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Modulus-686: 380W (4Ω); 220W (8Ω) Balanced Composite Power Amp with extremely low THD
Modulus-686: 380W (4Ω); 220W (8Ω) Balanced Composite Power Amp with extremely low THD
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Old 16th September 2018, 07:54 PM   #741
sledwards12375 is offline sledwards12375  United States
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Quote:
Originally Posted by BrianL View Post
There's no reason to make the measuring and drilling harder than it needs to be.
Brian:

Those dimensions are based upon locating his new brackets relative to the PCB to provide adequate lead length above and below the PCB, as shown in the photo I have attached. It really is a moot point what the numbers are if you use the template as intended...Tom has taken the measuring out of the procedure.

For those who may worry about the center punch maybe slipping or just being off a bit when aligning it to the center cross-hairs, here is tip/trick I use. Before center punching, tape the pattern to a piece of card box and then use a straight pin to pierce a little hole on each center point. I do this using one of those goofy looking headband magnifiers (aging eyes). Now you have a self-aligning template for the center punch. If you mess it up a bit, just print a few extra templates.
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Old 16th September 2018, 09:18 PM   #742
tomchr is offline tomchr  Canada
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Quote:
Originally Posted by BrianL View Post
You might want to move down slightly the top screw hole in the brackets so that they are in a line with the LM3886 screw holes. It would be much easier to have all 8 in a row. Also move the bottom bracket screws down slightly so that the spacing is still 0.5". There's no reason to make the measuring and drilling harder than it needs to be.
All you need to do is to print the .pdf at 1:1 and tape the template to your heat sink. Centre punch at the ten crosshairs. Drill, tap, done.

If you'd rather do the measuring work yourself, you're more than welcome to. You can always slide the LM3886es up. It'll give you a bit more lead length, but that should be OK. The additional 0.05" shouldn't be a big deal even for hand measurements, though. If you have access to a height gauge, you can make it even easier.

You could argue that I should have placed the holes in the bracket 0.05" lower. I do need to provide enough space that you can get a screwdriver in above the PEM nuts (and any components in the way on the PCB). Those considerations drove the hole placement in the face of the bracket that faces the heat sink. I could drop the top hole down 0.05", but that makes the hole spacing 0.450", which is harder to find on a ruler than 0.5".

Tom
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MOD686: Up to 240W/8Ω, <0.00025% THD. MOD86: 40W/8Ω, 0.000054% THD. HP-1: 3W/20Ω, -130dBc THD, 128dB DNR.
Neurochrome : : Audio - www.neurochrome.com - Engineering : : Done : : Right

Last edited by tomchr; 16th September 2018 at 09:21 PM.
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Old Yesterday, 04:26 PM   #743
TioFrancotirador is offline TioFrancotirador  Poland
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Tom, what is the input impedance of mod-686?
I am trying to get custom output transformer for es9038q2m to be feeding mod-686. I do not have any volume pot on the way. I use es9038q2m digital volume.

Last edited by TioFrancotirador; Yesterday at 04:35 PM.
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Old Yesterday, 05:11 PM   #744
tomchr is offline tomchr  Canada
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48 kΩ differential.

Tom
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MOD686: Up to 240W/8Ω, <0.00025% THD. MOD86: 40W/8Ω, 0.000054% THD. HP-1: 3W/20Ω, -130dBc THD, 128dB DNR.
Neurochrome : : Audio - www.neurochrome.com - Engineering : : Done : : Right
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Old Yesterday, 07:29 PM   #745
TioFrancotirador is offline TioFrancotirador  Poland
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Quote:
Originally Posted by tomchr View Post
48 kΩ differential.

Tom
Thanks Tom.
This is something you can consider to add to your documentation. Should someone need this in the future ...
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Old Yesterday, 08:32 PM   #746
tomchr is offline tomchr  Canada
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Quote:
Originally Posted by TioFrancotirador View Post
Thanks Tom.
This is something you can consider to add to your documentation. Should someone need this in the future ...
Done. I added the input impedance spec to my Modulus-686 page. If you don't see it, please hit Reload in your browser.
It'll make it into the design doc at the next update.

Tom
__________________
MOD686: Up to 240W/8Ω, <0.00025% THD. MOD86: 40W/8Ω, 0.000054% THD. HP-1: 3W/20Ω, -130dBc THD, 128dB DNR.
Neurochrome : : Audio - www.neurochrome.com - Engineering : : Done : : Right
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Old Yesterday, 08:35 PM   #747
tomchr is offline tomchr  Canada
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Getting ready for Burning Amp. Each amp is a stereo Modulus-686 running on 27 V from a pair of Mean Well RPS-400-27-C.

I should order some power cords.

Tom
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__________________
MOD686: Up to 240W/8Ω, <0.00025% THD. MOD86: 40W/8Ω, 0.000054% THD. HP-1: 3W/20Ω, -130dBc THD, 128dB DNR.
Neurochrome : : Audio - www.neurochrome.com - Engineering : : Done : : Right
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Old Yesterday, 09:47 PM   #748
BYRTT is offline BYRTT  Denmark
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Modulus-686: 380W (4&#937;); 220W (8&#937;) Balanced Composite Power Amp with extremely low THD
Have a best as possible journey and festival ... based on performance for HP-1 which happen have same father : ) as those nice looking power amps there guess there will be some good quality rock'n roll and a room full of visitors.
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