Some progress on my Brownface Princeton (6G2) build.

Discussion in 'Shock Brother's DIY Amps' started by RatBug, Oct 4, 2019.

  1. RatBug

    RatBug Tele-Meister

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    I'm sorry I didn't post during the process but I was much too busy overthinking things, second guessing decisions, and searching the whole internet for proof that I wasn't an idiot.

    I'm using the Mojotone style chassis that is for sale on ebay and the Mojotone face and back plate.

    So I had to deal with the wrong size transformer holes and the swapped power cable and fuse holes.

    I have a spare switch hole for the Ground Switch that I'm not installing so if you have any ideas for mods or extras I can use that hole for that would be awesome.

    Also any mods in general that I might want to try after I'm sure the basic amp works.

    here finally are some pics of the mostly completed chassis.

    Feel feel to point out where I have made a mess of things, I will try not to get defensive and tell you all you're wrong even though I'm new to this and y'all have been at it for awhile.

    [​IMG]

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  2. ladave

    ladave Tele-Holic

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    Very cool! What speaker are you going to use?
     
  3. RatBug

    RatBug Tele-Meister

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    Good question... I was going to be asking that question myself.

    I was considering a 12" or at least upsizing the cabinet a bit so I could later but lately I;ve been reading a lot about 10" speakers being a part of the sound that people like.

    So I'm up for ideas... 10" or 12"?

    As for which? This will be mostly for home use and some small jams, so I was looking at what you all call "Inefficient" speakers, but now I'm thinking something with some clean headroom.

    Mostly classic rock and old country with a bit of old punk rock for fun,
     
  4. ReverendRevolver

    ReverendRevolver Tele-Holic

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    If it does all of those, it wont do old country at as good a volume. I love 70s/early 80s punk, and old country. A 12 will have more lows exist than the 10, the 10 will have more punch. Old country leadwork doesn't care about the extra lows, but otherwise will be guitar dependent. Old punk..... it's a not widely talked about thing that East Bay Ray got his dirt from the amp and the knobs on the guitar Everything else was playing. Sure, he had a notoriously unreliable echoplex unit perched atop the amp, but no dirt pedals.
    I like 10s, but a 12 will probably get you where you want. Classic rock you just dial in the breakup.

    There are more opinions on 12" speakers than there are TDPRI users(we r indecisive?) But picking a flavor is part of the fun.
     
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  5. RatBug

    RatBug Tele-Meister

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    That is why I started looking at more efficient speakers. I think it may I have read that it might give the amp a notch or two on the volume knob before breakup.
     
    Last edited: Oct 4, 2019
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  6. JohnnyCrash

    JohnnyCrash Doctor of Teleocity

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    I used a 10” in a 40 watt “Super Reverb” I built into a blackface Princeton chassis and cab.

    Plenty of bass. Hell, many pro bass cabs use 10”s, so if they have enough bass for bassists...

    Anyway, it’s a Legend 1058. Sounds great. Classic Fender ceramic sound.

    For my brownface build (a 30 watt 6L6 version of the brown Deluxe), I used a new (Italian) Jensen C12. It’s alright, but nothing special.

    You might also want to go old school and try a low powered AlNiCo speaker. Especially if you want to sweeten highs (if they’re too sharp on the ears).

    Going with a “British” style speaker might add more mids than you might like: brown Fenders are more midrangey than blackface circuits... or it might make for a rock machine.
     
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  7. Hatfield92

    Hatfield92 Tele-Holic

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    I’ve got an Eminence Maverick in my 6G2. It doesn’t really color the sound, and it gives you a good deal of flexibility as far as the volume at which you hit breakup. I can’t recommend it enough.
     
  8. RatBug

    RatBug Tele-Meister

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    Thank you all for the tips.

    This will be the first real amp I've owned in 20 years (other than a 5 watt monoprice amp I got last year) I've mostly just plinked around on an accoustic.

    Heck even when I did have an amp in the 80's and early 90's I didn't pay any attention to anything but how loud it was and could I make it sound like it was broken.
     
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  9. King Fan

    King Fan Friend of Leo's

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    Speaker choices are so dependent on your taste, your ears, and your playing style, that any advice I give is likely wrong. I tried a couple ceramics to be like the originals, but ended up much preferring an ALK1028.

    Try a 10 and see, in any event. This is a big gutsy signal compared to later Fender 10s.

    As for mods, the best (and only) mod I found for my 6G2 was a simple NFB cut (to zero). The ground switch hole is down by the 120AC, so I just drilled a small microswitch hole for the NFB and used the ground switch slot for a Fender-style bias pot. Altho that makes it super easy to bias without dropping the chassis, that also requires external bias test points, and when I see your tidy bias pot I figure you don't really need to change.
     
