MQ475 Prototype

Post by **Eric D** » Mon Nov 09, 2009 4:45 pm

After a long long time it is finally coming together. For more info go here...

http://www.soundbuggy.com/Eric/Car%20Au ... index.html

When this is done I can build a Bride of Frank using this MQ475 and my MS2250 I set aside.

joyride · Post by **joyride** » Mon Nov 09, 2009 4:59 pm

Damn I love these build projects! Cant wait to see it as a BOFAS. Great work on the case too.

Post by **Bfowler** » Mon Nov 09, 2009 5:02 pm

Was that the mps i sent you back in the day?

rscecil007 · Post by **rscecil007** » Mon Nov 09, 2009 5:19 pm

Awesome!

I like the brushed aluminum looking finish as well. Do you plan on keeping it that way, or painting it eventually?

Irongoats · Post by **Irongoats** » Mon Nov 09, 2009 5:25 pm

Nice, going to follow this build.

Post by **Eric D** » Mon Nov 09, 2009 5:47 pm

Bfowler wrote:Was that the mps i sent you back in the day?

If you sent me the MPS2500 which needed a lot of work, then yes that is it. It now has a new purpose. I still have the MPS2500 board though, and I ended up getting another MS2125 heatsink I can use with it.

rscecil007 wrote:Awesome!

I like the brushed aluminum looking finish as well. Do you plan on keeping it that way, or painting it eventually?

Right now is it raw aluminum. In time it will oxidize and look like crap. I intend to get this working and them transfer the guts to my MS1000 heatsink, which I may get coated in Frank powder coat.

Post by **stipud** » Mon Nov 09, 2009 5:48 pm

Interesting... using the one input transformer for both amps. Running the speaker wire across both of them, while keeping the amp looking pretty, is going to be a bit of a challenge.

Post by **Eric D** » Mon Nov 09, 2009 5:50 pm

The fun part was moving the gain control from the back amp to the bass control position on the front amp. Major pain in the ass which took several hours today.

Post by **Bfowler** » Mon Nov 09, 2009 8:13 pm

nice, ya i traded it to you in exchange for you fixing one of my xs2300's. im not understanding how both amps are powered?

Post by **Eric D** » Mon Nov 09, 2009 8:22 pm

Look at the long straight red and black wires. They feed power from the first board to the second. The input nulling torroid is before these, so it filters the noise off the incoming line for both boards.

I really need some PG red and black 10ga power wire if anyone has any. I would like to use it for speaker wires and for the power feeds.

Post by **Bfowler** » Mon Nov 09, 2009 8:46 pm

those look like 16awg wires? those feed the power?

im fresh pout of small gauge PG.

i do think i have a couple of feet of 10awg zeropoint silver/purple speaker wire (twisted in a common jacket)

Post by **Rold Gold** » Mon Nov 09, 2009 10:20 pm

That and a 2500 in a 1K sink will kickass seabass.

bogart · Post by **bogart** » Tue Nov 10, 2009 1:06 am

SWEET!!!!!! Man, that is looking good eric....so did you make the endplate for that....looks really really good....

Post by **Eric D** » Tue Nov 10, 2009 6:09 am

Those wires are 10ga solid wire (house wire).

Jason the mad scientist cut the end plates for me. He said it was not easy as it has so many small holes, plus the square holes are difficult. If this proves out I will get some laser cut.

Post by **ttocs** » Tue Nov 10, 2009 7:33 am

[quote="Eric D"]Those wires are 10ga solid wire (house wire).

quote]

yer joking right?

Post by **mhyde71** » Tue Nov 10, 2009 7:47 am

are the plates also aluminum or steel? just curious---(?)

marko · Post by **marko** » Tue Nov 10, 2009 8:07 am

did you bypass the bass boost controls then?

Post by **Bfowler** » Tue Nov 10, 2009 9:45 am

ttocs wrote:
Eric D wrote:Those wires are 10ga solid wire (house wire).

quote]

yer joking right?

that actually makes sense lol. probibly makes it very similer to the buss bars

MW3 · Post by **MW3** » Tue Nov 10, 2009 9:57 am

Nice work...

Post by **ttocs** » Tue Nov 10, 2009 2:43 pm

I would prefer some good old power wire, rather then solid home wire myself. It is a short run, but that amp would seem to be limited by how much amperage it could take in on that thin wire.

Post by **fuzzysnuggleduck** » Tue Nov 10, 2009 2:52 pm

280W max output / 12V = About 23.5A. Assume 50% efficiency = 47A.

According to old IASCA info:

Code: Select all

Length of run (in feet)
    Current     0-4  4-7 7-10  10-13  13-16  16-19  19-22  22-28

      0-20A     14   12   12     10     10      8      8      8
     20-35A     12   10    8      8      6      6      6      4
     35-50A     10    8    8      6      6      4      4      4
     50-65A      8    8    6      4      4      4      4      2
     65-85A      6    6    4      4      2      2      2      0
    85-105A      6    6    4      2      2      2      2      0
   105-125A      4    4    4      2      2      0      0      0
   125-150A      2    2    2      2      0      0      0     00

35-50A draw over a 10 gauge can be done if the run is 0-4 feet. I assume this is with stranded wire as well, not solid copper.

Eric should be fine unless he's really pushing that MS275 pretty fairly far passed it's rating (which is of course, possible).

Post by **Eric D** » Tue Nov 10, 2009 4:39 pm

If you guys think that 10ga solid wire is not enough, I think you might be nuts. It is about 11in long. Now, consider the input nulling torroid on this amp is probably 6in long and is the same size (made of multiple smaller wires) wire. When done with the amp I can fully load test it for max current draw and see the drop. I am pretty sure any problem I have will not be this wire. Fuzzy is spot on with his current analysis, I should be just fine. Also, according to my MS275 manual, the amp requires a 40A fuse. If I were installing this in my car I would put a 40A fuse for the whole amp (20A a board), and that should be plenty. Blowing a 40A fuse playing music one these amps means you are doing something wrong.

I prefer solid wire over stranded so I can make it stay put. Like Brian said, these are like buss bars. It would be even better if I could get them gold plated. If I did that I would kick the size up a bit to make it look more "beefy".

The endplates are aluminum. I don't like how steel rusts.

The bass boost controls are gone. This may be a bad point for some of you out there. The way I see it, this belongs in a BOFAS, and in a BOFAS, the MS2250 will take care of the low end. The pair of MS275s are for components, which don't need the bass boost. I suppose I could mount different pots on the faceplate and run wires out to the boards to put the bass controls back in.

Post by **mhyde71** » Tue Nov 10, 2009 5:09 pm

thats so funny- i have every same train set here too- shown as your line driver is sittng on the train box... Athearn - got the engine oin my bench too- dont ask why- but thats funny we both have Athearn train gear on our bench

Post by **Eric D** » Tue Nov 10, 2009 6:16 pm

I use Athearn boxes for a lot of stuff, dremel bits, files, spare parts, on and on...

GX3 · Post by **GX3** » Wed Nov 11, 2009 6:40 pm

Question on the power wire ... Is that 75c (167F) or 90c (194F) rated wire you used? Just wondering how it will hold up right next to all that heat. I'm sure the wire will be fine but over time will the insulation start to break down? If it is the 75c or lower