Princeton 65 Reverb conversion

Discussion in 'Shock Brother's DIY Amps' started by Red Bread, Dec 12, 2020.

  1. Red Bread

    Red Bread Tele-Meister

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    Ok dumb question time
    Never did my own amp,,,done just bout everything else
    I have a Fender Soild state Princeton that fry’d out a while go and is now an a piece of furniture
    The cab and speaker and reverb tank etc are like new and im wondering what option there are to gut this sucker and make it reborn
    I dont need a cab for anything and it was just a home practice amp which has been replaced
    Is there anybody making kits that i can use this chassi for?
    Just wanta use the skeleton and make it glow inside,,,home use 3-5-15watts doesnt make a difference to me,,,just need nuff to push the 12” stock speaker and get a break up at respectable volumes
    Let me know thanks
     

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  2. chas.wahl

    chas.wahl Tele-Meister

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    I'm no expert, but if I had such an amp and wanted to convert it to a tube-driven circuit, the place I'd start is with the quality of the cabinet itself, and whether that's worth upgrading. Apparently many (or all?) of the solid-state Fenders are constructed with particle board, including the baffle. The latter is easy to change, if that makes a big difference (see this discussion). But sinking money and time into a cab-on-hand that's quite a bit heavier, and perhaps acoustically challenged, is a basic decision.

    Next would be investigation of the physical dimensions of the cabinet, and it's chassis. It would be a lot easier to convert if there were a readily-available tray-type chassis (which your amp appears to have, with slanted front panel) that would fit right in. If that doesn't work out, then you're looking at 1) trying to adapt a smaller chassis to fit, or 2) having a chassis custom-made to fit. Another approach would be to carefully measure the existing chassis (including all the holes for mounting components) to see if it could be adapted for a tube build. Bear in mind that aluminum sheet material is a lot easier to work with than steel, especially for the larger holes and any requiring non-circular shapes. Assuming that you have a power transformer and output transformer, if the former is a lay-down type (with one end bell poking through the chassis), then you'd have to do conversion to a circuit that could use a PT of the same size, or modify the cutout, or use a stand-up transformer (that may not be the correct term).

    In any event, not a simple conversion path, it seems to me; but worth investigating.
     
  3. glenlivet

    glenlivet Tele-Afflicted

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    The short answer is.... maybe.
    This particular amp is not a *great* candidate for a tube conversion unless you have a lot of time, and some decent tools.
    The metal chassis on these is an odd ball shape. Small in the front (where the knobs are) but large in the back (where the power plugs in). It's not a nice flat tray.
    It's been my experience with amps like this, that the metal chassis would require either a lot of bending and cutting or a complete replacement (as @chas.wahl said) ... which will either push the price up, or require a lot of labor and metal working. If you pull they tray out....you'll see what I mean.
    If you don't want to get into bending / cutting the tray, you *might* be able to get a micro type circuit (see rob robinets site) jammed in without too much trouble, but it's going to look a little funky, and might require some creative engineering for the placement of tubes and transformers.
     
  4. Mark the Moose

    Mark the Moose Tele-Afflicted

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    This amp has a ton of knobs to use or cover, probably a cheap cabinet and chassis that doesn't have proper cutouts for tubes or transformers. I'd rather start from scratch. Sorry to be a wet blanket.
     
  5. fatcat

    fatcat Friend of Leo's

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    There are several blackface kits out there.

    I think I recently saw Princeton kit on mojotone.

    But you do need to check the cab dimensions to make sure the chassis will fit.
     
  6. Red Bread

    Red Bread Tele-Meister

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    Thanks for all the input
    Tryn to get my brain wrapped round it
    I understand the stock tray is shallow,its never had tubes
    This might sound stupid but,,,,if i gutted the soild state out of the tray or even replaced the tray(whole family’s tin knockers)and just used the face,,is there a reason i couldnt mount a,say a vibro champ kit upside down in the cab to get the room for tubes etc and just run the input and couple of knobs on the stock face

    im not recording or playing out itd just be a living room amp so the cab wood type etc isn’t important
    I have other amps for that
     
  7. schmee

    schmee Doctor of Teleocity Silver Supporter

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    You can, hard to say what it will cost. You could use the existing Power transformer maybe, if you go with a SS rectifier. For heaters for the tubes you could put in a little filament tranny for that. ~$15
    Buy a cheap hole punch set to punch tube socket holes from Harbor Freight etc : $50
    Buy a Princeton turret board and sockets and caps etc. Say... $100?
    You may be able to reuse the pots if they are the right values. I have soldered to PCB mounted pots before and it was fine.
    Tubes $65?

    So.... $230 in parts to make a Princeton? Call it $250?
    Depends a lot on if you can use the PT and output tranny, That's where the money is, wonder what voltages the PT runs?
     
  8. glenlivet

    glenlivet Tele-Afflicted

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    The chassis tray and face plate are usually the most difficult stuff to get, and if you can get those crafted cheaply...your half way there!
    The tray is probably only and inch or so deep, but with a little planning, (or with a specially crafted tray) you should be able to get tube sockets mounted with room to spare.
    your tray is probably going to look something like this...when you pull it out and strip it.
    [​IMG]

    https://geekorama.weebly.com/frontman-25r-part-i.html
     
  9. Red Bread

    Red Bread Tele-Meister

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    Ive had the tray out while ago when it stopped working
    Well it just lost volume,,,,everything works but on full volume it sounds like it’s barely on
    It didnt have any burn marks or blown fuses,,,nothing looked fry’d
    I couldnt find an issue an it was just a 4th amp that looked cool in the studio so i put it back together and there its sat
    I just thought if i can use the chassi i can have some fun
     
  10. Willie Johnson

    Willie Johnson Tele-Afflicted

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    I thought about rehousing my Champion 600 into the cab from an old Fender Ultra Chorus; I thought better of it and just let the Champ 600 be its own thing, but I kind of regret junking the old solid state chassis--maybe if I would have had it checked out, it could have been something as simple as the volume pot or spraying the inputs with deoxit and could have kept it for nice, loud clean tones. Maybe give the 65 another shot before shoehorning some tube amp into there.
     
  11. Red Bread

    Red Bread Tele-Meister

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    Your right i havent really played with it
    Might be a volume pot or a broke conection i havent seen
     
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