[DavidMahler]

So I'm having a problem with my favorite portable Headphone amp. My Larocco PRII. I was wondering if any advice could be given to me besides sending it to the manufacturer being that the manufacturer is one of those who takes 10 months to deliver.

The problem seems to be that when I'm listening to the amp through my source (my ipod with LOD cable) I am getting a very high pitched hum which comes and goes and one way to get it to leave is to put my finger either on the amp or the headphone cable or the LOD cable. But the hum quickly returns. I don't remember always having this. Is there any cure for this which I can do by opening the amp and moving a piece or tightening?

I'm all ears.......also if you think you could identify what the hum is that would also be appreciated. I think something must need shielding but not sure what.

 

[DavidMahler]

anybody? hah

 

[wuwhere]

Could be a bad capacitor.

 

[DavidMahler]

Hmmm how would I diagnose this

 

[wuwhere]

Ask these guys.

Badcaps.net - How To Identify

 

[qusp]

sounds more like a grounding issue to me; does it do it with all of your LOD's? theres a chance the input jack has become loose and the ground wire is only just touching and not p[roperly connected; when you touch it with your finger you are grounding the case and the signal therefor improves? or if you only have the one LOD it could be a grounding issue with the LOD. is it a thick and chunky ALO?? could've damaged the input over time if you havent set it in shape. these are some options that are IMO more likely than a cap problem. if it was a cap problem I dont think touching it with you finger would fix it. also this ounds like a simpe issue, you might try contacting Phil larrocco who is now designing for triad ; he may not fix it for nothing, but he may get it done a lot quicker than the company that is now larrocco

 

[Punnisher]

I agree with qusp.

It could also be a static buildup problem, which is along the same lines as grounding. As soon as you touch it, your skin absorbs the static charge and the sound returns to normal. This has happened with my sansa clip before.

 

[EFN]

Yep. I agree with qusp and Punnisher. Sounds like a grounding issue. Porbably a solder joint getting loose. This happens sometime with my amp. I remember my SuperMicro-IV went humming for a preiod of time after a spectacular bike accident where the casing was almost smashed in. A few joints were cracked and loose - only can be seen using a magnifying glass. A simple fix of soldering iron touch got them back to normal

 

[mrarroyo]

On a few amps the case tolerances were not very good. This created a problem where the power switch when inserted would rub on the case and cause noises.

Have you checked that your board is still secured properly to the case. If it has moved relative to the case and it is touching then the noise you refer to is likely to be the result.

Here is a picture of the one I had. Free Image Hosting - xs.to - Image hosting - share images slideshow generator and screen capture tool