  10. RatBug

    RatBug Tele-Meister

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    I'm pretty set on going with a 10" now. I am still fussing about whether or not to make the cabinet a couple inches taller in case I later decide to try a 12".

    That might seem like a small thing, what is a couple inches? but it makes a difference on the Tolex. The material I bought is 54" long, if I add up both sides and the top of a standard sized Princeton cabinet I get about 52", that means that I can go from lower corner to lower corner leaving both seams on the bottom. Adding 2" to each side adds 4" to the total and suddenly my seems are no longer on the bottom. :eek:

    I was considering an NFB mod using that empty ground hole but I hadn't considered the location next to all that noise... Thanks for pointing that out.

    I added a bias pot to the bias board. I considered following your idea but I'm afraid I would bump a pot on the outside of the amp and screw things up, that sounds like me.
     
  11. King Fan

    King Fan Friend of Leo's

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    No, your bias pot looks great, and I wasn't suggesting you change it. FWIW the Fender style isn't prone to being bumped, as it only turns with a small screwdriver inserted into an access hole. From Doug Hoffman's great parts catalog...

    upload_2019-10-7_10-6-56.jpeg
     
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  12. RatBug

    RatBug Tele-Meister

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    Ah... I forgot about those, awesome. I considered one of those early on while looking through Hoffman's BIAS page but once I discovered the little PCB mount style I was done.

    I didn't do it the same way he did with a 50K ohm pot and a a 10K ohm resister making a voltage divider. I just added it (a 10k ohm) in series with a 27k ohm resistor
     
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  13. mjcyates

    mjcyates Tele-Meister

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    In case you are interested I have a nice Weber 10A100 that I can let you have for a good price. I bought it for my Harvard build but ended up keeping a WGS G10C in the amp.

    https://reverb.com/my/selling/listings
     
  14. monkeybanana

    monkeybanana Tele-Meister

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    mmhmm
  15. RatBug

    RatBug Tele-Meister

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    I will look at the specs on that and let you know.
    Thanks
     
  16. jhundt

    jhundt Doctor of Teleocity

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    re: 12" speaker

    is your cabinet the same size as a Princeton Reverb? Because it is possible to fit a 12" into a Princeton Reveb cabinet, you just have to experiment a bit with placement in regards to clearance between the speaker and the transformers.
     
  17. Garruchal

    Garruchal Tele-Meister

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    re: speaker
    My go-to amp is a 68 custom pr. I did the mod on it which installs a switch to convert it to the 65 prri circuit on demand.
    With the stock Celestion 10-30, it sounds fantastic. I have also used it with a 12" cab, both with a Veteran 30 (good sound and louder than the stock speaker) and with a Celestion 12T-100 (even louder, but a clearer, sort of sterile sound). I prefer the stock 10" to a 12" in the cab. It sounds the best to my ears, and has such a deep bass that I have to dial it down. The only time that I want as much bass as it has is if I am playing solo.

    One caveat: in my band, I dial in the Princeton to the tone I want, have it close to me so I hear it well, and mic it to get a good mix with the band. I have it at 5 or 6. At a recent concert, the guitarist in the opening band used my amp. She plays real loud and is used to a DeVille. Although I was enjoying how loud she could get the Princeton and what it sounded like turned up to 9, I think I was hearing the speaker being overworked and could imagine that for her needs a more efficient speaker and/or a beefier OT might be the answer.

    Still: I would recommend a 10" speaker. The extra bass that a 12" might produce is not part of the sound I can use.
     
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  18. RatBug

    RatBug Tele-Meister

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    From what I have been able to find the standard Princeton cabinet has a Baffle height of about 13".

    I could cut an 11" hole in that but that leaves only 1" top and bottom.

    As I said earlier. I could make the cabinet a couple inches taller but from what I'm reading here a 10" will probably suit my needs just fine.
     
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  19. jhundt

    jhundt Doctor of Teleocity

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    yes this is true, a 10" might be just perfect.

    But if you are building the cabinet, make the baffle removable - not fixed in place like my Princeton was!

    And do not fix any cleats permanently to the bottom of the cab. In any future attempt at fitting a 12" speaker you might need to leave a portion of the lower edge un-cleated.

    That's all. You may be happy with a 10". I wasn't aware of/couldn't afford a good new speaker when I modified mine. But if you are building it yourself, you might want to keep the option open. And I will say this: my Princeton sounds pretty good with an old 12" speaker in it.
     
  20. Mark the Moose

    Mark the Moose Tele-Meister

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    I’m running a tone tubby silver bullet alnico 10 in my 5f11...a very similar circuit. It kills.
     
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