MarkBass combo fan noise

[agedhorse]

I have a Markbass MB8R. Sounds great, is light.. but the fan noise is annoying. I replaced it with a original one I ordered at Markbass. Replacement was easy, apart from the 3 different hex sizes I needed to open up thw whole thing. But, unfortunately I still have the same annoying fan noise. I want to give it one more try, but which fan could I use?

Maybe you are more sensitive to the noise, but I would be careful because the air flow is important to reliability.

 

[PatTheDog]

I’ve had no issues so far after replacing my fan with Noctua NF-A6x25 FLX

 

[will4bass]

I’ve had no issues so far after replacing my fan with Noctua NF-A6x25 FLX

Ah very interesting. Did you need to modify anything?

 

[PatTheDog]

The fan had a different connector so I needed to make an adjustment there. I don’t remember if it was just a case of swapping some pins around or involved soldering. But it was a 5 minute job.

There is still some noise, but more of a low whirr than a Pentium rattle.

That said, I still use a small fanless practice amp when playing at home.

 

[will4bass]

The fan had a different connector so I needed to make an adjustment there. I don’t remember if it was just a case of swapping some pins around or involved soldering. But it was a 5 minute job.

There is still some noise, but more of a low whirr than a Pentium rattle.

That said, I still use a small fanless practice amp when playing at home.

Thanks I'm gonna give it a try!

 

[will4bass]

So… I replaced the fan 2 times, the first time with an original one provided by MarkBass customer ‘service’ in Germany (very slow and poor reply quality) the 2nd one being the Noctua. The Noctua was a bit more silent but still I had this awkward low whistle-like tone. Long story short… I found out that the fan was blowing air inside, instead of pulling the warm air outside. I simply turned around the fan, and the nasty tone is gone! It looks like some quality control would be a good idea. Meanwhile I also had to replace the on/off switch, which was causing short circuits and spontaneously turning off the amp and the jack input plastic ring is broken too. When you look inside the amp, which I had to do three times, you see it a lot of components are plastic and vulnerable. I like the sound and power but this is not a trustworthy workhorse. Much like my Alfa Romeo 33 in the 90’s!

 

[agedhorse]

Air direction is not the cause, it’s the orientation of the fan blades relative to the grille, the blades on the Noctra are very different from the original part.

Reversing the direction solved one problem but may have inadvertently created a new problem that might not show up for a while, or under heavy load.

 

[will4bass]

Air direction is not the cause, it’s the orientation of the fan blades relative to the grille, the blades on the Noctra are very different from the original part.

Reversing the direction solved one problem but may have inadvertently created a new problem that might not show up for a while, or under heavy load.

Don’t think so. The fan should blow the hot air out. It was installed wrong!

 

[agedhorse]

Don’t think so. The fan should blow the hot air out. It was installed wrong!

How do you know this for sure?

For example, some of my designs have the fan reversed from others because I am looking for a specific temperature gradient, insuring that the correct components get cooled at the correct rate.

 

[will4bass]

It's hard to know for sure. It seems Markbass uses both systems and I didn't find specifications in tehcnical sheets. However, this is what I found on AI
"Based on typical Markbass amplifier design, the cooling fan on the Markbass Little Mark 58R (and 58R combo units) is designed to exhaust hot air out of the chassis. Fan Direction: The fan pulls air from inside the amp and pushes it out of the chassis.'
the amp doesn't get hot and is silent, so I guess that's a good sign too.

 

[eniac]

How do you know this for sure?

For example, some of my designs have the fan reversed from others because I am looking for a specific temperature gradient, insuring that the correct components get cooled at the correct rate.

I can provide two other examples: G-K's MB200 and MB800. I own one of each. One pushes air in, the other pulls air out.

 

[agedhorse]

It's hard to know for sure. It seems Markbass uses both systems and I didn't find specifications in tehcnical sheets. However, this is what I found on AI
"Based on typical Markbass amplifier design, the cooling fan on the Markbass Little Mark 58R (and 58R combo units) is designed to exhaust hot air out of the chassis. Fan Direction: The fan pulls air from inside the amp and pushes it out of the chassis.'
the amp doesn't get hot and is silent, so I guess that's a good sign too.

So this is a great example of how useful AI appears, yet how useless the information it provides actually is.

You CAN'T extrapolate from a "typical" design to a specific design where they do in fact use both approaches.

 

[PatTheDog]

If it helps, both of the Little Mark 58R heads (fitted in MB58R Mini CMD 121 combos) that I've owned push air out of the chassis.