I would like to remove the interfaces from my 1+1s and send out for an upgrade/rebuild. The process looks daunting and I wish to proceed cautiously but correctly. Is their a YouTube video or written guidelines that I can follow?
Thanks for your reply.
It's really pretty easy. BIG thing is power down, (unplug) the interfaces OVERNIGHT. There are a couple of allen-head screws on each side that bolt the interface to itself.
Remove those and gently tip the interface BACK at about a 45% angle. Try to keep it close to the other piece because there are wires attached. Pull it out just enough to gain access to the wires. DO NOT touch any the metal connectors attached to the end of the wires. Use the wire itself to pull out the pins.
There shouldn't be any charge left inside the unit as long as you unplugged them overnight, BUT there might be. The first pin you pull out, touch it to one of the screwed down wires, this will discharge any remaining current. Remove all the wires.
You're done.
You're quite welcome!
https://www.audioservicemanuals.com/a/acoustat/acoustat-model/16165-acoustat-model-1-owners-manual
Page 7 has the removal instructions.
I own Model 3's.
I am working on a useful upgrade which I plan to post later when it is done and works.
I have two questions about the 2+2 model:
Are the panels angled in relation to each other as they are in the Model 3 and 4?
What is the exact measurement (front to back) of the vertical center board the panels are mounted to, on the outside faces (left and right sides) of the boards?
It is probably between 3/4" to 2", but I do not have one to measure.
Pictures of the back of the stock 2+2's, no grill cloth, from different angles, would help too.
Thank you,
Brandon
I am working on a useful upgrade which I plan to post later when it is done and works.
I have two questions about the 2+2 model:
Are the panels angled in relation to each other as they are in the Model 3 and 4?
What is the exact measurement (front to back) of the vertical center board the panels are mounted to, on the outside faces (left and right sides) of the boards?
It is probably between 3/4" to 2", but I do not have one to measure.
Pictures of the back of the stock 2+2's, no grill cloth, from different angles, would help too.
Thank you,
Brandon
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Yes, the panels in a 2+2 are angled with respect to each other, but I cannot quote the exact angle, nor if it was the same angle as used in Models 3 & 4.
As to your other questions, someone who has a 2+2 without grill cloth will hopefully make the measurements and photos for you. I have a Spectra 4400 which has no angles between panels - effective curvature is accomplished electrically. SPECTRA = Symmetric Pair Electrically Curved TRAnsducer.
As to your other questions, someone who has a 2+2 without grill cloth will hopefully make the measurements and photos for you. I have a Spectra 4400 which has no angles between panels - effective curvature is accomplished electrically. SPECTRA = Symmetric Pair Electrically Curved TRAnsducer.
Speakers that are three-panels wide have the center panel parallel with the front of the speaker. Same for one-panel speakers. For speakers that are two-panels wide (or four-panels wide) the panels are mounted at an angle with respect to the front of the speaker. All of this is intended to provide a curved wavefront for good dispersion. As far as panels facing directly at the listener (for any model), that all depends on how much toe-in you employ in speaker placement. With the later Spectra series, all panels are mounted parallel to the front of the speaker, with effective curvature achieved electrically (which tends to work much better than mechanical curvature, whether it be with flat segments arranged in an arc, or a curved diaphragm).
Acoustat's diaphragms were not tensioned mechanically. The DuPont HS65 Mylar used was a heat-shrinkable variety, which shrank equally (more or less) in all directions, and that provided the necessary tension. I do not have any measurements of the tension. Tension was not checked during assembly because the Mylar shrank a predictable amount, and no more.
You may be thinking of the longitudinal stretching of the wire stator grid. During assembly, the half-panel was bowed slightly in a fixture (concave towards the stator side) and the wires were run back and forth. Then, when the panel was bowed in the opposite direction for the gluing operation, the wire tension increased so the wires would be straight and taught (as well as sinking slightly into the louver structure, thanks to the solvent-based glue). Once the panel was flattened out, the glue held the wires in place. Then the Mylar was applied to one panel half, the diaphragm was tensioned with heat, and the conductive coating was applied. Then that panel-half was mated and glued to another panel-half without the diaphragm. An over-simplified description, of course.
