I just bought a Conrad Johnson Premier 4 - advice please

I have many vacuum tube amplifiers from the 1980s because it was an amazing decade of rapid improvement in the sound of high-end audio (particulaly tube gear), and the best equipment from that period has become so affordable.

Now I received a CJ Premier 4 amplifier, sitting in the middle of my EAR 509, various MFA, ARC, Melos, Citation, Heathkit, and more mono amps.

For anyone who has owned a Premier 4 (this model in particular please), I would like to hear your experiences about tube life, reliability, particular brands of NOS EL-34s, and mods to improve tube life.

As many CJ owners know, this particular model had a reputation for pushing it's power tubes very hard. Was this consistently true, or did this reputation actually vary from owner-to-owner's memory?

 

You said it, most of my system is from the 80's (I wish I was). Nice amp! Good luck with it.

 

I own a Premier 1B, which is a very close relative of the 4 which features 6 EL34s per channel, VS 4. These things definitely do consume output tubes fairly quickly. I would change the output tubes about every two years or so if you are using the amp regularly. The redeeming factor is that they are using EL34 outputs, which if you are using modern tubes, are one of the cheapest output tubes one can have.

The Achilles heel of all CJs in their SS regulator circuitry. This ages much less well than does the rest of the these units, and this is where most of the failures inside of these units stem from.

I have thought about doing some mods to extend the tube life inside of my amp. But I've been so busy with work over the last few years that I haven't had the opportunity to experiment with any of these yet. Consequently, I'm not sure if my ideas are going to work yet or not.

 

congrats !! such a beautfiful piece !!!

enjoy

 

Warren,
I didn't respond earlier as I didn't think that the amp that I owned for a while was so similar. It is in fact the direct descendant of your amp. The Premier 4 was made in 1984, and my amp, the MV100, was introduced in 1988. They have the exact same tube compliment and layout, and it appears, biasing arrangement. According to C-J, "The MV100 vacuum tube power amplifier evolved from the Premier Four. The regulated power supplies were redesigned to improve the isolation between the input amplifier and inverter stages of the amplifier. The MV100 delivered 90 watts per channel by using two pairs of EL34 output tubes per channel.".

I had the amp for about a year. It ate tubes for lunch. More infuriating perhaps, was its appetite for the extraordinarily hard to find and expensive B+ fuses it was fitted with. No reason in my mind that they could have done such a crazy thing as to choose those fuses except for bragging rights that "their fuses were bigger than yours". I think they were like $3 or $6 each and I bought them in packs of four because I kept seeing them fail. Normal, glass fuses, like every other maker uses cost about $60 per dozen...

I had to replace the tubes a couple of times. I started by replacing a pair at a time, then just bit the bullet and retubed the whole amp. I actually bought a full set of NOS tubes from C-J at their premium, since I was so concerned about any average tube holding up. I don't think they really helped too much and I sold the amp after replacing another pair of those. They sent good tubes too; GE for the signal tubes and Siemens for the power tubes.

The amp had the classic C-J sound, plus balls. I mean, I had heard their smaller amps and integrated, the Cav-50, which was quite popular. I always thought they sounded a bit too polite and lacked slam. The MV-100 improved upon that. It was a beast at 92 lbs, and pretty much identical to yours, but with the upgrades to the power supply. I used it to drive the mids and tweeters at 8 ohms on a set of speakers that had some difficult to drive 4 ohm woofers. I also ran it full range into the same speakers for some time. Bass was not especially tight, but was powerful and deep. The real magic was the midrange and top end, which is what optimized it for the bi-amp situation driving everything but low bass. I had a Bryston and a Hafler amp that I used to drive the bass drivers. I have a photo of it somewhere, and I'll post it if I can find it.

I liked this amp alright and I just had two issues with it, one being the cost of fuses and tubes that it fancied eating, and the lack of tight control of bass. I think the really sweetest all-rounder sounding amp that I heard from them was the actually their solid state MF2200. If you want to consider any mods, my advice would be to change the bias set point, lower it, and replace the fuse sockets with some that will accept standard 3AG types. In hindsight, C-J probably went with the larger, ceramic versions to meet the voltage specs at 500v. I haven't seen any other mfr do that though, so it might have been an insurance consideration.


