I would follow the suggestions of
@automojo from this thread you started. He has done a lot of experimenting with them. I have a pair of AMT4s, and used to have AMT1s and the AMT 1a Monitors. Very addictive speakers.
Why would you spend $100+ dollars to recap a speaker with blown tweeters? Tweeter needs new foil? I am not sure on this, but I think putting a new diaphragm on a Heil is expensive? Others might chime in one this. You didn't answer my question, do both speakers do it? I hate to disappoint you...
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I read in the other thread that you are getting a noise in places of the higher frequencies. That sounds suspiciously like the diaphragm is failing.
new diaphragms the factory part number is 689-1108 for the AMT4, for sale at a few places online ($80-$90)
I got this from another older thread. It might be worth investigating if it is the AMT and when it happens. Ie) the song part that is causing these sounds, or is it continuous?
Agreed. They can also be 'half blown'-low output/noisy. Make sure the fuse is not by-passed and correct value. Should be a fast blow as well.
FIY-esp if these are older diaphragms-you should plan on getting 2 new ones. Otherwise they most likely will have different output levels,
These can be excellent sounding-take time/care to set the mid/high levels correctly. Most time this is a set and forget.
My MOJO modded 3's have l-pads for both Heils and trans driver(here a Alpha 6A).
The trans driver is barley on to create the proper balance-Heil 1/4 on.
As far as caps-Janzten Superior Z's would be my first choice. The woofer caps-Jantzen El's-electrolytes are fine here-save your $ for the Heil caps.
Resistors Mills-or the new Dayton Audio DPR's.
FIY-the Mills have a slightly smoother sound-that works perfect with the Heils/ESS speakers.
IMHO-the DPR's work better/darn near perfect for fabric dome tweets.
Why they sound different-I don't know-but they do!.
Another cap choice-cap I like but have not used with Heils-are the Clarity Cap CSA.
They are less expensive.
Frankly if I went CSA-I would go 80% CSA/20% Jantzen Alumen's.
The mix works awesome for Infinity Emit's-so probably with Heils as well!!
Just IMHO.
I would lean towards the Jantzen Superior Z's if you can swing it$$
Otherwise the Clarity CSA should be more then fine.
Make sure the woofer is sealed properly as well. PE foam speaker tape is perfect.
