Conrad Johnson Premier 5 resurrection.

Do It Yourself - everything from building your own hardware to room
Post Reply
Posts: 5
Joined: Fri May 20, 2016 4:27 pm

Conrad Johnson Premier 5 resurrection.

Post by Hifiasylum » Fri May 20, 2016 5:21 pm

I am a longtime owner of a set of CJ Prem. 5 monoblocks.
Currently not working after being heavily modified by capable personnel. (or so I believed)
Reconfigured to Triode mode and changed all resistors to Beyschlag and caps to Mundorf silver in oil.
Also changed big caps to Rifa PEH169.
Have tried with substitute for EL34 - KT77, have understood that this was a direct replacement.
So, now I need to try a new road, having spent quite a sum of cash on improving these monsters.

I am thinking of separating the power section of the amplifiers and hardwiring these point to point.
The "other" part of the amplifier I was thinking to make new prints, with modern technology and modern prints.
The old prints are almost gone and it is no longer possible to purchase new replacements. :-(

I have mailed the schematics and parts list for these amps in order to support this forum (couldn't find them here my selves)
I will be trying to gather information sufficient to produce the prints for the pre-part of the amps and find a good solution to hardwire the rest.

I am attaching a few pictures from the work on the amps so far.

Later, Lars :-)
Modification done.
IMG_6253.JPG (324.59 KiB) Viewed 1078 times
New RIFA PEH169 caps.
IMG_6246.JPG (297.71 KiB) Viewed 1078 times
Bad printboards repaired, but not optimal solution.
IMG_6245.JPG (467.63 KiB) Viewed 1078 times
New Beyshlag resistors and teflon sockets. Bias adjustment modification made more precise.
IMG_6242.JPG (300.98 KiB) Viewed 1078 times

User avatar
Site Admin
Site Admin
Posts: 1170
Joined: Tue Jan 03, 2012 1:50 pm
Location: New Hampshire, USA

Re: Conrad Johnson Premier 5 resurrection.

Post by admin » Fri May 20, 2016 5:56 pm

Wow. What a great project. I look forward to seeing the outcome. I updated our database with your schematic and there is another version of the premier 5 schematic and parts list that you may want to look at as well. Let us know how it turns out.
Home Theater in Member Gallery
Conrad Johnson Main Page

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

Super Advanced
Super Advanced
Posts: 42
Joined: Mon Apr 13, 2015 6:04 pm

Re: Conrad Johnson Premier 5 resurrection.

Post by MLAS » Tue Dec 06, 2016 9:13 am

Great undertaking with probably the best electrolytics (RIFA).
How's the project going in the mean time?

I have a pair Premier Fives myself with a Premier Three pre and thinking about substituting the EL-34's for KT77's.
What was your experience with that?
I see you have now installed the Winged "C" (SED) EL34's instead.

Posts: 5
Joined: Fri May 20, 2016 4:27 pm

Re: Conrad Johnson Premier 5 resurrection.

Post by Hifiasylum » Tue Dec 06, 2016 10:01 am

Unfortunately, due to very busy times at work - I have not had any time to go forward with the project.
I am however, dependent on locating someone with the knowledge and the time to take one such a rather substantial project.
(As I am not "fluid" with designing and understanding complicated schematics myself.)

I do not have any hurry, I prioritize to achieve proper quality before I continue with such a project.
As you can see from the pictures, the prints are not something worth including in future plans...

Winged C was used by the last guy who tried to modernize and repair these amps, therefore I cannot say anything about quality in sound.
Premier 5 is a real keeper, have had offer to sell but will not incline to that.

Regards, Lars

Post Reply