New member williamorganist (Bill)

[Williamorganist]

I am a retired anesthesiologist in Columbus OH. I have and still play the classical pipe organ, giving recitals for friends about every six months. I have owned the same CJ pieces since 1986, keeping them up to date with available factory mods and the usual tube replacements. They are the PV-5 preamp and the MV 75a1 power amplifier. Over the years they have provided me with many, many hours of listening pleasure. I joined the cjowners blog to explore possible replacements. Or perhaps advice to just keep them. They are great, but is now 36 years out from purchasing them and, no matter how careful the maintenance, a little long in the tooth. Advice is welcome.

[Big Dog RJ]

Welcome aboard!
The PV5 & MV75 is a great combination. As you rightly pointed out, the music has been great for over three decades and you've enjoyed every minute of it... That goes to show what CJ is all about. If you're happy with it just sit back and enjoy!

As for suitable upgrades / replacements; well sky is the limit. You can start from the last PV series of preamps, which is the PV15 (no longer in production) and go for the MV60SE, which again was the last MV series in power amplifiers (also no longer in production).

Then they offered the newer LP series power amplifiers, which is also no longer in production, and now offer the refined Classic series amps and the ART reference standard power amplifiers. So really it's a matter of personal preference and finances, if you can afford it go for it!
Even the most loftiest pre-power combination, which is the GATS2 and ART300's down to the ET6SE and the Classic 62SE, in their simplest forms, are all fully worth the expense. They're all special in their signature sound quality when partnered with appropriate speakers and source gear. Also, with some of these systems, you can custom make them to suit the type of sound you prefer. By SE upgrades, tube complement, cap layouts, class AB mods etc., the options are many and the custom sound is yours to determine.

Sometimes, having much older gear, such as the pv5 & mv75 and upgrading every component over time may actually equate to the same cost if you purchased a newer model... CJ does charge quite a premium for such upgrades, sometimes you're better off getting a great deal on a carefully used item for a fraction of the cost. Keep an eye out and you'll see a number of top quality gear of used CJ amplifiers on sale every now and then. It's a matter of being lucky to pick one up at the right time.

Hope all goes well with you and do keep in touch with your upgrades...
Cheers mate, RJ

[joeinid]

Welcome to the forum Bill.

Wow! That’s a very long time to own audio gear. I totally commend you for being able to hold steady. Congratulations!

Just curious what speakers are you using?

[roberto]

Hola Bill,
Welcome to the Conrad Johnson Owners.

Pipe organ sound is very difficult to play and also are difficult to find good recordings. By a chance, can you share with us yours? I am another musician, and still play some classical guitar and have some musician friends where we get together and have fun.

Again, welcome. If is there anything that we could help to you, it would be our pleasure to try to help. Do not hesitate to ask!

Happy listening!

[admin]

Welcome to CJO, great to have you with. You exemplify the longevity and value that CJ has to offer. Let us know if you decide to upgrade and your thoughts.

[Williamorganist]

Thanks to all who welcomed me to the CJ owners club. I am glad it exists. I am about to retube the PV-5. Re the MV75a1, I usually keep the old tubes in case one of the 6550s bites the dust. When emptying cabinets for a remodel of the den, I stumbled on four pairs of older GE 6550s (two retubings worth). I generally tend to replace tubes in sets either by the clock (2 years) or when one blows up (red plates, the KTK-1 blowing along with it, etc). Reading that the GEs are pretty durable, I put two pairs back in. Surprise they sounded and are still sounding great. So retubing the MV75 is on hold for now.

[roberto]

Those are great news...by any chance, did you try the KT-120s? Most all tube brands makers are using it. To my ears, I really love them. Robust bass, with a warmth at the midrange that resembles the EL-34. And crystal highs...those are direct replacement for the 6550s. It is a newer design,
a little bit more power, and really is taking the marketplace. Just my liking...

Happy listening!

