Conrad Johnson Premier 11A

Discussion in 'Power Amps' started by pedalhead, Apr 10, 2017.

  1. pedalhead

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    Being a soundstage junkie, I've been keen to try out a CJ as they seem to have a reputation in this area. Well, I've got this mid-1990's Premier 11A power amp (and a PV12 pre-amp) on loan from a mate and the reputation is clearly well deserved. On the right material (eg, Tracy Chapman s/t on vinyl) my Audio Physic Tempo 25 speakers just disappear. Lovely bit of kit, really sweet and balanced sounding, and not exactly ugly to look at either :p. It's 70wpc & uses 2 x 5751, 2 x 6FQ7 and 4 x 6550 for output. Input tubes are all GE JAN, 6550s are Sylvania.

    Sadly the PV12 pre-amp is faulty so I'm using a Jotunheim instead, which actually does the CJ no favours at all, closing things in a bit. Connecting my DAC/passive preamp (DiDiT DAC212SE) straight to the CJ restores the soundstage, so Jot is doing something funky in this setup.

    I've also got a really nice upgraded First Watt F7 build here for a couple of weeks to compare. I'll update this thread if anyone is interested in impressions.
     
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  2. Dino

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    I have read a lot about conrad-johnson equipment back when The Absolute Sound was still a valuable resource. The soundstaging descriptions are what I found most interesting.

    There was a time when most of the TAS staff had the (then current) PV-5 preamplifier. I had an opportunity to get one as a loaner back in the 1990s. It was from a repair shop that also had used equipment for sale. I talked the owner into letting me take it home over the weekend. Unfortunately, it had such overwhelmingly boosted bass in my system that I couldn't really listen to it. I didn't blame the PV-5. I thought it might be the tubes in it (unknown usage on those, maybe original or whatever was handy to stick in there) or more likely (I thought) an impedance mismatch between it and my solid state amplifier.

    Anyway, I'm very interested in your comparison @pedalhead .

    EDIT: After @Daveheart 's post, forget about my impedance mismatch comment. Something must have been wrong with the PV5. My memory has just been jogged to that scene with the owner who lent the PV5 to me. I first started dealing with him when he was doing service out of his mother's basement. He seemed to do a good job at a good price. He also sold some quality stuff. Later he got his own storefront. By the time I borrowed the PV5, he had numerous components displayed in his showroom. Every thing I expressed interest in, would get a response of something like "You don't want that. It is kind of messed up.". When I asked about the PV5, he said "I don't remember how that one is. You can borrow it if you like". He was an honest guy, at least.

    By that time, he had changed. Every time I visited his shop, he was very friendly but it would always be a situation where he didn't seem particularly interested in his business. He would be sitting in the showroom with his employee and friends drinking beer and mostly interested in joking around. (Ah, trips down memory lane...)
     
    Last edited: Sep 7, 2017
  3. Daveheart

    Daveheart Friend

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    Having lived with a PV-5 for a loooooooooong time, I'd never say that preamp is perfect, but I don't think I've heard any combination with it that resulted in "overwhelmingly boosted bass". There's no real point in trying to retroactively diagnose it, but either something was broken or you stumbled upon the mother of all mismatches.

    @pedalhead I'd love to hear the comparison to the F7, and I'm sorry to hear that the PV-12 is borked.
     
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  4. pedalhead

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    Cheers chaps. I'll report back with some impressions in a bit :).
     
  5. Orkney

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    I ran the 11 with the sort-of matching baby ART preamp for a while, and loved it, though the bottom end was a little soft compared with more powerful tube amps, like the VTL or BATs and even the Rogue 100s. Very seductive sound with detail, texture and excellent recreation of recorded spaces. Ended up moving to a McIntosh MC275 VI when I found one on close-out. I never tried it with an SS or hybrid pre, though it've heard good things about such match-ups. It's certain;y a beautiful and highly-musical piece. Enjoy it.
     
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  6. pedalhead

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    Thanks. I'm really happy with the 11A, it's a wonderful piece of kit, as you say with a sweet, detailed sound and incredible staging. I do have some issues with the PV12 preamp though that I need to sort (new volume pot for starters). I'm in the process of changing the stock 11A tubes to RCA black plate 5751, GE 6FQ7 and just today I found a quad of 1960s Tungsol 6550 for a realistic price, which are as good as it gets from what I've read.

