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Premier 11A mods

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AudioDon
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Premier 11A mods

Post by AudioDon » Thu Apr 14, 2016 2:25 am

Hi all,
I bought a new to me Premier 11A recently, and I'm not as enamored as I'd hoped I'd be. This came after auditioning a
MF-2550 which I loved, but couldn't afford to keep. The bass on the 11a is kinda boomy, and I'm not hearing the liquid mid range I was hoping for. On the 2550, the bass was tight, and there was so much air around the music. It didn't have the liquid tube magic though.

So, do I sell the 11A, and find something between the 2?, which will no doubt cost me a lot more money? Or I wondered if it was time for new caps in the 11A? I don't think I want to go with Teflon. For 1, I cant afford them, and from what I've read, while they are super clean sounding, they're not as musical as say the Mundorff's.

My other system components are;
Premier 14 Pre
Arcam CD-92
Rega Planar 3 TT
Totem Forest speakers

I'd appreciate any help you can give.

Thanks,
Don

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Joe Appierto
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Re: Premier 11A mods

Post by Joe Appierto » Thu Apr 14, 2016 9:34 pm

Your 11A may be 20+ years old. It could indeed be the caps.
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Re: Premier 11A mods

Post by petertg » Fri Apr 15, 2016 5:58 pm

Hi Don,
I am a long time owner of a Premier 11a which I had upgraded with teflon capacitors about 5 years ago. To me, the midrange is very liquid sounding with great imaging and sound staging. It is not tubey and lush sounding the way you might expect tube gear to sound. In fact, the 6550 tube is regarded as a more transparent and accurate sounding tube vs the el34 for example. What tube amps have you listened to as a base line for comparison? There are relatively lusher sounding 6550's on the market such as the Tungsol reissue or jj tesla that you might want to try. I dont find the bass boomey either. It is not as powerful as most solid state gear but it well controlled and not offensive sounding to me in any way. Maybe you are looking for a more lush sounding tube amp like the mv50/55/60 or another amp based on the el34 or 6l6/kt66 tube type? Also, What input and driver tubes do you have in it and how old are they?

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Re: Premier 11A mods

Post by unclekanus » Thu May 12, 2016 12:36 am

Hi Don,

Not sure if you are still toying with this but I would replace the .15uf styrene coupling caps with some copper foil caps. Go for something in a .22uf value as .15uf isn't always available. The Audyn true coppers are about $20 a throw or the Jupiter coppers are roughly $50. I use the Jupiters in my 11a and they are well worth the spend and certainly a whole lot cheaper than teflons. I don't much care for the sound of styrenes that are that big in value and the Jupiters helped get rid of that slowness in the sound as well as imparting a lovely richness to the tone, tightening the bottom end and they were a huge leap forward in the top end too. Nothing at all wrong with the Audyn's either for a bit less money and they will give you a similar result.
Replacing the uf4007's with some 1200v schottky's will clean things up a lot too though the uf's I find are quite musical.
Let us know how you get on.

Cheers

Chris

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Re: Premier 11A mods

Post by Wildcat » Tue Jan 31, 2017 4:47 pm

@AudioDon You might consider the tubes. For the output tubes, presumably a KT-120 will work, if perhaps a little under-utilized in the amp. The driver tubes may make a bigger difference in sound. One of the good tube dealers like Upscale Audio could probably help you in your quest, if you let them know what you do not like about the sound, and what you want to see improved. Or, you could order a new set from C-J directly.

And yes, it is a bit older, so the capacitors could likely use some freshening.
C-J PV-14L/C-J Premier 11/Vandersteen 2Ce

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Re: Premier 11A mods

Post by ronenash » Wed Feb 01, 2017 7:21 pm

Joe Appierto wrote:
Thu Apr 14, 2016 9:34 pm
Your 11A may be 20+ years old. It could indeed be the caps.
The Premier 11A does not have electrolytic caps in it apart from the heater power supply. The polypropylene and polystyrene caps last forever with no degradation. I would check the heater electrolytic cap which will probably need replacement at some point.
My guess would be the tubes are probably old and degraded. The Pr11 is a great performer and with a new set of tubes will most likely sound great. with that said the Teflon cap upgrade although expensive would certainly improve the sound considerably. Some signal path resistors will also make a big change.
CJ can perform the upgrade but if you have some technician skills you can do it yourself.
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Power:CJ LP125m SE, Beard P100
Pre:CJ ACT2.1, Pr14, Pr15
Analog:VPI Classic/Falcon/Blackbird, Thorens TD125mk2/AT1005MK2/2M Mono, Lenco L75 rebuild
Digital:J.River-->AP2-->Chord Qude HD
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Re: Premier 11A mods

Post by Wildcat » Wed Feb 01, 2017 7:48 pm

Don't mean to hijack the thread, but since it is somewhat related...

