PRRI: Built with care

Discussion in 'Amp Central Station' started by Luthier Vandros, Aug 14, 2019.

  1. Luthier Vandros

    Luthier Vandros Tele-Holic Silver Supporter

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    Well, in between juggling two babies, I found a small window of time to tear down and clean the 2013 PRRI I just took in on trade. Aside from some pet hair and a chewed up pick trapped beneath the reverb pan bag and two small indentations in the tolex, the amp is in excellent condition.

    The tubes are a mix of OE GTs and EH 6V6s. I have some NOS tubes coming in to replace them.

    Anyhoo, once I liberated the chassis from the cab, I was pleasantly surprised by the construction of the internals. Despite the lack of through-plating on the board, obvious care was taken in assembly and the Belton octal clamps suggested this before I even gained entry. The use of hot glue as a strain relief measure is appreciated, as are the backup rectifier diodes and etc. Unfasten a few headers and one has easy access to the bottom of the board.

    Here’s an electron’s eye view..

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    Last edited: Aug 14, 2019
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  2. Uncle Daddy

    Uncle Daddy Tele-Holic

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    My first printed circuit amp lasted about 2 years before the traces started cracking. The tec told me that lead-free solder is brittle and doesn't stand up well to repetitive heating and cooling. That got me interested in building my own, and so recently finished a PR kit, and I'm really pleased with the sound, but totally understand why manufacturers would want to build something that can be assembled much faster.
     
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  3. Luthier Vandros

    Luthier Vandros Tele-Holic Silver Supporter

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    I’ve rolled my own and prefer to in general, but do enjoy robo-builds too. It’s purely anecdotal, but I’ve never had issues with PCB amps. I recognize some have.
     
  4. Texicaster

    Texicaster Tele-Holic

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    Cool!

    Thanks for the photos!

    I've been considering the Alessandro rewire (mostly deciding against this) and curious of what the innards of the PRRI are like.

    It kinda dawned on me...Solid state hi-fi amps from the 70's are still rocking just fine! The idea these PRRI's are routinely crapping out in <10 years is a myth I think. Especially since they normally don't get the play time as a hi-fi stereo amp.

    Sure moved around a bit more maybe and may run hotter but that looks pretty well put together!

    TEX
     
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  5. Luthier Vandros

    Luthier Vandros Tele-Holic Silver Supporter

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    Ha! My recent journey into PCB/RI amps has everything to do with me not having time to DIY. I considered just hand-wiring the Thing, but I know all the other parts would start gnawing at me and Id end up with an empty shell and wallet. The thing sounds excellent as it is! Just rolling some nice tubes through it and am making sure it’s all good to go.
     
  6. Bob Womack

    Bob Womack Tele-Holic

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    Have you ever thought about the Marshall designs with the vents on the top? I'm thinking they would attract picks, hair, and assorted detritus far more efficiently.

    Bob


    (I recently traded a great AS-100D that I used to stare into and wonder about.)
     
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  7. Luthier Vandros

    Luthier Vandros Tele-Holic Silver Supporter

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    Lol!! My old band once recorded a single that was mixed on the same board that, “we are the world,” was mixed on. The thing sat in new orleans, at least until Katrina hit. The engineer told us there’s a French fry from the disco era inside of the console. No one had the guts to remove it.

    Off the tangent, I have to start a new thread about sole of the measurements i took from the amp. Yikes!
     
  8. Dacious

    Dacious Poster Extraordinaire

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    A distinction can be drawn between Fender's reissue amps like the PRRI, TRRI, SRRI, DRRI Bassman and the entry line of amps, in the Hotrod and Blues series.

    The historic resissues and sortas like the Custom Vibrolux/Vibroverb generally have chassis mounted power and sometimes preamp tubes. The old fibre tagboard has been replaced by a solid PCB and the controls are on a daughter card. Many quality amps, Mesas, Marshalls, Rivera's are built this way. It's serviceable and because components like heaters are separated they won't get cooked With good PCBs and solid traces they're good for decades

    The lower price amps have PCB mounted power tubes, flimsy boards and other shortcuts in construction like heater traces in the board. These are prone to long-term damage by heating and resulting trace lifting failure.

    A friend's HRDx cooked a tube, which burnt the bias and grid resistors and crisped the sub-board. It was repaired but isn't pretty.... Long-term? I told him sell it or trade it.

    If I had a choice I'd pick a SF or BF simply for better quality components (overbuilt) and simpler to service tagboard. But I wouldn't knock back a well made reissue amp.
     
  9. King Fan

    King Fan Friend of Leo's Ad Free Member

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    Luthier, those are great close-up yet wide-field photographs. Seriously.

    I know good photography is technique not gear, but what'd you use, and yeah, any technique tips?
     
    Last edited: Aug 15, 2019
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  10. Luthier Vandros

    Luthier Vandros Tele-Holic Silver Supporter

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    Hey, KF.

