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EQUIPMENT FORUMS >> TORII MK IV >> Replacing Output Tubes
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Message started by Andrew77 on 08/18/22 at 02:18:35

Title: Replacing Output Tubes
Post by Andrew77 on 08/18/22 at 02:18:35

I just spent the last several hours replacing tubes one at a time to determine why I was losing 90 percent volume after 10-20 minutes of play time on my 1+ year old Torii MKIV.

The problem occurred on both left and right but at different times.  Each tube replacement still resulted in volume loss until I replaced the KT66 output tubes.  Problem solved.  Right channel..... Then left.

At least one tube on both channels failed within a couple of days of each other?  What are the odds?  Is this an indication of a problem with my power (not conditioned, straight from the wall) or other common component?  I would have replaced all 4 as a matched quad anyway, but seemed odd to have simultaneous failures.

I don't play super loud. Moderate listening time in the evenings.  Any insight would be appreciated.

Title: Re: Replacing Output Tubes
Post by safebelayer on 08/21/22 at 22:36:34

Andrew,

I recommend writing to Steve directly, if you haven't already. He's the designer same creator of your amp, so will have the most comprehensive understand of your situation. He's generally very prompt with his responses.

Very sorry to hear about your experience. I had tube issues right out of the gate as well. Mine was likely due to tube damage during shipping. The good news is all will end well with Decware helping you, particularly with an amp under warranty. Good luck.

Title: Re: Replacing Output Tubes
Post by Tommy Freefall on 08/25/22 at 22:32:54

Andrew,
Over the course of about a year I experienced pretty much the same thing about 3 times with KT66 tubes. About every 4 months one or both of the channels would weaken or go silent.
I was convinced it was an amp issue.
I was on the verge of sending it back to Decware to diagnose.
As a last ditch effort, I decided to pop in a fresh set of EL34s instead of the usual KT66s.
That was about 10 months ago and the amp has run fine ever since without any issue.
I guess I was having bad luck - kept getting weak KT66s.


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