Eminent Technology ET-2 Tonearm Owners

Hi Dave

After converting the TNT to thread drive and eliminating the tri-pulley system, I made a 2 spring I-beam and moved the weight way out on the I-beam (past 6). All three of these tweaks made a significant improvement in sound quality and it was all free!

You gotta love that. For me improving sound for nothing is the best "lasting" feeling in this hobby. Its a special feeling imo when you discover something on your own. I guess because I want to know why it works. It needs to be repeatable and when reversed, should bring things back to where you were.

I was wondering if anyone has experience with even higher pressures with the stock 2.0 manifold? I think 12psi is probably pushing it, so thought I would ask here before going higher.

When you refer to PSI are you referring to the PSI at the pump itself or at the ET2 arm ?

Reason I ask - the MEDO AC0110 pumps that I have owned in the past all lose some psi along the way. They deliver 12 at the pump itself pump but about 7-8 PSI at the actual arm.

From my reading of this thread, it seems that most of you have reached a pressure “threshold” where the sound quality starts to fall off. What exactly do you hear when this happens?

01-19-12: Apbiii
...My arm is a very early version, so certainly not optimized for higher pressure, and I can feel the air escaping at 19 psi but I can't hear it yet. I have not tried to determine if it introduces significant horizontal force. As I stated in my post I could hear some of the life or vibrancy go out of the music when I increased the pressure...

"Some of the life or vibrancy go out of the music"

imo these are very good and effective words by Archie of what happens - "life and vibrancy" I wonder if he is still around ?

Someone asked me about this on my system blog. This was part of my response.

"So to answer your question based on my experience. If too much air is put through and starts affecting the spindle the actual spindle will start resonating. The detail in the music will start blurring. Its kind of like when your stylus gets a little dirt on it if you are lazy to clean it. I take notice of it from familiar recordings - something is amiss or off and you clean the stylus. Likewise sonically the music sounds thinner, leaner with less information. imo - this is how you will know what pressure psi your system can handle based on your own system / room."

So I think we are all saying similar things as to what we hear.

Now here is something to think about.

IMO outside of our own room/gear tuning, the "PSI threshold" itself for each of our systems is determined as a result of two separate things but both need each other to work.

The pump delivery system itself and the ET2, 2.5 spindle starting to vibrate/resonate.

Both the pump system and the ET2 and ET2.5 can be at varying stages of setup and condition with each of us. Consider someone using a 20 year old ET2 that has never been cleaned out or has leaking air around it; over a newer one, maybe a new Et 2.5 that Bruce just delivered to someone. The beauty here is that the older one is easily cleaned and air leaks tightened and brought up to spec again.

The pumps are the real moving targets here as we all use different pump setups.

I am willing to bet 100 Canadian dollars if you asked Bruce in the last 20 years of the ET2, ET2.5; if there was one thing he could change he would say something about having more control over the pump systems that people have used.

We can help to assess how much the PUMP is contributing to the PSI threshold with the PUMP test.

Have you tried the Pump Test yet Dave ?

This requires the help of a friend.

*****************************************************
Turn your system on and place it on mute at lowest volume.
With your ET2 setup properly (level and balanced) and NO air on - lower the stylus onto a lead in groove.
Again with NO Air on - unmute the system and start raising the volume.
Keep going till you reach the level on your dials that represents high volume in your room.
Your room has now become a listening chamber for your system and gear and more importantly - NO PUMP.
Its isolated and not a factor yet.
If all is well to this point,
with the stylus acting like a stethoscope in that groove, go up to one of your speakers and wait there.
Tell your friend to go turn your pump on while you keep your ear up close to the speaker.
*****************************************************
What do you hear when your friend turns the pump on ?
Have your friend turn it off and on again.

If you are hearing any noise at all, the pumps air delivery is not optimized and is sending nasties to your ET2.
The noise is putting a layer in the music.
This is also affecting the PSI you can run with your ET2.
It is my opinion that improving the air delivery should allow you to reach the best PSI threshold for your room/gear with the high pressure manifold ET2 or ET2.5 and gain benefits.

I am not a scientist. I am hobbyist, I trust my ears and I base this on my personal experience.

Very Important
For anyone reading that is a new ET2 user do not attempt the above test until you are familiar with the ET2, it is setup properly, level and balanced.

