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.
@mulveling- I hear you and thanks for the warning. My curiosity was driving my actions on this one- I had to know how long they would last. This confirmed that the recommended usage time of 2K hrs was accurate and from what I’ve learned here I’ll probably replace them at 1700-1800 hrs going forward. Anyway, I replaced the entire set earlier this evening and it’s all good!
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OP I use an Accurate Model 157, this is slightly larger 257.
Don't let the rust on the hinges scare you, they all corrode/rust. here's the one I use
You need to know it can test your tube types. I got a 257 for a friend, kept the 157 for myself, so we have both books. If interested, give me a list of your tube types and I will check for you. |
OP this Mercury looks like a variation of the Accurate 157. Perhaps Accurate made it for Mercury, who knows Seller says it works and takes Paypal, so if it doesn’t work, you have Paypal protection.
................................... same thing, a Jackson, ask seller if your tubes are in the chart. ........................................................ I don't know about B&Ks, but he shows an old tube and the unit registering tube strength and shorts, also takes PayPal, but it probably doesn't 't qualify as he doesn't 't say 'works' just shows it does seem to.
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Those old emission tube testers aren't going to tell you much about how your KT150 (or really any tube) are doing. A MaxiMatcher and MaxiPreamp can be pretty useful tools ($830 + $990), but if you only have a quad of KT150 and 6H30 to worry about (the latter typically being very reliable), it's more cost effective to just keep track of the hours (check bias periodically) and replace when prescribed. |
