12ax7a question

[vintage 5.0]

I have a California Audio Lab Sigma II dac. It uses one 12ax7a tube in it. Can a 12ax7 tube be used as well or is there some reason I should stick to the 12ax7a. I have some 12ax7 tubes and was curious.

 

[Big Harry]

You can use a 12AX7 in place of a 12AX7A. The 12AX7A has a controlled warm up time which is the difference between tubes, otherwise they are the same.

 

[StuartB]

Same.

 

[vintage 5.0]

Thanks guys as always this site has so many people with so much knowledge.

 

[century tek]

Golly, I would think that as long as you have been around that you could have certainly looked it up. All tube manuals explain the suffix "A" or any other added letter but we are glad to help so I am not really picking on you am I?



I'm just giving you a hassle. It's all out of fun!

 

[vintage 5.0]

I actually did look it up. It was a little confusing and made some mention of voltage difference. It might have meant in regards to how it warmed up. I was not sure so wanted to make sure and not have another repair bill. Just wanted to run it by someone else that knows tubes more. I only now have one tube system and a old 1958 tube juke box. All of my other systems are solid state.

 

[century tek]

No problem!

 

[triode17]

The "A" version had a controlled heater warm up for use in series string devices, that have no power transformer. All the heaters were set up to add to 120v. they were finding that some tube heaters couldn't handle the initial strain and would blow open upon power-up. Now, it doesn't matter anymore. Its an anachronism.