Audiolab M-ONE help please

[Argieleo]

I have a Audiolab M-ONE class AB integrated Amplifier. It has a stated power of 65wpc, it is utilizing the LM3886TF by Texas Instruments.

I have had mine for about 2 years and it has been mostly a great little amp, I am driving some PSB Alpha P5s speakers and they are meaty and balanced, great sounding and over excelling in a lot of ways. I am experiencing a weird fault with mine recently and I am hoping someone may be able to help. The fault I am getting is that there is some clipping or crackling in the midrange on low volumes. Interestingly it does not seem to happen when driving at higher power / volumes. I initially thought it was a speaker cable or connection, I have tried new cables and speakers and the fault is with the amp, I have tried different inputs, Bluetooth / RCA inputs. Still the weird annoying problem is there at mid to low volumes, its intermittent and very annoying. Its otherwise works great and would be a shame to get rid of it.

Any help with this as suggestions to test or if anyone has a service manual/ schematic for the M-ONE it would be greatly appreciated.

 

[xXDEATH666Xx]

Could be the pots need cleaning. I'd start there and see what happens

 

[Argieleo]

Could be the pots need cleaning. I'd start there and see what happens

Apreciate the response, I believe the M-One doesn't have volume pot... like most new amps, it has an encoder that feeds a PGA2311 volume control IC. I was hoping someone could confirm and has a schematic or more know how about these amps.

 

[sae-7125]

The fault I am getting is that there is some clipping or crackling in the midrange on low volumes.

sounds like something in the signal processing chain. which would be an smt/smd component and that could be one of the big chips. first steps would be evaluating the power supply(s) and if there is insufficient power (amperage) for the chips and possibly amplifier.

how is the treble output quality? any indication of distortion or an increased veil i.e. lack of high frequencies?

a few years ago i made the mistake of trying an ifi pro idsd and it lasted less than 30 days, thank goodness for warranty return and full refund. the unit had increasing dc issues on the signal output, amplifier responds with big pop sound on preamp power up. the dsd 512 and 1024 upsampling was amazing but didnt last long. minimal shielding inside the chassis, lots of rf noise bleed. i now avoid the brand completely.

https://ifi-audio.com/products/pro-idsd/

a few possibilities of root cause exist for your m-one but until something is confirmed with measurements all i can do is speculate. since there is two years of use on the system it could be thermal design issue that cooked an electrolytic or two. once again, just a guess until a thermal camera can be used to analyze the situation.

 

[sae-7125]

I have tried different inputs, Bluetooth / RCA inputs.

does the noise exist through the headphone output?

 

[Argieleo]

does the noise exist through the headphone output?

Ahh, I don't know why I haven't tested that yet, I am away for the week so will try as soon as I'm back thank you. That should distinguish if the fault is in the signal processing side or the amplification side. I also have access to a thermal camera so will utilise it to see if I notice anything above normal, Thermally I would of thought it would worsen when driven harder / louder but it seems to clear up on the upper range. I have emailed audiolab but no response

 

[sae-7125]

I have emailed audiolab but no response

not surprising, i have bumped into other people/reviews mentioning "zero contact" type of customer service. tends to paint a picture of "pump & dump" sales strategy. there is an abba song that sums that up nicely, three words in its title.

something else to add to the diagnostic arsenal is a can of freeze spray. if the anomaly gets better or worse when a specific chip or cap or component is sprayed, that would be a step closer to understanding what has gone wrong.

Ultimate Guide to Diagnostic Freeze Spray

Diagnosing and repairing electronics can be painstaking and sometimes frustrating work. Problems can be intermittent, with the faulty area on the PCB difficult to locate. Freeze spray is an essential tool, because it helps identify faulty components, solder joints, and other problems that can...

www.chemtronics.com

*one example of many on the market.