Help! Little Mark II problems...

[dangee]

I bought my Little Mark II about 8 months ago. I gigged it on Saturday and, intermittently, the sound would die for between 3-10 seconds. It was definitely the amp- I took the pedal board out of the equation, changed basses, etc.

I spoke to Proel today and they basically said that it was my fault, as I wasn’t pairing it with Markbass cabs! I have it running through two EBS neo 112’s, both 8 ohm cabs.

I’m still waiting for them to get back to me.

So…is this a Markbass issue, or is it the Gallery’s fault for not making me aware that the LMII can’t be used with any non-MB cabs?

[DirkThrust]

[quote name='dangee' post='508661' date='Jun 8 2009, 10:39 PM']I spoke to Proel today and they basically said that it was my fault, as I wasn’t pairing it with Markbass cabs! I have it running through two EBS neo 112’s, both 8 ohm cabs.

So…is this a Markbass issue, or is it the Gallery’s fault for not making me aware that the LMII can’t be used with any non-MB cabs?

[/quote]

I've never heard of that before. I think they're talking crap.

If it's only 8 months old can't you take it back to the dealer you bought it from. It's their responsibility to honour the warranty rather than Proel, who are the importer.

Edit: Having read your post properly I see you got it from The Gallery. I'm sure they'll sort it under warranty. As long as you haven't been running it below the minimum load recommended by Markbass, which is 4 ohms, then the make of speaker you use with it is irrelevant.

Edited June 8, 2009 by AndyMartin

[Dood]

Agree with both points above. Talking absolute nonsense. Your two EBS Neos are well within the amplifiers tolerance when paired together (4 Ohms) . I use my MB with an Epifani cab.. and that is yet to even wince when I drive it.

Andy is correct, you are within your 12 month guarantee. Take it back to where you [i]bought[/i] it from and get a swap or repaired. You should not have to pay for this.

Do me a favour will you? Turn it on and see if the fan spins up correctly. A failure there could mean the amp over heats.

[Musicman20]

[quote name='AndyMartin' post='508670' date='Jun 8 2009, 10:44 PM']I've never heard of that before. I think they're talking crap.

If it's only 8 months old can't you take it back to the dealer you bought it from. It's their responsibility to honour the warranty rather than Proel, who are the importer.

Edit: Having read your post properly I see you got it from The Gallery. I'm sure they'll sort it under warranty. As long as you haven't been running it below the minimum load recommended by Markbass, which is 4 ohms, then the make of speaker you use with it is irrelevant.[/quote]

Agreed...go back to The Gallery. Not running it with Mark Bass cabs is probably the norm! They are small light heads and good for travelling...hence people borrow cabs or just buy different makes anyway.

[dangee]

[quote name='dood' post='508678' date='Jun 8 2009, 10:53 PM']Agree with both points above. Talking absolute nonsense. Your two EBS Neos are well within the amplifiers tolerance when paired together (4 Ohms) . I use my MB with an Epifani cab.. and that is yet to even wince when I drive it.

Andy is correct, you are within your 12 month guarantee. Take it back to where you [i]bought[/i] it from and get a swap or repaired. You should not have to pay for this.

Do me a favour will you? Turn it on and see if the fan spins up correctly. A failure there could mean the amp over heats.[/quote]

The fan seems to be running fine. I'll give Alex a call tomorrow.

I went direct to Proel as I called the Bass Merchant yesterday for advice and I was told they would just go straight to Proel, so I might as well.

As a point of interest, Proel immediately told me the problem was that I was using two cabs. I heard them saying that my head needed 'the mod'. A known issue?

In a discussion with a second person they then said that I was running the head below 4ohms and that was the problem (as EBS advertise the 112s as 8ohm cabs, but they probably aren’t). They even wanted me to test the impedance of the cabs!

[pete.young]

[quote name='dangee' post='508690' date='Jun 8 2009, 11:06 PM']The fan seems to be running fine. I'll give Alex a call tomorrow.

