Lots o vibroverb questions...

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by coolhand78, Jan 7, 2008.


  1. coolhand78

    coolhand78 Supporting Member

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    first off i have a fender 64 vibroverb custom, and i'm wanting to re-tube it...
    I have to admit that i'm pretty green when it comes to the inner workings of tube amps...
    Im quite keen on using JAN Philips 7581A's & JAN GE 12AX7A's however, the local fender authorized repairer doesnt use NOS tubes... he refuses as he states that even if you bought a matched pair they may not neccessarily be matched in your amp? is this true and what difference would it make...?

    I'm also thinking about replacing the speaker, from what i gather the JBL D130F is the benchmark, but given that they're pretty hard to get what would people recommend i use instead... I'm quite prepared to spend around the $500 mark to get my amp cooking...

    Also, i've read in gerald webers' book that a 'cap job' is highly recommended on new fender amps... any thoughts on this...

    also, what would people suggest i use for the other tubes in the amp eg, reverb, vibrato etc...

    thanks for you help

    Luke.
     
  2. phsyconoodler

    phsyconoodler Member

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    "A matched pair would not necessarily be matched in your amp".Why not?
    Interesting statement.Maybe he means you would have to check the bias,which is standard practice with any tubes.
    If you want to pay the price for NOS tubes,go for it.I like TAD 6L6's and JJ's and some other new production tubes just as much as many NOS ones.GE12AX7's are nice tubes,but a nice set of EH's work fine too.
    Can't really see any need for caps unless they are damaged.Try a nice Weber speaker.I like the Weber Chicago_Or a nice Jensen 15".I find JBL's to be way too bright unless you play country all the time.They lack the warmth of a nice Alnico Jensen or Weber.
     
  3. coolhand78

    coolhand78 Supporting Member

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    this is Gerald Weber's response in relation to getting the best tone out of a 65 DRRI,

    "It uses the worst sounding filter caps known to man. The brand name is Illinois capacitor and they are made in Taiwan. There are no cheaper capacitors available anywhere on the planet. So the first thing you need is a complete cap job using American made Sprague filter caps. I mean replace every electrolytic capacitor in the amp, including the bypass caps, filter caps and bias caps."

    not being technically minded i haven't opened up my amp to see what cap's it has in it... does anyone here know?

    I thought that if the 'matched' tubes didn't match in the amp then that was where biasing came into play, but i may be wrong...?

    any suggestions on other tubes that may go with the ones i stated earlier?
     
  4. chaz

    chaz Member

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    The single biggest improvement for tone in one of these is to have someone who knows what they are doing install a push/pull tremolo pot that bypasses/engages that portion of the circuit. The tremolo circuit sucks tone in a big way. Fender also used some inexpensive tone & coupling caps in these, some Mallory caps will improve things some too. Speaker replacement would be next, and then maybe tubes. Check the power tube bias as mine came way too cold from the factory.
     
  5. twangbanger

    twangbanger Supporting Member

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    If you go w/ NOS power tubes definately get them from a reputable dealer that screens and matches them,don't try to get them off of Ebay. Aside from that I put the TAD6L6's in my Allen Encore(Based on a Vibrolux and really like them.) If you can find any RCA pre's give them a whirl too!
     
  6. coolhand78

    coolhand78 Supporting Member

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    theres a mod switch on the back of the amp that removes the normal channel and the vibrato, which adds gain to the vibrato channel, making it break up a lot earlier...
     

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