hi all,
looking for old laptop bricks, i found this SMPS300RS, i had from a previous project, this is quite power full PS able to deliver up to 300W at 24V.
this is quite small and would fit in my chassis to power un both channels!
i am just wondering if it is really the right choice in comparaison with 2 bricks at 19v 3,5A
looking for old laptop bricks, i found this SMPS300RS, i had from a previous project, this is quite power full PS able to deliver up to 300W at 24V.
this is quite small and would fit in my chassis to power un both channels!
i am just wondering if it is really the right choice in comparaison with 2 bricks at 19v 3,5A
Attachments
I remember that being R15 the boards from the store have had these holes for a couple of year s so yours probably has a place for it.
It doesn’t necessarily make the heatsink require a fan. Most people use the stock sized heatsinks just fine. The environment the amp is in makes a huge difference. If the amps is on a well ventilated shelf in a room with moderate temperature, it should be fine..
It doesn’t necessarily make the heatsink require a fan. Most people use the stock sized heatsinks just fine. The environment the amp is in makes a huge difference. If the amps is on a well ventilated shelf in a room with moderate temperature, it should be fine..
Thank you, Variac.
I ordered the boards from diy store, but the components from NP's digikey list at the beginning of his article. It was not until after I ordered that I noticed tweaks and such while reading on. Originally, I was waiting for the kits to return for some months now, so I just assumed this was all adaptable from the original.
There is not much info on the board page (a parts guide, or link to, if there is an upgrade would be nice!) other than a link to a "build guide" that uses the actual kit, IIRC. Also, the pictures of the boards on that listing, show no R15 unless those are older models shown?
Half of why I asked for perhaps links to posts in this thread where these changes started showing up given the age of this project, for a newb starting in 2018. Maybe I am just overlooking the obvious or haven't read enough of the right threads yet, which is highly possible.
I have looked at both old, and new build guides, which just show how to assemble the kits. The assembly part I get. And NP mentions the dissipation needed for the heat sink to be: "This means that the rating of the sink should be around 1 deg C per watt."
Some links lead to "Error 404 Not Found." So, I go to look in diy store at heat sinks, and even though I can guestimate size with pictures of the ACA, I cannot understand the values anywhere near 1 deg C/watt. Perhaps 'ADD' on my part but in this case, just stating the physical size of heat sink they used in the kit would be great, especially seeing as the option to source the parts yourself exists and someone wanted to copy the originals, as designed.
When getting the LSK170.......is the Toshiba version still be best or is the version sold by DIY store as good?
The IRFP240 you have to find your self....e.g. this one?:
IRFP240PBF | Vishay N-Kanal, MOSFET, 20 A 200 V, 3 ben, TO-247AC IRFP240PBF | Vishay
The IRFP240 you have to find your self....e.g. this one?:
IRFP240PBF | Vishay N-Kanal, MOSFET, 20 A 200 V, 3 ben, TO-247AC IRFP240PBF | Vishay
Until they do, do a google search: diyaudio amp-camp-amp sink
...it'll turn up what people have used, e.g.,
Amp Camp Amp - ACA - Page 356 10 posts Nov 21, 2017
Amp Camp Amp - ACA - Page 355 10 posts Nov 18, 2017
Amp Camp Amp - ACA - Page 350 10 posts Oct 26, 2017
Amp Camp Amp - ACA - Page 278 10 posts Jul 19, 2016
diyaudio amp-camp-amp sink site:www.diyaudio.com - Google Search
Thank you. That's where I was at, believe it or not and did find the discussion on page 355+ on this thread via google. So then I go to the diy store and the shipping is as much another heat sink!
I am an aluminum fabricator/weldor by trade for 30 years by now. I think I am just going to make my own custom heat sinks and just overbuild them slightly based on weight and average surface area, and at least make the enclosure my own.
That is true DIY spirit MrBoat! If you can build nice sounding speakers then this should be a breeze.
I have a question about the input impedance:
Normally the input impedance is just a resistor from input to ground as the input normally has a very high impedance so you just shunt it with a resistor. In the ACA R11 is a serie resistor. How can I from the schematic see that the input impedance is 10k? is this true also at DC? .....the joint between R11 and R12 must be close to "zero"?
Normally the input impedance is just a resistor from input to ground as the input normally has a very high impedance so you just shunt it with a resistor. In the ACA R11 is a serie resistor. How can I from the schematic see that the input impedance is 10k? is this true also at DC? .....the joint between R11 and R12 must be close to "zero"?
I see......I found this:
https://www.electronics-tutorials.ws/opamp/opamp_2.html
.....I remember I learned about it 30 years back......since then I have mostly been a software developer.
I can see that the point between R11 and R12 is the so called "virtual earth point". Then it makes sense.......
The ACA has quite high open loop gain......I assume........so the NFB is a necessity for it to work as an audio amp.
Then I better understand the R12 mod.........I may need the 68.1 k when using a passive pre-amp.......
https://www.electronics-tutorials.ws/opamp/opamp_2.html
.....I remember I learned about it 30 years back......since then I have mostly been a software developer.
I can see that the point between R11 and R12 is the so called "virtual earth point". Then it makes sense.......
The ACA has quite high open loop gain......I assume........so the NFB is a necessity for it to work as an audio amp.
Then I better understand the R12 mod.........I may need the 68.1 k when using a passive pre-amp.......
RN60 are plenty enough ... there's a "thing" with Dale resistors, CMF/RN, and mil-spec derating...try comparing CMF / RN datasheets of the same size/value resistor and you'll see by yourself
RN60 is good for 600mW no doubt !
