This is how I test my vinyl setup for Structure Feedback and my ET2 (2.5) Pump for Noise and Vibrations.
I am interested to know what techniques others use. I’d like to learn different ways of doing this.
TEST FOR STRUCTURE FEEDBACK
Some people think that direct sound waves affect our cartridge. Some people put plastic shields around their turntable. If you think that direct air waves really affect your cartridge “trying yelling at your cartridge and see what happens” infamous quote from Audiogon user Halcro.
Can you hear yourself through your speakers when you do this?
Henry – if you see this I hope you don’t mind me quoting you.
My test for structure feedback is to set up the TT on mute and lower the stylus onto the lead in groove. Record not spinning. Unmute the phono and turn to a level that is considered high for your room.
Start jumping up and down right beside your TT. Pretend you are dancing with your spouse. Actually invite her/him in and jump together with no music. Just be prepared she may ask you to boogie to real music later as she gets warmed up. If your setup survives this test you should be good to go.
TESTING THE PUMP for NOISE and VIBRATIONS.
This test should actually be good for any air bearing linear tracker that uses a captured bearing like the ET2 and ET 2.5.
No jumping this time just listening.
Same as the above in regards to muting your phono with a still record and unmuting but with a BIG difference.
1st – DO NOT turn on your pump and lower your stylus onto the lead in groove. Unmute and turn the volume up. Listen to how quiet it is. When finished mute system and raise the ET2. I say raise the ET2 because I don’t know how good your pump and setup is. More on this later.
Now have a friend turn on your pump and repeat the above procedure and lower the stylus again. Is there any noise in the background now that has been transmitted down the airline into your system that was not there before?
Is it the same level of quietness, or is there now a little more background noise with the pump on. If you are using a regular aquarium type pump and no surge tank you will hear differences. For those with good pumps and a properly setup ET2, ET 2.5 there is no need to raise the stylus or unmute after listening with no pump. Have the friend turn your pump on and off while you have your ear on one of the speakers.
If you are introducing noise with your pump down the airline you are not hearing what the ET2 can do. The sound is being glazed over by air noise vibrations from the pump.
I came across this years ago – maybe 8? by accident. I had an actual small ground hum type noise and could not for the life of me figure out how to solve it. I tried for two days. I could just hear the pump at the time in the other room running faintly. It was a Medo AC110.
Finally after a couple of days of trying to fix the problem, I unplugged the pump and I tried the above test. No more noise. Damn! I substituted my backup Medo pump at the time and all was quiet again. The bad pump was still delivering PSI but had a piston problem sending noise and vibrations down. I also found back then that a long run of air tube coiled up also helps to minimize the vibrations.
I didn’t discover the above problem until I had swapped in cartridge, wires, amps, preamps, speakers first ! That set me on my pump journey the next few years and I ended up with the pump I use now.
So how do you guys test for structure feedback and airline noise/vibrations with an air bearing?
Cheers.
I am interested to know what techniques others use. I’d like to learn different ways of doing this.
TEST FOR STRUCTURE FEEDBACK
Some people think that direct sound waves affect our cartridge. Some people put plastic shields around their turntable. If you think that direct air waves really affect your cartridge “trying yelling at your cartridge and see what happens” infamous quote from Audiogon user Halcro.
Can you hear yourself through your speakers when you do this?
Henry – if you see this I hope you don’t mind me quoting you.
My test for structure feedback is to set up the TT on mute and lower the stylus onto the lead in groove. Record not spinning. Unmute the phono and turn to a level that is considered high for your room.
Start jumping up and down right beside your TT. Pretend you are dancing with your spouse. Actually invite her/him in and jump together with no music. Just be prepared she may ask you to boogie to real music later as she gets warmed up. If your setup survives this test you should be good to go.
TESTING THE PUMP for NOISE and VIBRATIONS.
This test should actually be good for any air bearing linear tracker that uses a captured bearing like the ET2 and ET 2.5.
No jumping this time just listening.
Same as the above in regards to muting your phono with a still record and unmuting but with a BIG difference.
1st – DO NOT turn on your pump and lower your stylus onto the lead in groove. Unmute and turn the volume up. Listen to how quiet it is. When finished mute system and raise the ET2. I say raise the ET2 because I don’t know how good your pump and setup is. More on this later.
Now have a friend turn on your pump and repeat the above procedure and lower the stylus again. Is there any noise in the background now that has been transmitted down the airline into your system that was not there before?
Is it the same level of quietness, or is there now a little more background noise with the pump on. If you are using a regular aquarium type pump and no surge tank you will hear differences. For those with good pumps and a properly setup ET2, ET 2.5 there is no need to raise the stylus or unmute after listening with no pump. Have the friend turn your pump on and off while you have your ear on one of the speakers.
If you are introducing noise with your pump down the airline you are not hearing what the ET2 can do. The sound is being glazed over by air noise vibrations from the pump.
I came across this years ago – maybe 8? by accident. I had an actual small ground hum type noise and could not for the life of me figure out how to solve it. I tried for two days. I could just hear the pump at the time in the other room running faintly. It was a Medo AC110.
Finally after a couple of days of trying to fix the problem, I unplugged the pump and I tried the above test. No more noise. Damn! I substituted my backup Medo pump at the time and all was quiet again. The bad pump was still delivering PSI but had a piston problem sending noise and vibrations down. I also found back then that a long run of air tube coiled up also helps to minimize the vibrations.
I didn’t discover the above problem until I had swapped in cartridge, wires, amps, preamps, speakers first ! That set me on my pump journey the next few years and I ended up with the pump I use now.
So how do you guys test for structure feedback and airline noise/vibrations with an air bearing?
Cheers.