Speaker Hum

[pablo78]

Hi Everyone.

Can anyone help me. I've an edirol pcr-1 soundcard and i get the most irritating hum from my speakers. It's connected to my mac by usb and it's only when the computer gets switched on do the speakers start to hum. Does anybody know how to fix this problem? It ruins my sessions.

[Monarch]

Hi pablo78, check these links out they might help...

1. Monitor Hum

2. Low Hum

3. Hum Problem

4. How to get rid of Ground loop problems

HTH

[I_Am_Bic_Pentameter]

Hopefully and I mean hopefully, you have one with an easy solution.
But it can be a nightmare to get rid of. Be careful on solutions that cost money and try them last as they do not always work.

I've found some are equipment related so no amount of tweaks and changes would make a blind bit of difference.

My power conditioner hums a little bit - oh the irony.

Anyway it's just a note to say that you may need to try a few things before getting a result. I wish everything had a grounding switch of some description.

If you sort it, post your solution.

[Monarch]

Originally Posted by I_Am_Bic_Pentameter

If you sort it, post your solution.

Excellent point. That could save other forum members in need of similar help a great deal of time.

[pablo78]

Thank you Monarch.

I shall spend my sunday working through some of your suggestions and let you know how i got on.

[tyronehowe]

Ok – so you are welcome to laugh at this, but I found it very helpful.

I have had ground loop problems with both my Mac Pro and MacBook, never had a single such problem with PCs (or PC laptops) - only the Macs.

So I wanted to try to a cheap ground loop solution to see if I was on the correct track. I purchased this from Maplin:

http://www.maplin.co.uk/Module.aspx?ModuleNo=33172

It’s only a tenner, so it was cheap enough to try (yes, I know it’s for a car stereo). But it proved to me that I had a ground loop problem. If you look at the first customer question on that page, they also ask about using it in a studio.

[saxman]

Originally Posted by tyronehowe

Ok – so you are welcome to laugh at this, but I found it very helpful.

I'm not laughing but I think I might try similar items at Amazon for £4.84 or £5.99, free shipping. There are a couple of products there with positive reviews from guys who have tried them with PA systems.

[ecc83]

Pablo, you have a hum loop.

The bit of kit that Tyrone suggests should cure it but it cannot be regarded as cutting edge quality.

The best way is to make up some leads to the monitors with broken shields but exactly how depends upon whether the monitors are balanced in or not.

I am assuming they are actives?

Tyrone: This is the second time I have seen the Maps' earth breaker suggested ( it was not Maps but same wee thing) I am now off to buy one and then run some numbers on it.

If it is absolutely B awful you shall all know P.D bloody Q!

Dave.

[I_Am_Bic_Pentameter]

Originally Posted by tyronehowe

Ok – so you are welcome to laugh at this, but I found it very helpful.

On a related but entirely different connection problem, I use the ground loop box from Behringer - HD400 Hum Destroyer - for guitar preamp to amp loops etc. Works fantastically well. This is a different thing to the posters problem but I always recommend it for that different type of hum problem.

[Monarch]

Originally Posted by I_Am_Bic_Pentameter

On a related but entirely different connection problem, I use the ground loop box from Behringer - HD400 Hum Destroyer - for guitar preamp to amp loops etc. Works fantastically well. This is a different thing to the posters problem but I always recommend it for that different type of hum problem.

Sounds good...how much did you buy it for?

[I_Am_Bic_Pentameter]

They are cheap - should be around £15 maybe more now - I bought mine a long time ago.

As I said, it's for a different problem but just as annoying if you have the infamous grounding amp hum. It looks bigger than it is on adverts.

[tyronehowe]

Originally Posted by ecc83

The bit of kit that Tyrone suggests should cure it but it cannot be regarded as cutting edge quality.

Too right!


This one is three times the price but (apparently) has a frequency range of 20hz to 20Khz:

http://www.maplin.co.uk/Module.aspx?ModuleNo=226569

Originally Posted by ecc83

Tyrone: This is the second time I have seen the Maps' earth breaker suggested ( it was not Maps but same wee thing) I am now off to buy one and then run some numbers on it.

If it is absolutely B awful you shall all know P.D bloody Q!

Dave.

Let me know what you think Dave. I embarrassed to say that I’m still using it…

[sureno]

are there ones with jack connectors? Dave your handy with electronics, you could make up a few boxs and sell them to us, looks like there may be a niche for quality built ground iso's, could be quite profitable and who know's DV may even commision you to distrobute in their branches?

be sure to drop me a PM if you ever did build one, il be your first customer

[Monarch]

Originally Posted by I_Am_Bic_Pentameter

They are cheap - should be around £15 maybe more now - I bought mine a long time ago.

As I said, it's for a different problem but just as annoying if you have the infamous grounding amp hum. It looks bigger than it is on adverts.

Ok...cool and thanks.

[ecc83]

Well I have one,
Bigger than I thought 75mm x 40mm but not as heavy as I would like, not a lot of iron in there!

I have tried to get it apart but don't have the kit to hand here, I shall go in early tomorrow and crack it at work. I also have a dB test rig and 'scope there to do some tests.

Sureno, I did try to get Oxford Electronics Products interseted in marketing a rival to the ART CleanBox 2. OEP make some fine transformers at very reasonable prices I use their type A262A7E as a output balancing transformer from amy 2496 cards. They very nicely sent me a pair of high grade 10k10k input trannies as samples and they are ensconced it a nice diecaste box close to the pc and unbalance (and earth break) the signals back from a variety of kit some 4mtrs of cable across the room. Their type OEP1200 is useful at low levels -10dBV, for isolating all sort of kit and are only about a fiver.

Well! What would you know? In sitting here fiddling with the Map thing I have just popped the can! Reveals two decent sized trannies mounted on a pcb but in the tranny world, size definately is not everything!

If these spec out ok I shall put them in a civilized tin, fit some proper connectors and put it on Ebay! Nah! 1stCFS, it's yours if you want it S!

OEP? You had your chance!! (actually I might send them one.)

Dave.