I've actually seen a Premier 11 locally for sale. Tempting, provided it has the cage. But I wonder if there really is any noticeable sonic difference between the two. I seem to recall that the "A" modification involved some circuitry change to counteract noise caused by the bias LEDs...? Who knows if I would ever hear it? But the cost to upgrade at C-J to me is way too expensive, last I heard. And while I do work on electronics (I've recapped components before, and built other gadgets), I would almost rather not attempt to do anything myself on something that has this much value in it.
C-J PV-14L/C-J Premier 11/Vandersteen 2Ce

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Re: Premier 11A mods

Post by ronenash » Thu Feb 02, 2017 7:03 am

To be honest, I have never seen a non "A" version. If asked I would have thought the "A" version was the only one out there. Maybe it's worth a call to CJ tech support.
ronenash
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Power:CJ LP125m SE, Beard P100
Pre:CJ ACT2.1, Pr14, Pr15
Analog:VPI Classic/Falcon/Blackbird, Thorens TD125mk2/AT1005MK2/2M Mono, Lenco L75 rebuild
Digital:J.River-->AP2-->Chord Qude HD
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Re: Premier 11A mods

Post by Wildcat » Thu Feb 02, 2017 11:36 am

The "A" version was very short lived, less than a year:

"Introduced in February, 1993 | Eleven-A in January, 1994 | Eleven XS in June, 1995"

"The Eleven-A added a noise filter on the bias indicator circuit, first employed in the Premier Twelve. The Eleven-XS is an Eleven-A with the output stage configured to use a pair of EL34s operated as triodes."


http://conradjohnson.com/vintage-conrad ... -products/
C-J PV-14L/C-J Premier 11/Vandersteen 2Ce

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Re: Premier 11A mods

Post by Big Dog RJ » Fri Feb 03, 2017 12:37 am

Spot on mate!

I had the original 11A version that was later converted to the "XS" version- superb level of musicality with the EL34's. The only thing is the output drops to half around 35w instead of 70w. It was marvellous driving a pair of older Quad ESL63's with Gradient subs, and a MF2300 used on the subs.

Although the soundstage and depth was fantastic, there was a slight mis-integration from panel to mid bass - lower bass. The Gradients using an active crossover had far too many signals passing through with too many variants, does not deliver that total synergy. Hence got rid of the Gradients and just enjoyed the ESL63's on their own. Later on it was another the 11A version partnered with the Martin Logan CLSIIz, now that was at another level of refinement and transparency in sound but not quite the same bass as the Quads.

Fast fwd nearly 25 years... and I'm back with that level of musicality plus soundstage depth and all the required bass- with the CAV45 & Ethos. What a marvellous amplifier to speaker combination.

Anyone looking to try out CJ's triode versions or push pull in ultra linear mode using EL34's- go for it! You will be amazed at the level of musicality offered, the way it engages your listening experience and delivers all the emotions of music, regardless of listening levels.

But they are not for thumping out music and over-energising the room. That can be achieved from their larger offerings with KT120's.

I was not aware of another version either, I thought it was just the 11"A" that was introduced and the "XS"...
Anyway, good to know.

I also sometimes do wonder, whether previous 11A owners actually thought what a classic and highly valuable amplifier the 11A is! Until they parted with it- I still regret selling both of them!

Cheers and enjoy your 11A, trust that you can get it back towards that superb sound it is well capable of.
RJ

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Re: Premier 11A mods

Post by Wildcat » Mon Apr 03, 2017 1:10 pm

I wonder if there is a schematic out there of the Premier 11 as opposed to the 11A, as that would make it possible to find out exactly what is different about the biasing circuitry. I have a line on an 11 that is very nicely priced, but in a way I don't want anything that might be compromised. Having C-J do the upgrade would probably cost more than the amp, and that is not in my budget. And, I don't know if I trust a third party to do it properly. Definitely something to ponder.

I have, however, been reading a lot of good things about the KT-120 tube--I get the impression it is a powerful, sonically well-balanced tube, and would be willing to try it.

I see a lot of Premier 11a amps for sale. I just wonder if they would have the juice to power the Vandersteens. Those really need a lot of power to fully wake up. The amp I have now (in my signature) energizes them quite nicely. I actually would prefer a VTL amp (more power, switchable UL/triode operation), but the model I am after rarely comes up for sale. The one good thing is that if I bought a C-J amp, I likely could get most of my money back out of it when reselling it.
C-J PV-14L/C-J Premier 11/Vandersteen 2Ce

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