Bass problem - volume drain?

[Heket]

Hi, I hope you good folk can help a newbie out with a problem.

I have a Sterling by Musicman SUB Ray, which has an active humbucker and Vol/Bass/Treb controls playing through a Fender Rumble V3 40W. Yesterday when I was playing at home (admittedly on a stormy day although the nearest storm was far away by then) I experienced a popping sound and within each "pop" the volume decreased by about 50% then went back to normal before the next "pop". I went through a couple of the steps below when the popping stopped but there seemed to be a permanent decrease in volume ie the volume was now the same was it was within the "pops" before.

Here are the following troubleshooting steps I went through:

* Fiddled with controls on bass - didn't do much
* Tried a different amp (Yamaha THR5) - still popped
* Turn the Rumble on and off again - popping gone but now the volume change is permanent
* Replace the battery - no change from the previous step
* Tried THR5 again - definitely quieter than before, had to turn the volume up about 50% more to get the same loudness and the same goes for the Rumble
* Put old battery just in to see if the pops come back, but nothing new happens.
* Tested different cable - no change
* Unplugged the Rumble and left it for an hour or so - no change
* Check under the hood for any suspect looking solder joints - all looks fine on a cursory inspection although I have no experience with bass or active circuits.

Further observations of note:

* The pots still act as I would expect.
* When plugging an electric guitar into the THR5 the amp behaved normally albeit louder because I had to turn it up to hear the bass. Ditto with the Rumble.
* From the above I believe it is a problem with the bass and not the amps or cables.
* The only playing I do at the moment is practicing for lessons so the amp was at low volume and my gear does not see any kind of heavy usage.
* I put the new battery back in.
* I do not have a multimeter


All in all it's not a *huge* deal because I can just turn stuff up, but I can imagine if it "pops" back to place and I blow my windows out It's also just annoying - my instrument isn't working properly and I want to know why! Thank you for any ideas and opinions. I'm at a loss!

[RAY AGAINST THE MACHINE]

Sounds like it could be the active circuitry in the bass at fault. My washburn status was giving police signals and radio stations at one stage.
Bump for more opinions from others ..

[HowieBass]

I've never heard this with any of my basses (4 of which are active) but it does seem to be an electronics problem with the instrument (as you've managed to eliminate all else). Pots are simple components and I can't see how they could behave in the manner you've described, same goes for the pickup which leaves the active EQ module. You could replace the EQ section with an advanced John East module that offers both traditional Stingray and more flexible tone control like this http://www.east-uk.com/index.php/bass/mmsr/mmsr-4-knob-3-band.html though I'm sure there are less expensive alternatives.

[Heket]

Blimey, that's a lot of dough for a guitar that cost £270! Then again, I know nothing about active circuity and it would be easier for me to replace the whole thing. I've replaced pickups in electric guitars but my soldering skills are not really that hot, especially not to work on a circuit board.

Ray, yours might have been a fault but it was quite a fun one! I'm not picking up any weird sounds, just feeling a bit flat that my bass seems to have myseteriously lost a big chunk of volume. It's a shame because I think it's a top quality instrument otherwise.

[Dad3353]

Good evening, Heket...

I'm not familiar with your particular bass, but the symptoms you describe make me think that one of the coils in the humbucker is intermittent. They have two coils, and if one fails, the volume would drop. The 'popping' would be the broken wire making and losing contact.
What to do..? It should be possible for a decent tech to measure the pickup, preferably comparing to another, working, one. Multimeters would be involved,so either get one, and learn how to use it, get a buddy in who has one, or get to a decent tech for analysis. I don't think you can do much more than the reasonable steps you've already taken; you need a bit of help to go further.
Hope this helps; keep us 'in the loop' with progress, please..?

[Davebassics]

Never heard of anything like this before. Sounds like faulty electronics in your bass to me.

Because the volume comes back within a specific time of the pop, I would say the component at fault could be something with a time constant. Most likely a capacitor. If for example there is a loose wire as suggested by Dad3353, then it could short a capacitor and discharge it. Depending on where the cap is and what its doing this may cause a drop in volume until it is recharged.

When the volume comes back, does it come back all at once or does it fade back in?

As I said, I've never seen this before and I have no evidence that my theory is correct, its just an initial hunch!

[Heket]

Interesting about the humbucker coil failing idea. Would that just mean that I'm technically playing a single coil bass if that were true? Would I then hear hum? I didn't notice any particular change in tone although admittedly I've never heard the difference between a single and humbucking bass.

Funny story - I went to buy a multimeter today, wandered all day and was on my way home before I realised I'd forgot the multimeter. Damned shopping centres! I'm going to try and get out to see the tech tomorrow, but it may have to wait until next week.

