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Old 4th September 2008, 01:35 PM   #1
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Default Pass/Thagard A-75 build HELP!!

I am currently in the middle of construction of my A-75 amp. A question I have is the BOM. The paperwork which arrived with the pcb's from AudioExpress has several wrong numbers associated with the resistor locations. The pcb's also have errors.
Is the information which is available at the Pass DIY site accurate?? The main discrepency is with the r-22,24,21 locations.

One other question -- when using thermistors for the resistor part of a crc power supply would it not be better to parallel two on each rail. The leads are not too terrible large and I do not want a current restriction. Thanks Tad
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Old 4th September 2008, 06:07 PM   #2
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Here's a pdf describing the corrections.
Attached Files
File Type: pdf a75 mods.pdf (5.7 KB, 128 views)
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Old 5th September 2008, 08:15 AM   #3
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tryonziess,

About your CRC with thermistors:

The thermistor is choosen for the exact current going through

Too much current it goes overheating and can break
Too low current and the internal resistance will stay too high

Example: Keystone CL60 = 10 ohm cold value and a 5 amp current rating

mounting 1/2" over the circuit board ....

You will have to try, and if you want to parallel some
just roll the pins over the one soldered on the circuit...


regards.

Alain.
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Old 5th September 2008, 08:48 AM   #4
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And much thanks. Tad
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Old 5th September 2008, 08:28 PM   #5
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Quote:
Originally posted by Alain Dupont
You will have to try, and if you want to parallel some
just roll the pins over the one soldered on the circuit...
There's no rule against paralleling thermistors, but they do exhibit
current hogging when heated.
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