ESS AMT Heil Ribbon Tweeter without Model Number (used in ESS PS9a)

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tiefbassuebertr

tiefbassuebertr

Member
Joined 2005
tiefbassuebertragung.de
This tweeter needs service. Who knows the model of this tweeter? It is in use by follow ESS speakers
ESS PS9A speakers pair with air motion transformer tweeters Photo #219772 - Canuck Audio Mart
and
http://i.ebayimg.com/00/s/MTIwMFgxNjAw/z/8KoAAOSwoydWqRNJ/$_1.JPG
Here pics of the tweeter itself:
http://img.canuckaudiomart.com/uploads/large/86840-ess_heil_ps5a_speakers.jpg
http://bilder.hifi-forum.de/medium/178783/ps8a_244986.jpg
There are no informations under
Heil AMT – ESS Labs., LLC
Maybe it is the predecessor of the AMT-2 - go to
LSV Dieter Achenbach
If I have the model number, I hope to find the instruction manual for disassebmly and reconing.
Thanks for your advices.
 
Thatch_Ear

Thatch_Ear

Member
Joined 2001
What is wrong with it? I think if it is open in front and back there is only one size diaphragm in differing resistance for Xovers. Later there were 2 sizes, but the shorter ones were only for front firing AMTs. I think now you can only get them from Germany and won't be cheap. Try the search.

Thatch
 
tiefbassuebertr

tiefbassuebertr

Member
Joined 2005
tiefbassuebertragung.de
Thatch_Ear said:
What is wrong with it? I think if it is open in front and back there is only one size diaphragm in differing resistance for Xovers. Later there were 2 sizes, but the shorter ones were only for front firing AMTs. I think now you can only get them from Germany and won't be cheap. Try the search.

Thatch
Click to expand...
One devicve has too low efficiency. The question is, which steps are to perform for opening/dismanteling for replace the diaphragm. To find out this I must have an instruction manual. To order or find such an instruction manual, I must know the exact model naming. Therefore the quesstion in post #1.
 
V

VaNarn

Member
Joined 2010
Paid Member
Originally the Heil AMT units were only sold as complete speaker systems by the ESS company.At one stage the only model description given indicated the effective area of the pleated diaphragm as being twenty one and a half square inches or as ten and half square inches. In Post #3,Thatch-Ear has supplied the link to Simply Speakers and they list 3 diaphragms from the re-established ESS factory together with their dimensions and the speaker systems that used them.I would suggest that you remove a diaphragm and measure its' dimensions to confirm the physical size as it does pay to be cautious,and order a replacement to suit.
 
R

rherber1

Member
Joined 2004
This thread is a bit old now so maybe nobody is watching. Oh well, here goes...

I am refurbishing a pair of PS9A's and one of the AMT diaphragms is open circuit (how it got this way is another story). The good AMT diaphragm measures 6.2 Ohms DCR.

ESS Labs has the correct sized diaphragm for the tweeter but the DCR quoted for it is only 3.7 Ohms https://essspeakers.store/collections/heil-amt/products/ess-amt-heil-speaker-diaphragm-689-1109

If anyone has a pair of PS9A I wonder if you can measure the diaphragm DCR and let me know what you measure.

I am afraid that if I go ahead and order a new diaphragm the 4 Ohm impedance will not match the x-over - which I think may be designed for a 6.2 Ohm AMT. Unfortunately there apears to be little information around for this speaker and its x-over schematic. Any pointers and assistance would be appreciated.
 
M

mdpaudio

Member
Joined 2014
At one point in time they did make 8 ohm units but that was a long long time ago. They moved to all 4 ohm diaphragms and don’t make the 8s anymore. You might get lucky and find one on the bay. Or you’ll have to change both and the crossovers too! Yes, it sucks!
 
M

Marveloudio

Member
Joined 2004
You can purchase a single 4 Ohm replacement and add a series resistor to match the impedance!

Buy 2 replacements , add resistor to each and you have a good chance to get a low-tolerance twin pair for good stereo performance! (localisation of center voice exactly in the middle in a near perfect symmetric layout ....)

good luck
 
R

rherber1

Member
Joined 2004
Marveloudio said:
You can purchase a single 4 Ohm replacement and add a series resistor to match the impedance!

Buy 2 replacements , add resistor to each and you have a good chance to get a low-tolerance twin pair for good stereo performance! (localisation of center voice exactly in the middle in a near perfect symmetric layout ....)

good luck
Click to expand...
I think adding a series resistor is the wrong way to go. Yes, you may well approximate the 8 Ohm resisistance of the original diaphragm, but half the power to the tweeter will be wasted in the added resistor and not appear at the diaphragm where it is needed.

I found the x-over schematic for the PS-9A and it is a simple 1st order 0.16mH inductor to the 8" woofer and a 2nd order consisting of a series 5uF capacitor and parallel 0.24mH inductor to the heil tweeter. Maybe just a slight increase (or decrease) to the parallel inductor is all that is needed.

I am open to suggestions from those more experienced in x-over design.
 
M

Marveloudio

Member
Joined 2004
rherber1 said:
I think adding a series resistor is the wrong way to go. Yes, you may well approximate the 8 Ohm resisistance of the original diaphragm, but half the power to the tweeter will be wasted in the added resistor and not appear at the diaphragm where it is needed.

I found the x-over schematic for the PS-9A and it is a simple 1st order 0.16mH inductor to the 8" woofer and a 2nd order consisting of a series 5uF capacitor and parallel 0.24mH inductor to the heil tweeter. Maybe just a slight increase (or decrease) to the parallel inductor is all that is needed.

I am open to suggestions from those more experienced in x-over design.
Click to expand...

Intelligence waits for nobody! Obviously your are heavily underengineered in your mind!

Remember there are always 2 options in life to decide , but sadly it will be too late to return if you recognize your decision was wrong because you are undereducated and not willing to accept a good advice ....

never mind!
 
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rherber1

Member
Joined 2004
Further to my Post #8 I decided to bite the bullet and order a pair of diaphragms for the PS-9A from ESS (part 689-1109). The first shipment arrived with only a single diaphragm, plus a complimentary pair of one of their non-selling headphones (which I don't want). After voicing my concern over the apparent oversight ESS made a second shipment containing the missing diaphragm. This must have cost them a pretty penny to make 2 shipments to Australia when only 1 was required (poor supervision in the despatch department?).

Today I finally got round to commencing the replacement so I pulled one of the new units out of its clear packaging and noted that the leads had a label saying "6.3". Upon measuring the DCR of this diaphragm I was surprised to find that it was indeed around the 6.3 Ohms mark. I then checked the second unit (which wasn't labelled) and it also measured around 6.3 Ohms.

Now the ESS website says this diaphragm measures 3.7 Ohms DCR (nominally 4 Ohms impedance) but that is obviously incorrect. I then checked the resistance of the original diaphragm in the still working PS-9A and guess what - it also measured around 6.3 Ohms. So while ESS are advertising the 689-1109 as nominally 4 Ohms I think they are mistaken. The supplied diaphragms appear to be the same as originally fitted to the PS-9A in the factory. It looks like I do not have to play around with the crossovers at all.

Now I have a spare diaphragm.....
 
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