Questions About MPX3
Oct 29, 2007 at 2:14 PM Thread Starter Post #1 of 3


100+ Head-Fier
Nov 2, 2002
Hello all,

I have owned a maxed out MPX3 that I purchased from forum member Voltron around December of last year, and I am very happy with it, but I have gone through four different tubes in my driver socket within that period. Three of the tubes were the stock EH6SN7, with each creating static and noise when in use after about a hour of power, the final driving tube I used was a Ken Rad VT231 which also has serious static issues too when used for more than a hour. The other two tubes that do not seem to have a problem are Sylvania VT231 6SN7GT which I use as the two output tubes. I enjoy the sound very much, especially with the stock EH6SN7 in the driver socket and the Sylvania VT231 6SN7GT's in the output but I am now interested in trying out some new tubes improve my experience and maybe last a little longer then my old tubes.
Can any recommend me some points or directions on where to start, as I am fairly lost reading all the threads here about tubes? I am also interested in learning about the "SLAM" upgrade that seems popular and from what I understand I can use with my amp with a simple set of adapters. Yet again, I really do not know where to start so any direction would be great. Also I would like to keep my cost reasonable, I understand that some tubes can go for 100's for each but I rather not spend that much on one single tube (but to purchase a whole set of tubes then I might be flexible).
Oct 29, 2007 at 4:42 PM Post #2 of 3


Headphoneus Supremus
Aug 15, 2003
Unless you have really bad luck, you shouldn't be going through tubes so quickly. I think you should be, if you aren't doing it now, wire brushing the pins of the tubes before installing them, this may cure your problem with static.

If you have a fully maxed out MPX, you should already be SLAM capable, all you will need is the 5687 adapters, which fit in the 6sn7 sockets.

As to which tubes to experiment with the choice and combinations are so many, it's hard to tell you what to try without knowing what music you listen to and with which headphones.

I can tell you that I prefer the 6bl7's to the 5687's as output tubes. For the input I enjoy various 6sn7's and their variants in the driver spot. There are a couple of the 9 pin miniture tubes that I enjoy and many I do not.

Much depends on the sound you prefer. Myself I prefer my "sound fat" and my "women lean", but not everyone has that same preference.

- augustwest
Oct 30, 2007 at 9:11 PM Post #3 of 3


100+ Head-Fier
Mar 24, 2006
Call Mikhail at Singlepower and buy one ECC TYPE#1 adapter for the 'drive' tube position. (He also has tubes!)
6sn7's can be very microphonic, especially in the 'drive' position. You won't see them used in Pre Amps by major manufacturers for this reason.
The Sylvania VT231's are quiet but don't add much to the sound in the 'drive' position (with the exception of a metal base 'W') but are very nice IMHO as output tubes.
Do a search on the ECC adapter. You will find a great variety of tube choices at low prices in comparison the pricier NOS 6sn7's.
I have been using an ECC #1 adapter for the past year and my collection of NOS 6sn7's is gathering dust.

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