How to tell when power tubes need to be replaced?

[Jerome W]

Don't get how it is set up Bob.
In serial with the power plug of the amp ?

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[vintage_tube]

Originally Posted by Jérôme W

Don't get how it is set up Bob.
In serial with the power plug of the amp ?

Sent from my iPhone using A.Aficionado

Tigger out on any component that offers a 6v or 12v trigger out. You can check out their web site for more options. Most who have ordered on AA for the MC2301's use model ENM T44D69A which powers from 115v -275v.

Happy Holidays Folks

Bob

[Jerome W]

Originally Posted by vintage_tube

Tigger out on any component that offers a 6v or 12v trigger out. You can check out their web site for more options. Most who have ordered on AA for the MC2301's use model ENM T44D69A which powers from 115v -275v.

Happy Holidays Folks

Bob

Oh I see !
No more in the Mc tube amps camp so cannot use such a unit.

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[Allan W.]

I have lived with high powered tube amps for 10 years. If a (6550C or GL KT-88) power tube went I changed all 16. Looking back my average life span was 18 months. That got a little pricy. A few years back I upgraded from VTL-300 to VTL450MKII which have fault protection. Now I just change the tube that shows "Fault" and move on. Strange, I have not noticed a performance change. Up side I ended up with lot of extra 88's and 6550's with lots of life left.

[MyPal]

Jérôme... I prefer the DC variety & simply hang these off the Trigger Out ports on the various McIntosh components I want to measure.

Remind me to dust this weekend!

[AudioGremlin]

Wouldn't it be great if tube equipment manufacturer's provided a built in resettable hour meter on their products. Years ago when I serviced tube based radar sets they all had hours run metering. Surely with expendable components the small extra cost of a meter would make sense.

[Niles]

Originally Posted by AudioGremlin

Wouldn't it be great if tube equipment manufacturer's provided a built in resettable hour meter on their products. Years ago when I serviced tube based radar sets they all had hours run metering. Surely with expendable components the small extra cost of a meter would make sense.

I like the tube sentry feature in the new version of Mac's MC275.

For me, this is even better than an hour meter, since not all brands run for the same hours, especially if the bias has been neglected or the amp has been abused.

[MyPal]

Originally Posted by Niles

I like the tube sentry feature in the new version of Mac's MC275.

For me, this is even better than an hour meter, since not all brands run for the same hours, especially if the bias has been neglected or the amp has been abused.

Apart from the amp's protection circuitry, Only a tube tester like the Amplitrex AT1000 or Maximatcher will offer certainty on tube condition. Power tubes deteriorate at different rates. I use an Amplitrex AT1000 to test & rematch the quads / octets periodically, say every 12 months or 1500 hours.

[Niles]

Originally Posted by MyPal

Apart from the amp's protection circuitry, Only a tube tester like the Amplitrex AT1000 or Maximatcher will offer certainty on tube condition. Power tubes deteriorate at different rates. I use an Amplitrex AT1000 to test & rematch the quads / octets periodically, say every 12 months or 1500 hours.

In the case of the new McIntosh MC275, this is not the only way to accurately assess the condition of the power tubes. About the McIntosh tube sentry feature:

A high speed sentry monitor circuit turns off the power when a worn tube is detected. When the tube is replaced, normal service is resumed. An LED beside the power tube glows green when the tube is good and red when it needs replacing.

Although this is not as detailed as a tube tester, i.e., you don't get an analog value of the tube's condition, the McIntosh tube sentry feature is entirely adequate to accurately advise the user when to replace a worn out tube. Every power amp should have this feature.