Markbass problem!! What do I do?!?

Tysonhiseler · #1 01-29-2013, 08:54 AM

I recently got a markbass f1 and I'm having a bit of a problem with it. I love the sound and how small it is but every now and then it just shuts off. I'm not sure if it a power issue or if i got a lemon. I'm inning it through an older Eden 4x10 ( no ports, white logo ). The cab is 500 watts and 8 ohms. The head is supposed to run at 300 watts at 8 ohms and 500 watts at 4ohms. Could it be the pairing? Any help would be awesome!

KJung · #2 01-29-2013, 09:19 AM

Most likely one of two things:

1) hinky power, causing the safety shutdown to engage

2) If you are playing quite loud, you might just be pushing that head to its limits and beyond at 8ohms, causing safety shutdown.

I would recommend making sure it is not 'power related' by checking your rig in different locations. And also, determine if it is only briefly shutting down when you are really cranking.

If it seems to randomly do this though, at multiple locations and at multiple volumes, unfortunately, a repair is probably in your future. This might be the case, since there are very few reports of 'safety shutdowns' with these specific amps... very robust.

Edit: The power rating of the cab means nothing regarding this issue.

Tysonhiseler · #3 01-29-2013, 09:29 AM

Thanks. It happens more in some rooms then others. I usually keep all the settings, volume and gain at 12 o'clock. I was afraid of someone telling me I needed repair. I had someone tell me a power conditioner might help. Would I get more head room if I was using a 4 ohm cab?

Got2SadowskyNYC · #4 01-29-2013, 09:32 AM

Yes you'd get exactly 200watts more head room at a 4ohm load

domdec314 · #5 01-29-2013, 09:36 AM

Make sure the air vents are free. I had something similar happen with my F500 once and it ended up being because I had a pedal blocking the side vent.

KJung · #6 01-29-2013, 09:49 AM

Quote:

Originally Posted by Tysonhiseler

Thanks. It happens more in some rooms then others. I usually keep all the settings, volume and gain at 12 o'clock. I was afraid of someone telling me I needed repair. I had someone tell me a power conditioner might help. Would I get more head room if I was using a 4 ohm cab?

Power conditioners are useless, and some EE's feel they do more harm that good.

Assuming your bass provides a relatively strong signal, noon and noon on that amp, given the taper design and gain structure, is pretty much dimed. Hinky power, and pushing the amp (even at 8ohms) might cause what you are experiencing.

Popping the top (when the amp is unplugged please!) and making sure the fan is working and the vents are clear is a good idea also.

nobodysfool · #7 01-29-2013, 09:50 AM

A power conditioner might help, but your best bet for consistent power is a power regulator. You can get an APC Line-R 1200va from Walmart for around $52. It will correct over and under voltage. I have a Furman regulator that I've had for some time now, and use it with my Markbass LM800 Tube, and have never had a problem.

BassmanPaul · #8 01-29-2013, 12:34 PM

In all my years of playing I have never needed a power regulator on any gig. If correctly designed, an amplifier for MI amplification SHOULD have all the filtering and surge protection it needs. That said, I do like to have a filter in my racks but it is more for keeping my power cables neat than anything else.

KJung · #9 01-29-2013, 01:20 PM

Quote:

Originally Posted by BassmanPaul

In all my years of playing I have never needed a power regulator on any gig. If correctly designed, an amplifier for MI amplification SHOULD have all the filtering and surge protection it needs. That said, I do like to have a filter in my racks but it is more for keeping my power cables neat than anything else.

+1 I would stay away from those things. Really not necessary, and my guess is, the cheap ones really don't do what they are meant to do.

B-string · #10 01-29-2013, 01:37 PM

I use the rack strip "conditioners" for one additional reason. Here in the Monsoons I have lost a rack strip but not the equipment plugged into it during lightning storms. Other bands that didn't were not so lucky.
That is actually experience BTW not theory or conjecture.

Silas Stingy · #11 01-29-2013, 01:37 PM

My LMII does the same thing but only running at 4ohms (still unresolved), never heard of this at 8ohm. As others have said check the inside of the amp is clean. Also if possible try in a different location to eliminate voltage drop.

B-string · #12 01-29-2013, 01:40 PM

Quote:

Originally Posted by Tysonhiseler

I recently got a markbass f1 and I'm having a bit of a problem with it. I love the sound and how small it is but every now and then it just shuts off. I'm not sure if it a power issue or if i got a lemon. I'm inning it through an older Eden 4x10 ( no ports, white logo ). The cab is 500 watts and 8 ohms. The head is supposed to run at 300 watts at 8 ohms and 500 watts at 4ohms. Could it be the pairing? Any help would be awesome!

