Sorry, but I am not aware of anyone besides Roy that is both qualified and in possession of the correct parts for Acoustat interface repairs. And quite frankly, the cost of shipping will likely be small compared to the cost of doing any repairs and/or upgrades. Transit time for UPS Ground is rarely more than 5-6 days for coast-to-coast.
![spectra_sectors[1].jpg](/community/data/attachments/342/342639-ed9a5c3f22aaa64b9de5858e3244bb72.jpg)
The BLUE group of wires is for the rear stator, and the WHITE group is for the front stators. Besides the color coding, it's easy to look at the edge of the panel where the wires exit, and it should be obvious which are the front and rear stator wires. The RED wire, of course, is the diaphragm bias connection.
Spectra panels CAN be used as a subsitute for the older, non-Spectra panels, but not vice-versa. All Spectra panels are 9" wide, whereas some of the inner panels on the older models are 8" wide, so the Spectra panels can only be used as direct replacements for 9" panels.
For example, your current three panel Monitor has two outer 9" panels, and one inner 8" panel. But nothing says you can't add another 9" panel to the array to make it a quasi-Monitor Four.
You'll probably want to change the low frequency transformer tap, from its current ORANGE position (for 3 panels) to the YELLOW position (for 4 panels).
I have done this mod years back..................it dose make a diff in the sound...littel sweeter....if you get the right cap?? not a lot of 5-6k caps just laying around!...
An moray,s Chok mod works well also........
But For me the best mod anyone can do with the 121 Acoustat interfaces....is to re-new all parts in the bias !......thay all are over 25years old now an on all the time........the bias can make are brake the sound of any ESL ...........Bias,Bias,Bias.....people are funny...thay spend $200.or more... on caps in the crossover...but wont spend $40-60 for new bias parts.....an the setup on the stock board is alway low............
i have had 3-4 pr interfaces....all were at about 3-4k at best...you can just addone are two more diodes an caps to the bias an get it back up.....there info here on this site on just how too do this...
The best mod i have done to my Acoustats in to pull the bias out of the mixer....an i now can set my bias from ....3-7k....My Acoustat sound better now than any mod ever done to the bias...................good luck.......have fun....
Long live Acoustat
An moray,s Chok mod works well also........
But For me the best mod anyone can do with the 121 Acoustat interfaces....is to re-new all parts in the bias !......thay all are over 25years old now an on all the time........the bias can make are brake the sound of any ESL ...........Bias,Bias,Bias.....people are funny...thay spend $200.or more... on caps in the crossover...but wont spend $40-60 for new bias parts.....an the setup on the stock board is alway low............
i have had 3-4 pr interfaces....all were at about 3-4k at best...you can just addone are two more diodes an caps to the bias an get it back up.....there info here on this site on just how too do this...
The best mod i have done to my Acoustats in to pull the bias out of the mixer....an i now can set my bias from ....3-7k....My Acoustat sound better now than any mod ever done to the bias...................good luck.......have fun....
Long live Acoustat
I'll be honest and say that I am not a fan of any chnges to the bias supply other than replacement of existing parts with identical parts.
The modification shown probably won't hurt anything, but I'm not sure that it will improve the sound, either. Your mileage may vary. Note that the extra capacitor is connected before the 500-megohm resistor. Connecting it after the resistor (as some people have erroneously done) will violate the constant-charge principal of the speaker and will certainly decrease the linearity of the system.
One caution: the capacitor shown will retain significant charge after the power is shut-off, so the usual advice to carefully discharge the power supply is especially important. Otherwise it has the potential (pun intended) to give a MUCH nastier shock than the stock power supply.
Just got these Spectra 3s in the pic......... can someone give me any info thay may have on this Acoustat....i think there the frist.Spectra ?..........
Can thay be ran fullrang.??........... dose the... looks like a 10"bass driver have to be used?....it faces down............I have the .Spectra 33 setup in the pic..........is it this same setup??...
cant seem to find much on the web........about theses..
i only have info from the saler..........an thay have know idea what these are...
i paid $400. for the pair....i can always use more panels..
.
Thanks for any an all info on Acoustats............
long live Acoustats
Can thay be ran fullrang.??........... dose the... looks like a 10"bass driver have to be used?....it faces down............I have the .Spectra 33 setup in the pic..........is it this same setup??...
cant seem to find much on the web........about theses..
i only have info from the saler..........an thay have know idea what these are...
i paid $400. for the pair....i can always use more panels..
.
Thanks for any an all info on Acoustats............
long live Acoustats
Attachments
![00404_fnNi6JbdG1S_600x450[1].jpg](/community/data/attachments/345/345524-d053f09e69dd766e9326b63763c73013.jpg)
![spectra33[1].JPG](/community/data/attachments/345/345545-1300c496c26724208254d383236cbc51.jpg)
Congratz to a nice purchase. Maybe you can complement your panels with an OB line bass array. I'm building one to use with my Spectra 11's and think it will work very well. For the lowest range I use twin subs.
Yes look like a great bass set...........i have two 12"subs ..........
looks like jim put all the goods in the Spectra 2-3s....10" woffer bi-pass.....or bi-wire-bi-amp....an then with the Spectra 22-33 you had to add the subass............i gess the funky look did not cut it.........ezy to make a frame like the Spectra 33
...thanks
looks like jim put all the goods in the Spectra 2-3s....10" woffer bi-pass.....or bi-wire-bi-amp....an then with the Spectra 22-33 you had to add the subass............i gess the funky look did not cut it.........ezy to make a frame like the Spectra 33
...thanks
Attachments
![AcoustatSpectra3303_zpsc23ca386[1].jpg](/community/data/attachments/346/346660-f437c1718ebc85cd6836133febd31e91.jpg)
![525449796_tp[1].jpg](/community/data/attachments/346/346662-85a3cf711bf1359091b28ecab6650709.jpg)
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Yes, the model shown is the Spectra 3. Along with the 2-panel Spectra 2, these were Acoustat's first Spectra models. They can be run full range or as a hybrid with the enclosed woofer. There are switches on the bottom of the woofer enclosure for selecting these options. Electrically, these models are the same ESL's as the later Spectra 22/2200 and 33/3300. The only difference is the built-in woofer. These models did not sell well due to the higher cost and the cosmetics were not to everyone's liking. The later Spectra models were much more popular.