Davebassics - the popping was temporary, now I'm stuck with permanent volume loss. Could that mean a capacitor has been discharged and doesn't recharge any more or would it not work at all then? When it was happening the volume came back instantly like you were snapping your fingers. Where are the caps anyway? I didn't see them attached to the pots, I'm guessing they're on the circuit board which I didn't looks too closely at (nuts on the pot shaft were too tight to free them from the plate!)

I'll let you know what happens when I do see the tech.

[geoffbyrne]

If you need a replacement preamp, this one's affordable....

http://www.ebay.co.uk/itm/NEW-Retrovibe-Stinger-Classic-MM-Stingray-Bass-EQ-pre-amp-2-band-pre-EB-circuit-/281130564526?pt=UK_Guitar_Accessories&hash=item4174affbae

G.

[Dad3353]

[quote name='Heket' timestamp='1400965506' post='2458733']
Interesting about the humbucker coil failing idea. Would that just mean that I'm technically playing a single coil bass if that were true? Would I then hear hum? I didn't notice any particular change in tone although admittedly I've never heard the difference between a single and humbucking bass.

[color=#800080]... a single coil bass..? Yes, just like P and J basses. You won't hear any hum if there's nothing generating hum in the vicinity. Humbuckers work well in rejecting hum if there's any present, but single-coil basses have been used world-wide without hum problems. As for tonal change, every p/up will be different in that respect. Some will change radically, others hardly at all.[/color]

Funny story - I went to buy a multimeter today, wandered all day and was on my way home before I realised I'd forgot the multimeter. Damned shopping centres! I'm going to try and get out to see the tech tomorrow, but it may have to wait until next week.

[color=#800080]I like this, and it certainly rings a bell. It won't get any better with ageing. You heard it here first.[/color]

Davebassics - the popping was temporary, now I'm stuck with permanent volume loss. Could that mean a capacitor has been discharged and doesn't recharge any more or would it not work at all then? When it was happening the volume came back instantly like you were snapping your fingers. Where are the caps anyway? I didn't see them attached to the pots, I'm guessing they're on the circuit board which I didn't looks too closely at (nuts on the pot shaft were too tight to free them from the plate!)

[color=#800080]For my money, I wouldn't be looking for caps for the symptoms described. Not impossible, but it's very, very rare for caps of this sort to fail, and if they do, you'd hardly hear the difference. A different kettle of fish with amps and such, where failing caps can cause havoc in some circumstances. Not a dumb suggestion, just highly unlikely for now, imo.[/color]

I'll let you know what happens when I do see the tech.

[color=#800080]Something to try out whilst waiting..? Get access to the 'guts' of the bass, and, with the bass plugged in and at very moderate volume, use a chopstick to gently tap the components, pots, soldered joints and even the p/up casing. Keep playing any string (no, no particular melody, you chump, just keep a signal going to the amp..!), and see if any mechanical fault can be provoked. Don't go crazy with the tapping, though; I did say 'gently'. There's nowt decent on'telly tomorrow, so you're not wasting your afternoon, and it could help a 'tech' if you find a sensitive spot.[/color]
[color=#800080]Hope this helps.[/color]

[/quote]

[Davebassics]

I'm revoking my caps theory!

[Dad3353]

[quote name='Davebassics' timestamp='1400998865' post='2458863']
I'm revoking my caps theory!
[/quote]

Which one..?

[attachment=163508:Caps_Gun.jpg] [attachment=163509:Caps_Lock.jpg] [attachment=163510:Caps_Mili.jpg] [attachment=163511:Caps_Recy.jpg] [attachment=163512:Caps_Scho.jpg] [attachment=163513:Caps_Thin.jpg]

[Davebassics]

very good!

[Heket]

Hey, I didn't get time to try the tapping today, but the local tech won't be around until next weekend so I have time before then. I'm also a bit reluctant as I've already scratched the control plate trying to get the darned nuts off the pots so I wanted to wait until my other half was home to help me. The volume is still the same so it looks like it's not going to "pop" back. Thanks for the suggestion of additional tests to do

I've made a note of that pre-amp, should I need one. Hopefully all I need is a bit of re-soldering somewhere.

[Davebassics]

How are you getting on with this?

[Heket]

Today I tried the "tapping components with a chopstick" thing and didn't really get very far. The only thing that made a bit of difference was a bit on the side of the bass pot which has the active circuit attached and gave an effect like tapping on a microphone would. Sorry for the lack of technical description, I searched for a picture of "bass active circuit" and this one shows the part I mean:



The three grey, flat pins attached to the pot. I have no idea if that would produce this effect anyway. Tomorrow I'll call the music shop and see if the doctor is in this weekend. I have a lesson on Monday though and don't want to be bassless as they had their lesson bass stolen and don't have one for teaching any more.

