static/crackling in left channel

Paul Birkeland said:
The left RCA jack ground lug and the chassis earth lug by the power entry module do not look adequately soldered, just as an example.

reflowed those 2 connections. pics attached. didn't change anything. then tried to go over a bunch of joints and reflow them and now i actually think it sounds worse. so it probably is something to do with a soldering joint but short of redoing the entire thing, not sure how i can isolate it.
 

Attachments

  • low 2.jpg
    low 2.jpg
    1.1 MB · Views: 16
  • flow.jpg
    flow.jpg
    1.1 MB · Views: 22
The last "flow" pic basically hasn't. I use Cardas solder and it flows easily and gives a smooth finish. I use #7 bits in my old Weller solder station. It has no adjustment. If this pic shows a joint similar to others in your build I would say that upping your technique would be a useful move.
 
Im resurrecting this thread since I never resolved my issue and had just shelved the BHC until now. Id really like to get it working. I added this mod: https://forum.bottlehead.com/index.php?topic=11676.0 and it didnt solve the issue. Snapshot attached.

I was able to grab a voice memo recording of the crackle from my iphone. I held the phone about 1" from the driver. There are no RCAs hooked up to the BHC during this recording. 
 

Attachments

This looks like a poor solder joint to me. I don't see much of a fillet. It might just be the pic. But if it does accurately capture the joint, I would add solder here until a nice fillet is visible.
 

Attachments

  • Screenshot 2024-09-25 at 5.21.13 PM.png
    Screenshot 2024-09-25 at 5.21.13 PM.png
    1.3 MB · Views: 12
I finally solved the issue!!! It turns out it was a bad 22.1K Ω resistor that is soldered to terminals 4 and 5. I replaced the resistor and there is zero crackle, zero static. Dead silence until the music kicks in! I can finally enjoy some Crack! Now Im going to give it a few months and then I will do the speedball upgrade.

I do have a question. I bought the replacement resistor from digikey.  It appears to be rated the same and has the same color banding..but it is considerably smaller. See pics below. Is this OK?

 

Attachments

  • 22.1 resistor 2.jpg
    22.1 resistor 2.jpg
    793.8 KB · Views: 10
  • 22.1 resistor 1.jpg
    22.1 resistor 1.jpg
    1.5 MB · Views: 12
It's a funny thing about that resistor, as it dissipates a bit under 1/2 a watt in the amp.  On that basis, you'd want to opt for a 2W resistor for optimal operation (PR-02/RR-02 are good for this).  The resistor we use is extremely conservatively rated, so it won't cause problems.  In practice, what you bought should run just fine for 2-5 years.
 
Back
Top