[Big Dog RJ]

Hey Roberto mate,

I was under the impression that the MV75 was based around the EL34's... Since Bill mentioned that he's using 6550's in it, then this must mean that his MV75 version accepts 6550's. I am correct? Or wrong?

Was also wondering whether the MV75 can handle the much larger KT120's...

I know the MV60SE can handle it with ease and it's sounds marvellous because I owned one previously to drive the Quads ESL2905's. The MV60 was a replacement to the MV75 and it used the wide bandwidth transpectral transformers in then, this was the first time CJ used these transformers in an amplifier outside of the premier series.

Therefore, I'm sure if the original transformers of the MV75 can handle the KT120's... Just wondering.

Any thoughts?
Cheers mate, RJ

[paulCJ]

Bill, welcome to the forum, though I'm relatively new myself. Every once in a while my system just sounds blah. The fix? A new set of tubes and the CJ gear sounds like magic again. If you are looking to learn about the sonic differences between the older and newer CJ gear I can't help, lol. (Roberto and Big Dog can) (on the serious side, the newer gear is reportedly more neutral and less warm than the older gear). I have older CJ gear, though a little newer than yours (PV10 preamp & MV55 poweramp). I will never get rid of them, as female vocals and string instruments sound so good, so smooth, so natural. When going to stores and listening to $30,000 and $90,000 speakers driven by well-respected solid state pre and power amps, there is a lack of midrange refinement in those systems that I have grown accustom to hearing with the CJ gear. If you have had your pre and power amps upgraded with the Teflon capacitors you should be set for a long time. One other thing you could focus on (other than speakers) is interconnect. A power regenerator from PS Audio is also something you could look into. My amp definitely sounds more refined when connected to one of PS Audio's powerplants.

[admin]

I had the same experience with my first tube failure and in retrospect, I wish I had identified it much sooner. I found that over the course of a few months the sound just got more dull and lifeless. Because the change was so slow and subtle, I initially chalked it up to myself. It finally got the point that I was putting on music that I had not listened to in 6 months and it just became obvious that something had changed. I called up CJ and they were super helpful with diagnosing the problem. Sure enough, it was a tube that had gone bad. With replacement, my PV-12 came to life again. I am much more critical of the sound quality now. My suggestion to anybody now is that if you perceive any hint of sound degradation in the system, start looking at the tubes. I think bad tubes can be deceiving as they often fail slowly vs solid-state components that just "blow" one day.

@paulCJ,
We just had a big discussion on power management in this thread: https://www.conradjohnsonowners.com/vie ... =11&t=1712

Maybe you can throw in your 2 cents and experience with the PS Audio gear. I think most of us are big fans of the PS Audio power units (but don't have that many funds to allocate to power alone).

[paulCJ]

Thanks admin!!
Wow, as I reading the other thread I was just starting to think that I will have to set up the delay feature on the PS Audio powerplant to protect the CJ pre and power amps from the type of scary power issue Roberto had. And then I continued reading about the advice Roberto was given to get a delayed power turn on...But even if I don't set up a delayed power turn-on for certain outlets on the powerplant, there is a delay period for the device itself to re-initialize, which should allow me just enough time to turn the amps off.

[admin]

Again, my APC unit is not as fancy as the PS Audio gear, but it does have the ability to delay power on to components. You can set delay between 0 and 12 seconds for the components. I think I have mine set to 2 seconds. Just to give a little time for the initial power draw of each component, most importantly the amp. There is some delay in the self power-up in my Amp (CJ Evolution 2000) but it seems like the rest of the components are almost immediate. I don't think there is any downside for setting up a short delay on the power management side of things.

[paulCJ]

I just played around with the settings, and reached 122 seconds for a delayed power startup before I quit seeing how high the delay can be set. I then set the 4 different sets of outlets to wait for 30 seconds to power up. This should allow me enough time to quickly turn the tubes off in case of the power flipping on and off several times quickly (which it has in the past, but luckily the stereo was off each time). Thanks for linking me to that discussion!

