Yes. But a bit busy at the moment since I'm in Ireland and next week/weekend I'll be at RMAF/Denver.
Best,
Anand.
The top panel is fully vented, but there is no venting on the bottom. The amp resides in a very open A/V stand. I'll probably check the temp rise on the heatsinks during my heavier listening sessions until I get an idea of how hot they get.
The heatsinks are extruded aluminum that they cut to length. Their ordering system charges you on a per inch basis, but it is possible to specify fractional quantities. I ordered 3" of extruded length but requested them to cut it to 2.5".
Really nice layout. What are the internal height, width and depth dimensions of your Modushop case. What brand and model is the transformer? I built a modulus86 with a smaller modushop chassis and am about to order stuff for a parallel86 build. Your layout gives me some new ideas for my build. I'd just need to go with a larger chassis.
Thanks,
henrylrjr
Thanks,
henrylrjr
You can find the chassis in formation in Post #2580.
You will notice Post #2580 says it's a Modushop Slimline 2U chassis. The internal dimensions of the Slimline 2U series can be found on Modushop's website: Modushop.biz Slimline 2U Series. Click through on the various options and a table with specifications is shown.
How to order a non-integer length of heat sink from Heatsink USA is described in their FAQ. If you go to Heatsink USA's website, you'll find the link to the FAQ both in the menu bar and the text right below their welcome message. Here's the deep link to the relevant section: Heatsink USA FAQ - How to Order.
The information is available right at the tips of your fingers.
Tom
You will notice Post #2580 says it's a Modushop Slimline 2U chassis. The internal dimensions of the Slimline 2U series can be found on Modushop's website: Modushop.biz Slimline 2U Series. Click through on the various options and a table with specifications is shown.
How to order a non-integer length of heat sink from Heatsink USA is described in their FAQ. If you go to Heatsink USA's website, you'll find the link to the FAQ both in the menu bar and the text right below their welcome message. Here's the deep link to the relevant section: Heatsink USA FAQ - How to Order.
The information is available right at the tips of your fingers.
Tom
I'm very familiar with modushop because I've bought from them several times. Each series comes in a number of different depths and heights. The slim line 2U is available in four different sizes. That is why I asked that question.
I asked about the transformer because the one I used for my mod86, including mounting hardware, was a tad over 3" tall. I was curious about the height of the transformer and thought brand and model would allow me to get the dimensions.
In my mod86 build, the 2U with 80mm internal depth would have put the transformer bolt close to the top cover. The fully ventilated aluminum cover is very flexible and if it were pushed down or anything was put on top it could possibly contact the bolt. That is why I went with the 120mm depth chassis.
I'm also very familiar with heatsinkusa and their options, so didn't ask anything about the heatsinks.
I asked about the transformer because the one I used for my mod86, including mounting hardware, was a tad over 3" tall. I was curious about the height of the transformer and thought brand and model would allow me to get the dimensions.
In my mod86 build, the 2U with 80mm internal depth would have put the transformer bolt close to the top cover. The fully ventilated aluminum cover is very flexible and if it were pushed down or anything was put on top it could possibly contact the bolt. That is why I went with the 120mm depth chassis.
I'm also very familiar with heatsinkusa and their options, so didn't ask anything about the heatsinks.
I used the 280mm depth Slimline 2U chassis with the AnTek 200VA [p/n AS-2222] transformer. The height of the transformer is 56 mm, so it works with the 80mm internal height of the 2U case just fine. The supplied mounting hardware didn't extend beyond the height of the transformer. Also, it is positioned in the corner, so the deflection of the top panel is less than a point in the center of the case.
The layout was based on the early picture of your build, but it did appear that you used a larger case. I used Excel's drawing capabilities to create a rough layout and make sure all the components fit in the case with ~1 inch clearances.
Thanks for the reply. I used a Galaxy Maggiorato 3U GX388 330 x 280 X 120 so mine is same depth but about 100mm narrower and 40mm taller.
Your transformer is about .8" shorter than the AS-3224 I used and based on transformer recommendation in the parallel86 pfd I'll be going with the AS-3224 again, so will be getting a 120mm tall case. I like the 415mm internal width you used and will have to see if a 4" wider amp will fit next to my preamp.
Thanks,
henrylrjr
Your transformer is about .8" shorter than the AS-3224 I used and based on transformer recommendation in the parallel86 pfd I'll be going with the AS-3224 again, so will be getting a 120mm tall case. I like the 415mm internal width you used and will have to see if a 4" wider amp will fit next to my preamp.
Thanks,
henrylrjr
akapezi, just a thought. When you first use it, with the top cover on, check the temperature. Your heatsinks are, I think, more than big enough but with a non-vented bottom cover and the top cover with only one row of ventilation slots near the back, you may not get much convection cooling. That is why I got the fully ventilated top and bottom covers. The only problem I ran into was that, even with the transformer in a corner, the bottom cover sagged a lot. That's why I made a simple stiffening brace and it solved the problem.
