Class D amplifiers without fans

[Osiris]

The Genzler Magellan amps, both the 350 and 800 have fans but they are totally silent, never heard a peep from either amp and at low, in-house use volumes. 

[fretmeister]

My recently obtained Tech21 VT500 has a fan but it is speed controlled and at home TV volumes it doesn't come on at all.

I've not used it next to a drummer yet to see how annoying it gets at proper volumes. Have to wait for September for that.

[2020Jazz]

These design engineers are working with weight. A class D amplifier circuit can achieve up to 90% efficiency, so that 10% has to go somewhere. To design a fan free amplifier, it has to have enough meat in the heat sink to dissipate the 10% or it will overheat(and kill) the semiconductor. Or one can run a fan across a smaller sink and all stays well. Personally, I'd rather have the bigger heat sink so if Mr. Fan goes on permanent vacation my amp doesn't start smoking. The payoff is weight.

[dafonky]

An amp with a meaty, juicy tone , TH style, but without a fan or a very, very quiet one, would be my choice .......

any suggestions ? Even if it is not the smallest one 

Trickfish and  Steamhammer seem to be less meaty/ juicy ?

[MOSCOWBASS]

I bought a Baby Sumo for house use and as a backup for my Mesa d800. The d800 is great and is my main gigging amp, don't hear the fan at gigs, but at home at low levels, the fan was annoying me. I use the Baby Sumo with a Mesa d800+ DI pedal, very happy with it, it's pretty loud and could easily do most of my gigs(600 watts at 4 ohms). I have 2 x 4 ohm cabs, so can only use one cab with the Sumo as min 4 ohms.

Edited May 28, 2021 by MOSCOWBASS

[Hellzero]

Earlier AER One, Two, Three and BassCube didn't have a fan, but a heatsink almost the size of the back of the combo. The next generation had a small dead silent temperature controlled fan : full German quality !

I'm only using dead silent fan or no fan amps or combos as I really can't stand added noise when I'm playing.

The Glockenklang fans make a hell of a noise when starting and are then dead quiet.

The Warwick LWA 1000 has a very small fan that I've never heard or seen running.

The worst amp with fans was the Hartke LH series : noisier than a jet at take off and some (deaf) people pretend these heads are quiet ! 😱

[MacDaddy]

 

Can fans be counter-productive?

At a hot sweaty gig, isn't a fan just pulling in warm air to 'cool' the amp?

[fretmeister]

3 minutes ago, MacDaddy said:

 

Can fans be counter-productive?

At a hot sweaty gig, isn't a fan just pulling in warm air to 'cool' the amp?

It's still cooler than the air in the amp. It's all relative.

 

Even on a really hot day when my PC is pulling in room air at 26C - that is still way cooler than my Graphics Card that can hit 80C.

 

As long as the delta (difference between the unit and the air) exists there will be heat transfer / balancing.

Cold air would be better, but any cooling is better than none.

[TrevorG]

On 09/10/2020 at 10:01, BillyBass said:

Except the Elf's fan is a bit noisy.  I'm guessing that due to its form factor, the fan is more important.  It is certainly louder than the fan on my MarkBass Marcus Miller 500W head

I have two ELFs and they're really noisy. Doesn't bother me though.

[Woodinblack]

The BAM200 is fairly quiet in normal home use and until it is driven hard, then it can get quite loud, but that is the way with smaller fans, they have to make more noise to pull the same amount of air..

[EmpInfNed]

I found this: Bh Amps D542H

 

https://www.basschat.co.uk/topic/465062-bh-amps-d542h/

 

it's fanless.

 

With modular output: 

• 270W 8 Ohm / 500W 4 Ohm
• 220W 8 Ohm / 400W 4 Ohm
• 110W 8 Ohm / 200W 4 Ohm

Edited May 26, 2022 by EmpInfNed

[tauzero]

On 24/09/2020 at 08:03, bassace said:

Puma 500 doesn’t have a fan.

 

Early Puma 900 don't have a fan. I did modify mine with Thomas Eich's guidance, the (tiny) fan is near as dammit silent. Not sure that I actually needed it as it turned out.

[Downunderwonder]

On 04/06/2021 at 22:03, fretmeister said:

any cooling is better than none.

Almost true. Stacks of rack gear are vulnerable to one unit pushing while the others pull and recycling occurs.

[Chienmortbb]

I realise that fan noise is an anathema to many but like many things, fans are a necessary evil. On the plus side a fan can improve the cooling efficiency by up to 4 times,  the downside is possible noise and the fact that fans are an electromechanical device.

 

The best compromise is a temperature controlled fan but that adds to the cost and complexity. GK came a cropper by not fitting fans to some of their 200 watt combos. They used the ICEPower 50ASX2 in what was effectively a closed box. They added fans in the MK2 versions. The active cooling in some Aguilar amps is sub-optimal and I am sure they are not alone.  Am anything be done? Yes but more on that later. 
 

As @Passinwindsaid earlier, it is possible to add passive cooling to a class D amp but that comes at the expense of weight, size and cost. Shipping is charged by weight and size so a bigger amp will cost more if everything else is equal. 

 

 

 

[Skinny]

Hartley Benton guitar power amp GPA-400, 150 smackers, class D, no fan, bridgeable and 3kg. Has some very detailed and positive reviews on Thonman. 

[Skinny]

Or Hartley Benton GPA-100 pedal size amp. Definitely no fan in that. 60 odd quid. 

[EmpInfNed]