@Slaw
I kept wondering why he didn't question Ct0517's ongoing use of 19 psi?
My 2.5 HP manifold is a custom build by Bruce designed for 19 psi. I run it at the psi it was designed for.
Here is a real life example of a situation that may help understand what I said a few posts earlier in the Air Bearing Sticky Post.
A long time ET2'er is running a base ET2 which has had a recent cleaning maintenance done. He runs it with the stock original Takatsuki pump that still produces the 3.0 needed for the base ET2 to work, but not the 3.6 PSI the pump produced when it was new. It sounds good to him. On a whim he buys a little Medo medical pump on ebay. He notices that it makes 12 psi at the pumps output, but after travelling down 15-20 feet of air line he discovers the PSI drops to 7 psi at the gauge mounted near the tonearm. The music sounds better to him so even though this Medo makes enough noise to have to isolate in another room, he keeps it in place as it is worth it to him. He has it hooked up to 20 feet of hose and in another room. He's happy. He puts the stock pump away as a backup.
Now the maker of the our tonearms teaches us that if we improve the air supply the sonics will improve; but that over PSI'ing the arm can't hurt it physically as it is a robust design.
Based on the above example and info, did the sound get better with the little Medo pump because;
1) The PSI at the ET2 was increased to 7 psi from 3.5 stock pump.
or
2) The overall air quality delivered by the little Medo pump was better.
What do you think .... 1 or 2 above ?
btw
If anyone here is running a system with 10-15 feet of air line, and you have a quality pump that can still produce the PSI you need with a 60 - 100 feet of air line. Buy the air line as it is cheap - coil it up like a car's coil spring to save space. You will improve your sonics but only if your pump is of a design that can deliver the PSI for the longer run. Try it and find out.
From Bruce' website.
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3.6 PSI - 0riginal Takatsuki and ET-2 or 2.5
5.0- 7 PSI - WISA 300 air pump and ET-2 or 2.5 with high pressure manifolds
>10 PSI - users with shop compressors and ET-2 or 2.5 high pressure manifolds
Note, if the pressure readings are higher than those listed above, the manifold could be clogged, if the pressure readings are lower, this suggest that the pump may not be performing correctly.
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Slaw - you got your tonearm direct from Bruce correct ? What PSI was your HP manifold designed for ?
Lets start there.... imo this is your personal reference point for your system ...