Fender 400PS,,,

Been looking thru schematics, to find an interesting tube amp to clone and retro fit into an SS bass amp I got recently... And I tripped over this monster!!

Any one own, play, work on,, or even see one of these?

I'm not going to try to build one,,, the tubes would be out of budget!!!
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I know it's been almost three years since you posted. Yes, I own a 400PS. I "inherited" it from one of my friends, the local amp guru, after he died and I ended up handling his final affairs as there was nobody else to do it. No family or relatives. The 400 had been partially disassembled and as I cleaned up the place and got things back to their rightful owners I found almost everything that was supposed to go with this amp. It only took a few hours to restore it to working condition, and that's funny because once I asked about this thing sitting on the bottom shelf of his storage shelves, and he said I couldn't handle it. (Turns out, on numerous occasions I solved problems he couldn't. Eventually he came to accept my troubleshooting skills as being equal to or better than his.)

Anyway, the 400 is a very classic sounding Fender amp...but enormously louder when hooked up to the right speaker system. Yet it has a very effective master volume that will allow it to be turned down all the way without bleedover. When I hit the front end with a cranked Tube Screamer set to max clean boost, and play my guitar through it with the input volume maxed and the master volume set to taste, it's a pure rock and roll MACHINE. It goes head to head with my vintage early 70s Marshall amps.

Time Electronics has pages on the 400 and they have the full alignment procedure (30 steps) for it. It's picky about power tubes and will melt down a substandard tube. (They benefit from a cooling fan over the power tubes.)

A very neat design feature is that each pair of power tubes (there are three pairs of 6550s) is on its own output transformer circuit and via the magic of a switching speaker jack, a pair of tubes that does not have a speaker connected to it is held in standby mode. So it is literally safe to run with no speaker loads attached. That's nearly as unusual as its brutal 435 watts RMS power rating. (It'll go over 500 watts if all is in good order with it.)

Yes, I've cranked it all the way, into three 4x12 speaker cabinets. Yes, it was very, very, very loud.

The head weighs 90 pounds. Getting the chassis into or out of the head shell requires muscle and technique.
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