tommyc
New Head-Fier
- Joined
- Sep 1, 2012
- Posts
- 27
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- 39
I just switched out my stock JJ 12AT7 for NOS British Military Mullards matched pair tested for low noise and harmonics. Best $100 I have ever spent. I had assumed that most reports of tube changes were the typical exagerations and hyperboli that you typically read about on these forums.
My honest assessment is that the stock tubes should immediately be removed from any MHA200 and dropped in the trash, you will not listen to them again. If you have not tried any other tubes in your MHA200, I suggest going to your local McIntosh dealer and ask if you can try out some Mullards or anything else they have on hand. If you can not hear the difference between Mullards and JJ you may need to re-evaluate your system or make sure there are not medical issues.
I have put in another order for two more pairs of these military grade tubes. As soon as I have more cash available, I plan to order several more matched pairs.
Spending money on $2000 interconnect cables, $100 fuses, $200 power cords, etc to me now seems quite foolish if you have not swapped out the stock tubes for $100. You will get much greater sonic improvement immediately (no burn in, no sitting for hours A/B testing) over any of the above. I think the best way to describe the change is to imagine all your high resolution music has been re-recorded by Chesky using Binaural microphones.
http://www.mullardtubes.com/Mullard-ECC81-12AT7-CV4024/?ID=0&ProductID=152
Totally, those stock tubes are really a hinderance to the wonderful machine below.
If you like the Mullard sound, you may want to hunt for a pair of their 1950s square getter version from the Mitcham factory. My currently favourite is a pair of Marconi branded B309 from Mullard Blackburn. I have very good result with Made in Holland Mullards too (Those are Phillips made and branded as Mullard).
Telefunken ecc801/ecc81 and Brimer 6060 yellow/white T are very good too but they sound different from Mullard.
I am waiting for a pair of GEC a2900 to arrive, they are supposed to be one of the best 12at7, but my local tube store said they might be too bass heavy for head-amp use.
P.S. Here are a couple links that I find very helpful for tube identification/selection.
Mullard factory and date codes
Factory ratings (it's just someone's personal opinion, don't take it as gospel, but a nice starting point nonetheless)