A while back I went on a mission for a few years with pumps. I ended up with the Aridyne timeter medical pump that is used for patient respiration. You flick a switch to turn on and off. It dumps moisture at the pump just like a cars AC system. These are purchased on ebay cheaply but required being picked up. They do require a separate room as they are around 60 db as far as how loud they are when you stand next to them.

I have come to terms with idiosyncrasies of the VPI air bladders, but I sure would like to find some of those feet. Would be interested in hearing Ct0517's impressions of the TNT with and without the AT616s.

Regarding the TNT

As with noise above being the resonance vibration hobby it is - I have always found consistent results whenever we are able to remove "noise or structure feedback" from entering our system/gear. The result being more music comes through for us. We have all experienced this sensation and it generates the same kind of comments on the forums -

"I did not realize the "noise" was there until it was removed"

The TNT and thread - congratulations for implementing this! this was a biggie for me. A sort of analog revelation.

http://cgim.audiogon.com/i/vs/i/f/1366420145.jpg

If you read my system blog thread, the thread controlled with the SDS controller, truly elevated the performance of the TNT.

Air bladders like the VPI legs work but keeping them inflated and level can be a PITA and as we know out of level is disaster for an air bearing tonearm. I found the Pneumatic AT616 footers insulate and decouple really well, but where they supersede others is that they have a smooth and excellent leveling system - and once set - don't go out of level. The Verdier also has a pneumatic suspension.

Welcome to the thread Dave.
Very nice setup btw. I wish everyone here could post virtual systems.
sorry for the long post and any errors.
Cheers Chris

Hi Chris,

Thank you so much for the comprehensive response. Very helpful.

I shamelessly stole the TNT thread drive mod (all the way down to using unwaxed dental floss) from your posts here. BIG improvement!

Ditto for the second low pressure regulator that I installed behind the table (stole it from your posts). There is only 2 feet of 1/8" tubing and a check valve between this regulator and the arm, so all pressures quoted in my posts are essentially "at the arm".

My compressor is the Medo AC0910. Compared to the AC0110, the 0910 puts out a lot more air volume at higher pressures and has a higher max operating pressure (21.4psi vs 17.1psi for the 0110). Frogman uses the 0910 and says that it does a great job with this HP 2.0 bearing at 17psi. The compressor sits in my DIY baffle box in a closet about 12 feet from my listening position. Can't hear it there. The first regulator/filter and 4 foot long 4" PVC surge tank are in the closet as well.

I just did the Pump test. Turned the preamp volume up way beyond normal listening levels and put my ear close to the midrange drivers. No added noise at 3.5psi, but I hear a slight hissing sound from the midrange drivers starting at 5psi and increasing slightly in volume at 7psi. The noise does not pulse, but is a smooth and faint sound of air flow. Sounds a bit like tube rush. The noise does not seem to increase as I move up from 7psi to 17psi. I can't really hear it at my listening positions at max listening volume, but I think your point is that if I can hear it, it is affecting the performance of the arm. Any suggestions on how to reduce/eliminate this (may be solved with the HP manifold)?

Agree that the air bladders are, and have always been, a PITA. I recently called VPI about the leakage issue and they sent me some modified round rubber bushings to place around the outside of the schrader valve so that it seals the metal cap to the corner pods. Seems to be working great so far.

The AT616s are so cool looking on your TNT. I saw a set on "that auction site" for 400 bills. They show some deformation on the top. For that price, I would want an audible improvement over the air bladders in addition to eliminating the aggravation of maintaining level. Any opinion on that?

Thanks again, Chris.

Best,
Dave

Any suggestions on how to reduce/eliminate this (may be solved with the HP manifold)?

Dave - just so we understand.
so no noise in your system with NO pump on - stylus in groove - and the preamp volume high.
this is with a stock ET2 which is designed to work at about 3 psi.
When you turn the pump on there is no noise in your midrange driver up to 3.5 psi,
So we can assume the ET2 with your pump works well to 3.5 as designed ?
In fact it is quiet to just under 5 psi. So all is good.

but at 5 psi you start to hear what sounds like air (like tube rush) in your midrange driver.
It is not a mechanical piston type noise, or drone like noise - it is the sound of air - maybe like air escaping ?
It gets louder to 7 psi and then stays the same to 17 psi.
I would think if it was mechanical / piston problem it would maybe be heard at the lower pressure too. Maybe the hydraulic guys? can chime in - Richard ?

try something - with your system on mute and the ET2 raised and at rest.
crank the PSI up all the way to 21 and put your ear right next to the ET2 manifold- do u hear any sounds like a balloon with a leak ?
If yes is there air coming from a bolt ?
Try wiggling the tube at the input nozzle around. It would be shame if a great pump system and that connection at the plug is not tight.
If there is a leak at the plug - pull the plastic out - cut an inch off so the plastic is tight and fresh - re-insert. Is there significant air coming from the manifold where the spindle enters and exits? You will feel the air coming out with your finger near both ends.