[roberto]

Hey Roberto mate,

I was under the impression that the MV75 was based around the EL34's... Since Bill mentioned that he's using 6550's in it, then this must mean that his MV75 version accepts 6550's. I am correct? Or wrong?

Was also wondering whether the MV75 can handle the much larger KT120's...

I know the MV60SE can handle it with ease and it's sounds marvellous because I owned one previously to drive the Quads ESL2905's. The MV60 was a replacement to the MV75 and it used the wide bandwidth transpectral transformers in then, this was the first time CJ used these transformers in an amplifier outside of the premier series.

Therefore, I'm sure if the original transformers of the MV75 can handle the KT120's... Just wondering.

Any thoughts?
Cheers mate, RJ

RJ,
As far as I know, the EL-34 internal wiring is totally different than a 6550. The MV75 is design for the use of 6550s. If he is using this tube, his power amp must be already accept the 6550s. The KT-120 is the same and direct replacement of the 6550s. This tube offers a little bit more power, but you can safety use on any power amp that has the 6550s with no issues. If he is playing at maximum power all the time, perhaps the MV-75 might be have an issue. But knowing the quality parts that C-J uses, I do not see why not he could do the change for the kT-120.

I do believe that you are thinking in the MV45 that uses the EL-34. This amp is rated at 45 watts/channel. The MV75 is rated at 75 watts/channel.

Being said that, I think that Mr. Bill can use it with success and he can enjoy all the benefits of the KT-120s, and being another musician KT120 user.

All what Mr Bill has to do, is re adjust the bias for each tube again.

Happy listening!

[Big Dog RJ]

Thanks for your clarification Roberto, makes perfect sense.
I'm sure he will be very pleased using the KT120's, it certainly add new life into the MV75.
Cheers, RJ

[roberto]

Yes RJ,

I do not see any reason why he could not use the KT-120s. The MV75 comes with the 6550s.

By the way, I got a phone call from a dear friend asking me if I have a spare KT-120. I told him yes, and he told me that it was for an Audio Research Reference 75 Watt/channel power amp. He came, and called me again, letting me know that it did not work. The bias adjustment for this power amp, is for matched pairs, and if you do not have the spare tube with the same gain, it will not be possible to adjust the bias. We don't have this issue with CJ power amps, because each tube has its own bias adjustment. Good for CJ with this type of circuit!

Happy listening!

[c-jman]

Bill. I also am the proud owner of the PV5 and MV75a1. Also bought in the 1980’s and still enjoy listening to them. I had Bill Thalmann at Music Technology upgrade the PV5 and it really brought out the best of it. I am planning on sending him the MV75a-1 for its upgrade. Bill was one of the original C-J engineers who designed the MV75, so he knows what upgrades are perfect for them.
I’m running Synthesis LM300 speakers (Conrad-Johnson) w/ 8TC cables doubled runs and Black And Silver Dragon IC’s. Will never replace the C-J components. Give Bill a call or find him on the internet, you won’t be disappointed.

[Cjmvpv]

right channel bias lights stay on always after outputs tubes blew in rush fuse replaced tubes and 20ohm resistor that was cracked any idea what else a bad 6550 tube would take out in the bias circuit?

[roberto]

right channel bias lights stay on always after outputs tubes blew in rush fuse replaced tubes and 20ohm resistor that was cracked any idea what else a bad 6550 tube would take out in the bias circuit?

Hola, when an output tube Led is on, this is telling the output tube could bad, even being a fresh tube. Swap the output tubes from the left channel and bring all the way (counterclockwise) bias screws. If the LED stays on in the left channel, you have to change the IC that is controlling that bias tube or both ICs for both tubes. Usually interchanging the output tubes fixes that problem. It is wise too, to change those 20 ohms resistors for 7watt power dissipation instead a 5 watts.

Happy listening!