My AR-3 restoration

[bhamham]

I'm restoring a pair of AR-3s (SNs 26387 & 26865). Replacing the old 24uF & 6uF box cap with ERSE pulseX caps. Curious to know if it's recommended to add a small resistor in series to simulate the old esr level?

Thanks for any help.

[Tetrode]

Considering how old the drivers are I'd say no.

[Carlspeak]

Considering how old the drivers are I'd say no.

agree

[bhamham]

That makes it easy. Many thanks, chaps!

[bhamham]

Got another question... the AR-3a restoration guide sets the 'white dot' mid & high pots respectively at 3-1/4R & 1-3/4R. OK for the AR-3, too?

[Carlspeak]

That's only a guide IMO. The pots are adjustable in order for you to 'tune' the sound to your listening environment. That's really the beauty of having them in the first place. Every room is different.

[genek]

Carl, he's referring to the orientation of the pots in their mounting holes to align the "white dot" setting with the proper resistance. Which I suppose could be subjective if you're not going for a factory-original reassembly.

[Carlspeak]

I don't know exactly what the 'factory-original settings' resulted in acoustically. Was it derived from some anechoic 'flat' or BBC dip type response?

In any case, I believe most folks tweak those knobs until things sound right; or at least they should - regardless of original-factory settings.

[genek]

The only clue to what the thinking was is in that sheet from AR about level settings that is in the library. Nevertheless, if you want to reassemble the speakers the same way they came from the factory, there is a specific resistance that the pots should be at to calibrate against the arrows on the knobs against the white dots when they go together. Otherwise, any attempt to discuss level settings with another AR owner will be futile. This isn't about setting the level controls for optimum sound, but about installing the pots in their original orientation against the markings.

I think if there was a difference in resistance settings between the 3 and 3a the guide would probably note it, it's that thorough. Some people just seat the tab in the can into the dent in the crossover panel left behind by the original pot, but there's a fairly wide variation (around +/- 1 ohm) between these old pots. I would use a VOM to set each pot to the specified R and then orient the arrow on the knob to the dot and install.

[bhamham]

Nevertheless, if you want to reassemble the speakers the same way they came from the factory, there is a specific resistance that the pots should be at to calibrate against the arrows on the knobs against the white dots when they go together. Otherwise, any attempt to discuss level settings with another AR owner will be futile. This isn't about setting the level controls for optimum sound, but about installing the pots in their original orientation against the markings.

I think if there was a difference in resistance settings between the 3 and 3a the guide would probably note it, it's that thorough. Some people just seat the tab in the can into the dent in the crossover panel left behind by the original pot, but there's a fairly wide variation (around +/- 1 ohm) between these old pots. I would use a VOM to set each pot to the specified R and then orient the arrow on the knob to the dot and install.

Thanks, that's exactly what I had in mind. I'm sure I'll vary them to the particular setting but just wanted to approximate the factory 'starting point'.