Crown CTs Fan Mod

[johanwholst]

Hi Rob
I have a 1200 and a 2000. They both have 24v fans.
Thanks for the tip. I will do a search for those.

Yes cutting away away the mesh should really help.
These amps are lovely sounding, so I probably never gonna sell them anyway.
Just blasting away now with cts2000 on a pair of 2225s!

[JeffW]

What is the size? Noctua makes RPM reducers that go in the fan lead, you might be able to get a low RPM 12V fan and put a reducer in the lead (probably just a resistor, I never used them but have fans that came with them) to get by on 24v.

[johanwholst]

What is the size? Noctua makes RPM reducers that go in the fan lead, you might be able to get a low RPM 12V fan and put a reducer in the lead (probably just a resistor, I never used them but have fans that came with them) to get by on 24v.

Both cts1200 and 2000 takes 80x80x25mm fans.
I don't think these amps need high airflow for domestic use. Ran the 2000 a whole evening with fans disconnected, and on fairly high levels. It was warm to the touch when I went to bed but far from hot.

[johanwholst]

Just installed Papst 8414ngl fans in my cts1200 and it's excellent! Just as quiet as a fairly new laptop. I can just hear them from listening position, but with quiet music 50dB or so, they disappear completely.
Highly recommended mod!

[loach71]

I have always used the Papst line of fans for replacements in my BGW amps.

Just installed Papst 8414ngl fans in my cts1200 and it's excellent! Just as quiet as a fairly new laptop. I can just hear them from listening position, but with quiet music 50dB or so, they disappear completely.
Highly recommended mod!

[sebackman]

Brilliant.

I always use Papst for heavy duty and Noctua othervise. The fan's in the CTS 4200 and CTS600 är 12v so there Noctua works fine.

Kind regards
//RoB

[johanwholst]

I have been running my cts1200 now for 4 months with noctua 12v fans in serial and no issues. Completely silemt and cool to the touch even after house parties with continous loud music for a whole evening.
Thanks for the headsup regarding cts2000 and above. I will put more powerful pabst fans in my cts2000

[johanwholst]

Thanks again Rob for the tips! it's like getting a new amplifier, and I now realize how annoying the original fan noise was before the change

And my goodness how good the CTS amp sound with 2216nd... next step would be to try 1200 on D2 and 2000 on 2216nd. Just need to change the fuse for the living room first to 13A slow blow. 10A fast does not like the startup inrush from these amps

[sebackman]

Dear all,

As per above the fans in the CTS600 and CTS1200 (probably also CTS2000 and CTS3000) are 24v fans, not 12v as in the newer CTS4200a (one 12v 80mm fan).

The older 4200 (not "a") runs two 12v 60mm fans. CTS8200 runs 3pcs 12v 60mm fans and a single 12v 80mm fan.

However in CTS600 and above there are two fans in each amp and the fan controller runs both fans in electrical parallel, ie not for each channel. Hence two 12v Noctua (or other) fans can be connected in series to accept 24v from either of the two fan connectors. The fan connectors are electrically the same but located in different places on the mainboard.

The original fans in my CTS 600 and CTS 1200 are Mechatronics F8025X 24V and runs at 4800rpm @ 39 db noise with 53CFM / 90m3h @ 260mA each.

The Noctua NF-R8 Redux 1800 12V runs at 1800rpm @ 17db noise with 54m3h @ 110mA each.

I understand that 180m3h is more than the 108m2h I’m getting from the Noctua fans, but the CTS-series are manufactured for installations in potentially high ambient temperatures.

I do think given that my amps very seldom gets warm, even after being run hard (powering subs), I do think 108m3H would be enough for cooling full load unless the ambient temperature is very high.

So I’m now mounting two 12v Noctua fans in series in my CTS600 andCTS1200's. :-)

Kind regards
//RoB

[bubbleboy76]

Dear all,

As per above the fans in the CTS600 and CTS1200 (probably also CTS2000 and CTS3000) are 24v fans, not 12v as in the newer CTS4200a (one 12v 80mm fan).

The older 4200 (not "a") runs two 12v 60mm fans. CTS8200 runs 3pcs 12v 60mm fans and a single 12v 80mm fan.

However in CTS600 and above there are two fans in each amp and the fan controller runs both fans in electrical parallel, ie not for each channel. Hence two 12v Noctua (or other) fans can be connected in series to accept 24v from either of the two fan connectors. The fan connectors are electrically the same but located in different places on the mainboard.

The original fans in my CTS 600 and CTS 1200 are Mechatronics F8025X 24V and runs at 4800rpm @ 39 db noise with 53CFM / 90m3h @ 260mA each.

The Noctua NF-R8 Redux 1800 12V runs at 1800rpm @ 17db noise with 54m3h @ 110mA each.

I understand that 180m3h is more than the 108m2h I’m getting from the Noctua fans, but the CTS-series are manufactured for installations in potentially high ambient temperatures.

I do think given that my amps very seldom gets warm, even after being run hard (powering subs), I do think 108m3H would be enough for cooling full load unless the ambient temperature is very high.

So I’m now mounting two 12v Noctua fans in series in my CTS600 andCTS1200's. :-)

Kind regards
//RoB

RoB, do you have a picture of this? How the cabling is done? Would be nice to see, I just ordered 8pc of Noctua NF-R8 Redux 1800 for my amps.

[bubbleboy76]

I have now done this fan-mod to one of my CTs-1200. Great success.
Thanks for the info previous in this thread sebackman.

[baldrick]

Have ordred an Crown DCI that probably also need new fans, org is 24v 60x60mm... I've read that some have used 12v Noctua and "transformers" to make them work With 24v, is this the best way or are there any quiet 24v 60x60 that could work instead?

[johanwholst]

so you will run both fans off one connector?

Im still happy with papst, but I would like it to run quieter for those late night sessions with low volumes, as I can still hear them with music playing at 40-50dB

[sebackman]

Hi,

Yes, both on one connector. Works just fine. Both connectors are the same.

Kind regards
// RoB

[oivavoi]

Hi, forum newbee here. Just reviving this thread, since it's the only thread I've found online on this topic.

I'm considering to buy a Crown CTS 8200. They can be found on the cheap on ebay these days. Has anybody tried modding the fans on those? It seems to me to be a bit more complex than on the other models, since it's four fans (one 80 mm and three 60 mm, according to folks here).

And this might be a stupid question, but... assuming there's four "silent fans" running in tandem. Is there a reason to believe that it won't actually be so silent anymore? I've no experience with noctua fans, that's why I ask. Could it in principle be possible to only use two fans - for example one 80 mm and one 60 mm? I never listen very loudly - most often around 68-75 db baseline, but lots of classical so large dynamic peaks. So the amp isn't going to run extremely hot anyway. But I don't want to risk destroying the amp.

Or I could rather go for a 4200... I only need four channels, in order to actively biamp a two-way. The woofers are long excursion drivers, have a sensitivity of 86 db (impedance should vary from 6 to 9 ohm according to the manufacturer), and are eqed to go all the way down to 34 hz. I have a hunch that more power for the woofers is always a good idea. I was therefore thinking that it could be a good idea to bridge four of the channels in the 8200 for the woofers, and use two channels for the tweeters, with two channels to spare.

Alternatively, two CTS 600 (or a CTS 1200 and a CTS 600) could do the trick. Are the 2-channel CTS amps supposed to be better than the multichannel ones? I've noticed that the damping factor of 2-channel amps his super high, while the multichannel amps have a much more common damping of 180. Don't know if that would make a difference in my case though.

Alright, some confused thoughts there.
Any feedback or advice appreciated!