Caps and Tubes

My pre-amp is an Audio Research LS-16. It was more or less inherited. It is the only pre-amp I have ever owned.

Looking down into it through the screen on top there are four large capacitors that say "Wonder InfiniCap". There are some numeric specs on them as well.

I'm wondering if these were original to the unit or added later as an upgrade. It has four fairly large tubes. They do not appear to have anything written on them that I can see. I'm wondering how to know if these are the original tubes.

This is all academic since there is little or no chance that I'd hear much difference between different types of caps and tubes but I'd still like to know if they were original or not. Of course if no one knows I can contact AR.


You can get a new set of tubes from Upscale Audio. They're a little bit expensive but they have good quality tubes and if you contact them they will be very helpful. If you don't know how old the original tubes are, then it's a good idea to get a new set.

Leave the InfiniCaps alone. Audio Research gear is definitely not the equipment to learn DIY repairs or soldering skills.

Also, never change filter capacitors if the amplifier works. You'll know the power supply caps need replacement when the unit gives out a 120 hz hum or if you see physical damage (bulging top, orange goop indicating leaking electrolyte, dark colored deposits on the circuit board, things like that) . 

And yes, the InfiniCaps are stock. AR also uses the expensive REL caps (the yellow ones) as standard equipment. 

You have a nice little preamp there, with new tubes I don't see why it won't last you another ten years or so.
Lots of opinions. Ha! @atmasphere is right as usual in that it is best to replace those old electrolytic caps as a prudent preventive maintenance step.  They are old and certainly have started to dry out with time. 

Those coupling caps you mentioned are very easy to replace. Any good tech or experienced DIYer could do it within 30 minutes. You can do much better in SQ than those dated caps. Many good ones to choose from that will improve the sound quality nicely. No need to, but just a nice to upgrade in the future.  
I used to own the LS16/PH3 combo, very nice gear but tell the truth, the thing yr most psyched about is the remote, right?  I knew it!;)
Thanks for the advice and references. Will do some reading at the AR database. 

Chazro, no remote. And AR no longer have them in inventory. Fortunately a programmable remote works for volume. But nothing else.