Does the amp go dark as in powered down? Or do you just loose output with the amp still lit. It should recover quickly from thermal overload. Maybe a bad power connection inside the amp case is to blame, like a bad crimp on the power leads.

nobodysfool · #13 01-29-2013, 07:14 PM

Quote:

Originally Posted by KJung

+1 I would stay away from those things. Really not necessary, and my guess is, the cheap ones really don't do what they are meant to do.

APC doesn't build cheap junk. I have a Furman, and it has performed flawlessly since I bought it. I run into low voltage a lot. My Furman tells me what the incoming voltage is, and very often i see voltage in the 100 volt to 105 volt range. Clubs aren't usually too aware of the state of their wiring, and if it's an older building, It's probably substandard, We play an outdoor gig every year where the power is run to us through long extension cords, long enough that the voltage drop at the end is around 95 volts. I guarantee you, you amp will not sound good running at 95 volts. It's hard on the amp, because you'll crank it up higher to get the same volume you want, which makes the amp work harder, and with less dynamic range available. A power regulator will correct the voltage to 117 volts, and your amp will have what it needs to sound its best. I've tested it out, and it does make a difference.

Spaldo · #14 01-29-2013, 08:56 PM

I use a power conditioner in my pedalboard, and it's never sounded better!

But as for your F1, I have the same problem when I run it hard, which i guess is a thermal shutoff. Switching on/off solves the issue, if temporarily. Over the last 3 years I've only used it for studio dates, jazz gigs and rehearsals where i don't need to push it.

KJung · #15 01-30-2013, 03:10 AM

Quote:

Originally Posted by Spaldo

I use a power conditioner in my pedalboard, and it's never sounded better!

But as for your F1, I have the same problem when I run it hard, which i guess is a thermal shutoff. Switching on/off solves the issue, if temporarily. Over the last 3 years I've only used it for studio dates, jazz gigs and rehearsals where i don't need to push it.

Just FYI, my primary gigging heads over the past 5 years have been an F1, replaced by an F500 when they came out. Run HARD at 4ohms, I mean HARD into low efficiency cabs. Never a thermal shutdown in the 5 years (even playing outside in the heat with no front of house support.

Very rarely is this issue reported with these heads. Something not quite right. I do admit that I don't play dives, so maybe these heads are a bit more sensitive to hinky power... that could be. Although, I've played outside through generators on occasion with no problem.

Who knows.

craig.p · #16 01-30-2013, 06:12 AM

Quote:

Originally Posted by Tysonhiseler

I recently got a markbass f1 and I'm having a bit of a problem with it. I love the sound and how small it is but every now and then it just shuts off. I'm not sure if it a power issue or if i got a lemon. I'm inning it through an older Eden 4x10 ( no ports, white logo ). The cab is 500 watts and 8 ohms. The head is supposed to run at 300 watts at 8 ohms and 500 watts at 4ohms. Could it be the pairing? Any help would be awesome!

Do you play with a lot of treble content, e.g. slap? If so, does that cab have a tweeter, and if so, it is actually working?

My second guess would be 1 or more drivers in the cab aren't working or have partially shorted voice coils from being hammered on. Measure the resistance of the entire cab and let us know what it is.

Third guess: 1 or more drivers wired out of phase with the others. Do "the battery test" on the cab and see if they all move in the same direction.

Tysonhiseler · #17 01-30-2013, 02:13 PM

I was looking into a fender rumble 4x10. It's 4 ohms so I would get the extra head room. With the extra head room would I be able to run the amp at lower volume and run less risk of over powering the head? Any thoughts on the rumble 4x10 performance/quality wise?

musicman7722 · #18 04-13-2013, 10:07 AM

First gig last night with my MB F500 into an Avatar Neo212 at 4ohms. Amp staopped three times. Each time still powered up but no output. A quick restart and back up. this happened once with my old F100 which I took back the next day.

I can't see why the new cab would cause this. I feel the power is ok. I run a Mackie Digital mixer on the same line and it has no issues. As I said it is a brand new cab from Avatar. I was using a B210 Neo from Avatar.

craig.p · #19 04-13-2013, 10:17 AM

ISTR a spate of this sort of problem with MB and certain cabs some years ago. My guess is the way MB checks for "proper" speaker impedance is different from the way others do it. The "go/no-go call" may be more sensitive than other amps to one or more reactive components of the impedance your speaker cab presents it. My guess is the crossover is the prime contributor, though we can not fault Avatar because those things are being used everywhere, by the thousands, with great success. It may just be a bad match between that model amp and that brand of cab. If you want, you can temporarily rewire the cab to use only the bass drivers (do NOT feed the crossover at all, i.e. don't just pull a wire off the tweeter, 'cause then the amp REALLY won't like it and you might even burn it out). If your amp can tolerate that bass-driver-only load, then that would prove the bad-match hypothesis.