Finished with my valve junior...for the moment

Discussion in 'Amps & Cabs' started by acdcrocker, Jul 11, 2006.

  1. acdcrocker

    acdcrocker Member

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    The parts came in the mail today so I did some more mods:

    This pic shows the new, isolated (Cliff 502)input jack and standby switch:
    [​IMG]

    Here I cut the trace of the diodes to C6:
    [​IMG]

    Then I added a 100uF/450V cap along with a 1K 5 watt resistor(brung down the B+ voltage to 308!):
    [​IMG]

    You can see four things in this pic.
    1) I finally decided to cut the traces and put the heater wiring above-        board.
    2) You can see the SoZo musturd caps I replaced with C1 and C2.
    3)I refernced the 100-ohm resistors R10 and R11 to pin 3 and 4 and pins 3 and 5 on the EL84.
    4) I cut the trace from the volume pot wiper to pin 7 on the 12AX7 on the board and ran a sheilded wire instead.
    [​IMG]


    The results were fantasic!!! Its much sweeter and it doesnt fart at high volumes. Its silent when its dimed!!

    But afterwards when I had the amp plugged in (but seperated from the cab for testing purposses) I accidentally touched the positive lead from the 450V cap!! OUCH!!!! I blacked out for 2 seconds and when I woke up I tried to scream help! but I couldnt, my whole body was numb. Thank god Im ok. The only thing i suffered from is a tiny blister on my index finger. Listen though people, be very careful with high voltages. I didnt think I would get shocked in a million years but It can happen to any one. Electricty works in very percular ways and I dont want you guys to expereince what i did! :roll:


    Overall mods:

    -Replaced jack with an insulated one(Cliff 502)
    -Installed jumper on the back of the PCB board
    -Replaced C1 and C2 with .022 SoZo mustard caps
    -Cut traces and ran heater wires above the board
    -Referenced R10 and R11 to pins on EL84
    -Lowered B+ voltage with a 1K 5 watt resistor
    -Added 100uF/450V cap
    -Added wire running from volume pot wiper to pin 7 of the 12AX7
    -Replaced R1 with a 1 meg resistor
    -Replaced R2 with a 10K resistor
    -Added a standby switch
    -Switched tubes!!!

    WOW, so much work for a 14 year old!!! :D
     
  2. If You Want Blood

    If You Want Blood Active Member

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    That looks awesome. I wouldn't know the difference from amp blueprints from jet blueprints, but that looks killer O0
     
  3. the bacon

    the bacon Member

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    hows the tone on the valve juinor? ive heard its a pretty good amp.
     
  4. SG dan

    SG dan Active Member

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    looks like someone did his homework. not that id know really........
    anyway so you got electricuted from touching the lead end? what was it plugged into on the other end?
     
  5. Bonfire

    Bonfire Active Member

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    ground....?

    but well done dude! excellent results! only hope i can pull off a similar feat!
     
  6. Spunky

    Spunky Active Member

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    OK acdcrocker,

    you have really done a good job............
    I hope you enjoyed the high voltage in a perverse way!....ha

    The OT probably is a 7.5 OHM unit and for the EL84 you need a 5.0 OHM OT....

    The first mods were cheap and now the OT is going to be expensive.

    I just took the plunge.....$47.55 delivered for a Hammong 125ESE. CRAP......

    I'll be gone for a week and then install it......dang!
     
  7. Spunky

    Spunky Active Member

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    acdcrocker,

    I forgot to mention that your wire and wiring is beautiful!

    Way cool dude!..... :rockin:
     
  8. TattooedCarrot

    TattooedCarrot Well-Known Member

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    Glad you're ok. For those who don't realize, not only can an amp sohck you, it can kill you - even a little amp, and even anunplugged amp. Yep, that's right. An unplugged amp can still be storing active electrical current that can wax you, so if you don't know your business stay the hell away from amp inards.
     
  9. Spunky

    Spunky Active Member

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    I've taken the full high voltage ride from a 81' JCM800 with 6550's and lived to tell.....

    Learned my lesson the hard & expensive way!

    My body was blown back 6' into a wall while my amp rolled off the bench and crashed on the ground smashing all the tubes.

    I'm used to repairing TV's and monitors so I'm not nervous around high voltage. The flyback transformer on a color TV/monitor puts out 26,500 volts and will KILL you fast. I used to assemble and test military B/W monitors and they were only 18,500 volts...he he
    he

    We used to charge the connector end of a condenser (capacitor) from a car ignition system with the spark plug wire on a running engine and toss it to the pump boys at the gas station. Great to watch them catch it and get the crap shocked out of them! Almost as good as beeping the horn when they were checking the oil..... The good old days when gasoline was 36 cents a gallon..... Crabs was the only disease you could catch from sleeping with someone, a computer was a PDP-11 and the internet was still the ARPANET.
     
  10. acdcrocker

    acdcrocker Member

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    Thanks, If you want Blood and Bonfire! And thanks about the wiring Spunky!  :) What do you mean the OT is a 7.5 ohm unit? Are you meaning I need a 5 ohm OT instead?? Like the Hammond 125ESE? And also, what does changing an output tranny have to do with tone?-(Curious.)