With the info you provided it sounds to me like the HP manifold would fix this as its lungs are designed to inhale the higher PSI.

Frogman uses the 0910 and says that it does a great job with this HP 2.0 bearing at 17psi.

Frogman provides clear support for the HP ET2 model with the same pump.

It is very easy to spend other peoples money :^)

Since you are hearing benefits of the higher pressure - but you have a stock ET2 it makes sense to me to do it, if you feel its worth it? Bruce charges a reasonable amount for both upgrades ? Making the ET2 HP or by using his magic to transform the ET 2.0 into the 2.5 HP. As you said this would take a few weeks.

Some input from the others?

I recently called VPI about the leakage issue and they sent me some modified round rubber bushings to place around the outside of the schrader valve so that it seals the metal cap to the corner pods. Seems to be working great so far.

What a great service company. I bet they didn't charge you for those either, and if they did a very nominal charge.

I saw a set on "that auction site" for 400 bills. They show some deformation on the top. For that price, I would want an audible improvement over the air bladders in addition to eliminating the aggravation of maintaining level. Any opinion on that?

http://www.ebay.ca/itm/Audio-Technica-AT616-Pneumatic-Suspension-Audio-Insulator-4-pcs-/321244326789

Probably 500 by the time they get to you.
I don't know what to say - everything in this crazy hobby just keeps going up in price.
What you see in the picture may be marks only and not an actual indent.
The seller can verify this.
Sounds like your VPI fix is working so I would hold off. I'd put money into the manifold ?

Chris

HI CHRIS - ANSWERS IN CAPITALS BELOW:

Dave - just so we understand.
so no noise in your system with NO pump on - stylus in groove - and the preamp volume high. RIGHT
this is with a stock ET2 which is designed to work at about 3 psi. RIGHT
When you turn the pump on there is no noise in your midrange driver up to 3.5 psi, RIGHT
So we can assume the ET2 with your pump works well to 3.5 as designed ? YES
In fact it is quiet to just under 5 psi. So all is good.

but at 5 psi you start to hear what sounds like air (like tube rush) in your midrange driver. YES
It is not a mechanical piston type noise, or drone like noise - it is the sound of air - maybe like air escaping ?

NOT MECHANICAL OR PISTON NOISE OR DRONING, JUST THE SOUND OF AIR, LIKE AIR ESCAPING. SIMILAR TO THE AIR SOUND YOU HEAR WHEN INFLATING CAR TIRES FROM AN AIR TANK WITH NO COMPRESSOR, BUT SOFTER.

It gets louder to 7 psi and then stays the same to 17 psi. RIGHT. MAYBE SLIGHTLY LOUDER AS PRESSURE IS INCREASED.

try something - with your system on mute and the ET2 raised and at rest.
crank the PSI up all the way to 21 and put your ear right next to the ET2 manifold- do u hear any sounds like a balloon with a leak ?

DID THIS AND FOUND OUT THAT THE AIR INLET NOZZLE WAS LOOSE WHERE IT SCREWS INTO THE ARM HOUSING. HAD TO TURN IT 180 DEGREES TO TIGHTEN. NOW AIRLINE FORMS A U-CURVE BETWEEN ARMBOARD HOLE AND INLET NIPPLE. LOOKS FUNNY BUT WORKS. NO MORE AIR LEAK THERE. WILL ASK BRUCE ABOUT THIS.

If yes is there air coming from a bolt ?

I STILL HEAR A VERY,VERY FAINT AIR NOISE FROM AROUND THE BEARING AREA. TIGHTENED BOTTOM VTA ADJUSTMENT BOLTS TO SEE IF ANY EFFECT , BUT NONE. CHECKED OTHER BOLTS QUICKLY. I BELIEVE THE REMAINING AIR NOISE IS COMING FROM THE BEARING ITSELF, BUT IMPOSSIBLE TO TELL FOR SURE.

