Hello from Seattle

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TarnishedEars
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Hello from Seattle

Post by TarnishedEars » Sat Jun 07, 2014 6:36 pm

Hello. I'm brand new to this forum, but I'm not remotely new of to audio forums and am a member of several others including AK, Steve Hoffman, Tapeheads, Computer Audiophile and DIY Audio.

I've been a CJ owner for over 15 years with my first upgraded PV6, and I also have had a Premier 1B for about 11 years mow. I recently purchased a PV12AL, and while in some ways it sounds superb, so far it is not giving me the 3-D soundstage that I have come to expect from CJ.

So I plan to avail myself of your CJ database and to look into the possibility of some mods to see if I can get this preamp into the truly magical category where it by all rights should be. And I will also be interested to hear what other's experience has been with this preamp, and if there are any special tricks which I need to try to get the most out of it.

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Re: Hello from Seattle

Post by admin » Sat Jun 07, 2014 6:59 pm

Welcome to the site, it's great to have you with us!

I am also a fellow PV12 owner. I think it really sounds great. You mention that it's not giving you what you hopped for... may I ask how old the tubes are? Let's face it, our PV12's are not "spring chickens." :)

I had a tube slowly go bad in my PV12 and it wasn't "terrible" quality sound, but it lost the soundstage, dynamics, and clarity. It was a very subtle change so I didn't even notice it until I went back and started playing CD's that I heard prior to the tube issue. I replaced that one tube and it immediately came alive. I would probably recommend looking into perhaps getting a new tube. One simple trick you can try is to simply switch the 2 tubes inside as if one is defective you should notice a change in the sound.

Even if the tube is not bad, I would still recommend you experiment with different tubes as I have found that some work well, others not. Also, I think it is highly dependent on the rest of the equipment in your setup so there is no "right or wrong tube." People have discussed tubes on the forums here many times so you may want to hunt some of those threads down as they may be helpful.

Also, if you have a chance to post your setup in the "members gallery", that would be awesome. We may be able to give better advice if we know the rest of the equipment.
-admin
Home Theater in Member Gallery
Conrad Johnson Owners.com Main Page

Current Conrad Johnson Equipment in System: Evolution 2000, PV-12L, and D/A-2b.

TarnishedEars
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Re: Hello from Seattle

Post by TarnishedEars » Sat Jun 07, 2014 7:34 pm

Thanks for the welcome.

I don't know how many previous owners this preamp had. However I suspect that it has had its volume control replaced. The supposed "12AU7s" which came in mine do not in fact appear to be 12AU7s at all so far as I can tell (despite their markings). They have the tiny plates which I normally associate with 12AT7s. When these started oscillating within an hour, and so I have been rotating through a bunch of different genuine 12AU7s and 5814s tubes which I have on hand. It sounded amazing with some GE 5814s that I tried, until it started to scream again. I finally got it to stop oscillating with some Sylvania 12AU7 tubes. I'll probably try rolling in a pair of mullards a little later, but I think that the mullards may be a bit thicker than the sound that I am looking for (nor do I know if they will be stable).

I'm an old hand at tube rolling, and have been running tube equipment in my system for about 35 years now. The Sylvanias sound decent, but its not the same kind of magic that I get out of the 5814s of some of the other premium 12AU7s which I have on hand. I know that kevin at upcale audio recommends exactly one 12AU7 for these preamps. But I'm not willing to spend nearly $200 for a pair of 12AU7s which I may not even like the sound of without more info.

I'm also an old hand at modifying gear, and have been doing so since I was a teenager. And I'm an EE as well. And I strongly suspect that this oscillation can be fixed with a well-chosen capacitor which will allow me to roll-tubes to my hearts content.

However, all of that said, I am finding the sound (when the preamp is not oscillating) to be substantially more 2-D (as in less 3-D) than I am accustomed to hearing out of my ancient, but upgraded, PV6. Although it is faster, more detailed, and has tighter bass.

So I am interested in seeing if anybody else has had this experience with their PV-12A and what they have tried to resolve these issues.

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