I went direct to Proel as I called the Bass Merchant yesterday for advice and I was told they would just go straight to Proel, so I might as well.

As a point of interest, Proel immediately told me the problem was that I was using two cabs. I heard them saying that my head needed 'the mod'. A known issue?

In a discussion with a second person they then said that I was running the head below 4ohms and that was the problem (as EBS advertise the 112s as 8ohm cabs, but they probably aren’t). They even wanted me to test the impedance of the cabs![/quote]

And how do they expect you to do that?? What utter cack.

Nevertheless, your contract is with the shop you bought the head from, not with the importer. Sale of Goods Act as amended etc. It's their responsibility to sort it out.

FWIW I've been using an LMII with an EBS 2x12 (4Ohm) , which is exactly the same thing you have but in one box not two, with no problems. There's no way this can be blamed on the cab.

[mhuk]

Connected in series or parallel?

If you were running 2 x 8 ohm cabs in parallel the impedance would be 4 ohms.

[url="http://www.tunemybass.com/bass_amps/how_to_hook_up_heads_and_cabinets.html"]http://www.tunemybass.com/bass_amps/how_to...d_cabinets.html[/url]

As above, I'd suggest speaking to the people you bought the amp from.

Good luck

[dangee]

[quote name='mhuk' post='508704' date='Jun 8 2009, 11:24 PM']Connected in series or parallel?

If you were running 2 x 8 ohm cabs in parallel the impedance would be 4 ohms.

[url="http://www.tunemybass.com/bass_amps/how_to_hook_up_heads_and_cabinets.html"]http://www.tunemybass.com/bass_amps/how_to...d_cabinets.html[/url]

As above, I'd suggest speaking to the people you bought the amp from.

Good luck [/quote]

They're 'daisy-chained' (which according to your link would make it series). There's no other way- there is only one speakon output on the head.

[alexclaber]

Which moron wrote that article on tunemybass.com? Daisy chained cabs are in parallel, not series. Series requires completely different and rather weird looking cables. I seriously doubt the problem is with the cabs, there's nothing unusual about them which could result in a particularly challenging impedance curve (like some EA cabs).

My guess is that there's something wrong with your Markbass - can you test it with another 4 ohm rig?

I gather Markbass's reliability record is absolutely outstanding but they've sold a hell of a lot of LMIIs so they can't all be fault free!

Alex

[Monz]

Does the back of your amp look like this?



If so then both of the "speaker out" sockets, 1/4" and speakon take an 8ohm cab each... you will need to use a 1/4 jack for one of them though

[dangee]

[quote name='Monz' post='508772' date='Jun 9 2009, 06:55 AM']Does the back of your amp look like this?



If so then both of the "speaker out" sockets, 1/4" and speakon take an 8ohm cab each... you will need to use a 1/4 jack for one of them though[/quote]

So I can't daisy chain them then??

[Monz]

[quote name='dangee' post='508800' date='Jun 9 2009, 08:33 AM']So I can't daisy chain them then??[/quote]

I had a Jeff Berlin Combo which uses the same head (badged differently) and I used all manner of cabs and it never gave me one iota of trouble. I would try running two cables rather than persisting with the daisy chain idea which seems to be causing you a lot of grief.

For the cost of buying another amp > cab cable it would definately be my next step

PS Thinking logically... if the amp is shutting itself down but then working again I would summise it has some kind of protection against incorrect loading on the outputs and so is effectivley "tripping out" rather than just just melting

Edited June 9, 2009 by Monz

[dangee]

[quote name='Monz' post='508803' date='Jun 9 2009, 08:40 AM']I had a Jeff Berlin Combo which uses the same head (badged differently) and I used all manner of cabs and it never gave me one iota of trouble. I would try running two cables rather than persisting with the daisy chain idea which seems to be causing you a lot of grief.

