Microphonics issues with first Quickie Kit

steelisreal · 12363

0 Members and 1 Guest are viewing this topic.

Offline steelisreal

  • Newbie
  • *
    • Posts: 3
on: July 08, 2010, 04:31:57 PM
My son just completed his first Quickie kit and is having huge microphonics issues.  He didn't use the acrylic plate, but instead mounted the tube sockets on an aluminum plate on top of a wood box with all the other components inside.  He is using a separate box that contains rechargeable batteries.  We double checked the layout and everything seems correct.  He even tried switching the polarity on the heater inputs (1.5v).  The ringing is so bad you cannot listen to music.  Any ideas on what to check next?  We do not have another set of tubes to try at this time (it came with Delco tubes). 

Thank you for any assistance.

John



Offline Paul Birkeland

  • Global Moderator
  • Hero Member
  • *****
    • Posts: 19578
Reply #1 on: July 08, 2010, 05:07:06 PM
Different tubes can help. Also, some kind of isolation under the wood base is good. Try a dish towel to get an idea of possible results.  Also, you can try mechanically coupling the tubes to the chassis better. Some like adhesive backed copper tape for that. 

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline steelisreal

  • Newbie
  • *
    • Posts: 3
Reply #2 on: July 14, 2010, 11:56:26 AM
He finally got it working.  My son bought some NOS Tung-Sol tubes and they completely eliminated the microphonics issue.  The Delco tubes that came with the kit were unusable.  I don't know if it's the case with Delco tubes in general, or just the ones that came with this particular kit.  Anyone else using Delco tubes?



Offline steelisreal

  • Newbie
  • *
    • Posts: 3
Reply #3 on: July 15, 2010, 05:14:20 AM
Here's a picture of my son's Quickie.  The box on the left is the power supply for the Quickie (rechargeable batteries).
« Last Edit: July 15, 2010, 05:15:59 AM by steelisreal »



Offline Paul Birkeland

  • Global Moderator
  • Hero Member
  • *****
    • Posts: 19578
Reply #4 on: July 15, 2010, 10:30:41 AM
Very cool!

Some 3S4's are extremely microphonic, and some are not.  Part of the low price of the Quickie kit comes from not doing any testing on the tubes before they are packed, just knowing that they are new old stock has to be sufficient.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline bundee1

  • Jr. Member
  • **
    • Posts: 44
Reply #5 on: July 19, 2010, 11:00:32 AM
Hi Steel is Real, That quickie is very nice. Do you have any pictures of the bottom wiring?