[cjc]

The MG Head comes with a 12ax7. Has anyone tried other base 9a tubes (ea. 5965,6211,5814,12bz7,12az7,6829,...)?
Is it SAFE to try the more than 40 variations?
Could it cause any Damage to the headphone amp?

 

[lextek]

I don't know about those. But there has been a lot of sucess with various 5751's.

 

[ServinginEcuador]

You CAN and WILL damage teh unit if you tuberoll in the wrong pair of tubes into any tube amp!!! Make sure you do a search on the internet and come up with a list of all the variables that work with this particular family of tubes.

Here's all the ones I know: 12ax7, 5751, 12au7, ECC803S, ECC83, 7025, ECC82, 7316, 6189, 5814, and so on and so on. Find people selling these tubes on the net and look at what they list as drop-in replacements and you shouldn't go wrong.

When in doubt: ask before you buy or try something out!!!! An amp is an expensive thing to fry!! Take a second and make sure a tube in question works as a drop-in.