For the cost of buying another amp > cab cable it would definately be my next step

PS Thinking logically... if the amp is shutting itself down but then working again I would summise it has some kind of protection against incorrect loading on the outputs and so is effectivley "tripping out" rather than just just melting[/quote]

But surely the amp is designed to be able to be daisy chained?

[dave_bass5]

Could it be that one of the cabs is causing the head to shut down? I had this happen with my SA450 once at a rehearsal room when i was using a dodgy cab (they didn't bother telling me it wasn't working properly).
Although thinking about it im pretty sure i had t turn the head back on each time.
Just a thought.

Oh, and LMII has been nowhere near a MB cab in two years.

Edited June 9, 2009 by dave_bass5

[dave_bass5]

[quote name='Monz' post='508772' date='Jun 9 2009, 06:55 AM']If so then both of the "speaker out" sockets, 1/4" and speakon take an 8ohm cab each... you will need to use a 1/4 jack for one of them though[/quote]

Actually both take a 1/4" Jack.

Just pointing that out.

[Monz]

[quote name='dangee' post='508819' date='Jun 9 2009, 09:37 AM']But surely the amp is designed to be able to be daisy chained?[/quote]

I would have thought you can put what you like on the single output as long as it equals 8ohm. With the greatest of respect I suspect you don't know what the resistance is of your daisy chained cab setup. Can the resistance not be checked by putting a multimeter (set to measure resistance) across the jack that you would plug into the head?

I am no expert in the field and have nothing to gain by sticking up for Markbass I am simply pointing out what seems glaringly obvious to me.

[i]Edited to remove comment that sounded curt even though it was not meant to[/i]

Edited June 9, 2009 by Monz

[51m0n]

There is a company who are causing issues by incorrectly labeling a cab as 8Ohms (more specifically the tolerances allow the cab to be lower than 8 ohms). But I think that is EA, there was some talk on talkbass about this issue as MB amps do protect themselves in that case.

In any event I'm pretty sure it wasnt a problem related to EBS cabs at all.

I've run my sa450 with a berg for some considerable time at 4ohms. No issues. That is what the amp is specified to deal with.

The persons on the other end of the phone were talking rubbish and it is a shame you werent confident in your knowledge to bring them up on it!

Daisy chaining vs using two outputs shouldnt make any diff, unless there is a short somewhere (which could be in the cabs or speaker cables or head).

IMO it could be an issue with cabs or amp or even your speaker cable, unless you try it with a different amp and different leads, you cant be sure I'm afraid. Taking the pedal board out of the equation doesnt solve any of these. You need to get to the bottom of exactly where the issue is yourself. The MB amp could well have just been protecting itself from an issue else where.

Si

[dangee]

[quote name='Monz' post='508877' date='Jun 9 2009, 10:57 AM']I would have thought you can put what you like on the single output as long as it equals 8ohm. With the greatest of respect I suspect you don't know what the resistance is of your daisy chained cab setup. Can the resistance not be checked by putting a multimeter (set to measure resistance) across the jack that you would plug into the head?

I am no expert in the field and have nothing to gain by sticking up for Markbass I am simply pointing out what seems glaringly obvious to me.

[i]Edited to remove comment that sounded curt even though it was not meant to[/i][/quote]


Bit of a tricky one…as I don’t have any other cabs to A/B it against (or any means of measuring the impedance). And you’re right…I don’t know the combined impedance. I have simply done what I thought was the ‘normal’ approach for someone who doesn’t have a clue (i.e. 2x8 ohm cabs =4ohms).

I do know that I have used the cabs with many heads over the last couple of years without any problem whatsoever.

The fact that the tech’s at Proel immediately said to each other that the head needed ‘the mod’ did suggest some known issue.

[dave_bass5]

[quote name='dangee' post='508904' date='Jun 9 2009, 11:33 AM']The fact that the tech’s at Proel immediately said to each other that the head needed ‘the mod’ did suggest some known issue.[/quote]

Ive not heard of any mods on MB gear other than the jumper settings.
Ive had my LMII for just over two years so its probably older than yours and hasn't been modded.

