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Conrad Johnson Classic noisy channel.

I have owned this from new and upgraded it to se.Before and after the mod,the left channel tube rush becomes noisy after 3 months use.I am a moderate user,approx 3-4 hours use per day and do not leave the pre on when not in use.I have used 3 sets of mullard m8080/cv4058 tubes with the same result.Swapping tubes from left to right,noise swaps to right channel.Have had pre checked and all tube voltages are within spec.Are there any other classic users with this problem.Dave.
dre

Showing 1 response by elizabeth

elizabeth
6,726 posts
 
An aside: odd how hard it is to pin down a minor issue in a new product. And how even tiny internal parts variations can have a profound effect.
I had a Phono box, and got a second one. They were supposed to be identical, in fact they had sequential serial numbers! yet one (the 2nd one) sounded better than the first. So much so i returned the first one for a restocking fee!! As i would always reguard it as inferior. (even thought nothing was really wrong with it.)
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