Changing my pre amp's tubes

Discussion in 'Preamps / Channel Strips' started by mrbwnstn, Oct 3, 2005.

  1. mrbwnstn

    mrbwnstn Guest

    Ok, so I've got some old Presonus Blue Tube mic pre's that have been collecting dust. Let me first say this, I personally don't think the Blue Tubes are as "terriable" of mic pre's as everyone makes them out to be. True, they are on the low end of the spectrum, but they do add gain and a level of warmth.

    That being said, I want to try and see if I can get the most out of these pre amps and I'm wondering if a lot of the lack luster performance with these is the actual tube? I've never changed tubes in an amp (guitar, pre, or otherwise) and I don't know how they're rated, or how to shop for a good tube. They're elusive, sort of like a guitar pick-up. You don't know how they're going to sound unless you spend the cash to change them out... and THEN decide you don't like them. ;)

    Anyway, so my questions are:

    A) Do you think there would be an improvement with new tubes.
    B) How do you shop for replacement tubes? (ie, power ratings, etc.)

    Any help would be appreciated.
  2. Wooly

    Wooly Guest

    Hey I'm new here but not new to recording so hi everyone:

    I have a Digitech VTP 1 that I just swapped tubes in.

    I came with Sovtek 12AX7A's and one of the fizzled out on me a year ago. So then we put some chinese 12ax7's in. Pretty muddy, but they got me by till I got serious about tightening up the sound:

    I tried some Telefunken tubes *ECC something* I think (I'm no expert but they are the 12 ax7's equivalent and then I bought some NOS phillips tubes 12AX7WA's on ebay.

    I played tracks off "Dark Side of the Moon" and picked the best set to my ears and that was that.

    Just read the manual or open the box and read the printing on the tube and find a replacement. You can try ebay or a tube/electronics shop you trust. Swap them in and out and listen to the ones that you like the best! You might be surprised at what you pick. :) :) :)
  3. jonyoung

    jonyoung Well-Known Member

    Tubes will definitely affect the overall sound quality of a pre, and the better the components in the rest of the circuit, the more noticeable the improvement. There's an ebay store named BNB Tubes, and also try . He has very good descriptions of the different flavors of tubes on his site. Go to the 12AX7 page and pick from there. Some of the lower gain models like 12AU7 or 12AT7 will be warmer sounding with very low noise. Might as well get a few different kinds to broaden your pallette if you have a few of these pres, it's a relatively cheap way to come up with different tones & textures.
  4. CoyoteTrax

    CoyoteTrax Well-Known Member

    Home Page:
    Jonyoung's right about the 12AU7's and the AT's. I like the AY's as well for low noise and smooth freq response. Rolling those tubes will always do you good from the stock tubes already in there.

    Shoot for the american tubes where you can (IMO). The specs are fantastic and they're so smooth. GE, Sylvania, Philips, are brands you can't loose with. Also the new Tesla/JJ's are fantastic. They're 12AX7/ECC83S tubes and are identical to some 60's GE tubes I have. Smooooooth and very quiet.
    sandyphoto (on ebay)
    riatla (on ebay)

    ...are places I've purchased excellent tubes from for great prices and trusted tube measurements and guarantee's.

    Also, different tubes will sound muddy or clean with different instruments in different pre's. So keep that in mind. Some tubes are great for vocals but muddy with vocals...and vica versa.

    Spend the money, you won't be disappointed. If you have single channel mic pre's buy tubes in singles where you can and spend the money you'd spend on pair's buying a variety of tubes to switch out for different applications.
  5. twenty5south

    twenty5south Guest

    This place has it all at very reasonable prices, not to mention great service, huge inventory, no minimun order..... check out their page it'll tell you all about their staff and operation.

  6. CoyoteTrax

    CoyoteTrax Well-Known Member

    Home Page:
    Nice link Ben. Thanks.
  7. twenty5south

    twenty5south Guest

    No Problem..... :cool:

  8. schizojames

    schizojames Active Member

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    Hey you still around mrbwnstn?

    I have a Blue Tube DP which is essentially the same thing. Replacing the stock tube with a Tesla/JJ was a cheap way to get a little improvement. A slightly more expensive way to get get a higher degree of improvement would be to contact Matt over at

    He did a modification to my BlueTube DP that, in combination with a nice tube, makes a very considerable improvement. Just shoot him an email, order some free sample op amps from texas instruments, and time willing, he might be able to take care of you. He also did a special mod to my 3630 that lets it compete with compressors in the $500 range.

    Keep getting all you can out of that cheap-o equipment,
  9. CoyoteTrax

    CoyoteTrax Well-Known Member

    Home Page:
    Yeah James those Tesla/JJ's a great deal and a great way to smooth out freq response and lower your noise floor.

    If I had had to pick just one modern tube to recommend for dramatically improving the freq response for a cheap mic pre it would be the Tesla/JJ's every time.

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