Why is my rig ticking?

[northstreet]

Wondered if anyone can identify the likely cause of a problem with my amp.

As briefly as possible - I buy a brand new Hartke LH500 and plug it into my (used) Hartke VX115 cab. Straight away I notice an unusual noise. As I strike a note I get a noise the cab that sounds just like a 'tick'. It's only at the start of the note, on the lower strings, with the volume & bass EQ up (but not excessively so), and when the amp's warmed up. The tick volume doesn't appear to depend on how loud the amp is - I can drown it if I play loud enough. I don't have other bits of kit to find out whether it's amp or cab, but I get the same noise with different basses.

Now I know should have done something about it straight away, but soon after I used the rig at a gig and blew up the speaker. In goes a brand new Eminence Kappa Pro, but the noise is still there. So it must be the amp. Back it goes to the shop, and it comes back noise free. Hurrah.

Now, I played a gig last weekend for the first time with the repaired amp, and at the end the noise is back. Grrrrrrr. So I'm taking it back to the shop at the weekend. But, if I had some idea what the problem was, I reckon I'll have more chance of getting it sorted properly (always works for me with car repairs). So is there anyone out there who has any ideas what could be wrong?

Thank guys.

Edited April 19, 2010 by northstreet

[Jean-Luc Pickguard]

a bomb?

[northstreet]

[quote name='Jean-Luc Pickguard' post='770909' date='Mar 10 2010, 08:49 PM']a bomb?[/quote]

"Boom! boom!", as Basil Brush would say.

[Kraken]

this may seem a bit daft, I assume the picture next to your posts is you...

you've not switched wearing your watch from your left wrist to your right wrist?

I've had watches with hands (hour, minute, second - you get the idea) get their motion reported by the pickups on basses before.

Apologies if that isn't it, and good luck getting it fixed.

[largo]

You've not noticed a rucksack beside your gear have you ?

Edited March 12, 2010 by largo

[northstreet]

Thank you for all comments received, whether sensible or not. I've now been told that the ticking is coming from the cab itself - ie not the speaker - but the actual box. I guess that means there's some sort of structural failure - a glued joint broken or something, and it's moving in sympathy with the speaker. Which is probably why the speaker has started to fail as well!

I'd like to try a repair (on the basis that if I can fix it it's cheaper to buy a new speaker than it is to buy a whole new cab), but has anyone come across this before and have any ideas of where to start. Or should I just give up and bin it?

More bomb jokes are always welcome.

[Buzz]

Er, you blew up a speaker? I'd be more worried about the cause of that first, as that's normally down to driving it far too hard.

Edited March 24, 2010 by Buzz

[ped]

Hmm. Strange. Does the noise happen at all if you don't play anything? Does it ONLY happen at the start of a note? Are you able to try a different amplifier with the same cab?

I wonder if it could be an electronics issue (grounding/clipping) possibly in the bass or amplifier? It could also be interference from something else in the room - when my TV is on I used to get a faint but constant ticking through my IEMs.

ped

[Golchen]

Do you also get a loud ringing at about 7.00am?

[JPAC]

[quote name='northstreet' post='785103' date='Mar 24 2010, 08:22 PM']More bomb jokes are always welcome.[/quote]

A beumb? ~ Chief Inspector Clouseau

Could be one of the switches/controls needs cleaning or replacing, but you would have to take it apart to do that. As it's new, get it done under guarantee.

Anybody you know lost a metronome ?

Edited March 24, 2010 by JPAC

[AlanP2008]

[quote name='northstreet' post='770902' date='Mar 10 2010, 08:42 PM']Wondered if anyone can identify the likely cause of a problem with my amp.

As briefly as possible - I buy a brand new Hartke LH500 and plug it into my (used) Hartke VX115 cab. Straight away I notice an unusual noise. As I strike a note I get a noise the cab that sounds just like a 'tick'. It's only at the start of the note, on the lower strings, with the volume & bass EQ up (but not excessively so), and when the amp's warmed up. The tick volume doesn't appear to depend on how loud the amp is - I can drown it if I play loud enough. I don't have other bits of kit to find out whether it's amp or cab, but I get the same noise with different basses.

Now I know should have done something about it straight away, but soon after I used the rig at a gig and blew up the speaker. In goes a brand new Eminence Kappa Pro, but the noise is still there. So it must be the amp. Back it goes to the shop, and it comes back noise free. Hurrah.

Now, I played a gig last weekend for the first time with the repaired amp, and at the end the noise is back. Grrrrrrr. So I'm taking it back to the shop at the weekend. But, if I had some idea what the problem was, I reckon I'll have more chance of getting it sorted properly (always works for me with car repairs). So is there anyone out there who has any ideas what could be wrong?

Thank guys.[/quote]

It is possible that the blown speaker and the ticking are completely unrelated.

