Thank you! What would that work out to for total capacitance as seen by an amp for a pair of 6600's?
Thanks again!
Thanks again!
The amp I am intending to buy is good down to 1ohm and can handle .47 microfarads so I should be fine. Thanks for the assistance...
Very cool, the Stax 009 headphone driver (diameter 80mm) has a capacitance of 100pF.
What is the area of the Acoustat driver?
If you decide to test and sell I have the perfect some with a couple of Acoustat speakers including a pr of Acoustat Spectra 6600 which would be right home with being driven by a friendly amp.
I thought you were after the capacitive load that would be seen by a direct-drive HV amp since you were asking about the panel capacitance.
If you are using the OEM setup with Spectra 6600 step-up transformers, the amplifier load in the top 1.5 octaves can be approximated by a series RLC load of 1.5 ohm + 1.2uF + 40uH.
What amp are you looking at?
Interesting that it includes a capacitive load specification...that isn't something you see often.
Purifi 9040. The people at Hypex and Purifi are both on top of the measurements. I have been using a Hypex NC1200 on a pair of Model 3's until I get the 6600's up and running (need to build the frames for them - I had to abandon the original frames to move them across country)...Thank you!
Hi all,
This seems to be a good thread to ask a Acoustat question.
Tomorrow I’m looking at some 1100s. They were from Australia and owned by a recording engineer there. He upgraded the caps to clarity.
The current owner hasn’t really used them at all but believes they are fine and has them hooked up for audition. These are on audiogon and us Audio mart if you wanna look.
Based on my research these things can have scraping woofer issues. I’ll bring a bass torture track and plan pumping the woofers by hand.
Reading the stereophile review these panels came with an unprecedented lifetime warranty however as we know, Rockford is long gone.
My question is…
Are these panels pretty reliable? I can’t find many (any??) people rebuilding 1100 panels. Are replacements available?
If not is it a difficult process?
Secondary is there any thing else I should look for tomorrow that are known faults of these?
Thanks I have owned Maggie’s my whole life but never an electrostatic.
And yes I have the juice to run them. Aragon Iridium monoblocks. 400 watts ea. into 8 ohms, 600 into 6 ohms.
Thanks in advance for any suggestions!
This seems to be a good thread to ask a Acoustat question.
Tomorrow I’m looking at some 1100s. They were from Australia and owned by a recording engineer there. He upgraded the caps to clarity.
The current owner hasn’t really used them at all but believes they are fine and has them hooked up for audition. These are on audiogon and us Audio mart if you wanna look.
Based on my research these things can have scraping woofer issues. I’ll bring a bass torture track and plan pumping the woofers by hand.
Reading the stereophile review these panels came with an unprecedented lifetime warranty however as we know, Rockford is long gone.
My question is…
Are these panels pretty reliable? I can’t find many (any??) people rebuilding 1100 panels. Are replacements available?
If not is it a difficult process?
Secondary is there any thing else I should look for tomorrow that are known faults of these?
Thanks I have owned Maggie’s my whole life but never an electrostatic.
And yes I have the juice to run them. Aragon Iridium monoblocks. 400 watts ea. into 8 ohms, 600 into 6 ohms.
Thanks in advance for any suggestions!
I've never heard any reports on "woofer scraping", but it certainly would be worth investigating. Most likely, any scraping of the voice coil would be caused by overdriving the speaker.
The lifetime warranty is no longer honored, of course. But Acoustat did have enough confidence in the reliability of the panels that they could offer such an unusual warranty. Generally speaking, the panels are not reparable, and the only source of a replacement panel would be the used market. A panel from any Spectra speaker can be used. I wouldn't worry too much about the ESL panel itself.
The one "Achilles heel" of this speaker is the power handling capacity of the woofer crossover. These parts can get overheated under conditions of very hard drive, especially the inductor. The only way to inspect for overheating is to remove the input cup on the rear of the woofer cabinet, to which the crossover is attached. The seller might not be too keen about opening the speaker, so this might have to wait until after purchase. In any case, these parts can be replaced easily if needed.
