Why are the interfaces not grounded?

[HankF]

The interfaces (121-A) on my Model 3's that I bought a few months ago have a 2-wire power cord. Does anyone know why these things are not grounded?

 

[DUG]

They don't need the gnd wire if they can pass tests for higher isolation voltage.

I am not sure of the numbers but it is something like 2500V instead of 1750V.

Someone in the CSA or CE community could answer this one better.

 

[tyu]

Well.......we are talking about ...earth...right....we can look at some esl bias setups.....looks like the Acoustat 121s.....jim did it right thing to get full out put out of the panels.....an even ML used the earth on the bias on the center tap of the setpup trans...........then thay stop!

I have allways like the earth out of most audio paths for better sound for over 30 years.......but i have found with ESLs...if the bias an center taps are not earth.....the highend gets pulled down...an the bias is all over the place....an a littel rain an the ESL drops out put by as much as 3db.....i have found living in the south......if earth is in.....maybe only 1db is lost...

All esl panels leak......Acoustats panels are about as good as it gets....

When there is NO earth in the mixs......this leakegs in panels pushes back on the bias ....from the secdary windings an out the center tap to the bias.... that feed the front an back of the panel....an lets the mylar pull closer to the front are back of the panel

So you lose some push or pull.....an this rolls the top down...

when the earth in the mix.....the secdary winding in the stepup tran are held tight....an cant push back on the bias...much better bal ....an you get more output..... an the sound is better becase you get all the topend back....an the top end output well make or brack the sound of the esl.....well for me

As for my earth setup i have it in my audio room.....the earth rod comes right out of the floor....an is used for nothing but my ESLs

Long live Acoustats.....

 

[HankF]

tyu, I see you have grounded the T1, T2 and T3 secondaries and M-L grounds their tranny secondary and it appears Acoustat grounded the Spectra tranny secondary. Also, it appears you've grounded the shield of T1 - why? Also are those the only ground connections to your power cord ground wire? Did you not ground the interface enclosure? Please keep it simple, as I'm not an engineer.

 

[tyu]

Here a pic of the Acoustats 121 interfaces.... green wire in the back of the pic..........come in an gos to the metel box... then to the bias board where the cen taps are... all stared there... ones that look like this...thay all have 3 prong plugs....
yours had some mod??...i gess ...some times maybe....??/
.post a pic....good luck

 

[HankF]

Yep, it appears that the original owner for who knows why, replaced the 3-wire power cord with the current 2-wire cords. Go figure. I will go with 3-wire and ground as the originals were.

 

[AcoustatAnswerMan]

The interface should be earth-grounded, but ONLY for safety reasons. The line cord's ground wire should be connected directly to the chassis in the unlikely event that a high voltage should come into contact with the chassis. Other parts of the circuit should be chassis-grounded per the original schematic (which will vary with model). If the chassis is not grounded, then a shocking potential could exist on the metal case under fault conditions.

The earth ground has no impact whatsoever on the audio performance.

 

[tyu]

"The earth ground has no impact whatsoever on the audio performance." .......

I gess it has a inpact only on the Audio performance of all the Acoustats an other ESL i have......i dont like the sound of the chassis Earthet.............just the center taps an bias board.....just saying

HankF......
Can you tell us what your 121 interface box with the two prong plug Mod is ???
post a pic.......................
Long Live Acoustats..........

 

[tyu]

If your ESL....stepup.trans...cent tap..........has no Earth.....you well never get FUll output....yes NO maybe???......how will the mylir ever be in the center......hehe....
anyone....What do you know i dont??
i know your on....... your i phone ...or your ......texing........

If i lived where there was only 30-50 % humit.....all may be good...................................but here i got 70-80% all the time.....like 300 days a year...............an i wont my ESLs......to give me the output of my B&w 801s..........................................
Dont you??........
here the amp to drive any ESL.............if it has NO fan.......it is week at best.....over 30 years driveing....or trying too....drive ESLs.......an $100k on amps.................QSC pro amp....are Kings....what a give away................

long live Acoustats...................

 

[DeltaStar]

I always thought that the better the ground, the cleaner the sound

 

[ticknpop]

The ML CLX has an IEC type AC input connector which takes regular and after market AC line cords, but has NO connection to the AC ground on that connector.

 

[tyu]

Yes i posted that fact.............ML earth the CLS...an others....then thay stopet
thay use the amps neg leg on the centap with one side of the bias tran.....i have seen Volts on the binding post with there setup....if the panel vary leeky...i dont like that much.....so on the logan i use the earth now not the neg amp in the panels setup....
i have earth just the center tap on the stepup tran in my logans.....sound is much better an less blur to the sound an i get better output.....
When jim Strickland went to his new bias....Acoustat only had two bias i have ever seen.....looks like he made his neg earth ground type out of diodes ....it only has two prong plug in a wall wort that sends 12-15Vdc to the board......but my Spectra 3s.... i have the frist bias..just like in the 121...i have floted the chassis an put 500ohms from the earth center tap to the bias board............sounds much better....better base an topend...out of the panels...
an now i well be earthing my Specta11 that has the new Acoustat bias setup......