Intersting.
I prefer a little bit "cold air" near the transformer.
I can put there, (and probably i'll make) between transfo and PCB, a sheet of aluminium.
I have yet, it'is'nt a problem..1 mm thick. (here in Italy people use this alluminium for windows, so, it very easy find, e work it..) I'ts painted on a side, and naked in the other one..
Consider that the two "side" of chassis (black) are little heatsink too..1 cm thick, 29 cm long...8 xcm height.
Ciao
Riccardo
I prefer a little bit "cold air" near the transformer.
I can put there, (and probably i'll make) between transfo and PCB, a sheet of aluminium.
I have yet, it'is'nt a problem..1 mm thick. (here in Italy people use this alluminium for windows, so, it very easy find, e work it..) I'ts painted on a side, and naked in the other one..
Consider that the two "side" of chassis (black) are little heatsink too..1 cm thick, 29 cm long...8 xcm height.
Ciao
Riccardo
riccardo said:
Rather than drill lots of holes, why not replace a section of the base and top of the case with mesh so you get really good convection air flow.
I think Russ had his heatsink inside the case when he first built his Mauro, but he switched to an external heatsink. Was that because it was running hot, Russ? How many holes did you have?
The Layout looks great Riccardo. looks very professional.
My PCB is complete (unless anyone can see any errors...)
An externally hosted image should be here but it was not working when we last tested it.
Better get stuck into finishing the case now
Well, yes partly, but mostly I moved it to get the trafo on the other side of the board as Mauro suggested. I had it oriented originally with the HS toward the trafo.maf_au said:
I have a couple dozen 5/8" holes over the heatsink, and an entire slot as big as most of the fin area under it.
Cheers!
Russ
It is fairly simple if you have a right angle "L" shaped screw driver, or if you use socket head machine screws an allen wrench works fine.riccardo said:
Also, you could mount the big caps after you mount the board to the HS with a little planning.
Or, you could use a template and mount the chips to the HS before you solder the chips to the PCB.
Cheers!
Russ
riccardo said:
Difficult, but hopefully not impossible
I'm thinking that I will bolt it with a countersunk head bolt from the back of the copper heatsink - it will just mean spinning a nut and washer up to the chip from the chip side, before the heatsink gets mounted in the case.
Riccardo, with your heatsink, you could do the same by drilling and tapping a hole, and putting some threaded rod in the holes so that all you have to do is to push the chips onto the threads and tighten with nuts and washers.
Of course, getting the holes in the correct spot will be critical. Using the copper heatsink will make that a little easier for me, I can mount the chips to the heatsink, then mount the heatsink to the case.
Michael
Count me in !!!
maf_au said:Difficult, but hopefully not impossible
If you use allen head screws it will be easy. I use very nice looking button head stainless steel screws from RS Components.
Allen head screws seem ideal to me at getting the right torque on screws for output devices, especially in confined spaces.
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I think i'll give rev C a go as well
Still have to build a preamp for the Ref though (well, and a case)
Used thermal glue to attach the heatsink, works swell.
And after properly positioning my speakers and really listening to the amp i love it! My old amp used to add killer bass even at low volume, that's why i was disappointed at first. But this way there's so much more detail in the sound it's incredible. Often I find myself grinning when i crank up the volume
When punch is needed, the amp delivers just the right amount, so it's all good.
One question though, when I increase volume on one channel (source is some maudio soundcard), bass gets way boosted. But since both channels are pretty much seperate that's prolly my source, right?
Still have to build a preamp for the Ref though (well, and a case)
Used thermal glue to attach the heatsink, works swell.
And after properly positioning my speakers and really listening to the amp i love it! My old amp used to add killer bass even at low volume, that's why i was disappointed at first. But this way there's so much more detail in the sound it's incredible. Often I find myself grinning when i crank up the volume
When punch is needed, the amp delivers just the right amount, so it's all good.
One question though, when I increase volume on one channel (source is some maudio soundcard), bass gets way boosted. But since both channels are pretty much seperate that's prolly my source, right?
I've been talking with Russ offline about our experiences with the amp. I just made a mod to my RevA last night, which was to add the RevC resistors and capacitor to the op amp pins 6 and 8. I didn;t have a 10pF cap, so I used a 22pF for now. The idea it to make the op amp more stable without affecting the overall sound of the amp.
I made little modules that I soldered to the bottom of the board (see image). I also put heatshirnk around each resistor as I assembled the modules to prevent shorting.
It was late so I could only listen for a few minutes at low volume. All I can say right now is that it didn't seem to degrade the sound at all. I will do some real listening later today and this weekend and report back my findings.
I made little modules that I soldered to the bottom of the board (see image). I also put heatshirnk around each resistor as I assembled the modules to prevent shorting.
It was late so I could only listen for a few minutes at low volume. All I can say right now is that it didn't seem to degrade the sound at all. I will do some real listening later today and this weekend and report back my findings.
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BrianDonegan said:
Hey Brian, thats a lot nicer looking than the version I did.
I really like the mod so far, the real reason for the mod (at least for me) is that it seems to take some pressure of the LM3886 and makes it run cooler.
I was finding that even though my amp was not oscillating it was running warmer than I would like, even at idle. This mod simply uses the opamp offset adjusting part of the REV C design (actually it is on REV B too).
As Brian said, it does not negatively impact sound, but my amp at least is more stable now. Before I was a little affraid to leave it on all the time. This observation may be due in part to other factors (trafo and such), so it may be that it is not a problem for everyone.
Once again, good work Brian!
Cheers!
Russ