Thanks Andy.......... for more great info on Acoutats!
separate the two MK-121 trannies to their own separate panels (on a 2+2) run thru an active crossover - biamped...and bypassing the mixer circuit altogether - like Soundlabs...anyone do this yet?
John65b
Yes i have done this setup........... where just the 121 tranfourmers......drove just the panels.........two panes with the bass tranny........one panel for the high tranny..all 9" panels only like a pr of M3s.........No crossover at all !............bass 2 ohm on the neg input.
an 2 ohms on the high frc tranny primary +.............work well...sound great...
Moray even gave it a try.......an i think though sounded right?......
but he can speak for him self..............this was years back...
All soundLab ESLs have mixers...........just caps.......same as i use in my 121....0.015....
Thay dont need any bass res.........the panels sound dARK As it is....an would just eat More power............there like driveing a Dead short as is......just what i have found...
SoundLabs can sound good played low.......but i need output....Acoustats King..high out put ............get the bias right an 50 tubes watt work well........in the pic 1 this are not stock trannys but you can see the setup with out the 50kres......pic 2 SL crossover....pic 3 ....5 is the poted SL mixer..........just the caps in a box....i would think poting the caps would roll off some highs....???
Also i have ran the 121c stock setup.......... with out the 50k res in the mixer.. just like the SL setup.....get more output......work vary well .......
some like it better......sounds to me like theres less delay...an vary flat.....the res sound almost like a Loadnes buttem.........to me!
Long live Acoustats............
separate the two MK-121 trannies to their own separate panels (on a 2+2) run thru an active crossover - biamped...and bypassing the mixer circuit altogether - like Soundlabs...anyone do this yet?
John65b
Yes i have done this setup........... where just the 121 tranfourmers......drove just the panels.........two panes with the bass tranny........one panel for the high tranny..all 9" panels only like a pr of M3s.........No crossover at all !............bass 2 ohm on the neg input.
an 2 ohms on the high frc tranny primary +.............work well...sound great...
Moray even gave it a try.......an i think though sounded right?......
but he can speak for him self..............this was years back...
All soundLab ESLs have mixers...........just caps.......same as i use in my 121....0.015....
Thay dont need any bass res.........the panels sound dARK As it is....an would just eat More power............there like driveing a Dead short as is......just what i have found...
SoundLabs can sound good played low.......but i need output....Acoustats King..high out put ............get the bias right an 50 tubes watt work well........in the pic 1 this are not stock trannys but you can see the setup with out the 50kres......pic 2 SL crossover....pic 3 ....5 is the poted SL mixer..........just the caps in a box....i would think poting the caps would roll off some highs....???
Also i have ran the 121c stock setup.......... with out the 50k res in the mixer.. just like the SL setup.....get more output......work vary well .......
some like it better......sounds to me like theres less delay...an vary flat.....the res sound almost like a Loadnes buttem.........to me!
Long live Acoustats............
Attachments
![2bInCkt[1].jpg](/community/data/attachments/350/350715-a549ea59dec35fd6a63fad11939fa352.jpg)
![crossover-15B15D%5B1%5D[1].jpg](/community/data/attachments/350/350735-3805a1e7fc055e2a4d41a3eaab558f37.jpg)
![sound_lab_a-3_backplate_parts_id%5B1%5D[1].jpg](/community/data/attachments/350/350738-c6b7b510a47c21909044c62e5dc74cb3.jpg)
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Slew factor, or slew rate, is an entirely different specification. Usually specified as so many volts per (micro?) second, it refers to the amps ability to change output rapidly. So this is more of a high-frequency issue. Yes, it's an important specification, but I wouldn't get too hung up on it.
My first advice would be to avoid clipping the amplifier, and with as much power as the 208 has, that probably won't happen unless you play REALLY loud.
