So I’m thinking if you have 18 volts ac into that module, after the bridge and cap you should have about 25 volts DC.

Subtract about 18 to 20 volts for the COBs and resistor…leaving aprox. 4 to 6 volts across the regulator.

6 times .2 = 1.2 watts for the 317 to dissipate.

All figure are approximate.

 

Yes, thats about right. Which means I'd still need a bigger heatsink, which won't be a problem.

 

I'm pretty sure the heatsink on that module can handle 1.2 watts

 

I'm pretty sure the heatsink on that module can handle 1.2 watts

Even a 0 9m length of 12v LED strip? (30 LED's/m 7 2watts)

I say that as a first option, 2nd being the COBS

1st chioce

https://www.ebay.co.uk/itm/283722547029

1m length with controller but not adaptor.

2nd choice, COBS.......

 

http://ledcalc.com/#

........ Setting output of PS to 20v, forward voltage of 10v and forward current of 1000mA would need a 10ohm 10W resistor with the two COB LED's, as suggested by the calculator above.

 

Those are 50/50 RGB LED strips, I have no idea how you would want to use them without the special controller.

But I'm thinking if you keep the wattage on that 317 heatsink under 5 watts, you should be ok. (but 5 watts is only a guess without an actual wattage rating) And knowing all sorts of things such as ambient temp...airflow...etc.

So...@ 12volts you could probably drive a strip @ about 400mA. Possibly more.

But, again 5 watts is only a guess based on the size of that heatsink, you were running 2.88 amps x 20 volts. That's almost 60 watts.

You DO NOT want to run those COBs at 1000mA!!!

 

Use this calculator...

https://www.quickar.com/starresistorcalc.htm





Remember, you want to place 2 COBs in series.

I also feel the need to add this.

If you feel compelled to run any high power LEDs at or near their maximum power...you must...MUST use a constant current driver, and place them on a proper heatsink, and at 10 watts, that would be quite large.

 

Thank you for all your advice ElectricSpidey, it is very much appreciated. I've learnt a lot about LED's and power consumption.

The LED strip would be with the controller but not the adaptor as that would be the existing power supply in the amp itself. So controller and strip only.

However, the 2 COBS are appealing on the basis I have never used them before and, like you say, I'd run them at 200mA.

If you bear with me for a week or so I'll post another reply with my final choice and finish this strand off.

 

Well, after a lot of much appreciated advice regarding a more appropriate method on powering LED's for my preamp, I have managed to correct and revert back to my original method of powering them using a SMPS.

Mounting it outside of the case, and earthing the volume knob, I now have a totally quiet, LED lit, excellent sounding preamp.

I wanted just to finish the strand off.

Hopefully no one is offended or feels like I've wasted everyone's time, it was a pleasure.

Thank you very much anyways.

 

No offence taken, enjoy your amp.