You may be thinking of the longitudinal stretching of the wire stator grid. During assembly, the half-panel was bowed slightly in a fixture (concave towards the stator side) and the wires were run back and forth. Then, when the panel was bowed in the opposite direction for the gluing operation, the wire tension increased so the wires would be straight and taught (as well as sinking slightly into the louver structure, thanks to the solvent-based glue). Once the panel was flattened out, the glue held the wires in place. Then the Mylar was applied to one panel half, the diaphragm was tensioned with heat, and the conductive coating was applied. Then that panel-half was mated and glued to another panel-half without the diaphragm. An over-simplified description, of course.
I thank you.
I cut the plastic grid by 1.5mm where the wire has to be stuck but having a diameter of 1.6 remains stuck without glue.
To pull the mylar I use a pneumatic and electronic system (using an arduino and a pressure gauge) that allows me to adjust (and repeat) the tension. Unfortunately I don't know the composition of the liquid to make the coating, I'm sorry because my Monitors 4 domes over 40 years work well, so the coating is stable over time.
Thanks again.
I cut the plastic grid by 1.5mm where the wire has to be stuck but having a diameter of 1.6 remains stuck without glue.
To pull the mylar I use a pneumatic and electronic system (using an arduino and a pressure gauge) that allows me to adjust (and repeat) the tension. Unfortunately I don't know the composition of the liquid to make the coating, I'm sorry because my Monitors 4 domes over 40 years work well, so the coating is stable over time.
Thanks again.
My point is that arriving at optimal imaging requires at least one panel on each speaker facing you directly which takes precedent over dispersion. Why they would make dispersion priority over imaging is bewildering. If you start your toe in process with directly facing as your primary focus (with the inner panel as your target), I would challenge you to prefer the intended arrangement. This is how I finalized my Model/Monitor 3. I have tried every other way. The center panels facing you is obviously the intuitive way but the sound is dark and convoluted compared to using the inner panels for alignment. The center and outer panels widen the field. I have no experience with 2+2s but I just can't see optimal performance with the panels facing away from you.
Good morning everyone.
Watching "Acousta Factory Tour" my interest was captured by "Maybelline", I would be interested in knowing more, especially the composition of the glue used. I would like, once the stator wires are wedged, to use the CNC to put a drop of this liquid at each intersection between the conductor and the PVC grid.
If you have any information, please share it.
Thanks again.
Watching "Acousta Factory Tour" my interest was captured by "Maybelline", I would be interested in knowing more, especially the composition of the glue used. I would like, once the stator wires are wedged, to use the CNC to put a drop of this liquid at each intersection between the conductor and the PVC grid.
If you have any information, please share it.
Thanks again.
NUDGE (re Post 2,825)
If you have a factory framed 2+2 or 4400 with grill cloth off:
What is the exact measurement (front to back) of the vertical center board the panels are mounted to, on the outside edges (left and right sides) of the boards?
It is probably between 3/4" to 2", but I do not have one to measure. Please mention the model.
Pictures of the back, no grill cloth, from different angles, would help too.
Thank you,
Brandon
If you have a factory framed 2+2 or 4400 with grill cloth off:
What is the exact measurement (front to back) of the vertical center board the panels are mounted to, on the outside edges (left and right sides) of the boards?
It is probably between 3/4" to 2", but I do not have one to measure. Please mention the model.
Pictures of the back, no grill cloth, from different angles, would help too.
Thank you,
Brandon
In the Facebook Acoustat group, I see this post regarding Roy Esposito's comment:
"In recent years I have recommended using a 3 ampere Slow-Blow fuse MAX fuse there. (#313003 or MDX3 or MDL3) ...instead of the factory specified 5 amp slow-blow fuse. This is especially important for when amplifiers of more than 200 watts RMS are employed. but is also the best protection for any number of abnormal conditions as follows.
