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Old 11-22-2011, 11:51 PM
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Default Conrad-Johnson Premier 350 discussion

This thread is for discussion of the famous Conrad-Johnson Premier 350 amplifier:

From the C-J website:
Hybrid Solid-State Circuit.
The Premier 350 benefits from an interesting hybrid of solid-state technologies. The distortion characteristics of an amplifier are dominated by it's voltage gain stage. We have selected FETs for this application, because, like tubes, and unlike bi-polar transistors, they produce almost no strident odd-order harmonic distortion. The output stage of an amplifier must efficiently couple the high amplitude signal produced by the voltage gain stage to the loudspeaker system to assure the power and control needed to produce a musically accurate response. Bi-polar devices have been specified for the output stages of these amplifiers because they offer about 1/4th the output impedance of a MOSFET, resulting in much better control of the loudspeaker. This is most noticeable in faster, more solid bass response.

Zero Feedback.
Negative feedback is an engineering technique used to reduce measured distortion. While feedback does achieve this goal, it also introduces aberrations in the tran-sient response characteristics of the circuit. The Premier 350 uses conrad-johnson's unique auto-linear gain block for the voltage gain stage, which achieves low distortion with zero loop feedback by exploiting the symmetrical distortion properties of n and p channel fets.

Solid Power Supplies.

Power supply circuits present a parallel signal path to the audio circuits. Ideally this signal path provides ac signals with a zero impedance path to ground. Any deviation from this ideal is reflected in the reproduced audio signal. Thus the power supplies are as important to audio performance as the audio circuits and must be accorded equal attention in design. The Premier 350 features a discrete dc regulators to power the critical voltage gain stage.

Quality Parts.

As with all Premier components, the Premier 350 is constructed from the highest quality, carefully selected parts for unrivaled sonic performance and reliability. The circuits employ polypropylene and polystyrene capacitors extensively, except in the main power supply storage, where special high-speed electrolytics are used because of the extremely high capacitance required. The audio circuit and related power supplies utilize precision low inductance laser-trimmed metal foil resistors. The obsession for parts quality extends to the high quality, gold plated input jacks and output connectors - even the internal wiring is chosen on the basis of its sound quality in its specific application.

Thoughtful engineering, specification of the finest available component parts, and painstaking care taken in production make this an audio amplifier without peer in music reproduction. We invite you to arrange an audition with your conrad-johnson dealer to confirm for yourself the extraordinary musical performance of the Premier 350.
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  #2  
Old 11-23-2011, 12:32 AM
dpod4
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Gentlemen, start your engines...
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Old 11-24-2011, 09:38 PM
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Quote:
Originally Posted by dpod4 View Post
Gentlemen, start your engines...
dpod my friend... I should add two more suggestions:

First... as you doubt already know, that thing is a heavy 85 lb. and is not a well balanced lift. The left side is so much heavier than the right. It's a hoss to move around... and please be careful. The cooling fins on the left side all have sharp edges and will show no mercy to your forearms.

Secondly... although this may be a good thing as you already like the sound...this was one of the first units in which C-J used proprietary teflon caps. I don't remember a break-in issue but the sound should only get better for you with time. I've never found the sound at all fatiguing and none of the reviewers that I've read did either. Is it as holographic as my LP140 tubes, probably not but it sure is faster with tighter lows. Back to the Ravens.

Enjoy the champaign beast!

Bob

Last edited by Coppy; 11-24-2011 at 09:44 PM.
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Old 11-24-2011, 09:50 PM
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Quote:
Originally Posted by Coppy View Post
dpod my friend... I should add two more suggestions:

First... as you doubt already know, that thing is a heavy 85 lb. and is not a well balanced lift. The left side is so much heavier than the right. It's a hoss to move around... and please be careful. The cooling fins on the left side all have sharp edges and will show no mercy to your forearms.

Secondly... although this may be a good thing as you already like the sound...this was one of the first units in which C-J used proprietary teflon caps. I don't remember a break-in issue but the sound should only get better for you with time. I've never found the sound at all fatiguing and none of the reviewers that I've read did either. Is it as holographic as my LP140 tubes, probably not but it sure is faster with tighter lows. Back to the Ravens.

Enjoy the champaign beast!

Bob
Bob

Where does it say it has teflon caps?

certainly not in the spec's

Quote:
The circuits employ polypropylene and polystyrene capacitors extensively, except in the main power supply storage, where special high-speed electrolytics are used because of the extremely high capacitance required.
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Old 11-25-2011, 12:09 AM
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Quote:
Originally Posted by turntable View Post
Bob

Where does it say it has teflon caps?

certainly not in the spec's
If it will come through, here is an excerpt from Roy Gregory's review in HiFi Plus of the P350 referring to the teflon caps: /Users/rbc7/Desktop/Screen Shot 2011-11-24 at 10.50.27 PM.png. Got to figure out how to add this stuff here, but maybe you can look it up on their site. There were reviews in both HiFi+ and ToneAudio. I might also have the original C-J product flier someplace. If so I can e-mail a picture to you.