Clipping does produce a lot high frequency 'splatter', which can cause damage to both speaker and amplifier if done to excess. So if you're worried about it, I would turn the soft clipping feature ON. If the guys and gals at NAD did a good job of designing the circuit, you shouldn't hear any difference when you're not clipping.
Acoustat 3 help
I have a problem I hope some of you guys can help me with. I have had my Acoustat 3, MK 121 – 2A speakers in storage for about 10 years. I recently tried hooking them up and the problem is no sound! I have been reading a number of posts on this site regarding capacitors and changing them out. I don’t understand the reasons for doing that. Could capacitors perhaps be my problem of no sound? I love the sound out of these things. I have absolutely no confidence in myself of doing any capacitors swap out if it entails soldering. I live in the greater Los Angeles area and would like to find someone locally that could assist me in getting these wonderful speakers up and running.
I have a problem I hope some of you guys can help me with. I have had my Acoustat 3, MK 121 – 2A speakers in storage for about 10 years. I recently tried hooking them up and the problem is no sound! I have been reading a number of posts on this site regarding capacitors and changing them out. I don’t understand the reasons for doing that. Could capacitors perhaps be my problem of no sound? I love the sound out of these things. I have absolutely no confidence in myself of doing any capacitors swap out if it entails soldering. I live in the greater Los Angeles area and would like to find someone locally that could assist me in getting these wonderful speakers up and running.
keeping membranes clean
I am switching topics, but that seems to happen often in this extremely useful thread.
I have a set of Acoustat Spectra 2 speakers that need new grills (cat scratched when I bought them). From reading on the web about replacing grills on Acoustats, I have learned that this can be done with care and use of a lint-free acoustically transparent grill material. However, I can find no mention of how to keep the membranes free of dust or lint when replacing the grills. I imagine this is important for an electrostatic speaker. I can make the new socks and carefully remove the old ones, but how do I keep this process clean?
Thanks very much for your thoughts.
I am switching topics, but that seems to happen often in this extremely useful thread.
I have a set of Acoustat Spectra 2 speakers that need new grills (cat scratched when I bought them). From reading on the web about replacing grills on Acoustats, I have learned that this can be done with care and use of a lint-free acoustically transparent grill material. However, I can find no mention of how to keep the membranes free of dust or lint when replacing the grills. I imagine this is important for an electrostatic speaker. I can make the new socks and carefully remove the old ones, but how do I keep this process clean?
Thanks very much for your thoughts.
I wouldn't worry too much about extra dust or lint produced during the cloth change. Plenty of dust gets past the grille cloth during the life of the speaker.
However, this is an excellent opportunity to clean any dust from the panel. Make sure the speaker is completely discharged, and then carefully vacuum both sides of the plastic grid. If you have compressed air available, you can use that too (but gently). This is also a good time to make sure the felt blocks on the rear of the panels are still firmly attached.
After all these years, your speakers may be suffering from bad or off-value capacitors, but let's check a few other things first.
1) Are the wires from the panels properly connected to the interface?
2) Are the two AC fuses intact (located inside the interface)?
3) Are the audio fuses intact (accessible from the outside of the interface)?
3) Are the speakers connected to AC power (plugged into the wall)?
If all connections and fuses appear okay, I suggest you contact Roy Esposito at acoustat.service.usa@gmail.com. Roy is a former Acoustat employee located in Florida and is your best bet for a qualified repair, and most importantly, Roy has the proper parts.
Leaving the speaker unpowered (i.e.unplugged from the wall) for a day or two will allow a complete discharge of the panel. Or, you can discharge the panel rapidly right after removing power. On the wires that connect the panel to the interface, remove the RED wire carefully (holding it by the insulated portion) and touch the pin plug to either the WHITE or BLUE wire connection. This will produce a spark and the speaker will be discharged.
If you're nervous about the high voltage, you can also use an insulated wire jumper to jump the RED to BLUE or WHITE wires. This will also produce a spark and discharge the speaker.
