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MC2 T Series Fan Question
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BJtheDJ View Drop Down
Young Croc
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Joined: 28 November 2012
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Points: 974 		Post Options Post Options   Thanks (0) Thanks(0)   Quote BJtheDJ Quote  Post ReplyReply Direct Link To This Post Posted: 11 January 2026 at 11:14pm
Originally posted by jblfreak jblfreak wrote:


I forgot and put my hand on the heatsink to check how warm it was and the bastard bit me, not recommendedOuchWink
Lidl currently have an infra-red thermometer
for sale at £9.99, it'll come in handy eventually :)
I started out in this business with nothing.
I still have most of it left.
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jblfreak View Drop Down
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Points: 63 		Post Options Post Options   Thanks (0) Thanks(0)   Quote jblfreak Quote  Post ReplyReply Direct Link To This Post Posted: 11 January 2026 at 11:47pm
Even more shameful as I have an IR camera as well Dead
Just a relatively cheap UNI-T USB-C dongle but it does the job.Confused

This is with the new fans:



(Also FYI - the 1500 runs warm to the touch with original fans too).

+
Spoiler Spoiler

I downloaded the schematic and the transistor right in front of the fan is a TIP120, which is actually driving the fans. Clever design.
The 1500 looks to have 3 NTC temperature measurements and 1 combined test point. If I understand correctly, the fan speed will increase if 'any' of the 3 points increase in temperature and value of the resistors R1-R3 will translate to how agressive the fan will react?
Now it makes me curious...I wonder if it doesn't matter what the fan RPM is, as the amp will aim to reach it's thermal equilibrium and then just start increasing the fan speed?


+++
Yes, as I thought - someone at MC2 knows how to design. The fan voltage is changing smoothly in accordance with the thermal sensor temperature, even blowing against the heatsink already makes the fan voltage start to go down. 
Cold fan voltage was 6.6V, overnight it increased to 7.6V.
Why oh why aren't they all designed like this Clap

p.s now I know why the heatsink is so spicy - it's not L and R channels opposing each other but rather positive and negative sides. 185.6V across. You better not drop anything inbetween Clap



Edited by jblfreak - 12 January 2026 at 11:57am
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kedwardsleisure View Drop Down
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Points: 5157 		Post Options Post Options   Thanks (0) Thanks(0)   Quote kedwardsleisure Quote  Post ReplyReply Direct Link To This Post Posted: 12 January 2026 at 1:26pm
I always prefer either live heatsinks, or grounded bridge, no worry about insulating washers punching through.
The MC2 amp I have here has FR4 spacers in between the fan and the heatsink which ensures the lid can not touch the heatsink.

Oh..and an insulating sheet with a lightning flash on it just to remind you.



Edited by kedwardsleisure - 12 January 2026 at 1:26pm
Kevin

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jblfreak View Drop Down
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Points: 63 		Post Options Post Options   Thanks (0) Thanks(0)   Quote jblfreak Quote  Post ReplyReply Direct Link To This Post Posted: 12 January 2026 at 1:30pm
A vintage MC2 1250? The T-series do have a similar spacer between the heatsink and the rear fan (at least the T1500 does) but interestingly enough, no plastic insulator on the HS, just 2 rubber strips fit inside a groove in the HS.


Edited by jblfreak - 12 January 2026 at 3:53pm
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Points: 63 		Post Options Post Options   Thanks (0) Thanks(0)   Quote jblfreak Quote  Post ReplyReply Direct Link To This Post Posted: 17 January 2026 at 10:19pm
Both T1500 and T2000 are fitted with new fans. After about 8hrs of runtime they both get just as warm so probably using the same thermistors.
By the way, the T2000 is even spicier, 212VDC between the railsLOL

In the end MC2 have been very helpful about the questions I had about the amps.
Lastly I asked about the idling current procedure but was told that there are no baseline values, the bias the amps for lowest distortion on the analyzer.


Edited by jblfreak - 17 January 2026 at 10:25pm
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