5F1 Kit Build - no sound

Discussion in 'Shock Brother's DIY Amps' started by brackp, Feb 14, 2019.

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  1. brackp

    brackp TDPRI Member

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    Now there's an idea. I'll give that a go.

    Here's a shot of the back, foolishly not taken just before I installed, I tidied up a bit after this was taken, and some ground jumpers were added too
     

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  2. D'tar

    D'tar Friend of Leo's

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    Well. If I'm seeing that right it looks correct. Maybe you have pin 7 and pin 8 mixed up. Measure pin 8 to ground while rotating the volume knob. Do the same with p7.
     
  3. D'tar

    D'tar Friend of Leo's

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    That would explain the 3vdc on the coupling cap earlier.
     
  4. brackp

    brackp TDPRI Member

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    You're absolutely right...the wire going to pin 8 is showing variable resistance with the pot... I could have sworn I checked this...the volume was definitely working last night...Fixing it now
     
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  5. brackp

    brackp TDPRI Member

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    Yup! That was it! The sad part is I triple checked these wires after swapping them the other night, dang dang dang! :) I fixed that, switched it on, nothing... nothing....LOUD SQEAL! My wife nearly ran out of the room :) with me screaming "This is a good thing!"

    Hope you guys don't mind helping me out over such a silly little thing, you guys are great!

    I reversed the primary output transformer wires and dhe sounds fantastic! A little quieter than I was expecting but very much pleasantly so. Now to make the cab I'm thinking of something like this box I made for my sister last year! https://imgur.com/6lpwT4E

    I'm sure ye'll see me back for more questions as my buddy is calling over tomorrow to try finish his one off. I've learned a lot here, thanks to you guys so hopefully we'll be able to muddle through, but don't be surprised to see me again! Also, I want to make more now!
     
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  6. brackp

    brackp TDPRI Member

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    Oh also, now reading approx 150V on both cathode pins on the 12AX7, seems about right to me. I'm running off the 550VCT from the power transformer, there's a 650VCT also. Is it worth trying that out or is that too much? Just curious is all.
     
  7. D'tar

    D'tar Friend of Leo's

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    Awesome! Congrats!

    Re: voltage tap... I would make a new complete voltage chart. Play for a while.

    Switch taps... Make a new voltage chart. Play for a while.

    See which way you like best.

    Now you have the build bug... When you order your switchcraft jacks go ahead and order the rest of the parts for the next project!!!Lol!Have fun!!! Enjoy. We want to see the cab too!!!


    Nice Dovetails!!!
     
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  8. King Fan

    King Fan Friend of Leo's

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    @D'tar drives the length of the field and scores, with an assist by @brackp who hung in, listened, and followed through.
     
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  9. sds1

    sds1 Tele-Afflicted

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    I watched!
     
    Last edited: Feb 17, 2019
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  10. jtcnj

    jtcnj Tele-Holic

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    Congrats, now go over the build to make sure things are in order.
    You have sound but verify things are at least close to where they "should" be.
    Compare all your voltages to the fender layout. Keep in mind the chart does say +- 20%, and today's wall voltages are typically higher than back then; at least in the USA.

    I think the 5F1 chart has been used so often the numbers should be right; I found one of the voltages listed on the 6G2 is likely wrong.
     

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  11. King Fan

    King Fan Friend of Leo's

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    Yeah me too. :) I like to watch, er, um...

    But sds1, you're way ahead of me, both in your understanding and the help you give others here.
     
  12. brackp

    brackp TDPRI Member

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    Great advice, I went over it tonight and took the following readings which I believe are in line with the Fender chart.

    B+1: 324
    B+2: 287
    B+3: 250

    5Y3
    2: 324
    3: 284 AC - diode jumped to 4
    5: 284 AC - diode jumped to 6
    8: 324

    My meter still isn't picking up the 5V AC on pins 2 and 8, could be the meter, could be a problem, I'm not sure??

    6V6
    2: 3.2 AC
    3: 313
    4: 290
    5: 0
    7: 3.2 AC
    8: 18 DC

    12AX7
    1: 166
    2: 0
    3: 1.3 DC
    4/5: 3.2 AC
    6: 155
    7: 0
    8: 1.3 DC
    9: 3.2 AC

    Does that all look ok to ye?

    On playing it for a while it's a bit quieter than I expected, especially through a strat. It's nowhere near as loud as my Blues Jr, which I don't really get the opportunity to turn up all that much.
    The 5F1 only really comes into it's own after 6 and just get's better and better from there, you can crank this thing and not worry too much about the neighbours. This is the speaker I'm using at the moment (https://celestion.com/product/8/eight_15/) I'll probably build the cab big enough to take a 12 inch at some point down the road.

    We finished up the wiring on my friends chassis today...I'll probably start another thread for that one LOL
     
  13. corliss1

    corliss1 Friend of Leo's

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    Some meters, especially lower-end/cheaper stuff, are not able to pick up AC signals when there is DC. It freaks them out. I know my meter will, but you'd have to check your documentation to see. If you didn't have the 5V there nothing else would be working. You could pull the rectifier tube and then you should only see the 5V AC as no rectification would be happening.
     
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  14. jtcnj

    jtcnj Tele-Holic

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    A decent multi meter is a must.
    YOu dont need a Fluke or pro level unit but the dirt cheap ones just dont get it done.

    Your numbers look good - I'm no expert, just comparing to the Fender layout.
    As part of shakedown / verifying before calling it good I would suggest playing it hard and watching the 6v6 for red plating.

    At those numbers for plate dissipation you have 18v/470Ω = 38ma x 324v = 12.4w.
    That will be close; I dont know the actual value of your cathode resistor.
    Typical numbers; the stock layout puts it closer to 13w.

    Always makes me a bit concerned about being over the 12w on 6v6gt spec. sheets, but its been done for decades.
    So, watching for red plating is a good thing.

    By the way, I'm just repeating the things I have learned from the pros here.

    Congrats and enjoy!
     
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