Not sure if this is against the rules , please remove if inappropriate. Just a heads up on some Acoustat gear not seen very often, 2pairs of Spectra 6600 and more . Here is the link
Acoustat Collection Spectra 6600 etc and other quality Audio for sale - Canuck Audio Mart
Andrew
Acoustat Collection Spectra 6600 etc and other quality Audio for sale - Canuck Audio Mart
Andrew
How cool - TWO Spectra 6600's in one place...and at a pretty reasonable price (original retail was well over $5K/pair). My seat-of-the-pants quess is that Acoustat made only about 25 pairs of 6600's, so rare indeed!
Bass towers for Spectra 11
I've now completed my open baffle bass towers build. The goal was to replace the bass boxes of my Spectra 11's with something better. I believe an open baffle line source with dynamic drivers is the best fit for ESL panels. After a very valuable discussion with Calvin on this forum I chose the Dayton Audio RS180-4 driver. It's a very high quality driver with nice properties for a reasonable price (even cheaper if you live in the US
). I used Calvin's purist ESL as inspiration for the project, but I only used 4 drivers in each tower not 6. I built four boxes with two drivers in each and then bolted them together two and two. Although I can't claim to achieve the same quality as Calvin's products, I'm very happy with the result both visually and sound wise. Subjectively the bass sound is very controlled and uncoloured.
The boxes are made of 19 mm thick MDF board which makes them very sturdy. I chose a board that was already died black as I'm not that skilled at paint work. The finish is ok by my standards, but maybe I'll consider improving it later on.
The bass towers are crossed over at 250 Hz with the Acoustat panels using a steep digital filter to avoid a quite nasty resonance at 335 Hz. I don't use any damping material in the boxes as I didn't see any need for it. At the bottom I crossover with the subs at 40 Hz as below that the distortion in the Dayton drivers rises quite steeply. At 40 Hz I measured about 3% THD for one tower. Above that the distortion drops to below 1% (all measurements were made in my living room so they should be taken with a grain of salt). After some driver break in all four boxes measured pretty much identically between 40 and 400 Hz which I think says something about the consistent quality of the Dayton drivers.
Digital EQ is certainly required for this kind of speaker and I use Audyssey MultEQ XT32 calibration for that. It does an excellent job of flattening the frequency response and seamlessly integrate the bass towers with the Acoustat panels and the sub woofers.
See this page for more pictures and measurement results of the build (warning: the page is in Swedish). My next project is probably to build a floor stands for the Spectra ESL panels and remove the bass boxes from them.
I've now completed my open baffle bass towers build. The goal was to replace the bass boxes of my Spectra 11's with something better. I believe an open baffle line source with dynamic drivers is the best fit for ESL panels. After a very valuable discussion with Calvin on this forum I chose the Dayton Audio RS180-4 driver. It's a very high quality driver with nice properties for a reasonable price (even cheaper if you live in the US
). I used Calvin's purist ESL as inspiration for the project, but I only used 4 drivers in each tower not 6. I built four boxes with two drivers in each and then bolted them together two and two. Although I can't claim to achieve the same quality as Calvin's products, I'm very happy with the result both visually and sound wise. Subjectively the bass sound is very controlled and uncoloured.The boxes are made of 19 mm thick MDF board which makes them very sturdy. I chose a board that was already died black as I'm not that skilled at paint work.
The finish is ok by my standards, but maybe I'll consider improving it later on.The bass towers are crossed over at 250 Hz with the Acoustat panels using a steep digital filter to avoid a quite nasty resonance at 335 Hz. I don't use any damping material in the boxes as I didn't see any need for it. At the bottom I crossover with the subs at 40 Hz as below that the distortion in the Dayton drivers rises quite steeply. At 40 Hz I measured about 3% THD for one tower. Above that the distortion drops to below 1% (all measurements were made in my living room so they should be taken with a grain of salt). After some driver break in all four boxes measured pretty much identically between 40 and 400 Hz which I think says something about the consistent quality of the Dayton drivers.
