Ampex 351 preamps

Ampex 351 preamps

Ampex 351 preamps

Well, it took a while, but I finally have most of my 6 Ampex 351 pre-amps built. They sound great, I’m really pleased. Following the mods and circuit edits developed by Electrical Audio, we made new circuit boards (thanks to Ian Anderson for his PCB help) and, having gutted the old units of all but the transformers and BIG meters, created our own version of this classic tube pre.

Using real high end components from manufacturers like Mojotone, Vishay and Hairball Audio, the result is a classic sound with low noise floor and a wide range of tone from clean to “OH MY GOD”. I’ve used the prototype with ribbons and condensers (we added an onboard soft start phantom supply) and just love it.

All the documentation from Electric is available in the Schematic Vault http://danrudin.com/Schematic_vault/index.php?dir=Ampex/ and I’ll try to post my own mods and tweaks when I have a minute.

3 Responses to “Ampex 351 preamps”

  1. John says:

    Terrible thing to do to such awesome vintage equipment. People like you should not own stuff like that. What a disgrace!!

  2. Dan Rudin says:

    Well John, to each his own. To me, the headroom added by removing the current sucking tape electronics and use of extremely high-end capacitors and resistors has done nothing but improve the sound of these old gems. The real magic is in the transformers (as I’m sure you know) and those are all original.
    All the best,

    Dan

  3. YUNG PAIK says:

    MAN HAS THE RIGHT TO DO WHAT HE WANTS TO DO
    I DO UNDERSTAND THAT THERE ARE PEOPLE WHO CHOPS B3S
    AND GUT OLD HAMMONDS FOR GREED
    THESE 351S STOCK ARE BIT NOISY AND LOTS OF CAPS IF ORIGINAL NEEDS TO BE REPLACED ANYWAY
    BUT THE MOD MAN DID NOT REALLY DISCOLOR THE TONE WE EXPECT OUT OF THESE REDWOOD CITY GEMS HE ENHANCED IT

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