To use fans or not on a head?

[greendy123]

Would you guys recommend using a fan to blow on the power tubes on a marshall 2100slx 100w amp? I think read somewhere it is a good idea to do that. I'm not sure if it may be good tone wise because the power tubes are kept cooler while playing. I know that heat coming from amps can get warm after playing a bit. I just wanted to get your guys thought on it.

 

[SlyFoxx]

Re: To use fans or not on a head?

If things are getting so hot that it's uncomfortable to touch the amp in the area around the tubes I go for a small fan. Obviously the tubes themselves will get too hot to touch but that's natural.

 

[Rich_S]

Re: To use fans or not on a head?

A fan will probably increase tube life slightly, but they're designed to run hot, and can give full life without the fan.

In my experience, fan have an effect on tone. My old Marshalls would sound different at the end of the night than the beginning, since they heated up over the course of three 45-minute sets. With a fan, they would sound pretty much the same all night long. Of course, which sound you prefer is up to you.

 

[The Golden Boy]

Re: To use fans or not on a head?

If you're not experiencing overheating problems I wouldn't worry about it. Chances are you're probably not running a 100w guitar head even close to 50% of it's capabilities.

I was having overheating problems with my rack mounted 900w bass amp. I drilled a couple of holes and installed a regular computer fan into the upper rack rail to remove excess heat from staying inside the rack.

 

[greendy123]

Re: To use fans or not on a head?

When the tubes are running hotter what would the difference in tone be? Would it just breakup earlier, with more power tube distortion.

 

[Robbiedbee]

Re: To use fans or not on a head?

If you're not experiencing overheating problems I wouldn't worry about it. Chances are you're probably not running a 100w guitar head even close to 50% of it's capabilities.

I was having overheating problems with my rack mounted 900w bass amp. I drilled a couple of holes and installed a regular computer fan into the upper rack rail to remove excess heat from staying inside the rack.

Forgive my ignorance here, but 900w?!?

Is that a lot for a bass amp?

I know nothing at all about bass amps.

 

[benjaturner]

Re: To use fans or not on a head?

I'm having a problem not too dis-similiar from this. My Marshall amp overheats all the time. Then cuts out intermittently until it fails completely. It's got to the point where I don't even bother turning it on on a hot day! I've tried putting a 'stand-alone' 240V domestic fan behind my amp pointing at the valves, put this genrates a horrible modulation type noise. Kind of like the worst tremolo pedal you ever heard, ever! Probably made by Danelectro or something. My Dad said I should try fitting a 12V fan internally because he thinks the noise is coming from the 240V motor. Does this sound plausible? And if so, is there anything I should know about fitting a fan? Like what I should be pointing the fan at/away from?

Cheers,
-Benja

 

[Mephis]

Re: To use fans or not on a head?

Forgive my ignorance here, but 900w?!?

Is that a lot for a bass amp?

I know nothing at all about bass amps.

*Whisper* I Bet guitarist hate him... *Whisper*

 

[DesertRose]

Re: To use fans or not on a head?

What Golden Boy did was totally ingenious. I could never think of an idea like that. What I thought was getting a small fan clipping it somewhere and just blow into the amp itself.

I didn't know that the fan could cause a difference and affects the tone. Prolly it could be just phychology effect instead =P

I'll go about doing what Golden Boy did, just to get rid of excess heat in the amp itself instead of blowing directly at the tubes unless otherwise stated.

Cheers

 

[Robbiedbee]

Re: To use fans or not on a head?

Now I've had time to think about it, I have come to 2 possible conclusions. That:

A: 900w is normal for a bass amp.

or

B: 900w is a typo of 90w.

 

[greendy123]

Re: To use fans or not on a head?

Now I've had time to think about it, I have come to 2 possible conclusions. That:

A: 900w is normal for a bass amp.

or

B: 900w is a typo of 90w.

I think it probably is normal for 900w as bass needs a lot more power. I checked some bass amps on the ampeg site and one the heads even output 1000 rms.

 

[DesertRose]

Re: To use fans or not on a head?

