Conrad Johnson Premier 5 resurrection.

Do It Yourself - everything from building your own hardware to room
treatments.
Post Reply
Hifiasylum
Regular
Regular
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

Hi.
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 :-)
Attachments
IMG_6253.JPG
Modification done.
IMG_6253.JPG (324.59 KiB) Viewed 1031 times
IMG_6246.JPG
New RIFA PEH169 caps.
IMG_6246.JPG (297.71 KiB) Viewed 1031 times
IMG_6245.JPG
Bad printboards repaired, but not optimal solution.
IMG_6245.JPG (467.63 KiB) Viewed 1031 times
IMG_6242.JPG
New Beyshlag resistors and teflon sockets. Bias adjustment modification made more precise.
IMG_6242.JPG (300.98 KiB) Viewed 1031 times

User avatar
admin
Site Admin
Site Admin
Posts: 1164
Joined: Tue Jan 03, 2012 1:50 pm
Location: New Hampshire, USA
Contact:

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.
-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.

MLAS
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).
Where
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.

Hifiasylum
Regular
Regular
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

Hi.
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