TL Audio PA-2 Resistor Values
« on: May 16, 2018, 05:32:09 PM »

Does anyone have experience with TL Audio PA-2?  Have two burned out resistors R3 and R9.  They're the big 2 watt ones off the high voltage rail.  I found a pic that looks like R3>47k and R9>68k.  I also saw recommendations to upgrade to 3 watt metal oxide.



Re: TL Audio PA-2 Resistor Values
« Reply #1 on: May 16, 2018, 05:50:54 PM »
Those are the right values from the schematic......

Are you sure they are burned out????? They and the  PCB can get pretty hot around these and discolor.......What is your question???

But bigger wattage is a good thing if that's what you are asking??? Wire wound works well in power resistors too....afaik.....

Are they not metal oxide already????

« Last Edit: May 16, 2018, 05:59:17 PM by scott2000 »

Re: TL Audio PA-2 Resistor Values
« Reply #2 on: May 16, 2018, 06:01:23 PM »

The unit belongs to a client.  R3 and R9 are burned out and the metal oxide coating has flaked off.  They measure 50k and 70k, they aren't burned open, but they look like they're in rough shape.  I'm replacing some bulging output coupling caps from someone feeding the thing 48V phantom. ???  Output caps were 330uF 16V.  Found two 10uF 100V that were > 20 ohms ESR, so replacing those and a 4.7uF 40V that didn't even register on the ESR meter, so > 40 ohms.  Client also wanted sockets, to mess with swapping out op amps.


Re: TL Audio PA-2 Resistor Values
« Reply #3 on: May 16, 2018, 06:15:53 PM »
Yeah those blue Rubycon 330uf are always a sore spot from the couple TL Audio units I've seen....Not sure why or if that's what's in yours......

I think the Nover caps are usually pretty decent though if they used them in that.... But yeah.....It's getting up there in age so electros aren't a bad thing to replace.....

Have fun with the mods........


Re: TL Audio PA-2 Resistor Values
« Reply #4 on: May 17, 2018, 12:02:26 PM »
I have replaced those same resistors in a PA-2.
The owner had them racked up with no fan, and no space between other rack gear. I would recommend both those things for anyone using one of these.
Wouldn't hurt to up them to 3 watts, as this seems to be a weak spot in the design.
Resistance is not futile. It is voltage divided by current.  (thanks, Bill)


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