Markbass cab distorting on low notes for a few seconds after powering up

[terrya]

Hi guys.

Wondering if anyone has some insight into this or if I am being paranoid. I play a Markbass Little Mark III hooked up to a MB 102HF cab. I've noticed for quite a while that for a few seconds after powering up the amp, low notes played on the E tend to distort/fart for a few seconds (maybe 10 seconds) before settling down, and it never happens again. I have EQ pretty flat, high mids rolled off a bit, VLE off and VPF at about 9 o'clock. This happens at practise volume, gain at about 11 o'clock and master pretty low at about 8. I'm not using any effects, just plugged straight into the amp.

Once the amp "warms up" I am able to play without any distortion. I live in Cape Town where it's been pretty hot, and I've noticed this in the last week or so since the temps have been dropping a bit, also seems more prominent early in the morning when I switch on for the first time, not as noticeable later in the day, so I am wondering if ambient temp has anything to do with it.

Bottom line is the rig sounds great and in the last three gigs I've played (last 2 weeks) I've had zero issues. 

Is this something to be concerned about, should I have the amp checked out or is it to be expected when starting up a cold amp?

Ta for any suggestions!

Terry

[mybass]

Both my LMB 3 amps take only a few seconds to ‘clear the pathway of sound’ before allowing the signal clearly through. You may have some other issues going on if you have ten seconds before the signal is clean and you reckon that possibly ambient air temps are appearing to affect. Check your cables too though, maybe just maybe one cable has a connection issue, maybe try the amp through another speaker if possible. If that works fine then maybe the cabinet has an ‘loose’ internal connection.

[JazzBass4624]

I have a LMIII which works fine without any distorting but after switching it on it takes several seconds before I hear a click. Only then sound is processed to the speakers. 

[Bill Fitzmaurice]

Don't play through it for a few seconds after powering it up.

[terrya]

Thanks for the replies guys!

I noticed a knob I don't turn much, my VPF (which I mostly leave alone) had a slight crackle when I turned it down, but turning it back up seemed to "clear" it up, and I read elsewhere that oxidation could occur on pots that are not turned frequently, and interestingly my issue has not recurred. I'm wondering if it's related somehow. I'll keep monitoring it and try a few different cables if it recurs.

 

[pbasspecial]

I'm with Bill.  Count to ten.

[Mastodon2]

On 26/03/2018 at 13:41, terrya said:

Thanks for the replies guys!

I noticed a knob I don't turn much, my VPF (which I mostly leave alone) had a slight crackle when I turned it down, but turning it back up seemed to "clear" it up, and I read elsewhere that oxidation could occur on pots that are not turned frequently, and interestingly my issue has not recurred. I'm wondering if it's related somehow. I'll keep monitoring it and try a few different cables if it recurs.

 

I use a Little Mark III through a MB 2x10 and I get some crackle on the knobs when turning them and it's been like that since it was new. It's irritating but doesn't affect the functionality of the amp. Like other users, after powering it up it does take a few seconds to actually produce sound. I'd suggest if your amp is noisy for a few seconds that you don't play it in this time and don't worry about it. 

What does irritate me is the way the tweeter died after 6 months from the amp being new. Now it just crackles so much I have turned it off completely. I don't miss and I can make back the highs with the active preamp on my basses  it but it is an annoyance that it broke so quickly. Internet reading suggests it's a very common issue on these amps. 

[yorks5stringer]

I'd have asked for a replacement if mine had died after 6 months.Not sure its the amp that's responsible if a tweeter goes in your cab mind? That said I've disconnected the one in my CMD121P which is the same amp and tweeter but in a combo....!

Edited March 30, 2018 by yorks5stringer

[Mastodon2]

2 hours ago, yorks5stringer said:

I'd have asked for a replacement if mine had died after 6 months.Not sure its the amp that's responsible if a tweeter goes in your cab mind? That said I've disconnected the one in my CMD121P which is the same amp and tweeter but in a combo....!

Sorry I probably conflated the issues there - the tweeter going crackly is not related to the amp head, it's due to the crappy tweeters Markbass are using in the cabs. The tweeters in the Alain Caron signature combo are a different type and considered to have much better reliability and longevity. 

[yorks5stringer]

25 minutes ago, Mastodon2 said:

Sorry I probably conflated the issues there - the tweeter going crackly is not related to the amp head, it's due to the crappy tweeters Markbass are using in the cabs. The tweeters in the Alain Caron signature combo are a different type and considered to have much better reliability and longevity. 

Yes, they are not the Piezo ones, hence the 'P' in  CMD 121P.  Incidentally there are some threads about replacing the OEM one with a different one where it is a Piezo version.

[Bill Fitzmaurice]

The tweeters used tend to be less of a problem than the high pass filters used with them. I'd say that's an industry wide issue, not just an Ashdown issue.

[yorks5stringer]

2 hours ago, Bill Fitzmaurice said:

The tweeters used tend to be less of a problem than the high pass filters used with them. I'd say that's an industry wide issue, not just an Ashdown issue.

There's a Feudian slip......!

[Bill Fitzmaurice]

Well , yeah, them too. I did say that it's an industry wide issue.