Please Help: Replacing tubes on ASL MG-Head

Hi everyone,
I have a Antique Sound Lab MG Head DT (the first version, not the OTL version). I would like to try changing the tubes on it... The problem is that I know NOTHING about tubes...

can anyone tell me what the 3 tubes are about? Also, what type of tubes should I get. Also, where should I get them? How much should I pay?

By the way, I own a pair of Grado RS-1 and the source is a Sim Audio Moon Eclipse CD.

Any info would be very appreciated...

Thanks ahead
If memory serves the older non-OTL version had the same tube complement as the current version. If that's the case, you're looking at two EL84's for output and a 12AX7 for a double triode. Currently they are shipping the unit with Sovtek EL84's and a JJ 12AX7. I am not sure if that is what yours has or not - probably.

We recommend the Electro Harmonix EL84 "EH" as an upgrade from the Sovtek's. I think it's a good step up. I have an MG Head at home and use EH's in it - sounds great. The JJ is ok - you can fiddle around with any one of a million 12AX7 replacements if you like. The Sovtek's are a fine choice, and that's what I use.

As for New Old Stock tubes - there's loads of NOS stuff out there and I am sure somebody will recommend the various choices and sources for these guys. I do not sell NOS for a variety of reasons I won't go into, so I only recommended tubes that are currently in production.

You can get the EH and Sovtek brands from New Sensor ( for pretty cheap. A matched pair of EH 84's will run you $12.80/ea. The Sovtek 12AX7LPS will run you $15.50.
Check around on -- there are several entire threads devoted to tube rolling the MG Head. I'm using NOS Sylvania black-plate EL84s and a NOS Telefunken 12AX7 -- paid about $70 for all three on eBay.

Start off with the 12AX7 -- that's the "preamp" tube, and it will probably make the biggest difference in the sound. Lots of people have experimented with about every 12AX7 under the sun, as well as other tubes like the 5751 that also work (I'm not too clear on what all tubes are "equivalent," myself, but the info is all in the threads on
Some interesting info here - I have posted before about how I auditioned the MG Head DT last year, but wound up opting to buy the MF X-Cans v.2 instead, an OTL design I judged to be better-sounding. But that MG Head had an output transformer - I didn't know they had since revised the unit to be an OTL. I wonder how the two units would stack up against each other now?