baseline
i have just bought myself a marshall from a guy who wanted to lay off some equipment. when you switch it on it has a fan noise that is so irritating, once it has warmed up the level subsides, does anyone else have this problem and what is the fix. >☹
AlanRatcliffe
Don't really know the model to the point of what fans they are using, but usually it's that a cheap, noisy fan has been used. Do you have any idea what size and voltage the fan is? I'm thinking if its a normal 12V case fan (80, 92 or 100mm size), you can get a much quieter one from any of the online stores that specialise in quiet computer components.
Lethe
i used to have one and so does my buddy. and both of them had that fan noise. never quite got to finding out what it was. Anyways, my amp blew up because apparently the fan malfunctioned... my buddies is still working though.
Sidecar
Just a note, I work for a computer supplier... so we work with a lot of noisy fans especially on power supplies and CPUs and so on. One thing that does happen is that "intelligent" (chip regulated) fans tend to spin up to full speed at start up before slowing down and eventually settling. However, it may speed up again when the power supply or amp heats up.
It might be possible to replace the fan with one that has a different bearing type? Maybe the fan needs some cleaning? Also if there is room for a larger fan, this might also be an option as larger fans tend to make a lower frequency noise and spin slower to move the same amount of air and are therefore perceptably quieter.
JoeyBones
We've got the same amps at church and we've never had that problem.
TomCat
My Laney RB-7 also has a fan that was noisy.
I opened the amp up and found the fan to be 12VDC so I added a resistor in series with the fan to reduce the speed as It was bowing way too fast for the requirement. Only a small reduction in fan speed dropped the perceptable noise by quite a large amount.
A word of caution here.....
1. I used a fairly high wattage resistor to comfortably absorb the power passing through it to the fan.
2. I only reduced the fan speed by a small amount to prevent the amplifier from overheating.
The amp now runs quieter and is still reliable and has given no trouble at all.
FenderBender
What I have found to work before is to add another fan and wire the two in series.
This way, you reduce the noise by a huge margin and still move enough air over the hot bits.
It may also help to have one fan near the bottom of the cab sucking cool air in and one near the top blowing the hot air out.
Most 120mm "boxer" fans can be supplied with external removable/washable foam filter carriers that keep you from sucking dust into the cab and this may be a worthwhile addition if you are "giggin in the dust" so to speak ?
baseline
Thanks guys.
I am going to open it tonght and have a look see, i think Alan is right in that they use a cheapie fan, we have beter ones in our store, so i will have a look and modify to suit, i will give you the feedback once i have solved the problem thanks for the feedback. Steve
