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MINT resistors?

Dec 14, 2004 at 1:26 AM Thread Starter Post #1 of 12
ChickenScrtchBoy

ChickenScrtchBoy

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I'm scared.

I can't figure out what resistors to buy. I know I want 1/4 watt resistors with metal film and 1% tolerance, but what about size? how do I know if they are going to be too fat, or long?

Any advise would be greatly aprechiated.
 
Dec 14, 2004 at 2:11 AM Post #5 of 12
Well, Mouser carries the Vishay Dale 1/8W (RN55 series) resistors which are more than adequate for a MINT amp; they will fit just fine.

Tangent says this in the part selection guide:


Quote:

Are 1/8W Resistors Sufficient?


1/4W resistors are the most readily available sort and the board will accept standard 1/4W resistors, but it takes extraordinary circumstances to make the circuit put more than 1/8W through one of the resistors.


If you put a dead short across the output of the amplifier and play music through the amp, you could potentially damage an 1/8W R8. If you go up to 1/4W, you'd need to stack output buffers to have a chance at damaging an 1/8W R8. With headphones plugged in, the headphones limit the current the amp can put out, so R8 can only be damaged if you're running the headphones so hard that you're likely to damage the headphones or your ears before R8. If you try to make the amp power speakers directly, you could damage R8; you deserve to smoke some resistors if you try this stunt.

Resistor Sizes


The resistor pads on the MINT board are only 300 mils apart, which limits the size of the resistors you can use. Standard 1/4W metal film and carbon resistors will fit in the board without a problem. If you use Vishay Dale CMF series resistors, use the RN55 series, not the RN60s. These are 1/8W, but as I explained above, 1/8W is sufficient. RN60s will not fit in the board without creative mounting.


I've used the Vishay Dale RN55 series and they are fine. You can get them from Mouser and Newark (and probably other places too.) Digikey carries Yageo resistors (the kind tangent specs in his CMOY tutorial) and they would fit on the MINT board as well. These are 1/4W resistors.

What you can't use are the Vishay Dale 1/4W RN60 series resistors, at least not without some creative mounting...they seem too big for the space allowed.
 
Dec 14, 2004 at 2:15 AM Post #6 of 12
looks like the XBK's are ok then?

also, I am attempting to dodge the $5 handling charge for not meeting a $25 minimum.... so far I have this in my cart...

Code:

Code: 
[left]Index Quantity Part Number Description Customer Reference Backorder Quantity Unit Price USD Extended Price USD 1 2 EF1105 1.0UF/100VDC METAL POLY CAP 0 0.99000 $1.98 2 2 P10273 CAP 330UF 25V ELECT FC RADIAL 0 0.44000 $0.88 3 1 HLMP1790 LED SS GRN DIFF LO CURR PCB 3MM 0 0.35000 $0.35 4 1 1N5822GICT RECT SCHOTTKY 3A 40V DO-201AD 0 0.83000 $0.83 5 1 296-1994 IC 1/2 RAIL VIRTUAL GND TO-92 0 1.30000 $1.30 6 1 226-1041 KNOB BLK GLOSS.50"DIA .250"SHAFT 1 Lead Time 4.73000 $4.73 7 1 360-1155 SWITCH TOGGLE SPDT 6A 0 4.20000 $4.20 8 3 CP-3535 CONN AUDIO JACK 3.5MM STEREO 0 1.04000 $3.12 9 2 2238K STRAP BATTERY 9V I-STYLE 4"LEAD 0 0.48000 $0.96 10 5 1.00KXBK-ND RES 1.00K OHM 1/4W 1% METAL FILM 0 0.10800 $0.54 11 5 475XBK-ND RES 475 OHM 1/4W 1% METAL FILM 0 0.10800 $0.54 12 5 221XBK-ND RES 221 OHM 1/4W 1% METAL FILM 0 0.10800 $0.54 13 5 2.21KXBK-ND RES 2.21K OHM 1/4W 1% METAL FILM 0 0.10800 $0.54 14 5 1.50KXBK-ND RES 1.50K OHM 1/4W 1% METAL FILM 0 0.10800 $0.54 15 5 100XBK-ND RES 100 OHM 1/4W 1% METAL FILM 0 0.10800 $0.54 16 5 47.5XBK-ND RES 47.5 OHM 1/4W 1% METAL FILM 0 0.10800 $0.54 Subtotal$22.13 Handling$5.00[/left]

Am I missing anything? Anything I should buy an extra of?

Thanks for everyone's help so far...
 
Dec 14, 2004 at 2:54 AM Post #10 of 12
Well, I changed it to dodge the handling charge...

Here is the final list... going to place the order shortly...

Code:

Code: 
[left]Index Quantity Part Number Description Customer Reference Backorder Quantity Unit Price USD Extended Price USD 1 3 EF1105 1.0UF/100VDC METAL POLY CAP 0 0.99000 $2.97 2 3 P10273 CAP 330UF 25V ELECT FC RADIAL 0 0.44000 $1.32 3 1 HLMP1790 LED SS GRN DIFF LO CURR PCB 3MM 0 0.35000 $0.35 4 2 1N5822GICT RECT SCHOTTKY 3A 40V DO-201AD 0 0.83000 $1.66 5 2 296-1994 IC 1/2 RAIL VIRTUAL GND TO-92 0 1.30000 $2.60 6 1 226-1041 KNOB BLK GLOSS.50"DIA .250"SHAFT 1 Lead Time 4.73000 $4.73 7 1 360-1155 SWITCH TOGGLE SPDT 6A 0 4.20000 $4.20 8 3 CP-3535 CONN AUDIO JACK 3.5MM STEREO 0 1.04000 $3.12 9 2 2238K STRAP BATTERY 9V I-STYLE 4"LEAD 0 0.48000 $0.96 10 5 1.00KXBK-ND RES 1.00K OHM 1/4W 1% METAL FILM 0 0.10800 $0.54 11 5 475XBK-ND RES 475 OHM 1/4W 1% METAL FILM 0 0.10800 $0.54 12 5 221XBK-ND RES 221 OHM 1/4W 1% METAL FILM 0 0.10800 $0.54 13 5 2.21KXBK-ND RES 2.21K OHM 1/4W 1% METAL FILM 0 0.10800 $0.54 14 5 1.50KXBK-ND RES 1.50K OHM 1/4W 1% METAL FILM 0 0.10800 $0.54 15 5 100XBK-ND RES 100 OHM 1/4W 1% METAL FILM 0 0.10800 $0.54 16 5 47.5XBK-ND RES 47.5 OHM 1/4W 1% METAL FILM 0 0.10800 $0.54 Subtotal$25.69[/left]

 
Dec 14, 2004 at 4:10 AM Post #11 of 12
Quote:

226-1041 KNOB BLK GLOSS.50"DIA .250"SHAFT


Digikey carries some 6mm Kilo knobs which will be a little better fit than the .25 inch ones will be for the Pana pots.

Perhaps you might want to get some extra resistors for trying out different gain values?
 
Dec 14, 2004 at 4:34 AM Post #12 of 12
Quote:

Originally Posted by Earwax
Digikey carries some 6mm Kilo knobs which will be a little better fit than the .25 inch ones will be for the Pana pots.

Perhaps you might want to get some extra resistors for trying out different gain values?


Already ordered.

Oh well, I've got a bunch of spare resistors of assorted values out in the garage for playing with the gain
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