The only thing those emissions testers are good for is maybe telling you if a tube is shorted or dead, the rest of those readings on those types of testers are very suspect.
KT-150 Tubes- Push Farther or Replace?
Hello All-
Seeking advice from others that may have been in this spot before. I’m currently running my trusty Audio Research GS-150 power amp and I’ve just crossed 2200 hours on this set of tubes. I have a new octet of KT-150’s waiting in the wings.
Within the last 200-300 listening hours I noticed that the bias was requiring adjustment after every 3-4 listening sessions. This seems to be driven by two of the tubes continually falling low in bias adjustment.
As the tube bias is slaved in pairs would/could it be beneficial to isolate the two tubes that keep falling low onto the same pair of sockets with the hope that bias can be more evenly maintained or does it just sound like it’s time for these to GO?
The amplifiers manual states that replacement should be around 2K hrs but I’ve read posts here stating 3K might be achievable. The current situation is lower quality bass response and weaker soundstage. Any thoughts would be appreciated.
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invalid. I'm saying, let go of perfection, go for basic knowledge, I think most people will NOT spend for a big/better one. IF it just finds shorts, not knowing and continuing using them can be quite harmful to your transformer, amp, If they appear to work, like an inexpensive sound meter: they do not need to be accurately calibrated. They will be relatively accurate regarding strength as well as find shorts. If meter shows bad or weak, even if off a bit, relace them, and test the new ones. the results tell you about your tester, and if they are ’matched’ the meter, if not calibrated, will still show you if they are closely matched. Better than being helpless, in the dark. |
We’re saying it’s not good data from those testers. OP sees a pair of KT tubes not holding bias in his amp, and knows the hours are in excess of 2000 - and that alone is far better quality data than an emissions tester will tell you. It’s not adding any information, and in fact might make one draw the wrong conclusions (i.e. that a bad tube is still good). If you buy a grab bag of old unknown tubes and want to quickly screen out the dead-dead ones - then that’s maybe a use case for these testers. A tester is not going to predict an oncoming short. Nothing can. Staying within tube usage guidelines and being an attentive user (check bias occasionally) is how you reduce the chances. If it happens, you can only hope the amp's protection circuitry kicks in in time to prevent board damage. |
@mulveling is a wise man listen to him. Enjoy the music |
- 28 posts total