Digital EQ is certainly required for this kind of speaker and I use Audyssey MultEQ XT32 calibration for that. It does an excellent job of flattening the frequency response and seamlessly integrate the bass towers with the Acoustat panels and the sub woofers.
See this page for more pictures and measurement results of the build (warning: the page is in Swedish
). My next project is probably to build a floor stands for the Spectra ESL panels and remove the bass boxes from them.Attachments
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Nice woofer system! The woofer section is the weakest link in the Spectra 11, so some of your ideas should prove to be popular for DIYer's. The Spectra 1100 has a somewhat better woofer system, but I would expect your new system would be an improvement for that model as well. Thanks for sharing!
The resistor before the audio transformer should be restored to its original value. It is there to keep the low frequency impedance to a reasonable value.
There was a time when Acoustat had trouble obtaining the 500-Mohm resistors, and resistors of a smaller value were substituted. The value is not very critical, and if both your speakers have the same value, you can probably leave it alone. Of course, if it bugs you, you can change them to 500-Mohm. These are not easy to find, but I have seen them sometimes on eBay - search for 'high voltage resistors'.
I ordered new components including the bias update from Mouser.
No problem getting parts from there!
I also took the advantage to order 0,4 and 0,6 Ohm resistors and flip switches to take advantage of the 1100 design.
The bass element is new and will be bi-amped but I will probably redo this completely and integrate the Audio Pro A4-14 instead as it's already amped and also incorporate their amazing ACE-Bass technology .
Yes, I have a couple at home.
But then again I also have Apogee Scintilla, Duetta II, Duetta Signature, Magnepan MG3.6, Infinity RS1b and QUAD ESL 57.
Welcome to the Acoustat club! It would be interesting to hear your opinion about the sound compared to your other speakers. IMHO the Spectra sounds quite a bit better with some calibration and DEQ.
This weekend I built floor stands for the Spectra 11 ESL panels and removed the woofer boxes which made the overall appearance much nicer together with my woofer towers. For the money spent on this setup I haven't heard anything that comes close in sound quality (actually I haven't heard anything better for any price ).
It would be interesting to hear your opinion about the sound compared to your other speakers. IMHO the Spectra sounds quite a bit better with some calibration and DEQ.This weekend I built floor stands for the Spectra 11 ESL panels and removed the woofer boxes which made the overall appearance much nicer together with my woofer towers. For the money spent on this setup I haven't heard anything that comes close in sound quality (actually I haven't heard anything better for any price
).
Welcome indeed Yuri, you are among the most devoted fan base of any brand/product, anywhere.
And to think that some of us have Acoustats that are now nearly 30 years old (I do, Model-3) and working just as good as the day they left the factory without a single problem is a testimony of how great the original design was!
I too "rejoined" the club a couple of days ago, with a pair of Spectra 44s, yeeiii!
Any kind soul out there to give me the lowdown on the interface (should be exactly the same as the Spectra 66/4400/6600, right?), any typical issues and remedies, modifications/upgrades, etc.?
First impressions: they are indeed bigger than life! And I don't mean that just in the physical sense of the word - the sound stage never felt this good ... big, bold, wide, deep... Brilliant, brilliant speakers.
And to think that some of us have Acoustats that are now nearly 30 years old (I do, Model-3) and working just as good as the day they left the factory without a single problem is a testimony of how great the original design was!
I too "rejoined" the club a couple of days ago, with a pair of Spectra 44s, yeeiii!
Any kind soul out there to give me the lowdown on the interface (should be exactly the same as the Spectra 66/4400/6600, right?), any typical issues and remedies, modifications/upgrades, etc.?
First impressions: they are indeed bigger than life! And I don't mean that just in the physical sense of the word - the sound stage never felt this good ... big, bold, wide, deep... Brilliant, brilliant speakers.