Well I am up and running, even without changing out c11, c15 the damn thing rocks.
Thanks again guys, sry for all the trouble.
Just one more question, how long should I use the amp without attaching the VR's to the heatsink??? LOL sounds to good to turn it off at the moment.
Thanks again guys, sry for all the trouble.
Just one more question, how long should I use the amp without attaching the VR's to the heatsink??? LOL sounds to good to turn it off at the moment.
The regulators don't have to be on heatsink if you only are feeding two opamps. As long as the regulators aren't burning hot 
everything is OK.
everything is OK.
Re: Any Leftovers?
I'm also preparing the BOM with article numbers. Farnell is 99.5%, next is Mouser, Digikey and ELFA.
I thought making an excel file with a couple of columns th same through a workbook. How do I do that? I don't want to duplicate only. The idea is to have R1, value, spec etc the same and for each spreadsheet page I want to have different supppliers article numbers, describing text etc.
I'm going to sell boards later. Check back in two-three weeks.Landoctor said:
I'm also preparing the BOM with article numbers. Farnell is 99.5%, next is Mouser, Digikey and ELFA.
I thought making an excel file with a couple of columns th same through a workbook. How do I do that? I don't want to duplicate only. The idea is to have R1, value, spec etc the same and for each spreadsheet page I want to have different supppliers article numbers, describing text etc.
P-A
You can have cells in one worksheet reference cells in another worksheet; so if you haveinformation in (say) Sheet 1 Cell A1, then put in Sheet 2 Cell A1 the formula "=Sheet1A1". If this isn't clear (or isn't what you meant), PM me and I'll set up the spreadsheet for you. I'd be happy to do it in return for you setting up the group buy.
Regards.
Aengus
First off, I'm a newbie to this website and groupbuy.
If anyone has an extra PC board and set of inductors that you don't plan on using, I would be interested in purchasing them.
Otherwise, I'll sit on the sidelines and wait for Peranders to start selling the next batch.
It looks like a few people have completed their amps and mentioned the performance. Any new opinions of this amp?
Dave
If anyone has an extra PC board and set of inductors that you don't plan on using, I would be interested in purchasing them.
Otherwise, I'll sit on the sidelines and wait for Peranders to start selling the next batch.
It looks like a few people have completed their amps and mentioned the performance. Any new opinions of this amp?
Dave
noise wise, quietest amp I have ever laid my ears on.
I did manage to overheat the LM4780 chip so for me to do again I would purchase a bigger heat sink 🙁
I did manage to overheat the LM4780 chip so for me to do again I would purchase a bigger heat sink 🙁
I bought the one that was posted on ebay for sale. U buy a foot piece and the guy cut it in 3 - 4" pieces. The base of the heatsink is 3/8" solid aluminum and the fins are spaced about 1/4" apart, the hole thing is a little over 5" wide.
The one question I do have... I just bought a pair of 5" square 120VAC fans. Here is the link.
http://www.bgmicro.com/index.asp?PageAction=VIEWPROD&ProdID=10694
Will hooking this up pre-transformer inject unwanted noise into the amp? I need find someway to cool this beast till I can purchase higher quality drivers.
http://www.bgmicro.com/index.asp?PageAction=VIEWPROD&ProdID=10694
Will hooking this up pre-transformer inject unwanted noise into the amp? I need find someway to cool this beast till I can purchase higher quality drivers.
jaybombalous,
I have the same heatsinks as you but I haven't gotten them installed on the amp yet.
How hard/long were you running the amp when you overheated it?
How do you have the chip mounted to the sink? Specifically what kind of insulators did you use?
The heastink is not the exact one specifed by the BOM but it's measurements are close enough. I am surprised it isn't adequate.
Would you suggest I not bother with it and find another? Thanks.
-claiborne
I have the same heatsinks as you but I haven't gotten them installed on the amp yet.
How hard/long were you running the amp when you overheated it?
How do you have the chip mounted to the sink? Specifically what kind of insulators did you use?
The heastink is not the exact one specifed by the BOM but it's measurements are close enough. I am surprised it isn't adequate.
Would you suggest I not bother with it and find another? Thanks.
-claiborne
I ended up just mounting it straight to the heat sink. I am thinking now I should have used some sort of thermal paste as well.
As for when I got it to over heat, well, I guess u could say I was definitely giving it a thorough workout. But, thats what I was wondering, if the heat sink would keep up with my demands of the chip. The answer was 'NO' in my case.
Still, I will keep trying to change things here and there and see if I can get any better cooling to the heat sink. First try some kind of thermal paste to transfer heat more efficiently.
Even then, with the overheating problem when giving the amp a workout the quality of the music can't be surpassed. So all in all I am saying win - win situation.
As for when I got it to over heat, well, I guess u could say I was definitely giving it a thorough workout. But, thats what I was wondering, if the heat sink would keep up with my demands of the chip. The answer was 'NO' in my case.
Still, I will keep trying to change things here and there and see if I can get any better cooling to the heat sink. First try some kind of thermal paste to transfer heat more efficiently.
Even then, with the overheating problem when giving the amp a workout the quality of the music can't be surpassed. So all in all I am saying win - win situation.
jaybombalous,
I think a couple other people on the forum purchased the same heatsink for this amp. Please let us know if using thermal paste or whatever else you do improves your cooling situation enough to make this a suitable heatsink. Did you have it in a case when it overheated?
What size/brand power supply did you use? Do you have any more picture of your build?
I'm happy to hear you are pleased with the sound. I'm looking forward to getting mine together soon.
-claiborne
I think a couple other people on the forum purchased the same heatsink for this amp. Please let us know if using thermal paste or whatever else you do improves your cooling situation enough to make this a suitable heatsink. Did you have it in a case when it overheated?
What size/brand power supply did you use? Do you have any more picture of your build?
I'm happy to hear you are pleased with the sound. I'm looking forward to getting mine together soon.
-claiborne
I bought one from digikey, amveco, 300VA 2x24V back when I did the gainclone LM3886 DIY kit from BrianGT. I just switched out the PCB's. Which is probly where I will start if the thermal paste doesn't work well.
I was just hoping to save a little money, at ~$100 w/ shipping it wasn't something I wanted to really have to buy ATM.
salesmonster said:
Yes looks fairly straight and quite well priced, looking at the pricing for 2boards & 4 inductors ends up being around $42aud...
so yea let us know if another GB or spares apear.
Cheers, stevo.
I'm interested to participate in a new batch Group Buy of PA03 or buying unused boards if any. Qty 2. Send MP.
Hi Guys,
fairly new to DIY but have enjoyed the simple projects like T amp, 3875,3886 and now want to have a go at 4780. are there any boards/inductors/resistors/parts about still.
thanks
fairly new to DIY but have enjoyed the simple projects like T amp, 3875,3886 and now want to have a go at 4780. are there any boards/inductors/resistors/parts about still.
thanks
Yeah, I would like to know that too.. it seems like i may have lost mine. But i'm gonna look once again first.