There's a Marshall bass amp at about 750 watts and its quite powerful. I'm not surprise if there are more power ones to boost the bass

 

[krankguitarist]

Re: To use fans or not on a head?

I think it probably is normal for 900w as bass needs a lot more power. I checked some bass amps on the ampeg site and one the heads even output 1000 rms.

+1

I played bass in a band once, and I used a 100W bass amp. That thing could barely cut it in comparison to the guitarist's 60W Line 6 flextone.

Low frequencies take a lot more power to amplify than highs, thus why the bass needs more power in order to be heard. The bass player in my old band had a 1000W head with a 8X10 cab, THAT thing definately did the trick.

 

[greendy123]

Re: To use fans or not on a head?

I tried using amp tonight without the fan and I found that the tones I was getting were thicker. I guess when the tubes are hotter the better the power tube distortion there is.

 

[Tom M]

Re: To use fans or not on a head?

The general rule for bass amps is about 4x the power of the guitarist. Bass frequencies and speakers take a ton of power to push at volume. My amp is 300w @ 4ohms, 600w @ 2 ohms.

Ampeg actually makes the SVT4-PRO which goes to either 1200 or 1600. There are lots of bassists who use a rackmount pre/power setup with like 2000+ watts.

Back to what's on hand - my Mesa bass amp has a fan on it. It'd die without it. I contemplate putting one on my JCM sometimes too.

 

[DesertRose]

Re: To use fans or not on a head?

I've a Peavey Basic 112. Its alright for room use. 75 watts, not really powerful or fantastic

 

[The Golden Boy]

Re: To use fans or not on a head?

*Whisper* I Bet guitarist hate him... *Whisper*

Having 900w and using 900w are entirely two different things! :laugh2:

The general rule for bass amps is about 4x the power of the guitarist. Bass frequencies and speakers take a ton of power to push at volume.

My personal opinion is for a bass player in a rock band setting to have around 300w SS power and at least a 4x10 or 1x15. A 2x10 doesn't quite cut it with a loud drummer and 2 guitarists with 4x12s. I don't really like tube bass amps quite as much- there's a certain 'immediacy' to a SS rig (as with a guitar rig, but that 'immediacy' is preferential in a bass tone rather than in a guitar tone- to me). However a 300w tube amp crushes- I don't know if it's "even order harmonics" or whatever-

 

[The Golden Boy]

Re: To use fans or not on a head?

I tried using amp tonight without the fan and I found that the tones I was getting were thicker. I guess when the tubes are hotter the better the power tube distortion there is.

I find that after the amp really warms up, there's a bit of a 'sag' to the attack of notes. Whether that's a part of thickness...

 

[Rich_S]

Re: To use fans or not on a head?

I'm having a problem not too dis-similiar from this. My Marshall amp overheats all the time. Then cuts out intermittently until it fails completely. It's got to the point where I don't even bother turning it on on a hot day!

Sounds like you're having a true temperature-dependent problem - a component that's failing, or a bad solder joint that's worse when it's hot, something like that. In you case, a fan is just a delaying the inevitiable failure. Get it to a tech before something really bad happens.

When the tubes are running hotter what would the difference in tone be? Would it just breakup earlier, with more power tube distortion.

I tried using amp tonight without the fan and I found that the tones I was getting were thicker. I guess when the tubes are hotter the better the power tube distortion there is.

I find that after the amp really warms up, there's a bit of a 'sag' to the attack of notes. Whether that's a part of thickness...

My experience is similar. My amp was a 6550-equipped 2203. It tended to have more clean headroom at the beginning of the night, and sounded squashier later, when it was hot. It's a taste thing - it sounded good both ways, but subtly different.

 

[The Golden Boy]

Re: To use fans or not on a head?

My experience is similar. My amp was a 6550-equipped 2203. It tended to have more clean headroom at the beginning of the night, and sounded squashier later, when it was hot. It's a taste thing - it sounded good both ways, but subtly different.

So it's NOT just my imagination!

The thing is I've noticed it with both SS and tube amps. My old Seymours get that way if they've been working for around 2-3 hours.