I have a weird buzz issue; can you help me solve the problem?


Hi - my integrated amp has a 25db persistent buzzing noise; I need help figuring out how to solve this problem.

Here’s my system:
CODA CSiB integrated amp - custom tuned to produce 25w Class A power before switching to Class B
Lumin T2 streamer/DAC
Dynaudio Focus 380 speakers
Audience AR2-T2 power conditioner w/Audience power cable
Audience AU24 speaker cable
Cardas Clear M power cable
Purist Venustas Luminist Revision RCA interconnect
Synergistic Research TeslaPlex SE outlet
Shunyata Venom Defender

Some background:
I’ve had the CODA integrated for about 5 years. The remainder of my system has come on-line subsequently (I had different speakers initially). Within a few months of purchase, I noticed a buzzing noise coming from the speakers whenever the amp was powered on (bias “on”), but no noise in standby mode (bias off). I took it back to the manufacturer, who plugged the amp into their dedicated circuit and it was dead quiet. I had the same experience taking it to a local audio shop. Thinking that it might be a noisy circuit, the local shop loaned me a lesser priced solid-state amp (I forget which brand) to bring home. I hooked up the shop’s integrated to my system and.....it was dead quiet. Now I was confused. 

A dealer loaned me a completely different system with a tubed integrated, different speakers and cables. There was even a worse buzz coming from this system than from mine. I went back to living with my system and forgetting about the buzz.

Fast forward 4+ years. I have moved to a new house in a new state. Unfortunately, the buzz remains :-( I even tried plugging the system into what the electrician was sure was one dedicated line in the house (it was in the kitchen, so I had to run an extension cord to where my audio system lived). Still, the buzz remains.

I really love the sound of my system, but this persistent buzz is a (ahem) buzz kill (sorry for the predictable and bad pun). 

I would love to get some thoughts on what I can do to get rid of this damn noise. Please help!



mwsl

Showing 7 responses by imhififan

Plug the CSiB directly to the mains without any conditioner, and only connect the outputs to speakers, no connection to any input, the buzz still remains if bias is on?
If buzz on both channel, I suspect the CSiB power supply section or internal grounding has issue, my suggestion is send it to a tech to diagnose.
Just out of curiosity, did you have CODA bump up the amount of Class A watts?
I wish I could, but I need most of the class B power to feed the power hungry Thiel.
I have a CODA CSiB v3 integrated plugged directly to the wall, without any shorting plug installed, no buzz, hum or any kind of noise while bias “ON” at any selected input.

I think the last thing you can try is to turn off all circuit breaker except the one for your amp, unplug everything from that circuit. power up the amp and see if the buzz still exist, if yes then the amp need to send for repair, if no buzz then you can plug back all electrical device one by one and see if buzz exist. If no buzz then turn on all circuit breakers one by one until buzz exists again so you will know what caused the issue.


I also like to add that something like a cold solder joint can caused intermittent problem like this, that explain why the amp was dead quiet when plugged into the mains at audio store and the manufacturer.
Many higher end components are designed by barely competent engineers.
Eric Lauchli?
The Prima Luna had both 4 & 8 Ohm speaker inputs; I used the 4 ohm inputs as that is what my Dynaudio Focus 380’s are rated at. The CODA only has one set of speaker inputs. Is there any chance at all that there is a mis-match between the CODA and the speakers due to impedance difference?
No, although I have no experience with Dynaudio Focus 380, but I've use the CSiB to drive power hungry Thiel CS2.4 and CS3.6 without any issue.
The Prima Luna had both 4 & 8 Ohm speaker taps because it is output transformer coupled.