Try wiggling the tube at the input nozzle around. It would be shame if a great pump system and that connection at the plug is not tight. If there is a leak at the plug - pull the plastic out - cut an inch off so the plastic is tight and fresh - re-insert. TUBE WAS TIGHT BUT NOZZLE WAS LOOSE - SEE ABOVE.

Is there significant air coming from the manifold where the spindle enters and exits? You will feel the air coming out with your finger near both ends. NONE DETECTABLE AT ~3PSI BUT DEFINITELY FEEL AIR ESCAPING AT EITHER END OF THE BEARING HOUSING AT 7+psi - MORE AS AIR PRESSURE IS INCREASED, BUT NO "KICKBACK" OF ARM AT END OF TRAVEL AS OTHERS HAVE REPORTED.

With the info you provided it sounds to me like the HP manifold would fix this as its lungs are designed to inhale the higher PSI. SURE HOPE SO!

Frogman uses the 0910 and says that it does a great job with this HP 2.0 bearing at 17psi.

Frogman provides clear support for the HP ET2 model with the same pump.

It is very easy to spend other peoples money :^)

FROGMAN IS AWESOME!

Since you are hearing benefits of the higher pressure - but you have a stock ET2 it makes sense to me to do it, if you feel its worth it? Bruce charges a reasonable amount for both upgrades ? Making the ET2 HP or by using his magic to transform the ET 2.0 into the 2.5 HP. As you said this would take a few weeks. I WILL CALL BRUCE TOMORROW TO CONFIRM THAT MY ORDER IS STILL IN QUEUE. SURE WOULD BE GREAT IF HE MAGICALLY FOUND A 2.5 BEARING ;^)

Some input from the others?

I recently called VPI about the leakage issue and they sent me some modified round rubber bushings to place around the outside of the schrader valve so that it seals the metal cap to the corner pods. Seems to be working great so far.

What a great service company. I bet they didn't charge you for those either, and if they did a very nominal charge.

THEY CHARGED $2.50 FOR A SET OF FOUR. ALSO GOT NICE PLUGS TO FILL THE HOLES IN THE TNT'S PLINTH WHERE THE TRI-PULLEYS WERE FOR $5 EACH.

I saw a set on "that auction site" for 400 bills. They show some deformation on the top. For that price, I would want an audible improvement over the air bladders in addition to eliminating the aggravation of maintaining level. Any opinion on that?

http://www.ebay.ca/itm/Audio-Technica-AT616-Pneumatic-Suspension-Audio-Insulator-4-pcs-/321244326789

THAT'S THEM

Probably 500 by the time they get to you.
I don't know what to say - everything in this crazy hobby just keeps going up in price.
What you see in the picture may be marks only and not an actual indent.
The seller can verify this.
Sounds like your VPI fix is working so I would hold off. I'd put money into the manifold ? RIGHT. MAYBE ALSO A NEW AUDIO NOTE WIRE LOOM PER FROGMAN. MY AYRE PHONOLINEPREAMP HAS XLR INPUTS FOR THE PHONO STAGE. WOULD LIKE TO GET THE BENEFIT OF THE DIFFERENTIALLY BALANCED CIRCUITRY AND ELIMINATE THE RCA TO XLR ADAPTERS I AM USING NOW AS WELL AS THE ARMWAND PLUG, ET RCA JACKS AND INTERCONNECTS (ALTHOUGH THEY ARE VERY GOOD ONES).

THANKS CHRIS! MUCH APPRECIATED.

DAVE

Re "escaping air". Even with the HP bearing/manifold there will be air escaping from the ends of the bearing. In my case you hear it only when the arm is at either end of its "trajectory"; and certainly cannot be heard when music is playing. IOW, you hear the air when it escapes and then has either the rear end cap or front elbow to make contact with. In general, the sound of a small amount of air escaping is normal, subtle, and should not be surprising. Chris is correct about the issue of pressure at the pump vs that at the arm, but the Medo 0910 is conservatively rated and actually outputs closer to 30 psi, so achieving 17-19 at the arm should not be difficult. Dave, you will be very pleased with the HP manifold and Medo; it is not a subtle difference. Keep us posted.