    SgDan- I touched the positive wire coming from the newly installed 450V cap while the amp was on. A BIGGG no no.

    Gearpig-Thanks. Yes while an amp is off the capicitors can still hold deadly voltages. And if you dont know what your doing...ZAPP!

    (Oh and the bacon, to be quite honest my version 1's tone kindof stunk stock. But once I modded it with tone and hum mods, it sounds beautiful!!! Rich and warm, almost sounds like a Plexi when cranked)
     
  11. SG dan

    SG dan Active Member

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    jsut to clarify whats a 450v cap?
     
  12. acdcrocker

    acdcrocker Member

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    [quote author=SG dan link=topic=9380.msg121803#msg121803 date=1152764976]
    jsut to clarify whats a 450v cap?
    [/quote]

    Well, Sg dan, cap is short for "capacitor" which is an electric component that stores volts in different values such as uF(micro-farad), and pF(pico-farad). This would be viewed on the cap as say, 100uF or 1uF. They are also rated in different volt values that tell you how much voltage it can handle such as 1V through 600V. The cap that I installed was a 100uF/450V capacitor. So, since caps store different amounts of energy while running(while the amp is on), touching the positive wire on it is almost deadly.
     
  13. Bonfire

    Bonfire Active Member

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    caps dont neccicarily store 'volts', they store a charge, and not only when the applience is on!

    now since i dont need the anti-hum mods, i might just do the input mods....should i bother having a hi and low jack to switch between configs?
     
  14. acdcrocker

    acdcrocker Member

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    [quote author=Bonfire link=topic=9380.msg121814#msg121814 date=1152769429]
    caps dont neccicarily store 'volts', they store a charge, and not only when the applience is on!

    now since i dont need the anti-hum mods, i might just do the input mods....should i bother having a hi and low jack to switch between configs?
    [/quote]


    Well thats really something you yourself can only answer. Ask yourself, " If I do the Hi and Low jack switch, would I keep the switch on the "Hi" mode all the time anyways?"
     
  15. Spunky

    Spunky Active Member

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    Meeeeeee Toooooooooooooooooooo
     
  16. Bonfire

    Bonfire Active Member

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    [quote author=acdcrocker link=topic=9380.msg121818#msg121818 date=1152769770]
    [quote author=Bonfire link=topic=9380.msg121814#msg121814 date=1152769429]
    caps dont neccicarily store 'volts', they store a charge, and not only when the applience is on!

    now since i dont need the anti-hum mods, i might just do the input mods....should i bother having a hi and low jack to switch between configs?
    [/quote]


    Well thats really something you yourself can only answer. Ask yourself, " If I do the Hi and Low jack switch, would I keep the switch on the "Hi" mode all the time anyways?"
    [/quote]

    yeah i thought about that....but....since ive never played it the hi-way (pun intended) i dont know.....
     
  17. CharlieB

    CharlieB Active Member

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    [quote author=acdcrocker link=topic=9380.msg121791#msg121791 date=1152761768] Like the Hammond 125ESE? And also, what does changing an output tranny have to do with tone?-(Curious.)

    [/quote]

    Try the 125DSE, and yes, the OT has everything to do with the tone. Everything.
     
  18. acdcrocker

    acdcrocker Member

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    [quote author=CharlieB link=topic=9380.msg121854#msg121854 date=1152789408]
    [quote author=acdcrocker link=topic=9380.msg121791#msg121791 date=1152761768] Like the Hammond 125ESE? And also, what does changing an output tranny have to do with tone?-(Curious.)

    [/quote]

    Try the 125DSE, and yes, the OT has everything to do with the tone.  Everything.
    [/quote]

    May I ask why?
     
  19. Bonfire

    Bonfire Active Member

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    [quote author=acdcrocker link=topic=9380.msg121912#msg121912 date=1152813944]
    [quote author=CharlieB link=topic=9380.msg121854#msg121854 date=1152789408]
    [quote author=acdcrocker link=topic=9380.msg121791#msg121791 date=1152761768] Like the Hammond 125ESE? And also, what does changing an output tranny have to do with tone?-(Curious.)

    [/quote]

    Try the 125DSE, and yes, the OT has everything to do with the tone. Everything.
    [/quote]

    May I ask why?
    [/quote]

    i'd like to hear this too!
     
  20. CharlieB

    CharlieB Active Member

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    Wait, total brain fart on my end....

    I meant to say the 125BSE

    Cat. No. Audio Watts Max. D.C. Bias(ma) Wt. Lbs.
    125ASE - 3 25 0.5
    125BSE - 5 45 1.1
    125CSE - 8 60 1.3
    125DSE - 10 70 2
    125ESE - 15 80 3

    THe BSE is a fine OT for a single ended 6V6 or 6L6. You can put in an impedance switch, and get some extra functionality.
    You might even want to put in the 125ASE, since Hammond generously overrates their specs. The smaller transformer will sound more "tweedy". Think: "Layla".
     

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