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Ken Ken is offline

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Showing Visitor Messages 1 to 5 of 5
  1. jensvonbustenskjol
    07-29-2012 06:33 AM - permalink
    jensvonbustenskjol
    Hey Ken,

    I was told by Hot Tubes 70 to contact you regarding bias of a marshall 6100



    I have a 1992 purple 6100SEV with EL34s. Just swapped all tubes. Plate voltage at 455V I thought of keeping the bias between 28 - 39mA, aiming for 34mA. I've done the biasing with 4 x probe meter and got the following readings:
    V8: 34,3mA
    V9: 27,5mA
    V10: 53,4mA
    V11: 36,4mA

    V9 and V10 is way off! I bought 4 matching tubes from a guitar shop. I would thought that V8 and V9 or V10 and V11 would be off, byt not V9 and V10. V10 is getting really hot Fried eggs? The old tubes are not bad, so I tried putting an old tube in V10. approx same bad value...

    My thoughts:
    Should I change out R232 - R235, R237 and R238 with high precision resistors?

    Got some small deviations in that area:
    R232: ~5.63k
    R233: ~5.62k
    R237: ~5.62k
    R238: ~5.60k

    Is it an idea to install trim pots for these resistors?

    Any other thoughts would be appreciated.

    Thankz
    Have a great Sunday,
    Best Regards,
    Jens
  2. MartyStrat54
    01-08-2012 10:20 PM - permalink
    MartyStrat54
    A Telefunken in V1 and a Black Plate Raytheon in V2 would do the job. You can get by with CP in V3 and V4. This would be $95 for the two tubes, plus $6 to ship.
  3. MartyStrat54
    09-07-2011 09:29 PM - permalink
    MartyStrat54
    Hey Ken. I sent you a friend's request. I should have done it a year ago. I thought I had, but I see now that I'm wrong.
  4. Ken
    11-17-2009 03:31 PM - permalink
    Ken
    It's hard to say value. People don't pay a premium for them unless they know what they are. The age and speakers make a difference. Get the age off a speaker code, and get the T# to get the model if you have the Marshall logo backs. I paid $375 for my A and I have the G12H80's in it (T2871), from Jan. 1980. 320 watts of capacity with the 120 watt sticker! LOL They usually sell for about the same price as a 1960 cabinet of the same vintage; mine was a little road worn but not too bad. I think I saved $100 over what it "should" sell for.
  5. son_ic86
    09-29-2009 08:32 PM - permalink
    son_ic86
    i have the 1982 a and b cab with small circle sticker reading "120watt" if you have any idea the value of this stack, it would be greatly appreciated. thank you

About Me

  • About Ken
    Location
    Arlington Heights, IL
    Interests
    Vintage Sports Cars
    Occupation
    Saving Rain Forests
  • Signature
    1999 Marshall DSL 50
    Music Man 65 Reverb late 1970's (?)
    Late 1970's (?) Fender Champ
    Marshall battery amp
    1980 Model 1982A 4x12 cabinet G12H-80's 444 cones
    1983 Model 1982B 4x12 cabinet G12-80's 444 cones
    PRO 4x12 from the 1970's
    Woodson 2x12
    1976 Les Paul Standard
    Epiphone Les Paul knockoff
    ESP Lawsuit Explorer
    1979 Chiquita Travel Guitar
    1995 Taylor 310

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  • Last Activity: Yesterday 11:49 AM
  • Join Date: 02-24-2009
  • Referrals: 0

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