clm811 said:
I got a bunch of nice caps from this source: http://shop.ebay.com/merchant/umo88
Of course you usually have to buy more than you need, but when can you say you have enough parts?
Cheers!
All stuffed!
Currently, both the Leach PCB's (and the cat) are stuffed!
Now to measure/match the drivers & output devices and install.
Unfortunately she has a recurring appetite (big eater), but she likes my music enough to come in while I'm listening and curl up on the chair.
-Chas
P.S. Nice work, Rob!
Currently, both the Leach PCB's (and the cat) are stuffed!
Now to measure/match the drivers & output devices and install.
Unfortunately she has a recurring appetite (big eater), but she likes my music enough to come in while I'm listening and curl up on the chair.
-Chas
P.S. Nice work, Rob!
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Actually I'm hoping, once these amps are finished, that
the Sound is Absolute-ly wonderful!
-Chas
p.s. It looks like I'll have some parts (resistors, caps, diodes, transformer, heat sinks) leftover from this amp build. I'll be listing them in a few days under the "Trading Post" section of the DIY Marketplace, but I'd like to give my friends here "first crack" at 'em. Anyone interested can email me for an advance list.
Clip light
Has anyone considered (or used) Leach's Clip indicator ? Personally, once I've had a few
, an indicator reminds me back down a few db
Front end testing begins this morning on 4 pcb's, still waiting for Digi-ket to deliver on Mills resistors - 36 BO'd
I hope to finish plan for delay relay and associated power supply circuitry, get a part order going on this. Also, need to get serious about drilling and tapping the sinks.
I've read very little about prepping the heatsink surface for the output transistors, lapping, mirrored surface and such. As Bob would say 'avoid analysis paralysis', I want to get on with it but I don't feel as I've put enough consideration here. Anyone have a reference or link on the subject? I'll be using aluminum oxide pads, uncharted territory.
Thanks,
Rob
Has anyone considered (or used) Leach's Clip indicator ? Personally, once I've had a few
, an indicator reminds me back down a few dbFront end testing begins this morning on 4 pcb's, still waiting for Digi-ket to deliver on Mills resistors - 36 BO'd
I hope to finish plan for delay relay and associated power supply circuitry, get a part order going on this. Also, need to get serious about drilling and tapping the sinks.
I've read very little about prepping the heatsink surface for the output transistors, lapping, mirrored surface and such. As Bob would say 'avoid analysis paralysis', I want to get on with it but I don't feel as I've put enough consideration here. Anyone have a reference or link on the subject? I'll be using aluminum oxide pads, uncharted territory.
Thanks,
Rob
Re: Clip light
Once you get beyond ensuring that you have deburred the mounting screw holes (absolutely essential), you're up on the diminishing returns curve. Unless your surfaces are particularly rough (to the touch) all lapping will buy you is a few extra watts of dissipation capability. If you aren't lighting your clip light constantly you're probably safe. Lots of commercial products, including pro sound work (and survive) just fine with an anodized mill finish on the sinks.
Deburring is as easy as twisting a drill bit larger than the hole on the surface until you don't feel any burr dragging your finger across the hole. Ensure that all chips are removed from the surface before mounting your transistors.
rob3262 said:
Once you get beyond ensuring that you have deburred the mounting screw holes (absolutely essential), you're up on the diminishing returns curve. Unless your surfaces are particularly rough (to the touch) all lapping will buy you is a few extra watts of dissipation capability. If you aren't lighting your clip light constantly you're probably safe. Lots of commercial products, including pro sound work (and survive) just fine with an anodized mill finish on the sinks.
Deburring is as easy as twisting a drill bit larger than the hole on the surface until you don't feel any burr dragging your finger across the hole. Ensure that all chips are removed from the surface before mounting your transistors.
Here are two helpful links I found:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=122531&highlight=
http://www.sound.westhost.com/heatsinks.htm#7
Good luck on your testing!
-Chas
Today I laid out all the parts, checking to see if my chassis have room for two channels, at the urging of another DIYer, who says there's room.
It looks like a tight squeeze, but everything just fits.
Anyone here foresee any problems locating the PSB's so close to the circuit boards?
The approx 600VA transformer is from a stereo receiver, so there's only the one set of center-tapped secondaries.
I'm hoping that I can split it (attaching two sets of leads in a "y") to feed both supply boards, but the total capacitance will be almost 2x greater than in the original receiver- sound feasible?
I will be using a CL-30/delay relay combo to limit turn-on surge.
-Chas
It looks like a tight squeeze, but everything just fits.
Anyone here foresee any problems locating the PSB's so close to the circuit boards?
The approx 600VA transformer is from a stereo receiver, so there's only the one set of center-tapped secondaries.
I'm hoping that I can split it (attaching two sets of leads in a "y") to feed both supply boards, but the total capacitance will be almost 2x greater than in the original receiver- sound feasible?
I will be using a CL-30/delay relay combo to limit turn-on surge.
-Chas
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Chas, where did you score the delay relay? Part number? A reasonable price point on this could simplify my efforts...
The chassis layout looks good. Admittedly, I have no idea how much heat the PS will generate but your build looks spacious. What rail voltage will you get from the 600VA?
Total rail capacitance?
The chassis layout looks good. Admittedly, I have no idea how much heat the PS will generate but your build looks spacious. What rail voltage will you get from the 600VA?
Total rail capacitance?
FleaBay, of course! They sell for an average of $15.
Check out the following:
eBay Item number: 330308432876 (lot of 4, similar to mine)
eBay Item number: 350167551297 (requires a 24vdc source)
Attached is a diagram of my relay setup, which shorts out the CL30 after a 5-6 second delay.
The secondaries are 45-0-45vac, so approximately 63vdc rails(no load).
I used six 4,700uf*snap-ins per PSB. If you count the 2,200uf KG caps(thanks Michael Percy!) on the PCB(C21/C27), that makes 16,300uf per rail. So the amp has 32,600uf per channel and that makes the total 65,200uf (the receiver the traf came from had one 15,000uf cap per rail, or 30,000uf total).
-Chas
*These were surplus, NOS caps, since my order for the Nichicon KG never did arrive from Taiwan.
p.s. You may need a relay socket and, if purchased new, these will set you back $5-$10 additional.
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Thanks Brutepuppy!
I just wanted to publicly thank "Brutepuppy" for going "above and beyond" to help me with my amps.
He just spent the entire evening showing me how to lay out and drill my heatsinks (and putting up with my lack of knowledge)!
Thanks also to Tad, Bill, Fred and Phil for their continued support.
I can't think of anywhere else that I've met so many quality people with interest in things DIY and audio!
I only hope that others here find such good friends in this hobby.
My sincere thanks again!
-Chas
I just wanted to publicly thank "Brutepuppy" for going "above and beyond" to help me with my amps.
He just spent the entire evening showing me how to lay out and drill my heatsinks (and putting up with my lack of knowledge)!
Thanks also to Tad, Bill, Fred and Phil for their continued support.
I can't think of anywhere else that I've met so many quality people with interest in things DIY and audio!
I only hope that others here find such good friends in this hobby.
My sincere thanks again!
-Chas