In Reply to: Need some trouble shooting advice please...... posted by vinnie2 on October 7, 2016 at 06:43:37:
Vinnie, since this on a bread board how are your ground lines from the circuit. Grounding is like a drain, going from the smaller pipes to the larger pipe that lead water out away from the drains and then from the house. If a pipe is too small the water will back up. remember, water follows the path of least resistance.So Current is like that also, so if the grounding wire is all the same size and you don't have that bigger/thicker wire or grounds not done correctly to move the current away...it will find a path of least resistance and get back into the circuit. That's why the metal chassis play a big part in the grounding scheme. That's one thing Counterpoint did really well, You could see on the PCB's the ground going from smaller to larger then out to the chassis then out through chassis ground.
Can you post a pick of this amp and all the wiring so we have better understand of what is going on?
How is the amp grounded? Is it grounded by the AC plug or through the RCA's ground from the amp RCA connectors to the preamp and then the preamp is grounded? Also do you have both RCA grounds tied together at the RCA Connectors on the amp's side? If so, maybe you may want to run individual grounds from the RCA connectors to the main ground bus on the amp's side to see if that has any effect on this noise. I had two Chinese made phono preamps do this and they were both tied together at the RCA connectors and then a single wire to the ground. When I redid them and put two individual ground wires go directly to the pcb ground where the one single ground wire was soldered before. After that, all the hum was gone and the phono preamps were quiet. Maybe this is what may happening here?
Also like the other post said. You need to determine if it's a 60hz or 120 hum or buzz. This will help narrow it down to where and what may be causing it.
60hz = Filaments or PS
120hz = B+
Edits: 10/07/16
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Follow Ups
- Return ground lines. - Cougar 22:24:12 10/07/16 (6)
- RE: Return ground lines. - vinnie2 06:27:39 10/08/16 (5)
- How far is the power supply/power transformer..... - Cougar 11:08:30 10/08/16 (2)
- RE: How far is the power supply/power transformer..... - vinnie2 12:12:44 10/08/16 (1)
- Have you tried.... - Cougar 18:14:14 10/08/16 (0)
- what does it sound like with ..... - Cougar 11:06:53 10/08/16 (1)
- RE: what does it sound like with ..... - vinnie2 12:15:48 10/08/16 (0)