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inexpensive "make-up" gain?

Discussion in 'Pro Audio Equipment' started by hollywood_steve, Mar 19, 2001.

  1. hollywood_steve

    hollywood_steve Active Member

    Jan 3, 2001
    Those "vintage" passive EQ units sure do sound nice, but the price you pay is the need for an extra gain stage. (unless someone has a better solution?) I need two channels of gain (30db or so) to compensate for a two channel passive Telefunken EQ I just purchased. A lot of the obvious choices are now being advertised as mic preamps so their prices have skyrocketed. Any well constructed, decent sounding line amps that are still sensibly priced?


  2. sapplegate

    sapplegate Active Member

    Mar 5, 2001
    Sensibly priced is a relative term so let's say $500 and under.

    Of course you could just buy a solid-state mic pre like a Behringer Ultragain (definitely low-end) or a PreSonus MP20 (a little better) and use it as a line amplifier, but mating one to a vintage tele would be considered sacrilege around here...

    The following four links are for mic/line amps in kit or pre-assembled form. I haven't used any of them, just run across them while surfing...

    Maybe Mr. Forssell would like to expound the virtues of his product at this point. Two channels will set you back $500. http://www.forsselltech.com/JMP-1.htm

    Billed as a mic pre, this one uses a discrete front end with a video opamp for the driver. Don't know how suitable for a line amp it would be. $250 for two channels. http://www.audioupgrades.com/products.htm

    This is a hi-fi line amp. I don't know the operating specs on it so it may not be suitable for pro-level (+4dBu) operation. $190 for a stereo single-ended card. Use two for balanced operation. http://www.welbornelabs.com/classa.htm

    This is just a PCB for a single channel line amp. You have to supply the parts as far as I can tell. Again, for hi-fi application so it may not suit for pro levels. http://www.sound.au.com/project37.htm#top

    Hmmm...seems like I'm saying "it may not be suitable" a lot so take all of the above with a grain of salt. Perhaps some real designers could comment on these designs and their suitability as make-up gain stages?
  3. hollywood_steve

    hollywood_steve Active Member

    Jan 3, 2001
    Thanks, Scott.

    I'm familiar with the Forssell & Audio Upgrades products and either of those should work very well if I go the DIY route. The "hifi" gear is cool, but I've run into problems before when trying to utilize "cool old tube hifi gear" in a pro level, balanced environment. So I'll stick to "pro" products.

    But before I break out the soldering iron, I'm still trying to find any existing products that might work in this application. All of the thousands of good quality modular consoles out there were stuffed with line amps for summing and other purposes. The Neve 1272 and Telefunken V72 line amps have magically transformed into high priced mic preamps over the years. But there have to be lots of other good quality line amps out there that should work fine for my needs. Any ideas for "plug & play" solutions? Thanks.

  4. Bear's Gone Fission

    Bear's Gone Fission Active Member

    Jan 4, 2001
    If you're thinking about DIY-ing it, you might want to look at the schematics from Jensen for ideas. (http://www.jensen-transformers.com/apps_sc.html) Plenty of options here, so you should be able to find something that will mesh well with your needs.

    da Bear

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