-Bill

 

I've only had one or two fuse go out on my Premier 1B. The fuses normally only go out when a tube fails. And yes these are hard to find and expensive. But they definitely did their job and saved the amp from genuine damage when an output tube failed. I will probably replace this fuse holder if I ever run out of spare fuses for this amp. But you DEFINTELY want to use fuses rated for at least 500V. I'm guessing that CJ used the busman fuses because it would keep people from replacing them with standard 125V rated fuses, and seriously damaging the amp.

It is absolutely CRITICAL to watch the bias like a hawk when replacing output tubes because it tends to drift for a week or more before finally stabilizing. If you don't do this, you WILL be replacing output tubes much more frequently than you should ever need to.

I also have done some tricks to protect my amp from brief power interruptions. This amp really does not appreciate power blinks at all. So I use a little GFI adapter on my power cord to ensure than in the event of a power interruption, the amp just harmlessly shuts down rather than receiving that quick off-on surge that it does not respond well to.

The midrange of that amp is the best I have ever heard, and the top end is really sweet too. Mine had tones of authority, but the bass is not as tight as it is with some other amps.

The soundstage is ENORMOUS too! It sounds like it extends way past the walls of my listening room. Really an amazing sounding amp from the classic era before they ruined the sound of their amps by trying to make them sound more neutral.

My amp is very picky about the speakers connected to it. A poor match can destroy the sound. Don't be afraid to try some alternate impedance taps from the output transformers if the sound is not immediately to your liking.

Also, tube choice makes all the difference in the world. This amp really responds well to rolling. And never chose dark sounding tubes for this amp unless you want for your sound to be dull. CJs are naturally dark sounding, And they do not need any more help in this department. I prefer the sound of the cheap Sovtek 5751s inside of CJs over the JAN Phillips 5751s because the Phillips tubes are too dark for this amp. And they do not sound good with black plate tubes. They came from the factory with GEs 5751s which are a bit more lively sounding than are the mellower Phillips tubes IMO.

 

Hi Warren,

I have owned an MV 100 for a few years now, and have had a couple seirous issues with it. It cought fire, not once, but twice. Lots of current pumping through that thing. Turns out that there was a chasie short that the tech somehow missed after the first try. Any way, while I was waiting for it to get fixed the second time, I came across a premier 4, and bought it.

Both are up and running now, paired with a premier 3 and some restored Ar3a's, both sound super!!! The mv100 gets a nudge due to slightly thighter base and better definded mids (the old ar's mids have allot to be desired anyway), but the sound stage on both are wide, deep and just plain magic!! The ultimate plan is to build some really nice 3 ways from madisound and biamp with the pair.

As far as tubes are concerned, i have only replaced 2 sets, and this was due to these minor house s I referred to eailier. I am running tung-soles in the mv100 and electro-hermonix in the 4.

I am kinda new to the hobby, and don't have a allot to compare my cj gear to. I have a Dynaco St70 that I pair with an old counterpoint pre, and a sansui 1000a receiver. Both are great little setups, but the punch of 100wpc on the power hungry ar's is in a totally different leauge. I also have an sx1250, which puts out 160wpc of SS power. Sonically, apples and oranges. That beautiful pioneer is really just a wall hanger. I like the pioneer. I love the CJ's

Congrats on the purchase. I'm sure it is one you will not regret.

 

Thanks for your VERY interesting comments. "Tighter bass and better defined mids" sounds to me like the Tungsol 6550 tubes I have in a pair of Moore/Franklyn (MFA) amps. I would suspect that Electro-Harmonix EL34s cannot get there, but probably another set of Tungsol EL-34s or Siemens EL-34s can. I suggest you try a set of USA or European made NOS power tubes, and THEN compare.

But the CJ website does suggest that the MV100 power supply was upgraded from the Premier 4's power supply.

By the way, I had a Premier 3 preamp for a time, and talk about "just plain magic", that preamp had it in spades.

 

I owned one for about 15 years, or longer. It eats tubes. Cheap tubes don't work well or sound well either. Then again, what tube out there doesn't claim a great midrange?

