KILLER Question!!!!!!!!

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by chris77, Feb 18, 2008.

  1. chris77

    chris77 Member

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    So I am going to mod my amp And I am for good reason it seems scared poopless. I have my handy multimetter but I can not get the the caps to show that they have any charge in them. This does not seem to jive with what I was told that I would find!!! Is this possible that they have discarged themselves? 04 fender hotrod deville. I set the meter to AC and checked my home outlet and all seems to read fine so I assume the meter is fine. Help with any and all comments and suggestions.!!!! I dont want to touch the chassis until I know for sure. I used the amp yesterday and it was plugged in for a couple months.
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  2. JimmyR

    JimmyR Member

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    You are wise to be cautious! Before opening up an amp to work on I usually drain the caps by playing a guitar through it and switching off the power while leaving standby open. I also (duh!) unplug the amp, leaving standby open. I sometimes check that they are drained by carefully touching a screwdriver from the chassis to the hot end of a filter cap - not a good idea if they are not drained at all! Don't touch any metal while doing this! I purely do this for peace of mind.

    Some newer amps have bleed resistors - I don't know if the Hotrods do. But it is possible that they have them as a safety feature and if so that would account for finding no voltage in the caps. They allow the filter cap voltage to bleed to ground when not in use.

    It is also good practise to attach a jumper lead from any plate pin of a tube to ground while you're working on an amp. Take it off before turning the amp back on!!
     
  3. TopBooster

    TopBooster Member

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    Make sure you're checking the caps with the meter set to your highest V DC range. If it's reading close to zero volts, that means they are drained. The Deville will drain itself, since it uses balancing resistors in the high-voltage power supply.

    You still should make it a rule to check the cap voltages every time you open the amp up.
     
  4. BBQLS1

    BBQLS1 Member

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    I usually check the caps on the highest DC rating, then go down and check again until I've gone through the ranges and found nothing (or almost nothing, less than 1 volt) on the caps. It is quite possible there is a bleed resistor on the amp. I put one on my builds.
     
  5. chris77

    chris77 Member

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    thank you all I completed my first amp mods and still have both hands in tact....thank you for all your help guys. I love this place I always know that there are great people on that can help when needed. I hope I will have the oppertunity to return the favor as I learn more about this stuff!
     
  6. Clutch21286

    Clutch21286 Member

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    What mods did you do? I thought the concensus was that Hotrod Deville's sounded pretty good stock.
     
  7. chris77

    chris77 Member

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    well I play at church and three is about the loundest I go. But the amp doesnt really open up untill you get it really going and I just cant do it in my situation. So down around two and three the amp leans toward the muddy side of things So I did a "treble bypass" mod to me the name seems misleading. But It REALLY worked great letting more highs through in the earlier stages. It really brighted it up. If anyone would like to do this to there's and I can be of any assitance just let me know! I would love to help.
     

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