[Dad3353]

Good evening, Heket...

You did good, I think. Show your tech what you were doing; I think it'll save him a lot of time. There's probably a 'dry' solder joint on that board, maybe where the pot is soldered. You can't fix it yourself (I assume you've not got soldering equipment..?), but a tech will make short work of a repair if he/she can confirm your findings. At the worst, could the music shop not lend or hire you a bass for your lesson..?
It's looking good, I'd say.

[Heket]

[quote name='Dad3353' timestamp='1401480470' post='2464147']
...You did good, I think. Show your tech what you were doing; I think it'll save him a lot of time. There's probably a 'dry' solder joint on that board, maybe where the pot is soldered. You can't fix it yourself (I assume you've not got soldering equipment..?), but a tech will make short work of a repair if he/she can confirm your findings...
[/quote]

Thanks I do have equipment but it's a pretty rubbish iron from Wilkinsons which probably doesn't get hot enough and my solder has quite a thick diameter. I've soldered a couple of pickup swaps and pot changes in other instruments but I've nowhere near the level of skill or precision to work on a circuit board. Many balls of solder fly about before I can get anything to stick! Shouldn't have given up electronics at school.

[Davebassics]

Try re-flowing the solder on the pot. Let it get hot and it should melt and take shape around the pot. This should be enough to ensure that any dry joints are taken care of.

[Heket]

Thanks for the suggesions, but I think I'm going to leave this one in the hands of the tech. I have an appointment with him tomorrow.

[iiipopes]

Recently, I had volume problems as well in my active bass. It turned out the substandard jack fingers wore prematurely and were not making proper contact with the cord plug end. A new, proper Switchcraft jack, and I was back in business.

Edited May 31, 2014 by iiipopes

[Heket]

I saw the "tech" today, he turned out to be more of a luthier with an interest in acoustic instruments. He said he could pass on my bass to his friend who deals in electrical parts but it could take up to week to get it back so I declined for now.

He plugged it in an played and declared it as "working as intended". Well yeah, when taken out of context I suppose it does work fine, but [i]I[/i] know that there's been a significant drop in volume. When I told him this he turned up the amp and the bass and proceeded to make the walls shake but... that's not the point. He said the humbucker is probably fine, in his words "pickups either work or they don't". He said it certainly sounded powerful enough to be an active humbucker. He told me to clean the contacts which I'll do once I source some fluid. At least I didn't have to pay for this short consultation, but I'm left feeling a little.. deflated?

I don't know, maybe I'm just being picky and/or a bass hyperchondriac. I'll probably leave it for now, especially considering I don't play with others, but I think it'll have to be seen to at some point, otherwise I'm going to find my amp is too quiet should I ever want to start playing in a band. Then I will send it to the guy who deals in electrics.

Is there any way I can easily test the humbucker coils? I can buy a multimeter if needed.

[Dad3353]

[quote name='Heket' timestamp='1401633887' post='2465361']I saw the "tech" today...[/quote]

Where in Essex are you..? I'm sure there's someone here that could recommend a competent tech near you; it's not as if it was the Gobi desert..! I'm in France, so can't help directly; maybe there's a kind soul who could pop in to check it out (or allow a visit to them, of course...)..?
Your bass may well sound fine in isolation, but if you're certain there's been a volume drop (no hallucinations..? No carpet smoking..? ), then it needs explaining and fixing.
I'd leave the multimeter for now (although they're always a useful instrument to have...); the chopstick test is still pointing more towards a solder joint. It would be a matter of minutes for a decent tech to confirm and fix that, but any clumsiness would do far more harm than good, so I won't recommend that you hone your skills on this yourself. When the time comes, 'look and learn' would be preferable.

[Heket]

I'm in Billericay, which is near Wickford, Basildon, Brentwood, Chelmsford. I saw a tech in Chelmsford for my electric guitar before and didn't like what he did and didn't have much luck finding more online.

I do have an update, at my lesson today my tutor noticed something amiss! Silly sausage that I am, I completely forgot to mention to the tech that he should try a guitar in the same amp and check the difference in volume, then again he didn't have any electrics up there anyway. My tutor did that with a passive/single coil Strat and noticed instantly that my bass wasn't packing the punch it should be. You could hear the guitar ring out probably across all the teaching rooms but the sound from my bass wouldn't have carried beyond the door. So there it is, completely different area, power supply etc etc.

When I can spare it for a few days I'll hand it to the proper tech and now I know exactly what to say for him to test it.

[Heket]

Update - oddly enough, following another storm today my bass is back to normal
I could have competed with the thunder when I started playing! Obviously this doesn't fix the problem but at least I didn't get to a tech yet and try and demonstrate a now symptomless problem. The whole storm thing is probably a coincidence, but it sure is an odd one.