Conrad Johnson Premier 5 resurrection.

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Hifiasylum
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Conrad Johnson Premier 5 resurrection.

Post by Hifiasylum »

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
Modification done.
Modification done.
IMG_6253.JPG (324.59 KiB) Viewed 6329 times
New RIFA PEH169 caps.
New RIFA PEH169 caps.
IMG_6246.JPG (297.71 KiB) Viewed 6329 times
Bad printboards repaired, but not optimal solution.
Bad printboards repaired, but not optimal solution.
IMG_6245.JPG (467.63 KiB) Viewed 6329 times
New Beyshlag resistors and teflon sockets. Bias adjustment modification made more precise.
New Beyshlag resistors and teflon sockets. Bias adjustment modification made more precise.
IMG_6242.JPG (300.98 KiB) Viewed 6329 times
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admin
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Re: Conrad Johnson Premier 5 resurrection.

Post by admin »

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
Main stereo: ART Amplifier and ET7s2. 2nd stereo: PV-14L and MV-55. Previously Owned: PF2 preamp, Evolution 2000 Amp, PV-12AL preamp, D/A-2b Vacuum-Tube Digital Processor.
MLAS
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Re: Conrad Johnson Premier 5 resurrection.

Post by MLAS »

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
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Re: Conrad Johnson Premier 5 resurrection.

Post by Hifiasylum »

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
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Re: Conrad Johnson Premier 5 resurrection.

Post by audiobill »

Hi Lars,

Could you give us an update on your project?

Many thanks!

Bill
Hifiasylum
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Re: Conrad Johnson Premier 5 resurrection.

Post by Hifiasylum »

Hi. Long time no update. Have sent the amps to a person with probably knowledge of this kind of repair / modification 1 year ago. But have not received any updates so far. Kind of a bad sign. Will collect amps if no work has been done. Need a reliable and competent person to take on this job. Long term plans these... Gotten a Lyra connoisseur 4.2 L SE meanwhile, would be interesting to see how that would work together with the beasts...
Regards Lars ☺️
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Re: Conrad Johnson Premier 5 resurrection.

Post by audiobill »

Thanks, best of luck!
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Re: Conrad Johnson Premier 5 resurrection.

Post by admin »

Hifiasylum wrote: Thu May 23, 2019 8:05 am Hi. Long time no update. Have sent the amps to a person with probably knowledge of this kind of repair / modification 1 year ago. But have not received any updates so far. Kind of a bad sign. Will collect amps if no work has been done. Need a reliable and competent person to take on this job. Long term plans these... Gotten a Lyra connoisseur 4.2 L SE meanwhile, would be interesting to see how that would work together with the beasts...
Regards Lars ☺️
Wow, a year... I would probably try to get those back as soon as possible. Hope everything turns out ok, best wishes. Keep us updated.
-admin
Home Theater in Member Gallery
Main stereo: ART Amplifier and ET7s2. 2nd stereo: PV-14L and MV-55. Previously Owned: PF2 preamp, Evolution 2000 Amp, PV-12AL preamp, D/A-2b Vacuum-Tube Digital Processor.
Hifiasylum
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Re: Conrad Johnson Premier 5 resurrection.

Post by Hifiasylum »

Hi again.
Yes, its been quite some time without action. And no reply from the person in charge. Will probably travel down to this individual to get the cj's back.
Will update when new info is present.
Best regards, Lars
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