Pcgab,
Those look close but make sure the overall assembly is not too tall. There is 12mm inside the tin on the bottom side of the board to the bottom of the tin. Those pins look a little tall. Also, do we have to buy female crimp pin that inserts into the body/shell?
Thanks,
X
Those look close but make sure the overall assembly is not too tall. There is 12mm inside the tin on the bottom side of the board to the bottom of the tin. Those pins look a little tall. Also, do we have to buy female crimp pin that inserts into the body/shell?
Thanks,
X
Yes, the ones I have 2,3,7 pin need the pins purchased and crimped separately. I thought it was going to be tougher than it turned out to be.
Very good point about the height. I'll poke around a bit more later today.
I think you can get 90degree through hole headers for those connectors, that might help the height issue. Of course it might be in the way of the batteries, or something else as well.
What's the deal with cost of 1% 0805 SMT resistors on Mouser? I was going to put together a nice one-stop shopping cart for everyone using Mouser including the SMT resistors but see that the pricing in ~20x higher than what Digikey charges. I can get a cut tape in qnty 100 for $0.71 total at Digikey and Mouser wants $0.14ea for qnty 100 ($14 for 100). I guess it's fine of you are ordering onesies and twosies, but that's the point of SMT - to get huge quantity of high quality parts for peanuts.
Looks like Digikey has the part I am looking for:
Male PCB mount socket (1 needed):
B4B-XH-A(LF)(SN) JST Sales America Inc. | Connectors, Interconnects | DigiKey
Female shell (1 needed):
XHP-4 JST Sales America Inc. | Connectors, Interconnects | DigiKey
Crimp connectors (4 needed):
SXH-001T-P0.6 JST Sales America Inc. | Connectors, Interconnects | DigiKey
Male PCB mount socket (1 needed):
B4B-XH-A(LF)(SN) JST Sales America Inc. | Connectors, Interconnects | DigiKey
Female shell (1 needed):
XHP-4 JST Sales America Inc. | Connectors, Interconnects | DigiKey
Crimp connectors (4 needed):
SXH-001T-P0.6 JST Sales America Inc. | Connectors, Interconnects | DigiKey
Here is the Digikey shopping cart with all the SMT resistors, bypass SMT caps, and 4 pin PCB and mating connectors with crimp pins. Enough parts for 2 amps plus lots of spares for resistors as they were most economical to order in qnty 100.
http://www.digikey.com/short/3f8r2r
http://www.digikey.com/short/3f8r2r
Of course, unless you are buying other stuff at Digikey, the $7 shipping is not worth it and you are better off buying the premade qnty 8 assemblies from Amazon with free shipping.
It's tough to be able to get all parts from one source for any project.
Update on GB Status
A reminder to folks (in red above and anyone else not yet on the list) who want to participate in the GB to please send me your PayPal address via PM. I need to confirm firm orders from members and I plan on placing the order tomorrow.
Thanks,
X
A reminder to folks (in red above and anyone else not yet on the list) who want to participate in the GB to please send me your PayPal address via PM. I need to confirm firm orders from members and I plan on placing the order tomorrow.
Thanks,
X
The folks in blue above still have not provided me their email for the invoice. We are currently at 31 boards for people who have paid and 41 if counting folks who have not yet paid.
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i got an invoice from you and paid a couple days ago. i just sent you a PM with the transaction ID, can you please check and let me know. thanks a lot!
Revised Board Schematic, Silkscreen, and BOM
Thanks to BDHM for revising the schematic to be easier to use with designations A and B for left and right and paralleled parts with sub-numbers. Below are the new schematic, board silkscreens on topside (through hole) and bottomside (SMT) so you can see where everything goes.
Schematic:
Top side Layout Silkscreen:
Bottom side Layout Silkscreen (note that 100nF C4A and C4B are mislabled 47uF - need to rework this before sending to fab):
BOM:
Thanks to BDHM for revising the schematic to be easier to use with designations A and B for left and right and paralleled parts with sub-numbers. Below are the new schematic, board silkscreens on topside (through hole) and bottomside (SMT) so you can see where everything goes.