Edited June 9, 2009 by dave_bass5

[jonny-lad]

Have you tried it with just one of your cabs on its own to see if it still happens with an 8ohm load?

If it does, I'd assume that it's a fault somewhere either in the amp, cable or cab. If it still happens with the other cab and/or a different speaker cable, I'd think it would be a fault with the amp.

If it doesn't cut out with just one cab, I'd think it would be an impedance issue.

[51m0n]

[quote name='jonny-lad' post='508919' date='Jun 9 2009, 11:49 AM']Have you tried it with just one of your cabs on its own to see if it still happens with an 8ohm load?

If it does, I'd assume that it's a fault somewhere either in the amp, cable or cab. If it still happens with the other cab and/or a different speaker cable, I'd think it would be a fault with the amp.

If it doesn't cut out with just one cab, I'd think it would be an impedance issue.[/quote]

Well it could be an impedance issue, or the other cab or the other lead......

You could narrow this down by drawing up a test matrix of your gear and checking everything out, but there is a chance that the fault is not the amp and yet only shows up when set up exactly as you have done (ie daisy chained from speaker A to speaker B and A has a fault in its connector) so you would have to even cover off the order of the daisy chaining (A -> B and B ->A) etc

Worst case scenario is its not the amp, but it only turns up when you plug everything in together, and you cant figure out why.

Testing like this where something (and you dont know exactly what) has failed can be very very difficult mate. It is an exact science, just a long drawn out and tiresome process...

If I were a betting man I would put money on it being a lead or connector though, and the LMII is protecting against an intermittent short mucking up the impedance....

[Mottlefeeder]

Reading the stuff on the Markbass website, it seems that the combo speaker plugs into the jack socket, leaving the Speakon free for any extension speaker. It is possible that this is deemed to be acceptable because the speaker cannot be disconnected without taking the amp out of the combo, and it may be that the 'mod' being discussed is to fit a second Speakon to reduce the risk of a shock from the amplifier when used as a stand-alone head.

With regard to what further work you can do, I suggest that you unplug the speaker connecting leads, and check each one for crush damage along its length, then dismantle the connectors and check for loose wires in each. The fault is more likely to be in the flexible cable than inside an amplifier box or inside a wooden box. It might also be worth checking that all four cable ends are connected to the +1 & -1 connector terminals, just in case you have aquired a cable which has been wrongly wired.

Stage two would be to check the connections on the back of the speakers - again, start by looking for loose connections/stray wires, then check that the speaker in/speaker out connections go to the same sets of terminals on the two speakons connectors.

[dangee]

Thanks for the advice...as the issue only happened after about 2 hours of playing at gigging volume, the wife will be well-chuffed with my forthcoming investigative work!

[51m0n]

[quote name='dangee' post='509019' date='Jun 9 2009, 01:51 PM']Thanks for the advice...as the issue only happened after about 2 hours of playing at gigging volume, the wife will be well-chuffed with my forthcoming investigative work![/quote]

Was it a very hot gig?

Did the amp have sufficient airflow?

MB stuff typically runs very cool IME, I have never even got my sa450 warm to the touch, but if you were in a confined space playing very loudly for a very long time it is conceivable - however unlikely - that with a restricted airflow the thermal shut down kicked in.....


Just a thought.

[clauster]

Don't bother with sticking a multimeter across the cabs' terminals - resistance and impedance and DC resistance are not the same thing.

The LM2 should not see any difference between using one or both outputs.

It's possible there's nothing wrong with anything.

4 Ohm is the limit of the LM2's loading and you've been driving it at gigging volume for two hours before the problem occurred, plus its a little amp. Even with nothing malfunctioning that poor little b*gg*r is going to be getting HOT in there and need a rest here and there.