    The Premier 11A is definitely a keeper for me. If I can't sort the preamp then I'll probably just go with a Schiit Freya, which has the benefit of remote control as well.
     
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  7. msommers

    msommers High on Epipens

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    I've been looking into tube preamps and Conrad Johnson keeps coming up. LS16 series 2 seems like a winner by most but incredibly hard to come by it seems. Also looking at Primaluna and Freya too (though some report it's kind of clinic which is not what I'm going for at all). Have a Pass Labs XA30.5 to mate with.

    Happy to hear the 11A is working out for you!
     
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  8. Puma Cat

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    Hey guys, been using Conrad-Johnson gear for 8 years now, including the Premier 11A and PV12 preamplifier. Pedalhead, fully agree with your assessment that the Premier 11A is a fine power amplifier. I really enjoyed mine when when I had it; eventually sold it when I bought an LP-70S, which is another jump up in performance with a superior (and simpler) circuit topology and Teflon caps.

    I also had a PV12, and liked that quite a bit. I had no issues with the preamp, eventually sold it to Jeff Dorgay of ToneAudio who did a C-J Teflon cap upgrade to it.

    Regarding Jodunheim, if it didn't sound that great paired with the Premier 11A, I would most likely attribute to a preamp output impedance to power amp input impedance mismtch. You have to watch this closely, particularly when matching preamps to tube power amplifiers. My recommendation would be to find a used C-J preamp and use that with your Pr11A; it will match perfectly impedance-wise. The output impedance of Freya is only 210 ohms, so it should work in pairing it with a Premier 11A, which has an input impedance of 100,000 ohms (the output impedance of a PV12 is 800 ohms). I had a Premier 17LS after I sold my PV12, and it was a beautiful, musical, sweet-sounding preamp, VERY musical. I sold it to a friend in France after it was relegated to a bedroom system that I wasn't listeing to very much. I'm now using a C-J CT-5 preamp that is from the exact same time-frame design-wise as the LP70S, so needless to say, they match up extremely well.

    Regarding your PV12, you can ship it to C-J for repair; they still service every product they have ever made, they are a great company with a sterling reputation in audio.

    BTW, check with C-J, but I think you can replace the 6550s with Tung-Sol KT-120s, which are sweeter, more musical-sound output tube. I replaced the 6550s in my LP70S with these, with the blessing of C-J.
     
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    Last edited: Sep 7, 2017
  9. msommers

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    Interesting...What pre ouput : power input impedance ratio is optimal? I'd always heard 1:10 minimum, 1:20+ is ideal.
     
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  10. Puma Cat

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    I remember there is a certain ratio that is optimal, but I don't remember the exact number. Now that I think about it though, I think I have this all mixed up: the key is to have a power amp with a high enough input impedance so you can obtain the ratios you reference, rather than the output impedance of the preamp being important.

    In which case, Freya should work fine with a C-J Pr11A. Silly me. :confused:
     
    Last edited: Sep 7, 2017
  11. purr1n

    purr1n Finding his inner redneck

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    Jotunheim is not a preamp. Sure it will work in a jiffy as a preamp for DSP'd AD DA powered monitors; but as it is primarily a headamp, it has no place as pre for high performance power amps.
     
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  12. Puma Cat

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    If you can find a Premier LS16 or LS 16 Series 2 preamp, buy it. The reason they don't come up often is quite simple: people don't sell them very often as they are SUPERB. And still rather pricey to this day, for good reason. Even the discontinued ACT2 preamps sell for over $6000 used, on average.
     
  13. Puma Cat

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    Msommers, there is a gorgeous Premier 16 LS2 for sale on Audiogon right now for about $3500.
     
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  14. msommers

    msommers High on Epipens

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    I recently picked up a PrimaLuna Diaglogue Premium preamp a little bit ago and ordered a bunch of new tubes for so not in the preamp market any more (at least for now haha), plus the seller won't ship to Canada. The PL matches quite well with the XA30.5, imo!

    Onto speaker upgrades from my little Totem Arros.

    Thanks for the heads up on the amp and I'm glad to see my impedance ratios weren't misunderstood. Cheers!
     
  15. Puma Cat

    Puma Cat Almost "Made"

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    Thanks, msommers, good to hear you settled on something you like. Admittedly, I am coming into the thread late as I just joined today.

    Regarding speakers, what is your budget? I have a recommendation if your budget alllows and if you're interested.
     
  16. msommers

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  17. Puma Cat

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