Keep in mind that these speakers are mirror-image and must be evaluated with the right and left speaker oriented correctly. For the Spectra 1100, the high frequencies should be radiating from the outer edge of each speaker when properly set-up. Otherwise, imaging can get weird. Also be careful with the amount of power you have available. The Spectra 1100s are capable of filling a medium sized room with a satisfying volume, but don't expect ear-splitting levels. You have enough power to damage the speakers, so moderation is the key. Good luck!
The lifetime warranty is no longer honored, of course. But Acoustat did have enough confidence in the reliability of the panels that they could offer such an unusual warranty. Generally speaking, the panels are not reparable, and the only source of a replacement panel would be the used market. A panel from any Spectra speaker can be used. I wouldn't worry too much about the ESL panel itself.
The one "Achilles heel" of this speaker is the power handling capacity of the woofer crossover. These parts can get overheated under conditions of very hard drive, especially the inductor. The only way to inspect for overheating is to remove the input cup on the rear of the woofer cabinet, to which the crossover is attached. The seller might not be too keen about opening the speaker, so this might have to wait until after purchase. In any case, these parts can be replaced easily if needed.
Keep in mind that these speakers are mirror-image and must be evaluated with the right and left speaker oriented correctly. For the Spectra 1100, the high frequencies should be radiating from the outer edge of each speaker when properly set-up. Otherwise, imaging can get weird. Also be careful with the amount of power you have available. The Spectra 1100s are capable of filling a medium sized room with a satisfying volume, but don't expect ear-splitting levels. You have enough power to damage the speakers, so moderation is the key. Good luck!
Pardon my late response - just saw joeljoel1947’s questions above. The reference to “woofer scraping” could possibly be the issue that plagued the MH series, and possibly later models such as the 1100s, that used a dynamic woofer to augment the bass. What happens is that after a few decades(!) the foam surround tends to decay which leaves the driver without support, causing scraping on the voice coil. See post #3,332. It is possible to repair them with a bit of patience.
As for the panels themselves, mine are still going strong after 42 years. They tend to outlast the electronics that drive them.
As for the panels themselves, mine are still going strong after 42 years. They tend to outlast the electronics that drive them.
For the record, both Spectra 11 and Spectra 1100 used woofers with a butyl surround, not foam. By that time in my career, I had already seen enough "foam woofer rot" to know it was best to avoid foam (at least in that era). That's not to say that these woofers can't experience "sag" or "voice-coil scraping", but if they do, it won't be due to a foam surround. I also seem to recall later versions of the Model One's woofer (with an improved crossover) used butyl surrounds, as opposed to the original design with a foam surround. Memory might be getting a little foggy on that one.
Also sorry for being late to the party but I just found this thread. I have a pair of Acoustat 2MH speakers and recently noticed a "fluttering" sound from one of the subwoofers, suspect that the foam surround is degraded. I had already replaced the surrounds, maybe 2001-ish, and was looking for new info on replacement kits. It went well the first time, hoping I'll be able to clean the glue off (again) and get them running.
fwiw, I paid $1050 for these in 1982 (new). My wife has replaced the fabric on them twice (as they act as electrostatic air cleaners lol). The last time (2018) I found replacement fabric from Acoustical Solutions that seemed to be a perfect match for the original.
My son was able to find a pair of used 2MHs about 5 years back for $700, and although they were a bit banged up, the panels and subs were like new, I suspect they were not powered on very much. The high-voltage panel leads were mint (I'm jealous). Considering that mine have been plugged in continuously for over 40 years, it's amazing that they are still working at all, let alone sounding fantastic.
cheers
fwiw, I paid $1050 for these in 1982 (new). My wife has replaced the fabric on them twice (as they act as electrostatic air cleaners lol). The last time (2018) I found replacement fabric from Acoustical Solutions that seemed to be a perfect match for the original.
