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chapitalist 07-27-2012 01:30 PM

LP70s bias question
 
Hi Guys,

First a big hello, and to say what a pleasure it is to have found so many CJ fans here at AA. :tresbon:

And secondly a question, would be very grateful for any suggestions. I recently shipped my LP70s back from asia to London and thought it would be a good opportunity to replace the tubes.

I took the plunge and ordered a quad of Tungsol KT120s. Problem is with the tubes in place I cannot get the bias right, doesn't matter how much I play with the setting the LED never lights. The sound is clearly wrong, compressed and scratchy. Do I need to do anything else to get these tubes working in the amp? Or more worrying could I have broken anything else inside?

Cheers,

Nick

jwhite613 07-27-2012 01:41 PM

chapitalist... Welcome To AA!!!

:welcome2.:

joeinid 07-27-2012 01:47 PM

Quote:

Originally Posted by jwhite613 (Post 342177)
chapitalist... Welcome To AA!!!

:welcome2.:


Welcome to AA.

:banana:

Myles B. Astor 07-27-2012 02:41 PM

Quote:

Originally Posted by chapitalist (Post 342170)
Hi Guys,

First a big hello, and to say what a pleasure it is to have found so many CJ fans here at AA. :tresbon:

And secondly a question, would be very grateful for any suggestions. I recently shipped my LP70s back from asia to London and thought it would be a good opportunity to replace the tubes.

I took the plunge and ordered a quad of Tungsol KT120s. Problem is with the tubes in place I cannot get the bias right, doesn't matter how much I play with the setting the LED never lights. The sound is clearly wrong, compressed and scratchy. Do I need to do anything else to get these tubes working in the amp? Or more worrying could I have broken anything else inside?

Cheers,

Nick

Did you check the fuses?

ronenash 07-27-2012 09:47 PM

There is clearly a problem with the amp. As Myles said check the tube protection fuse first, you have an LED next to the fuse that will light up if the fuse popped. If this is not the case there are more fuses inside the unit but it should be serviced by someone who knows what he is doing.

chapitalist 07-28-2012 04:29 AM

Quote:

Originally Posted by ronenash (Post 342368)
There is clearly a problem with the amp. As Myles said check the tube protection fuse first, you have an LED next to the fuse that will light up if the fuse popped. If this is not the case there are more fuses inside the unit but it should be serviced by someone who knows what he is doing.

Thanks, that's my worry too. Probably did too much at once with shipping, new tubes and a new environment.

rromeo 09-20-2018 03:09 PM

Thread revival. FYI- I had this same issue, led never came on and it was the tube. New tube and bias no problem.

Formerly YB-2 09-23-2018 10:36 PM

Yep.......... always look at what you did last (change tubes) and work back from there. Good luck. Miss my CJ gear. Great stuph.


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