Tubes Question

[Killergurt]

Hi all,

I wanted to ask a basic question: does the number of tubes matter to anything besides visual aesthetics?

Is the C2600 with its 6 tubes inferior to the C1100 with its 12 tubes because of the number? Will a device with more tubes also get considerably hotter when used?

Thank you!

[chessman]

Tube count is not a measure of superiority, but rather how many of a particular type is needed to produce the current needed for a particular function. However, the usual rules of “headroom” still apply - if the transient requires more current than is available the amp will “clip” (send a square wave instead of the correct one, which fries tweeters). Thus, a 6 tube amp might clip while a 12 tube amp might not, but similarly a 6 tube might not when a 12 tube does clip. What controls is aggregate current and transient response, rather than mere tube count. As a general rule more tubes means more heat.

[Msegal]

Originally Posted by Killergurt

Hi all,



I wanted to ask a basic question: does the number of tubes matter to anything besides visual aesthetics?



Is the C2600 with its 6 tubes inferior to the C1100 with its 12 tubes because of the number? Will a device with more tubes also get considerably hotter when used?



Thank you!

Since the C1100 is balanced it will require amplification of both the negative and positive leads. Therefore twice as many tubes.

Yes I would expect twice the thermal foot print.

Comparing different brands between one another may be more problematic.
Preamplifiers May contain between 2-4 gain stages each with its own amplification. Some brands may make ALL stages tubes and others only some. It is a matter of design and philosophy.

[Killergurt]

Originally Posted by Msegal

Since the C1100 is balanced it will require amplification of both the negative and positive leads. Therefore twice as many tubes.

Yes I would expect twice the thermal foot print.

Comparing different brands between one another may be more problematic.
Preamplifiers May contain between 2-4 gain stages each with its own amplification. Some brands may make ALL stages tubes and others only some. It is a matter of design and philosophy.

Thank you very much for the explanation. I am trying to learn more about tubes.
In general, does it cost more to own tubes if you factor in needing to replace them?

I read on the forum that tubes can last 4000-8000 hours which is a long time. Is it common for tubes to ‘burn’ prematurely? What would cause something like that?

Are tubes something that I can replace by myself or do I need to take the unit to a Mc dealer? Do you have any sense of how much do the original tubes in the C26000 cost if they need to be replaced?

And lastly, tube goes off, do you need to replace all of them or just the burnt one?

Thank you for indulging my so many questions.

[vintage_tube]

Originally Posted by Killergurt

In general, does it cost more to own tubes if you factor in needing to replace them?

Yes, over the life of a tube preamp verses solid state, it will cost more to own over a long period of time (decades I'm speaking of). How much more will depend on how many small 12v tubes are used. Each new McIntosh stenciled 12v tube costs around $50. The typical 12v tube has a life expectancy of 10K hours (416 days, 24 x7 operation).

Originally Posted by Killergurt

I read on the forum that tubes can last 4000-8000 hours which is a long time. Is it common for tubes to ‘burn’ prematurely? What would cause something like that?.

Tubes fail for three basic reasons. They wear out, short, or become gassy. It is very uncommon for a 12v tube to fail prematurely for shorts and gas; but, it does happen. Shorts are caused by excessive heating of the internal elements, which causes them to warp and touch. Gas refers to air molecules, which have forced their way inside. This is caused primarily by a faulty glass-to-metal seal, where the pin wire passes through the glass envelope to the tube element. Gas is bad news because it causes the tube to conduct more heavily (run hotter), reducing its life.

By the way, it is extremely rare for a 12v tube to "burn out." In other words, the filament wire has a break in it and won't light. This doesn't happen much because the filament is deliberately made rugged enough to outlast the rest of the tube.

Originally Posted by Killergurt

Are tubes something that I can replace by myself or do I need to take the unit to a Mc dealer? Do you have any sense of how much do the original tubes in the C26000 cost if they need to be replaced?

Most McIntosh tube preamps have a left & right tube stage -- so troubleshooting a faulty preamp tube is rather easy & owner replaceable.

Originally Posted by Killergurt

And lastly, tube goes off, do you need to replace all of them or just the burnt one?

Just the faulty culprit. Having said that though --lets say, the left line stage failed with approx. 7K hours (your guess as to how many hours it was in use). You may elect to replace the other 12v tube (right line stage) since it too had approximately that many hours on it as well.

Originally Posted by Killergurt

Thank you for indulging my so many questions.

Best Sir,

Bob

[crwilli]

What he said.

[Killergurt]

Originally Posted by vintage_tube

Yes, over the life of a tube preamp verses solid state, it will cost more to own over a long period of time (decades I'm speaking of). How much more will depend on how many small 12v tubes are used. Each new McIntosh stenciled 12v tube costs around $50. The typical 12v tube has a life expectancy of 10K hours (416 days, 24 x7 operation).



Tubes fail for three basic reasons. They wear out, short, or become gassy. It is very uncommon for a 12v tube to fail prematurely for shorts and gas; but, it does happen. Shorts are caused by excessive heating of the internal elements, which causes them to warp and touch. Gas refers to air molecules, which have forced their way inside. This is caused primarily by a faulty glass-to-metal seal, where the pin wire passes through the glass envelope to the tube element. Gas is bad news because it causes the tube to conduct more heavily (run hotter), reducing its life.

By the way, it is extremely rare for a 12v tube to "burn out." In other words, the filament wire has a break in it and won't light. This doesn't happen much because the filament is deliberately made rugged enough to outlast the rest of the tube.



Most McIntosh tube preamps have a left & right tube stage -- so troubleshooting a faulty preamp tube is rather easy & owner replaceable.



Just the faulty culprit. Having said that though --lets say, the left line stage failed with approx. 7K hours (your guess as to how many hours it was in use). You may elect to replace the other 12v tube (right line stage) since it too had approximately that many hours on it as well.



Best Sir,

Bob

Thank you very much for the detailed response Bob. Learning new things every day!

[Killergurt]

Another quick question about tubes please: are they sensitive to physical jarring? Do I need to be careful when moving my C2600 around? (Similar to hard drives where you don’t want to drop them or rattle them too much).

Thanks!

[jdandy]

Gurt.......Normal handling of tubes does not hurt them. Dropping them is not a good thing, but other than that you are able to handle vacuum tubes without worry.

[Killergurt]

Originally Posted by jdandy

Gurt.......Normal handling of tubes does not hurt them. Dropping them is not a good thing, but other than that you are able to handle vacuum tubes without worry.

Thank you!