My son was able to find a pair of used 2MHs about 5 years back for $700, and although they were a bit banged up, the panels and subs were like new, I suspect they were not powered on very much. The high-voltage panel leads were mint (I'm jealous). Considering that mine have been plugged in continuously for over 40 years, it's amazing that they are still working at all, let alone sounding fantastic.
cheers
AcoustatAnswerman, greetings from the Rocky Mountains. I have an issue I am looking to get insight on. Please read here:
https://www.diyaudio.com/community/threads/help-acoustat-spectra-11-volume.416144/
https://www.diyaudio.com/community/threads/help-acoustat-spectra-11-volume.416144/
I am looking to dip my feet in the electrostatic speaker pool. From what I can tell there are basically 3 options, Acoustat, Sound Lab or Quad. Sound Lab are out of my range as even defective ones are very expensive. The Quads can also be expense and most of them need the panels to be rebuilt. This leaves me with Acoustat. From my little research it seems that the Spectra panels are the most desirably ones to get, however I am not sure which models actually have the Spectra panels. I am looking for Acoustat Spectra speakers /panels that are available with reasonable driving distance from Philadelphia PA.
Here's a list of all Acoustat Spectra models:
Spectra 11...a single panel hybrid system (w/woofer)
Spectra 1100...a single panel hybrid system (w/woofer) Similar to Spectra 11 but with refined performance)
Spectra 2...a 2-panel hybrid system (w/woofer)...rather rare
Spectra 3...a 3-panel hybrid system (w/woofer)...rather rare
Spectra 22 or 2200...a 2-panel full-range ESL (the 2200 version is identical but with improved cosmetics)
Spectra 33 or 3300...a 3-panel full-range ESL (the 3300 version is identical but with improved cosmetics)
Spectra 44 or 4400...a 4-panel full range ESL (the 4400 version is identical but with improved cosmetics) Note these are 7' 10" tall)
Spectra 66 or 6600...a 6-panel full-range ESL (the 6600 version is identical but with improved cosmetics) Note these are 7' 10" tall)
Which model you choose will depend mostly on what you can find on the used market. Check your ceiling height before considering the 4 or 6-panel versions! Acoustat's Spectra models represent the pinnacle of Acoustat's achievement in ESL loudspeakers and include all learning and improvements from previous models. As a rule, Acoustat ESL speakers (even the non-Spectra models) are very reliable and exhibit very little degradation over time, not just for an ESL, but really for any speaker of that vintage. One always takes a risk "adopting" vintage audio gear, but the risk factor here is low compared to the other choices you mentioned.
Spectra 11...a single panel hybrid system (w/woofer)
Spectra 1100...a single panel hybrid system (w/woofer) Similar to Spectra 11 but with refined performance)
Spectra 2...a 2-panel hybrid system (w/woofer)...rather rare
Spectra 3...a 3-panel hybrid system (w/woofer)...rather rare
Spectra 22 or 2200...a 2-panel full-range ESL (the 2200 version is identical but with improved cosmetics)
Spectra 33 or 3300...a 3-panel full-range ESL (the 3300 version is identical but with improved cosmetics)
Spectra 44 or 4400...a 4-panel full range ESL (the 4400 version is identical but with improved cosmetics) Note these are 7' 10" tall)
Spectra 66 or 6600...a 6-panel full-range ESL (the 6600 version is identical but with improved cosmetics) Note these are 7' 10" tall)
Which model you choose will depend mostly on what you can find on the used market. Check your ceiling height before considering the 4 or 6-panel versions! Acoustat's Spectra models represent the pinnacle of Acoustat's achievement in ESL loudspeakers and include all learning and improvements from previous models. As a rule, Acoustat ESL speakers (even the non-Spectra models) are very reliable and exhibit very little degradation over time, not just for an ESL, but really for any speaker of that vintage. One always takes a risk "adopting" vintage audio gear, but the risk factor here is low compared to the other choices you mentioned.