HELP! EBS Microbass II - B channel massive volume drop

[warwickhunt]

I've read the manual, I've watched the videos, so I'm assuming it isn't me using it wrong but I need to check...

 

Plugged into input A, nothing plugged into input B, volume at 90%, Boost down and all buttons out/EQ centred.  The preamp has a nice healthy output and tone.

 

Hit channel B button and there is a massive volume drop (huge, almost inaudible).   Back to channel A, engage the A+B button and switch to B (the 2 channels should combine), massive volume drop.  I can increase the Drive setting but channel B is then full on Drive and not much volume, flick back to A and it is back to a healthy setting.

 

In summary, whenever channel B is engaged there is a huge drop in output.

 

I've tried engaging various buttons etc but nothing changes that basic issue; neither does increasing the Boost, that simply makes A even louder.  

 

Is this unit defective or am I missing something? 

[Al Nico]

Hi. It says that Ch B can be added to Ch A using the A+B button and selecting A/B

It says you can use a second instrument on Ch B through input 2

but it doesn't say you can monitor input 1 on Ch B

 

So with the instrument in input 1 you can have Ch A, and Ch A+B

That's what I'm working out from the manual?

[warwickhunt]

Agreed and I'm not plugging anything into B but when you plug into the A input and engage A+B button using the switch to go from A > A+B there is a massive volume drop which you can't compensate for (it literally feels like going from 10 down to 1 or 2).  Effectively with a single instrument it is a single channel pedal and trying to add channel B to add drive (or clean) reduces the volume to unusable levels.

 

I'm now off to plug basses into A and B to see what we get.

[warwickhunt]

Tried plugging 2 basses in (1 in A 1 in B) with A+B disengaged.  Channel A selected and the bass is nice and clear, select Ch B and the bass is inaudible unless the Drive is cranked and there is a low level (massively overdriven by now) output.  Pretty sure that is not how it is meant to work; I've even read the manual.  

 

I can only surmise that Ch B is fecked!  It can't be used as a 2nd channel nor can it even be summed with A to give a bit of Drive because any combination involving Ch B drops the volume and you'd need to put the Drive on 100% to even hear anything (which would still be loads quieter than A).  

 

Looks like a repair job or return to seller! 

 

[Al Nico]

Well, that would be the test. A signal into input 2 is expected to monitor through CH B.

In this case the output is unexpectedly low where it is expected to be similar to CH A

Have you tried switching it off and on again?

[warwickhunt]

2 minutes ago, Al Nico said:

Well, that would be the test. A signal into input 2 is expected to monitor through CH B.

In this case the output is unexpectedly low where it is expected to be similar to CH A

Have you tried switching it off and on again?

 

Multiple times.  I've also tried setting/unsetting all switches but it's exactly the same each time.  Pretty sure there's something died in Ch B, it'll make a great clean 1 channel preamp/DI but absolutely not fit for the 2 channel purpose or even to use the overdrive (as it is on the B channel).  

[Al Nico]

Have you tried blowing on it, or rapidly firing the mains switch to help purge the ROM?

Or what about using a higher voltage power supply to 'kick start' it?

 

te he

 

I'm done now. Right. I agree. Sounds Feecked. Poo.

[Kirky]

Are you testing it using the XLR, or with an amp, or with headphones directly plugged in?  I've found it behaves very strangely with different headphones.  I've ended up using it as a one channel preamp/DI as well - i haven't had the same problem as you, but I struggle to get a good balance between the channels.

[warwickhunt]

1 minute ago, Kirky said:

Are you testing it using the XLR, or with an amp, or with headphones directly plugged in?  I've found it behaves very strangely with different headphones.  I've ended up using it as a one channel preamp/DI as well - i haven't had the same problem as you, but I struggle to get a good balance between the channels.

 

I tried all options!   

[Hellzero]

Do you use it with a battery or a power supply?

[warwickhunt]

11 minutes ago, Hellzero said:

Do you use it with a battery or a power supply?

 

So far 3 different power supplies but not battery.  TBH the single channel (A) use is very healthy and no issues what so ever; it is only when you try to use or combine Ch B.  At this point levels drop off massively.  I've watched multiple user videos on YT and none of the videos show the symptoms that this has.

 

[Hellzero]

You could open it, disassemble it and reassemble it, it's really easy to do.

 

In fact, the fast connector of the B channel could be loose hence not having full contact...

 

After that, and, before, trying it with a brand new battery, if it's not working, you could definitely say there's a problem and send it back to EBS or the seller.

[warwickhunt]

Good point.  I'll check with the seller that they are cool with me opening it up and I'll give that a look.  TBH if I return it as it operates now, they are left with a pedal that is probably devalued by 50%, so they might as well let me take a look inside!  

 

New battery is an easy test.  

 

[Osiris]

19 hours ago, warwickhunt said:

I've read the manual, I've watched the videos, so I'm assuming it isn't me using it wrong but I need to check...

 

Plugged into input A, nothing plugged into input B, volume at 90%, Boost down and all buttons out/EQ centred.  The preamp has a nice healthy output and tone.

 

Hit channel B button and there is a massive volume drop (huge, almost inaudible).   Back to channel A, engage the A+B button and switch to B (the 2 channels should combine), massive volume drop.  I can increase the Drive setting but channel B is then full on Drive and not much volume, flick back to A and it is back to a healthy setting.

 

In summary, whenever channel B is engaged there is a huge drop in output.

 

I've tried engaging various buttons etc but nothing changes that basic issue; neither does increasing the Boost, that simply makes A even louder.  

 

Is this unit defective or am I missing something? 

 

At the risk of stating the obvious, that's definitely not behaving as it should. I've been using a Microbass II for a few years now so know the pedal well and while I tend to use mine exclusively with channels A and B combined, whenever I have run them independently I find that channel B is generally louder than A depending on where the drive/gain is set and usually end up suing a judicial amount of the Boost control on A to balance the respective levels. But fingers crossed it's a simple, or at least inexpensive, fix.