art mpa gold tube swap?

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i heard the stock tubes in this thing aren't anything special and should be swapped for some jj 12ax7s. have you guys heard any other tube ideas for this piece or tried them yourselves? I've got one on the way to match up with the pro vla i just got.. btw this compressor surprised me!! it really adds some nice warmth and punch to a mix.

also, hows the tube drive on this pre? is it too brittle? fixable with a tube swap?? any experience with it in general?

thanks a lot


Paul
 
I have this unit. I like it. The gain is good and I like it when working ribbon mics. It has decent gain and it's clean until you get into the upper 2/3's. I also like the variable impedance (again with the ribbon mics).

The stock tubes are 12ATs and 12AX series tubes are totally interchangeable but I wonder how you know you need to do this change if you don't have it yet?

I've had it for a year now and like it. It's cheap and pretty nice for DI'ing bass or e-guitar and keyboards. The high voltage setting does bring some tube saturation but not a night and day difference.

The preamp has it's place.
 
JJ's are often recommended for guitar amps too? strange same tube is recommended for a preamp:confused:.... JJ's for everything?
 
yea I heard that a tube swap helps these units out a lot from someone who has one. He said he put jj's in it and it helped the tone soo.... are you sure that it's 12at7? i thought it was 12ax7... hmmm. but out of the box it's got a good sound huh? even better.
 
Oops...my bad...had it backwards. I opened mine up and sure enough. A 12AX inside. :o BTW...I picked mine up used/refurb'd from GC. It's entirely possible that the stock tube was replaced. I don't know what these things come with from the factory.

I'm happy with it just the way it is but this thread caused for me to play around with a couple different tubes I had rolling around in the drawer. I put a JJ ECC83, a Mullard 12AT and a Tung-sol 12AU. I've got a Univalve amp which will turn a guy into a tube collector in a hurry.

The difference wasn't noticable when the plage voltage was set to "Normal". When I switched the plate to "High" I could tell a slight difference. The 12AX seemed just a touch louder and "smoother" sounding. I'm guessing due to the gain factor of the tube. The 12AT was pretty darn similar sounding to me while the 12AU was very clean sounding. Almost no difference when switched from high to normal.

Don't consider this a scientific test. I was just fooling around and thought to play with it a bit. I had a SM57 plugged into it and simply did some voice tests. I'm wishing now that I'd put it up in front of a guitar cab to see how the tube swaps sounded with a higher SPL source.
 
http://www.emerysound.com/Microbaby.html

at the bottom of the page at this link is a "Mad Scientist" set of small tubes...it looks pretty fun to compare all of them.

I think some people can actually hear more than others, and small changes seem larger than many would consider noticeable.

I don't know if its from years of hearing hi end audio components or lack of...
Supposedly some hear a big difference in tubes. I don't get it, but don't doubt it.

Mullard's are the hi end right?
 
COOLCAT said:
http://www.emerysound.com/Microbaby.html

at the bottom of the page at this link is a "Mad Scientist" set of small tubes...it looks pretty fun to compare all of them.

I think some people can actually hear more than others, and small changes seem larger than many would consider noticeable.

I don't know if its from years of hearing hi end audio components or lack of...
Supposedly some hear a big difference in tubes. I don't get it, but don't doubt it.

Mullard's are the hi end right?
Click to expand...

You may want to consider using a different tube in each side. Unless you plan to use the mpa for overheads. It gives you the option of having basicaly two different pre-amps.

As far as mullards go. There is "new old stock" And those are big bucks. Then there are the new production mullards that run about $15. more if you want them matched, ballanced, etc.

The stock tubes are not bad, they are pretty clean and bright though.
I have the mullard new production in one side and when driven hard it becomes VERY warm.

I would give some different tubes a test drive and see what you like.
There's alot of discussion on the MPA's over at GS. They are pretty popular over there. There's alot of tube swappers over there at cog whores.

F.S.
 
I have nothing to add, i have been interested in seeing what people are doing with this piece and i want to get e-mail notification. Cool thread.
 
I have the Digital MPA (basically the same thing with digital outs, I think). The 12AX7s that came with it were not what I wanted -- I don't want them to overdrive early like I might in a guitar amp -- rather, I want a lot of clean gain with a little even-order harmonic distortion at the top. The stock tubes fell over and sounded farty very quickly (i.e. - no good for a guitar amp, either). I wound up going with some Czech made 12AX7s (not JJs) that are working well. That's not to say that all the tubes they ship are bad -- just the ones I got :)
 
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