65Amps Soho Redplating Single Power Tube... goes away with swap?

Discussion in 'Amps and Cabs' started by Axeplyr, Feb 2, 2008.

  1. Axeplyr

    Axeplyr Supporting Member

    Messages:
    1,700
    Joined:
    Mar 26, 2004
    Location:
    Nelson Bay, Australia
    Serious redplating when I go from standby to on - accompanied by a fairly loud hum. I did a search, and the concensus was it's a tube if it moves with a swap. Otherwise it's internal. So I swapped the EL84s around, and now no redplating in either tube. Tubes are ARS.

    Has anyone seen this before? Maybe the tube wasn't properly seated in its socket?
     
  2. Babaji

    Babaji Member

    Messages:
    1,228
    Joined:
    Jul 11, 2002
    Location:
    Alexandria,
    ...You have a bad power tube. Put the other set in. If simptoms return, see your service tech.
    Bill
     
  3. rockon1

    rockon1 Member

    Messages:
    11,455
    Joined:
    Aug 12, 2005
    Location:
    Stamford CT
    Perhaps a bad contact. I'd hit the pins with some contact cleaner and work the tubes in and out a few times. After that if all is well i'd watch the tubes for a while while playing and see if it stays Ok. Bob
     
  4. somedude

    somedude Member

    Messages:
    6,695
    Joined:
    May 30, 2004
    Location:
    South of Heaven
    I had a similar problem when I first started using JJs. From what I've read since they have smaller pins than some other tubes and my sockets were probably worn from 20 years of using tubes with larger pins.
     
  5. Axeplyr

    Axeplyr Supporting Member

    Messages:
    1,700
    Joined:
    Mar 26, 2004
    Location:
    Nelson Bay, Australia
    Thanks.

    I've played the amp a bit, no more redplating. It's a new amp, so I'm watching closely.

    The pins seem really thin on these. It surprised me when I swapped the tubes. So I take it a bad contact can cause this... I was just wondering exactly how, but I guess a high-resistance contact is going to somehow pull more current?
     
  6. somedude

    somedude Member

    Messages:
    6,695
    Joined:
    May 30, 2004
    Location:
    South of Heaven
    I don't know the technical reason behind it, just that the tube would red plate in about a second flat and I had to switch to another tube brand.
     
  7. Axeplyr

    Axeplyr Supporting Member

    Messages:
    1,700
    Joined:
    Mar 26, 2004
    Location:
    Nelson Bay, Australia
    Hmmm... I wonder if these ARS tubes are rebranded JJ's. Guess I need to consider some substitutes.
     

Share This Page