And don't forget about the 5751's either. Changing them more often than required helped as well.

Thru the years I had numerous tube failures that always took out other parts. The best sounding tubes I ever had were the PSVane grey bottles. A distant second was the good old winged C. The reproduction Gold Lions were 3rd and fairly close to the winged C's.

As far as reliability--not sound--Winged C held up best. 2 failures out of 8 for the Gold Lion. PSVAne was 3 out of 8. I rolled tubes about every 2 years and tried JJ/EH/Tung Sol/Sovtek/ and so on. They were all a step or two below the above 3 and to me anyway, not worth considering. I went through 2 sets of winged C's and just got tired of the escalating costs, so I tried the PSVane. The Gold Lion Reproductions are a decent bang for the buck.

My tube failure rate went down once I bought exclusively from Upscale. Come to think of it, some RAM tubes I'd ordered way way back didn't break down either. But I didn't like their sound.

 

I also have a Premier Four and had significant issues with replacement tubes. A techie friend suggested the SED Winged C's and they've held up the best. I'm afraid to try any others as I've also had issues with other parts being fried!

 

I guess everybody had tube problems with their Premier 4 and MV100 amps. That is just not acceptable in my opinion. In contrast, my Emotive Audio Vita monoblocks which use a single pair of KT-120 outputs have never had an output tube fail, and they have never blown a fuse. That is now 10 years of everyday use. Plus they sound great.

It all comes down to design.

 

Interesting piece by forum member @TONEPUB on reviving an old CJ amp and his dealings with Lew Johnson.

Conrad-Johnson MV-50 – Old School | TONEAudio MAGAZINE

 

OT

From a person who has had several CJ tube amps. If you want the CJ sound without the hassle get a MF2500 (A) or a Premier 350 and never look back.

Just a different view.

M~

 

Can't argue with your personal experience on that amp, but I've had nothing but good times with my CJ gear, and the sound is very nice too. All tubes except for the EF-1 phono preamp in the top middle position for the Micro Seiki table...

 

Drool........

 

Warren: What bands of tubes is the Premier Four running at this point?

 

I have Siemens installed , made in East Germany. I am hesitant to use any Chinese or Russian tubes. But I have never turned on the amp yet. I dont even want to, until I am using the most reliable, stable and resilient EL34 power tubes known to mankind.

I am currently playing with my just received Thiel CS 3.7 speakers with various other amps in my collection: Audio Note Ginrei, MFA M120, EAR 509, and Voss. ARC M100 amps next.

 

a little confused because $60/12 = $5 each, which is in between what you said was expensive for a fuse at $3–6.

 

That was a typo. I meant to type "$6 per dozen", so .50 each for the more common glass fuses.

I would think that there should be a mod or two to help with the biasing in these.
-Bill

 

Hello !
I‘m new here in this forum.
I have a premier one and had always problems with burning through output tubes.
The solution of these problems is:
Change the screen grid resistors from 20 ohms to 220 ohms.
As the voltage at the screengrid is simply to high in the cj design, increasing the screengrid resistor value prevents the screengrid from glowing and being destroyed
therefore.
Since I replaced these resistors I never had problems with the output tubes.
I use Electro Harmonix KT88, selected quality.
Sorry for eventual bad english, I‘m german.
I hope I could help with this advice.

 

In these cj ultralinear designs you CAN use an EL34 tube, but this is a pentode.
The cj design works in tretode mode. A KT 88 is more useful here. But only if it’s a REAL KT88 (not a KT88 labeled 6550).
In any case one has to change the screengrid resistors for stability. With the 20 Ohm value cj wanted to squeeze out the maximum available power from the output tubes.
With no regard to tube lifetime. The screengrid of an EL34 or a KT88 was not designed for that.

 

I've read that the Siemens are fine with amps that have plate voltages up to 450 volts. The Premier Four is rated at 600 volts. What would be the second best option?

 

I knew that someone would have tackled this at some point. I should have looked further into it years ago when I had mine. I had also just found the sound to be too soft for my liking and traded it away for new front end gear.
-Bill