AU-X1 with missing Phono EQ board F2770

[KlausDK]

Dear All
I have had the good fortune to find an AU-X1 here in Denmark, pretty beaten electrically, but with the help of a friendly tech (and amongst other components, a new set of output transistors from Kale), its been brought back to life what regards the line and power section, and it plays beautiful!!

However, to my dismay, the tech found out, that one of the Phono EQ boards (F-2770) is missing. If nothing turns up, I will see if I can have new boards made from the prints in the service manual, but if any of you should have a spare board, also if it is non-working, as long as it is repairable, I will be happy to buy it. As far as I understand, this board was used only in AU-X1?
BRgds Klaus

 

[Ronito6]

Hen’s teeth. You can have a new board fabricated before a used 2770 becomes available for purchase. (Although you might try PMing willy6)

You should have your tech install the oscillation elimination mods and the 2770 and 2771 voltage management mods that have been referred to here on AK. You do want to protect those lovely new transistors you got from Kale after all.

Finally, has your tech replaced the small signal relays? The originals are certain to cause problems if left in service.

 

[KlausDK]

Thanks for your reply, no nothing has been done to the phono section yet, I took out the other EQ board, just to be sure nothing happened from that part of the amplifier.
I will see if I can find info on the "the oscillation elimination mods and the 2770 and 2771 voltage management mods", do you remember the name of the thread? Likely something with AU-X1
All the black flag caps has been changed in the line and output section, I can see a good deal of those in the phono section as well.
Brgds Klaus

 

[ghamilton]

 

[Hyperion]

This should give you a start:-
https://audiokarma.org/forums/index.php?threads/restoring-an-au-x1.709469/
https://audiokarma.org/forums/index...-au-x1-output-transistor-replacements.684619/
https://audiokarma.org/forums/index.php?threads/the-mighty-au-x1.672322/
https://audiokarma.org/forums/index...apan-to-export-model-plus-restoration.477461/

 

[Ronito6]

Thanks for your reply, no nothing has been done to the phono section yet, I took out the other EQ board, just to be sure nothing happened from that part of the amplifier.
I will see if I can find info on the "the oscillation elimination mods and the 2770 and 2771 voltage management mods", do you remember the name of the thread? Likely something with AU-X1
All the black flag caps has been changed in the line and output section, I can see a good deal of those in the phono section as well.
Brgds Klaus

Here ya go!
All my favorite X1 (or applies to X1) threads. Get that tech to reading....

Very good instructional with great pics.

• Summation of ALL Kuehne modifications
• Hyperion shows the Kuehne mod to his X1's 2770/2771 boards.
• Harolda's shows the Kuehne mod to the X1's flat amp.
• My (actually I found it demo-ed on websites here in Japan) small signal relay mod is described.

http://audiokarma.org/forums/index.php?threads/the-mighty-au-x1.672322/page-10#post-11068313

• EE guy Martin Kuehne comments on and explains his modifications.

https://audiokarma.org/forums/index.php?threads/the-mighty-au-x1.672322/page-8#post-9441630

https://audiokarma.org/forums/index.php?threads/the-mighty-au-x1.672322/page-8#post-9444292

• Mighty X1 (MM / EQ DC drift mod by Hyperion and Star Ground mod by Harolda as per Martin Kuehne's recommendations.)

http://audiokarma.org/forums/index.php?threads/the-mighty-au-x1.672322/page-10#post-11068313

• Diode replacement

http://audiokarma.org/forums/index.php?threads/sv03-sv04-diode-replacement.756284/

SV03 --> 3x 1N4150
SV04 --> 4x 1N4150.

• MOS FET for 919 from Kale Hyperion advice about matching

http://audiokarma.org/forums/index....osfets-need-replacements-advice.836505/page-3

• Santhosh AU-X11 restoration

http://audiokarma.org/forums/index....-x11-restoration.788908/page-11#post-11930567

• 2772 AU- X1 My custom board instructions. BeatleFred reference and Kuehne mod notes

http://audiokarma.org/forums/index.php?threads/installing-a-new-2772-into-an-x1.836320/

• AK member Bigdrive found the best header and sockets to fit my custom board

https://audiokarma.org/forums/index.php?threads/installing-a-new-2772-into-an-x1.836320/page-2

• Keuhne mods applied to a 919

http://audiokarma.org/forums/index.php?threads/replacement-filter-caps-for-au-919.831517/page-5

• Hyperions X1 restoration

http://audiokarma.org/forums/index.php?threads/restoring-an-au-x1.709469/

...and watching.

 

[KlausDK]

Thanks a lot, lots of reading to do
BRgds Klaus