hifi said:
I'm using 0.5W Riken. Also, for series 220R resistor, you might not need it, depending on your system. I'm using it only to prevent any excessive DC offset jump.
Vishay S102 is good in this position, and it seems to be more neutral than Caddock, but some people may prefer some extra touch and Caddock seem to add that extra bit of speed and dimentionality, but it could also be interpreted as edginess. The choice is yours.
elizard said:
Peter Daniel said:
As Peter stated, if you are using a 20k pot, you do not need the shunt resistor to ground [R2]. You also might not need the 220 ohm series resistor on the input pin. I made the second pad on the R1 pad (series resistor) larger, so that the input wire can be wired directly into this pad if the 220 resistor is omitted.
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Brian
Well, a little research done 
www.alliedelec.com has cheap resistors!
$2.20 for the 20k in 100+ quantities (model#: 524-5575)
$1.58 for the 220R in 1+ quantity!!! (model#: 524-9996)
so that's $3.78 for these 2, plus the $2.40 for the riken .. not too bad, $6.18 for the 3 resistors ..
am i missing a resistor here?
www.alliedelec.com has cheap resistors!
$2.20 for the 20k in 100+ quantities (model#: 524-5575)
$1.58 for the 220R in 1+ quantity!!! (model#: 524-9996)
so that's $3.78 for these 2, plus the $2.40 for the riken .. not too bad, $6.18 for the 3 resistors ..
am i missing a resistor here?
elizard said:Well, a little research done
www.alliedelec.com has cheap resistors!
$2.20 for the 20k in 100+ quantities (model#: 524-5575)
$1.58 for the 220R in 1+ quantity!!! (model#: 524-9996)
so that's $3.78 for these 2, plus the $2.40 for the riken .. not too bad, $6.18 for the 3 resistors ..
am i missing a resistor here?
Don't forget that you need a 20k for the negative feedback resistor, which mounts directly to the chip.
We are probably talking about $12 per board for resistors and Panasonic FC power caps, including the shipping of the components to me.
I have a prototype of the power supply board done, which is 2.5" x 1.5". 2 boards and the power supply board would make a single board that is 3.5" x 2.5".
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Brian
elizard said:
I am estimating $50 or less for all the parts, pcbs for 2 channels and the power supply (8 x MUR860 and 2 x 4.7uF caps), including packing and shipping. (this is for panasonic caps, not BG. I am considering omitting the BG caps from this order, since I can't seem to find good quantity discounts anyway. In addition, most of the interest for this order seems to be for the Panasonic FC caps.)
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Brian
elizard said:
You said they're surface mount types, right?
I do not like those
Well, the regular FC caps will work fine, and have proven to work fine, though the many gainclones built with them. I allowed for the option for trying the FK caps if anyone is interested.
Has anyone compared the different sized FC 1000uF 50v caps? They make 2 different sizes, 16mm x 25mm x 7.5mm or 12.5mm x 40mm x 5mm [ diameter x length x spacing ]. I have only used the 12.5mm x 40mm caps, which cost a bit more, and have a slightly lower ESR. Both will work on the PCB.
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Brian
Attachments
I am interested in 4 boards ( or more ) but I would like to have 3 mm mounting holes at both sides to support the board in the case.
The following comment is meant as positive input:
It seems the amp will be "hanging" at only one screw this way. The weight of the caps will cause mechanical stress at the solder joints possibly causing premature failure. Also the risk of short circuits with "loose" PCB's is higher than with well mounted boards.
The following comment is meant as positive input:
It seems the amp will be "hanging" at only one screw this way. The weight of the caps will cause mechanical stress at the solder joints possibly causing premature failure. Also the risk of short circuits with "loose" PCB's is higher than with well mounted boards.
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