Schematic:
Top side Layout Silkscreen:
Bottom side Layout Silkscreen (note that 100nF C4A and C4B are mislabled 47uF - need to rework this before sending to fab):
BOM:
Code:
All resistors 0805 package, metal thin film, 1% on specified parts, else 5%. Yageo 1% 0805 SMT from Digikey are $0.77 for 100
R1 100k (5%)
R2 47k (1%)
R3 1k (1%)
R4 33R (1%)
R5 270R (1%)
R6 47R (5%)
R7_1 470R (1%)
R7_2 470R (1%)
R7_3 470R (1%)
R7_4 470R (1%)
RL 270R (5%) User select (optional, use for higher current draw on amp)
RLED 15k (5%) Current limit for LED, 15k or value according to supply voltage
C1 Input cap 5mm pitch up to 5.5mm wide (Wima 2.2uF MKS2B042201F00JSSD)
C2_1 Output cap 3.5mm pitch, 8 dia (390uF 20v Panasonic OSCON 20SEPF390M)
C2_2 Output cap 5mm pitch, up to 9mm wide (Wima 1uF MKS2C041001F00KSSD)
C3 Rail cap 100uF 3.5mm pitch, diameter whatever you can fit in the tin (100uF 20v Panasonic OSCON 20SEP100MX)
C4 Rail cap 100nF 1206 package (50v X7R)
C5 Additional 100nF rail cap 1206 package (50v X7R)
Q1 BF862 (771-BF862-T/R)
M1 ZVN4306GTA
Switchcraft 3.5mm stereo jacks x2 (35RAPC4BV4)
Alps 10kOhm stereo pot with power switch (RK0971221Z05)
3mm round LED (red or green)
4-pin 2.54mm pitch power connector (see post #44)Attachments
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Yee-haw! Thanks for all the effort. 🙂
Question:
A gentleman on Head-Fi with 16 Ohm IEMs expressed interest in this amp. I used the formula provided by Andrew in post #25 and found F-3dB to be at ~26Hz.
(Also found this handy calculator: -3dB Cutoff Frequency Calculator)
This seems like it could present audible roll-off??
I'm planning to use the recommended 390uF Panasonic poly caps in the amp I'm building for myself to pair with my HD 598 headphones. But let's say I want to build my second amp to play well with ANY headphone. I've not quite mastered Mouser yet, but it looks like 390 is the largest value available for that type of cap... Would it be worthwhile to sub a regular electrolytic of a higher value, and what would be the sonic tradeoffs, if any? Any specific brand recommendations? Worth it?
Question:
A gentleman on Head-Fi with 16 Ohm IEMs expressed interest in this amp. I used the formula provided by Andrew in post #25 and found F-3dB to be at ~26Hz.
(Also found this handy calculator: -3dB Cutoff Frequency Calculator)
This seems like it could present audible roll-off??
I'm planning to use the recommended 390uF Panasonic poly caps in the amp I'm building for myself to pair with my HD 598 headphones. But let's say I want to build my second amp to play well with ANY headphone. I've not quite mastered Mouser yet, but it looks like 390 is the largest value available for that type of cap... Would it be worthwhile to sub a regular electrolytic of a higher value, and what would be the sonic tradeoffs, if any? Any specific brand recommendations? Worth it?
Probably need 1500uF caps - look for 16v ones to keep it smaller. Good brands like Panasonic FC, Nichicon Gold, Elna Silmic, etc. It probably won't fit in the tin though.
For example this is 12mm x 20mm (maybe lay on its side?):
http://www.mouser.com/ProductDetail/Panasonic/EEU-FC1C152/
For example this is 12mm x 20mm (maybe lay on its side?):
http://www.mouser.com/ProductDetail/Panasonic/EEU-FC1C152/
We just need to get the silkscreen fixed for C4A and C5B to show 10nF rather than 47uF then we are ready to get the boards made.
Update:
About 40 boards total
Update:
About 40 boards total
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