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what is the wattage?
#1
i bought all new caps for my gemini 2 and i'd like to change the resistors as well... but i don't know the wattage and i dont see that on the schematic...not that i can really read a schematic lol.
i've de coded all of the color bands, and i've already got some 1/4 watt resistors with the same color values but they are tiny in comparison. i thought that only resistors under 1 watt were color coded? anyways... i'll just replace the caps for now and hopefully someone will respond with an answer. thanks
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#2
Someone correct me if I am wrong, but standard policy for amps is usually that all resistors are 1/4w unless otherwise specified. Not surprising that modern resistors are going to be smaller than the ones in a vintage amp. Plenty of resistors, particularly in the power filtering section will specify a wattage rating. Be sure to check the value of the resistors you are replacing with your meter if your not clear on reading schematics and resistor color codes. It can be easy to mis-read a resistor, and colors can be weird even one batch/brand to another, let alone read backwards if you aren't paying full attention etc.
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#3
I have just replace most of the caps and several resistors in an old Ampeg amp. If the resistor checks out, I leave it. I had several that had drifted significantly from the markings on them.....they will be replaced. But I needed several higher wattage resistors, including what appears to be a 10-15 Watt cathode bias resistor. The physical size of the resistor should be a good indicator of the wattage. Larry
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#4
(10-23-2017, 03:18 PM)Fred Rocker Wrote: i bought all new caps for my gemini 2 and i'd like to change the resistors as well... but i don't know the wattage and i dont see that on the schematic...not that i can really read a schematic lol.
i've de coded all of the color bands, and i've already got some 1/4 watt resistors with the same color values but they are tiny in comparison. i thought that only resistors under 1 watt were color coded? anyways... i'll just replace the caps for now and hopefully someone will respond with an answer. thanks

resistor size isn't what it used to be. I've got 1/4 watt resistors that looks like 1/8th or 1/10 watt. things keep getting smaller. even things as archaic as axial through hole resistors. Wink

I've seen 2 and 3 watt resistors with color codes. at some point the resistor gets big enough that its silly to put color coding for something you can just write on it.
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#5
I typically install the biggest resistor that I can fit in the space. Not quite sure where I picked up this practice, but I'm pretty sure I have never put a 1/4-watt resistor in a tube amp. A higher rated resistor is going to last longer and be less noisy. On the other hand, a metal film resistor will last just about forever and produce less noise, so it is less of an issue. But people with better ears than mine seem to think that carbon-based resistors sound better. In any event, you really should give some thought to what wattage is actually required. You don't want to skimp on resistors where there is significant current flowing, such as a cathode or plate resistor.
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#6
that's awesome thank you
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