    Thanks for the kind words. I was reluctant to post this since I had such little time to set up the shots.

    I just use the onboard camera on my iPhone 10 and try to really get low angle shots of whatever I’m focusing on. This means getting the camera down into the chassis, which requires the usual safety precautions.

    I’ve always been fascinated by the micro. My parents gave me a microscope set when I was a kid, so I guess I took some of that with me as an adult. I’m no pro; I just know what stimulates my sense of sight!

    Edit: full transparency. My wife and I are crashing at her parents house with the kids. I know she doesn’t read my posts, so let me be honest. If I’d have taken the pics I wanted, some would have included wider shots that would have captured some background. It would have been obvious by the appearance of lacy doilies, tropical plants, virgin mary statues, and random bamboo that I was in a Filipino’s household. I have no idea why that mattered at the time lol.
     
    Last edited: Aug 15, 2019
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  11. King Fan

    King Fan Friend of Leo's Ad Free Member

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    Yeh, I have a couple pro / artist photographer buddies who now use iPhones for close-up work. Those cameras are nice. But not rare, and not a big DSLR on a tripod with an expensive macro lens. Which means your composition skills and good photographic eye get even more credit.
     
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  12. Luthier Vandros

    Luthier Vandros Tele-Holic Silver Supporter

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    I need to break out of these starving artist skill sets I’ve been equipped with hehe. I do love taking pics, so I really appreciate the feedback. You might dig some of my other restoration threads. Have much better pics.
     
  13. Tone Chase

    Tone Chase Tele-Meister

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    The inside of the PRRI looks quite serviceable to me. I have a FSR Fudge Brownie, and never felt the need to look inside. Thanks for posting this. I was confident that Fender put the right stuff in these Reissue amps to get them to sound right. After seeing these pictures, I am convinced that these are durable, serviceable amps.

    I have seen the insides of boutique, original handwired holy grail amps, low and high end PCB, etc.

    The Reissue amps from Fender seem to embrace building technology, in a nice, clean layout, that is simple, recognizable, effective, and durable.
     
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  14. Luthier Vandros

    Luthier Vandros Tele-Holic Silver Supporter

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    It literally takes 5 minutes or less to gain access to the bottom of the board. This is starting with the amp fully buttoned up.
     
  15. LudwigvonBirk

    LudwigvonBirk Tele-Holic

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    Very nice photography!

    Q: If one were/are a professional service person doing warranty or real-world, billable work, and this [out of warranty] ss amp needed new caps: would it be best practice to completely de-solder the old caps and re-solder in new ones (to the board), or, snip the cap leads and join those old leads to the new cap leads?

    (I get that it depends on the repair-friendliness of specific boards. Looking at these shots for this 2008 PR, I think I would go for the latter, snip and join...as the least invasive/lower risk solid fix. Maybe snip and join is part of the design, idk)

    ((I’m in CE land as a career. Under warranty we give you a new unit, swap boards on defective units and sell some of those as b-stock or employee discounts. Out of warranty, you are pretty much sol other than us giving you some proper-recycling credits))
     
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  16. Luthier Vandros

    Luthier Vandros Tele-Holic Silver Supporter

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    Hey, bub. Thanks for the kind words!

    If this was a PCB amp that wasn’t through plated, I’d snip the leads and twist/solder the new caps in. I’ve done it the other way using a lower heat setting on my iron, as well.
     
  17. Luthier Vandros

    Luthier Vandros Tele-Holic Silver Supporter

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  18. bumnote

    bumnote Tele-Meister

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    I have the PRRI FSR Fudge Brownie...love this amp.
    Responds quite well to different tubes. I left the stock tubes in there for about a year, honestly they sounded gr at.
    Played around with Brimars, RCA, Zenith 6v6's. All sound great, the Zenith were the last ones I tried and they're still there.
    I have a mixture of NOS RCA and Sylvania preamp tubes in there now...7025's and 5751's and a JAN Phillips 12AT7WC.
     
  19. tubelectron

    tubelectron Tele-Meister

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    Yes. IMHO, the Fender RI amps are correctly built to endure the test of time.

    Their circuits are simple, well designed. Their boards are single sided, with labelled components. All this goes in a easier servicing work direction, like the JCM800 Marshall were built.

    But this is far from being the case on other amps - highly regarded brands included ! :eek::confused::mad:

    -tbln
     
  20. homesick345

    homesick345 Poster Extraordinaire

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    Agreed - BUT HiFi amps are usually way less moved around than guitar amps. Big factor imho

    Another seldom addressed issue is the weight of the amp & what the board supports in general - taking into account the constant transportation & mechanical vibration from the speakers!

    In bigger Combo amps (like the blues deluxe etc..) the strain on the PCB is real; with shortened life for a constantly gigging specimen (I'd say 5 to 10 years depending..)... I think in smaller/lighter amps like the PRRI, it is less an issue.

    My 2c
     
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