Db Technologies Opera Sub 15 - Banging, popping and humming

[soundsalarming]

Hello everyone.



I own a pair of Db Tech Opera Sub 15 which I really like but they both seem to have developed a fault. When powered on there is an audible hum even with no inputs plugged in - one sounds a little bit worse than the other.

Another thing is when I go to adjust the output knob on the back the sub protests loudly with bangs and pops and hisses! It's like the knob is sensitive to the touch.

The back panel (black area within red box in pic) is also very sensitive - tapping it results in the tapping noise being amplified and output by the speaker.

Is there something I can do or are they broken? I ask because both subs are doing it all of a sudden after PAT testing was done though one is more sensitive than the other. Is it an expensive repair?

Thanks



Thanks

[Nakatomi]

Sounds to me like it could be quite a cheap & simple fix. The level controls have gone scratchy & need to be replaced. Should only cost a couple of quid each plus Labour.

[Excalibur]

Re the hum, usually an earth loop issue. If there's an earth lift switch, try it in both positions. One of my Proels was set wrong, and gave a very noticeable hum till we flicked the switch. For safety's sake, it's advisable to do this when it's powered off.

Sounds to me like it could be quite a cheap & simple fix. The level controls have gone scratchy & need to be replaced. Should only cost a couple of quid each plus Labour.

I would tend to agree with you, were it not for

I ask because both subs are doing it all of a sudden after PAT testing was done though one is more sensitive than the other. Is it an expensive repair?

I know it's possible to damage kit if you're a bit gung ho with the PAT tester. The admirable Davesounds would be able to shed more light. I'll give him a nudge.

Repair cost? If Justin's right, perhaps twenty or thirty pounds.
If old Cassandra's on the money, probably considerably more.

[soundsalarming]

Thanks for the responses guys.

Sounds to me like it could be quite a cheap & simple fix. The level controls have gone scratchy & need to be replaced. Should only cost a couple of quid each plus Labour.

Is it something I can try myself? The local dj shop just quoted me £35 to assess each speaker so £70 just to tell me what is wrong!

Re the hum, usually an earth loop issue. If there's an earth lift switch, try it in both positions. One of my Proels was set wrong, and gave a very noticeable hum till we flicked the switch. For safety's sake, it's advisable to do this when it's powered off.

I know it's possible to damage kit if you're a bit gung ho with the PAT tester. The admirable Davesounds would be able to shed more light. I'll give him a nudge.

Repair cost? If Justin's right, perhaps twenty or thirty pounds.
If old Cassandra's on the money, probably considerably more.

Thanks Guys

I have had a look at the back panel and there is no earth switch. There is an earth screw point and that's it. Cost wise....been quoted £70 and 2 weeks to have a look...must have been Cassandra's mother on the phone....

[Excalibur]

...been quoted £70 and 2 weeks to have a look...must have been Cassandra's mother on the phone....

That really doesn't sound good service to me. Replacing a couple of pot(entiometer)s isn't rocket science, but it's more than a five minute job, and involves a soldering iron, so not a novice job.
I wouldn't do anything rash, see if you know or can find someone with enough knowledge to have a look and listen. That shouldn't cost £70, more like a couple of pints.

I don't wish to be all doom and gloom, but if the PAT testing has caused this, I'd say that:
1) It's likely to be costly.
2) as long as he's a reputable tester, he ought to have PLI to cover damaging your kit.
Keep us posted, we'll do our best to help.

[DAVESOUNDS SERVICES]

Hiya.
Theres a possibility of damage but its remote and would only be if your PAT tester used a Bigger / Industrial PAT Tester and DIDNT set the Earth Test current to a "Low" figure or IT setting.
What sort of tester did he use ??? have you got the results sheet to show us?.
Scratchy volume controls are not a PAT Testing problem though.
Kind Regards
DAVESOUNDS

[Excalibur]

Hiya.
Theres a possibility of damage but its remote and would only be if your PAT tester used a Bigger / Industrial PAT Tester and DIDNT set the Earth Test current to a "Low" figure or IT setting.
What sort of tester did he use ??? have you got the results sheet to show us?.
Scratchy volume controls are not a PAT Testing problem though.
Kind Regards
DAVESOUNDS

Thank you for that Dave, much appreciated. As a fully paid up sceptic I'm inclined to regard the close proximity of test with the sudden appearance of seemingly identical faults in two items as suspicious. I hope the lad finds someone to look at them soon at a sensible figure.

[soundsalarming]

Hiya.
Theres a possibility of damage but its remote and would only be if your PAT tester used a Bigger / Industrial PAT Tester and DIDNT set the Earth Test current to a "Low" figure or IT setting.
What sort of tester did he use ??? have you got the results sheet to show us?.
Scratchy volume controls are not a PAT Testing problem though.
Kind Regards
DAVESOUNDS

I had a look at the report sheet and it says Seaward Europa. It was a yellow portable device about the size of a ream of A4 paper.

Thank you for that Dave, much appreciated. As a fully paid up sceptic I'm inclined to regard the close proximity of test with the sudden appearance of seemingly identical faults in two items as suspicious. I hope the lad finds someone to look at them soon at a sensible figure.

Thanks guys. At least I have an idea what might be wrong so if I hear something rediculous I will question it. Will also shop around for a cheaper price. Will update once I know in case it helps someone else.

Out of interest, how do you rate these subs? I bought them because I found the rcf 705s I had too heavy.
I run them with a pair of rcf 722s.

I also occassionally use a pair of the original Mackies SRM 450 which are the first speakers I ever bought but find them heavy. I don't really need or use them but maybe it's sentimental attachment? Usually I use 1 sub but use 2 in bigger venues or for weddings.

My target market is weddings and parties for over 30s - I'm part time and play maybe twice a month at most.

Is there a setup you recommend out there that would justify me selling everything above and topping up a bit to end up with a better bang for buck system? Weight and size reduction would be nice but sound quality is more important to me.

[Nakatomi]

Oh yikes. I missed the bit about them being PAT tested. Read it on my phone originally. D'oh! It might just be a sad coincidence (hopefully) or it could end up being very costly indeed. Still think you need the level controls replaced whatever happens though (which'll happen when the amplifier modules are replaced, if it comes to that).

The hum could still be all down to the dodgy level controls though.

Whoever you asked for a quote to repair them really needs a rocket up em IMHO. £70 just to have a look, plus a 2 week waiting time?! That's ridiculous!

[CRAZY K]

As a fully paid up sceptic I'm inclined to regard the close proximity of test with the sudden appearance of seemingly identical faults in two items as suspicious.

Have to go with that---wonder what odds you would get from the bookies on that happening---very generous odds ill bet