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Message started by DB2 on 10/18/17 at 00:18:21

Title: Expected tube life
Post by DB2 on 10/18/17 at 00:18:21

The ZMA has four KT66 output tubes. What is the normal expected lifetime for this type of tube in the ZMA?

Title: Re: Expected tube life
Post by Steve Deckert on 10/18/17 at 01:31:10

The typical tube life of most output tubes is between 3000~6000 hours and when biased right with lower voltages they can go a bit longer. The ZMA makes it easy to bias them right and it is aprox 100 volts lower than most amplifiers to enhance tube life and sound quality.

Steve

Title: Re: Expected tube life
Post by Lonely Raven on 10/18/17 at 14:18:35

I got about 2 years out of my stock set of output tubes. They were still usable when I pulled them, but noticeably less dynamic and "sharp" compared to a new set of stock tubes.

Doing the math, and knowing I sometimes play music 4-8 hours a day, it sounds like I got roughly 4500 hours out of my stock tubes, biased at 50 like the manual suggests.

My preamp tubes get swapped out a lot, so I'm unsure of how long they lasted, but I know my set were also tired when I swapped my power tubes.

So for me, I expect to get about 2 years out of a full set of tubes before I'm wanting a refresh. If I had more money I wouldn't mind swapping tubes out every year and keeping the used ones as spares. I do use my amp a lot, and like when it's punchy and dynamic and so very consistent.

Title: Re: Expected tube life
Post by stone_of_tone on 10/19/17 at 03:57:34

22 months on my first quad.
2nd quad got fried....Steve totally took care of me..... .
3rd quad right now, I expect 22 months again.
I put new rubber on my car early....so I also re-tube/outputs....a little early.
So, $120 to $140 for a quad/KT66 Tung-Sol, is worth it for my Listening durations and ware...... = ZMA/22 months.
I have $1600 of NOS Platinum 6922 tube variants and some sweet NOS RCA 0A3's. .....pretty much set.

Title: Re: Expected tube life
Post by DB2 on 10/19/17 at 22:34:52

"22 months on my first quad."

Basically the same here....