Wednesday, February 25, 2015

West Fillmore amplifier, ultra rare! BEAST!

  Got to restore this crazy piece of hippy history, a West Fillmore 200 watt bass amp. Rare as hens teeth!

I like this amp. It's stupid simple under the hood:

And it has the biggest output transformer I've ever seen on a bass amp! Bigger than an SVT:

Output transformer is ultra-linear and built by the legendary Dynaco. I wonder if they ever used this in a high fidelity amplifier? I'd love to see it.

Amp was blowing fuses. Fortunately it was a simple re-cap job. Transformers are okay. I added a bias pot and some bleeder resistors as well so it now bleeds off those massive filter caps when the amp is off.

Speaking of which, NO USER SERVICEABLE PARTS INSIDE! This baby has 575 volts running around in there. Leave it to the pros to work on. It'll put a massive hurt on you if you slip.

Circuit is pretty primitive by todays standards. It's basically just a big ol' Fender Bassman 100 circuit, just with way more power. Nothing fancy, just plug in your passive pickup loaded bass and enjoy some real warmth and depth in your sound.

Can't help but wonder if there is a way to make a recording of all the bands over the years are locked inside this beast. I don't know anything about this brand but it seems like perhaps it was built for the Fillmore West? Could be dead wrong about that. But either way, this amp makes me wanna play a Fender Rhodes!


I like this amp. It's stupid simple under the hood:


  1. thanks for this post. I have a West Grande I bought in 1994. Still my favorite bass amp. Used to have the matching 2-12 EV SRO cabinet, but got stolen 15 yrs ago. Would you happen to have schematics for the Grande and Fillmore? I'd like to build a Fillmore clone.

  2. Fender Bassman huh? I had a vintage 70's Bassman 100, but I thought the West was supposedly built like a Sunn, which was also based on a Dynaco circuit............

  3. Nope! Look up the schematic. 12AT7 driver / phase inverter rather than 6AN8 like Sunn or Dynaco. Thanks for chiming in! J