The tambour wood on the front of your speaker appears to be the 'teak' option. Several other real-wood finishes were available. Those woofer cabinets were a real bitch to build!
Thanks for all your feedback.............
this speaker dose NOt have the wall -tranfourmer........
so i gess its the same type of Bias setup as my 121 interfaces??
these have a fix 3 prong plug comeing out of the back................So when ran fulrang it looks like the one ohm res.........is all thats in the input before the tranfourmer......Dose that 1ohm need to be there if the caps are removed?
long live Acoustat
this speaker dose NOt have the wall -tranfourmer........
so i gess its the same type of Bias setup as my 121 interfaces??
these have a fix 3 prong plug comeing out of the back................So when ran fulrang it looks like the one ohm res.........is all thats in the input before the tranfourmer......Dose that 1ohm need to be there if the caps are removed?
long live Acoustat
Attachments
![spectra33[1][1].JPG](/community/data/attachments/350/350769-1300c496c26724208254d383236cbc51.jpg)
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Early Spectra models did not have the Ultrasonic bias power supply. The line-powered bias supply is exactly the same as used in the MK-121 series.
YES, the 1-ohm resistor should remain in-circuit regardless of switch settings. Same as the 1-ohm resistor in the MK-121 series, its pupose is to keep the extreme LF impedance above 1-ohm.
Got it ...thanks
Got most of what you......... an others posted on the TAC....................all panels work.......one speaker has a lower output than the other...........but plays fine..so looks like the tranfourmers are fine......
i well have to get in...an ck the res....an caps in the secdary side...an i well ck the bias frist..
i have my outboard bias setup..........for my 121 ......
an re-work the bias with all new parts...diodes an caps...........
can you say how the parts are monted .......are thay all on the plate?
like the 121............
long live Acoustat....
Got most of what you......... an others posted on the TAC....................all panels work.......one speaker has a lower output than the other...........but plays fine..so looks like the tranfourmers are fine......
i well have to get in...an ck the res....an caps in the secdary side...an i well ck the bias frist..
i have my outboard bias setup..........for my 121 ......
an re-work the bias with all new parts...diodes an caps...........
can you say how the parts are monted .......are thay all on the plate?
like the 121............
long live Acoustat....
I'm posting to share a piece of information that Roy Esposito gave me via an email exchange that I haven't seen mentioned anywhere on the net and I figure here is as good as anywhere to post it. I wrote him to ask about the Medallion mod because I had my (1980? with the fake woodgrain) Model 3 interfaces modified as soon as the mod was released and they came back with brown paper on the transformers rather than the black that has been said is the colour of Medallion transformers. Roy said that some of the early Medallion transformers were brown which was a relief as I was questioning my memory. As further indication of the era of my mod, the C-mod didn't get performed at this time, but my boards have the 5 stage hi voltage daughter board which I think may have been done at the same time, but I'm not sure if they didn't come originally like that.
All of the bias supply and audio step-up components are mounted on the metal plate underneath the woofer enclosure. Remove the screws, disconnect the internal wires, and you're in. You will find the transformers and HV circuit board to be identical to later full range Spectras.
I don't remember where the woofer crossover components are mounted: some of them may be on the metal plate, but other parts (such as the coil) may be mounted directly on the woofer cabinet. There might also be a component (like a resistor) mounted directly on the woofer terminals. Sorry, but it's been a LONG time since I looked at a Spectra 2 or 3!
The information regarding the transformers' paper wrapping is contrary to my own memory (and I was there, but Roy wasn't). As best as my memory serves (and it ain't perfect) all of the transformers used in the Medallion upgrade program had black wrappers on the two audio transformers. At the very end of the MK121 production run, some of the Medallion transformers had brown wrapping, but this was considerably after Acoustat moved to Arizona.
The early Medallion upgrade program did not include the C-Mod. This modification was developed at a later time. Some owners, who got the original Medallion upgrade, opted to send their interfaces to Acoustat a second time to get the C-Mod added. Those who waited got the C-Mod included with the Medallion upgrade.
A number of other things were upgraded along with the Medallion transformers, depending on the vintage of the interface. Some of the earliest units got a new bias transformer, along with a change from a 3-stage to a 5-stage voltage multiplier. There were also quite a number of the 0.01-uF capacitors upgraded to polypropylene.
All modified interfaces were identified with a 'Medallion' label on the outside of the interface, although after all these years, it's possible some of those labels have fallen off. If the label has BLUE lettering, the interface contains the Medallion transformers but NOT the C-Mod. If the lettering is RED, then the interface contains both the Medallion transformers AND the C-Mod.
If all of this leaves you in doubt as to what you have, take a look for a part number on each the two larger transformers. If it has a number beginning with '200' is is definitely NOT a medallion transformer. The '200' series number indicates manufacture before the acquisition by David Hafler. The Medallion program did not start until after the Hafler acquisition.
Thanks Andy. The plot thickens. I'm sure I didn't get a sticker on the back when I got them back from modification. Was the daughter board for the 5-stage HF only used during Medallion modifications or did they come from the factory pre-Medallion like this? My 0.01uF caps are the brown paper with black epoxy ends. I wasn't able to find any numbers on the transformers without unmounting them. I'll do that tonight.