You might look for any airleaks (ok, I don't know whether this is a sealed cab, or ported - if ported, then ignore this comment).
You might pull out the speaker and see if the internal wiring is touching the back of the cone anywhere, then check for any other loose components or "stuff" inside.
You might check to see if it has been dropped, and sprung a joint or seam somewhere - is the baffle securely attached?
There is reallly a limit to what it actually might be in a speaker cab - you'd like to think you could find it just by looking around, inside and out.

Best of luck.
Alan

[northstreet]

Problem sorted. How? I turned the cab upside down! Must be a dodgy joint somewhere and the change of weight is stopping it moving = stopping it ticking. Had a tidy up inside at the same time, junked the horn and the crossover, upgraded the wiring and refixed the fibereglass sound-deadening stuff. Sounds perfect now. But just in case, I've bought another VX115 for £65 on Ebay. Happy days.

[Phil Starr]

I think what has thrown us is the word tick. I didn't read theis thread until now because I couldn't think of anything which would make a rig give a regular ticking sound, but of course this isn't your problem.

My guess is that your problem is a simple overload on the transients. When you pluck a string it moves a long way with the first pluck then the vibrations gradually die away so all the energy is concentrated in the first movement of the string. You say the problem happens with bottom strings and with volume and eq up. When you turn the eq up you are demanding more power from the amp and speakers. If your eq is +/- 12dB which is common then turning the eq up to 3 o'clock is demanding an extra 6dB. this is 4x the power so if you were running at 50W you are now demanding 200W from the amp and through the speaker. all the way up and you are asking for 800W!

Now two things might happen which would cause a sharp sound (click?) The speaker cone is being asked to move a long way and it may hit something or simply be limited by the internal design of the speaker. You might even eventually blow the speaker. The second possibility is that the amp limits, chopping off the top of the waveform and creating some short term sharp distortion which will be audible. This sharp change in the wave will be turned by a crossover into an extra treble and passed on to the tweeter if you have one and could blow the tweeter. With my piezo tweeters I get an audible click when I handle the bass carelessly when it is up high.

You've blown a speaker and removed the problem when you disconnected the tweeter so it could be either or both of these. The root of your problem could be the excessive use of eq.

Cheers

[warwickhunt]

Is the speaker grill secure? Sometimes folk assume the worst when they hear a noise and go looking for the most complicated (expensive) answer, when in fact it can be the mundane and simple; so check everything is screwed down tight!

[northstreet]

Thanks very much for the recent contributions, but as in my last post the problem was with the cabinet itself. It's got a dodgy joint (I think at a bottom edge) and the air compression in the cab was making it move. This movement could be heard as a 'tick', mainly through the port. Turning the cab upside down has changed the weight distribution - and with the weight of the amp on top - and the noise has stopped. I think I was being given a duff steer about the speaker, it's working fine.

Like you guys I blamed the amp/speaker/eq/volume etc etc just because that's exactly what the noise sounded like - but it was actually something very simple.

But thanks again for the posts.

Edited April 24, 2010 by northstreet

[witterth]

[quote name='northstreet' post='817464' date='Apr 24 2010, 07:33 PM']Thanks very much for the recent contributions, but as in my last post the problem was with the cabinet itself. It's got a dodgy joint (I think at a bottom edge) and the air compression in the cab was making it move. This movement could be heard as a 'tick', mainly through the port. Turning the cab upside down has changed the weight distribution - and with the the weight of the amp on top - and the noise has stopped. I think I was being given a duff steer about the speaker, it's working fine.

Like you guys I blamed the amp/speaker/eq/volume etc etc just because that's exactly what the noise sounded like - but it was actually something very simple.

But thanks again for the posts.[/quote]
Hmm..Like Warwick says sometimes its those "little things" (that bugg%r things up)Eh?
well diagnosed Dr Northstreet!!

[Phil Starr]

[quote name='northstreet' post='785103' date='Mar 24 2010, 09:22 PM']Thank you for all comments received, whether sensible or not. I've now been told that the ticking is coming from the cab itself - ie not the speaker - but the actual box. I guess that means there's some sort of structural failure - a glued joint broken or something, and it's moving in sympathy with the speaker. Which is probably why the speaker has started to fail as well!

I'd like to try a repair (on the basis that if I can fix it it's cheaper to buy a new speaker than it is to buy a whole new cab), but has anyone come across this before and have any ideas of where to start. Or should I just give up and bin it?

More bomb jokes are always welcome.[/quote]

If it is just a matter of sealing the cab then you can do this by applying a bead of acrylic mastic (decorators caulk) and smoothing it with your finger. If it needs mechanical fixing then cut a length of 25mm square batten and glue it in with white woodworking glue and a few screws to hold it in place.