The few times I have seen LF-T damage is when digital, switching, magnetic or power-on-demand amplifier designs are used. Or when a tube preamp is combined with a solid-state power amplifier. In these cases even the 3 ampere slow-blow audio fuse may not always be able to save the day."
I get the first paragraph but not the second. Any thoughts appreciated.
"In recent years I have recommended using a 3 ampere Slow-Blow fuse MAX fuse there. (#313003 or MDX3 or MDL3) ...instead of the factory specified 5 amp slow-blow fuse. This is especially important for when amplifiers of more than 200 watts RMS are employed. but is also the best protection for any number of abnormal conditions as follows.
The few times I have seen LF-T damage is when digital, switching, magnetic or power-on-demand amplifier designs are used. Or when a tube preamp is combined with a solid-state power amplifier. In these cases even the 3 ampere slow-blow audio fuse may not always be able to save the day."
I get the first paragraph but not the second. Any thoughts appreciated.
More from that FB post:
"At the factory we recommended Acoustat speakers be used with 100 to 200 watt RMS at 8 ohm rated amplifiers. We said no more than 250 watts RMS MAX at 8 ohms."
So, as long as we keep the power rating in the safe range, we should be good.
But, does that mean we should avoid amps with too high a slew rate? Or, uese only Class A/AB amps? That would be a shame considering the good Class D and GaN amps available.
"At the factory we recommended Acoustat speakers be used with 100 to 200 watt RMS at 8 ohm rated amplifiers. We said no more than 250 watts RMS MAX at 8 ohms."
So, as long as we keep the power rating in the safe range, we should be good.
But, does that mean we should avoid amps with too high a slew rate? Or, uese only Class A/AB amps? That would be a shame considering the good Class D and GaN amps available.
In a word, no. Feel free to use whatever amp or preamp you want. The key takeaway here is to use your common sense when driving the speakers at high levels, and to know they can be damaged by driving them at too high a level (just like ANY speaker). If you are paranoid, or fearful you may accidently use too high a volume, use a smaller value fast-blow fuse. I saw plenty of LF transformer damage way before "digital, switching, magnetic or power-on-demand amplifier designs" were introduced, as I'm sure Roy did as well (since his time at Acoustat preceded mine).
For what it's worth, I dropped my membership in the Facebook Acoustat group. Too much misinformation bandied about by a bunch of know-it-alls. Facebook is a TERRIBLE place to attempt technical discussions. Too many splintered discussions that are too hard to follow, and that's why I gave up. DIYAudio is the perfect format for these discussions, and that's why I'm still here.
For what it's worth, I dropped my membership in the Facebook Acoustat group. Too much misinformation bandied about by a bunch of know-it-alls. Facebook is a TERRIBLE place to attempt technical discussions. Too many splintered discussions that are too hard to follow, and that's why I gave up. DIYAudio is the perfect format for these discussions, and that's why I'm still here.
I'm no expert in acoustats, but I have seen a bunch of transformer failures in my days, so take this with a bit of a grain of salt: That is possible, but somewhat unlikely in my opinion. In my experience transformers fail (beyond infant mortality issues) due to thermal issues. For example I had a citation II transformer than fried the conection to the screen grid tap. It burned out there because the thin magnet wire was not in contact with its neighbors or another material to help conduct the heat away. It burnt right in the air filled pocket where the magnet wire was attached to the lead wire coming out of the transformer. But the coil was fine everywhere else where the wire temperature was staked to the bulk transformer temperature.
So in your example of fuse vs. transformer winding, it's a thermal race between the very fine fuse wire and the much heavier transformer wire. Even if the transformer wire was the same gauge, it's copper and has great axial heat conduction properties, where the fuse is a different material designed to melt and break.
Anything is possible, but it seems like the fuse would still be the weak link here as it's designed to be.
Another anecdote for your reading pleasure: The fuse being the weak link is not always the case. I had a Counterpoint SA-100 amplifier many years ago and it has fused power rails, I assume to protect the output devices. The output FETS would fry if the outputs were shorted, and they would fry faster than the fuses would blow. So your fet's cooked, and then they would take out the fuses just to add insult to injury.
Sheldon