj does the work. That, IMO, should add to resale value. In my conversations with Bill and Bob, I came away with the impression that Bob’s mods were somewhat more invasive - not to say that the result isn’t stunning.

At this point, I would suggest that you develop a very precise set of objectives, and without initially disclosing those objectives, determine through your interviews which guy most shares your values - if he hears like you hear, he will do a better job.
Thank you so much everyone! I think I'm leaning towards Bill Thalmann.. I like that fact that he was an employee at CJ and that that will probably be ok if I ever sell either unit..
I'm excited to hear the difference!
No doubt they are all good options. Good luck and please post!!!
You may want to check out It's a forum site dedicated soley to Conrad Johnson owners. It's new but membership seems to be growing and it's a nice place to have a place for CJ owners to congregate. Also, you may want to post this issue there and get some feedbacks as the readership will be completely made of CJ owners.

I use a PV-12 and love it. I have listened to the PV-10 as a demo and it had a wonderful sound as well.
Yeah Bill Thalmann charged my friend $10 per diode to upgrade his amp plus labor. The diodes cost less then $2.00 each. Gee Thanks! Upgrades are only one way to go but just swapping out parts do not mean you are getting the best out of your equipment most likely just a change in sound.
I just noticed I misspelled the site in my previous post. It's Sorry about the mistake.
Thanks...promising site.