If you run into high temp. problems Modushop makes fully ventilated covers, for most models, and they can be used on top and/or bottom. Another option would be drilling a bunch of holes, through your bottom cover, in the rectangular areas that the heatsinks rest on. If you run into a sagging bottom problem you could screw a brace to the external surface of the bottom cover. I say that because your layout doesn't lend itself to an internal crosswise brace. The external brace would require feet that are at least 1/2" high. If your interested I can provide a sketch.
If you run into high temp. problems Modushop makes fully ventilated covers, for most models, and they can be used on top and/or bottom. Another option would be drilling a bunch of holes, through your bottom cover, in the rectangular areas that the heatsinks rest on. If you run into a sagging bottom problem you could screw a brace to the external surface of the bottom cover. I say that because your layout doesn't lend itself to an internal crosswise brace. The external brace would require feet that are at least 1/2" high. If your interested I can provide a sketch.
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If there is a risk of shorting the chassis to the fixing bolt, I have recommended adding insulation layers over the plate and bolt. Using a tough plastic film that cannot easily be punctured removes that risk.
True. I suspect for residential applications, it'll be fine for all but driving inefficient speakers in large rooms. In most listening spaces, you only need a watt or two, so the amps barely make it above idle dissipation.
Worst case dissipation is with a sine wave at half the rated output power. A common test is to run the amp at 1/3 the rated output power. That corresponds to a crest factor of 10 dB. I generally use a 14 dB CF for calculating heat sinks for amps intended for music reproduction, corresponding to sine wave operation at 1/5 the rated output power.
If you really want to test the thermals of the amp, run it with a sine wave (and dummy load!) at 1/5 to 1/2 the rated output power. That'll get it nice and toasty. Monitor the THD while doing this. If the amp gets too hot (bad THD or uncomfortably hot chassis), I'd have some holes punched in the bottom panel.
Tom
In my case the bolt and nut were about 1/4" above the plate so the rubber cap would have been protection if I had used the 80mm internal depth chassis. However, I used a 120mm internal depth chassis, to accept 4.7" tall heatsinks, so the cover is over 1.5" above the mounting hardware. I used the cap for protection of the wires.
I did get a fully ventilated top cover. The bottom cover has no holes, not even a row in the back. During my most recent loud listening session, my Benchmark DAC1 felt hotter than my Modulus-86 amp.
You may want to upgrade to the Modushop Slimline chassis for your Parallel-86 build. They have 3mm top and bottom panels. It looks like the Galaxy series has 2mm panels. My amp weighs 20 pounds, and I am guessing that 2/3rds of the weight is the internal components. With this weight, there is only a small but noticeable gap between the bottom panel and the rear panel due to sagging. This gap wasn't large enough for me to take any action on it.
This is true in my case.
When I was trying to decide on an amp to build, I determined the peak power that I would require. In a dedicated listening session (i.e. at home, alone, during day, allowing for any volume I wanted) with high dynamic range music, I noted the max pre-amp volume that I used.
I replaced my speaker with a 4 ohm dummy load and fed the preamp a 0dBFS sine wave. I measured the peak power to be 50 W. If my initial music source was 14 dB CF, this would put me at 2 W. It is more likely that my source was closer to 20 dB CF which would put me at 0.5 W.
This is off topic but relates to a post I made here asking about hi-res streaming. I think I mentioned a specific device. The post got some some good responses so I just wanted to share what I learned after the posts.
Some dealers wanted to sell me a device but I learned my OPPO BDP-95, at least five years old, can do what most of the latest streamers can do and at 24/192 with two Sabre 32bit DACS.
Thanks to the posts i'm now a believer that hi-res is snake oil. But those that have an OPPO player may not be aware, like me, of it's capabilities. Beware of the HI-END.
Some dealers wanted to sell me a device but I learned my OPPO BDP-95, at least five years old, can do what most of the latest streamers can do and at 24/192 with two Sabre 32bit DACS.
Thanks to the posts i'm now a believer that hi-res is snake oil. But those that have an OPPO player may not be aware, like me, of it's capabilities. Beware of the HI-END.
amp ventilation
Thanks for the tip. Lots of good info. I thought the Parallel 86 ICs might get hotter than the Lm3886 ICs, but will look into the slim line series. My concern about heat was that the speakers, to be powered by the Parallel86, are rated 8ohms to just under 4ohms. The two 8ohm woofers are in parallel, hence the 4ohm rating and the xover is 350Hz so everything below that is 4ohms or a tad lower, according to the Mfg.s spec. sheet.
Thanks for the tip. Lots of good info. I thought the Parallel 86 ICs might get hotter than the Lm3886 ICs, but will look into the slim line series. My concern about heat was that the speakers, to be powered by the Parallel86, are rated 8ohms to just under 4ohms. The two 8ohm woofers are in parallel, hence the 4ohm rating and the xover is 350Hz so everything below that is 4ohms or a tad lower, according to the Mfg.s spec. sheet.
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I've revamped my thinking about my preamp ideas. Rather than muddy up the build thread, I've updated my thing on my own thread from before : http://www.diyaudio.com/forums/chip-amps/293136-novice-dreams-novice-questions-4.html#post4845964
If this sort of cross posting isn't how things are done on this forum, let me know. Otherwise, I'd love any and all feedback from everyone about it.