I can remember discussing the caps with Tor Sivertsen (then sales manager for C-J) when I bought the 350 some years ago.

Bob

Last edited by Coppy; 11-25-2011 at 12:12 AM.
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Old 11-25-2011, 01:02 AM
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Quote:
Originally Posted by Coppy

dpod my friend... I should add two more suggestions:

First... as you doubt already know, that thing is a heavy 85 lb. and is not a well balanced lift. The left side is so much heavier than the right. It's a hoss to move around... and please be careful. The cooling fins on the left side all have sharp edges and will show no mercy to your forearms.

Secondly... although this may be a good thing as you already like the sound...this was one of the first units in which C-J used proprietary teflon caps. I don't remember a break-in issue but the sound should only get better for you with time. I've never found the sound at all fatiguing and none of the reviewers that I've read did either. Is it as holographic as my LP140 tubes, probably not but it sure is faster with tighter lows. Back to the Ravens.

Enjoy the champaign beast!

Bob
Thanks, Bob. I had read where most of the weight was on the left side so I was super careful lifting and placing it. Thanks for the good counsel. CJ and others have also advised about the burn in for Teflon caps - 300+ hours to hit their stride so I will be certain to listen for changes although I think it sounds awesome out of the box. Your description is very accurate. The sound is very fast. I feel like all veils have been lifted without any glare or edginess being present (I'm very sensitive to overly strident or etching sonics). Cheers.
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Old 11-25-2011, 01:06 AM
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Quote:
Originally Posted by dpod4 View Post
Thanks, Bob. I had read where most of the weight was on the left side so I was super careful lifting and placing it. Thanks for the good counsel. CJ and others have also advised about the burn in for Teflon caps - 300+ hours to hit their stride so I will be certain to listen for changes although I think it sounds awesome out of the box. Your description is very accurate. The sound is very fast. I feel like all veils have been lifted without any glare or edginess being present (I'm very sensitive to overly strident or etching sonics). Cheers.
Now all you need is a C-J preamp!
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  #8  
Old 11-23-2011, 12:45 AM
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We need Coppy to chime in...he's got a Pr350 IIRC....
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conrad-johnson CT-5 and LP70S, Michell Gyro SE MkII, SME V, Koetsu Urushi Vermilion w/ EAR324, Oppo BD-83SE, Sonore OpticalModule with Uptone Audio LPS-1.2 power supply, Uptone Audio EtherREGEN, SOtM UltraNeo with Keces P3 power supply, Shunyata Sigma Ethernet & Alpha USB cables, Schiit Gungnir Multibit Gen 5 USB DAC, Schiit Loki DSD DAC, Mac Mini/Roon, Harbeth 30.2 or Dynaudio Contour S3.4 w/ Esotar 2 tweeters, REL R-305, Shunyata Delta and Venom ICs, Shunyata Venom speaker cables, Shunyata Delta NR & EF, Venom NR-V10 and NR-V12 and Venom V14D power cords, Shunyata Denali 6000/S V2,
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  #9  
Old 11-23-2011, 05:29 PM
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Quote:
Originally Posted by Puma Cat View Post
We need Coppy to chime in...he's got a Pr350 IIRC....
I'm here... just tuned in to this thread. You folks know how I feel about this AMP, it's an incredible bargain for this level of performance... can't let it go. Some say it's a bit delicate but I've not had any issues although I'm careful not to connect/disconnect anything while it's on or has been on. Those big caps inside retain a good deal of their power long after it's shut down. As has been said, be careful not to short the outputs... ever. I think some folks at dealers who are constantly pulling equipment in and out for demo have had difficulty when they were too casual about connections.

Now that's said, enjoy the dynamics... the P350 will drive just about anything. And it's response is dead flat. It's still a reference amp for reviewers overseas. It's difficult for them to use our beloved tube amps as the don't always match speakers. Here's a ToneAudio review if it comes through on this post...
/Users/rbc7/Downloads/review_premier350_j_dorgay_ta.pdf

Hmm... maybe not. Got to figure out how to add this PDF file. In the meantime, enjoy the music.

Stephen... how are the KT120s doing?


Last edited by Coppy; 11-23-2011 at 05:34 PM.
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  #10  
Old 11-23-2011, 01:22 AM
dpod4
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Nov 2011. Unpacked brand new PR 350. I am living in a special time space continuum.



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Last edited by dpod4; 11-23-2011 at 01:27 AM.
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