i have the opportunity to purchase some 2+2's for around $800. Details, i would have to travel about 14 hours round trip and add 250 for gas. The socks would need replaced but otherwise he says they sound fine witout any problems. I have owned this model before and wish I hadn't got
rid of them. They do not have the medallion interface though. It has the mk121-B I believe. Considering these or maybe Super MMG from Magneplanar. Looking for opinions on this from the group.
rid of them. They do not have the medallion interface though. It has the mk121-B I believe. Considering these or maybe Super MMG from Magneplanar. Looking for opinions on this from the group.
A thou is a bit high, but not outrageous. They're great speakers. Examine the diaphragms closely for holes or tears; if they're intact, you'll be delighted, assuming you have enough room for them to breathe.
Not bad, I have seen them a little cheaper, but an OK price...14 hour drive? Yikes...
I have collected about fourteen 3 wire Acoustat panels and six MK-121 interfaces (and two pairs of Spectra 1100)...been trying to get to that 3 + 3 project for a while...If yours mine, I would remove panels and give them a nice bath...and do the C Mod (if not done already).
I have one pair of those MK-121 driving a pair of re-mylared ML CLS...nice!
I have collected about fourteen 3 wire Acoustat panels and six MK-121 interfaces (and two pairs of Spectra 1100)...been trying to get to that 3 + 3 project for a while...If yours mine, I would remove panels and give them a nice bath...and do the C Mod (if not done already).
I have one pair of those MK-121 driving a pair of re-mylared ML CLS...nice!
A few months ago I bought a pair of Model 3's from a gent in Ohio for $800. He built rugged crates, packed them well and shipped them to me in Texas. Total cost to me was about a thousand, but they are pristine and the sound is fantastic - I may never build cones and domes speakers again. If you get them, I have a spreadsheet with all the upgrade parts, sources, part numbers and costs - mainly from Mouser - I posted it in a thread about Acoustat caps - I could email it to you.
So the fact that they are not medallion interfaces wouldn't stop anybody from getting them? Can they be upgraded to medallion? What was that upgrade about? Can you get new socks for them?
AcoustatAnswerMan is our local expert; maybe he'll comment.
IME, the difference between Medallion and original is fairly small, but real. Playing around with some of the component values in the interface will likely get you most of the difference; the cynic in me can't help but believe that much of the Medallion hoo-hah was about sourcing, with the marketing add-on touting it as a feature.
But even stone stock and original, you're got something pretty impressive.
IME, the difference between Medallion and original is fairly small, but real. Playing around with some of the component values in the interface will likely get you most of the difference; the cynic in me can't help but believe that much of the Medallion hoo-hah was about sourcing, with the marketing add-on touting it as a feature.
But even stone stock and original, you're got something pretty impressive.
The medallion interfaces did one significant thing. They moved the "HF" transformer's turns ratio so that it matched higher in freq. Comensurate with that, they reduced the coupling cap for said xfrmr from about 200ufd to about 45ufd.
In reality there's not a whole lot of sonic diff between them.
No matter what it is essential to replace the caps with 100% polypropylene, regardless of what value you put in there. You can put the 45ufd in, and it's very close to what the result of the "medallion" version is.
The goal as far as I can see was to permit more power before saturation in the little HF xfmr and to extend the highs slightly. The latter is only partially successful since what is limiting the HF is the mass of the diaphragm.
What I would be wary of is stator wires that have pulled free - mostly on the ends is where this happens. But with care and laying on ur back you can fix them.
As far as the price? That's something you have to decide, and since they are not floating about the used market as much as years past, perhaps they are worth the effort and price.
You need a proper amp, and amp appropriate for these speakers to get best results. Fwiw.
You might want to consider repackaging into "model 4s" over the 2+2, unless you have just the right space and room, the 4s will give you max bass, except maybe for Model 6 and 8...
All opinions expressed are not those of the management...
PS. unless the caps in the HV bias multiplier have been replaced, I'd shotgun the lot with new caps, and replace them all - they tend to fail this many years out since they were manufactured... it's an easy replacement. De-solder, insert, re-solder, done.
In reality there's not a whole lot of sonic diff between them.
No matter what it is essential to replace the caps with 100% polypropylene, regardless of what value you put in there. You can put the 45ufd in, and it's very close to what the result of the "medallion" version is.
The goal as far as I can see was to permit more power before saturation in the little HF xfmr and to extend the highs slightly. The latter is only partially successful since what is limiting the HF is the mass of the diaphragm.
What I would be wary of is stator wires that have pulled free - mostly on the ends is where this happens. But with care and laying on ur back you can fix them.
As far as the price? That's something you have to decide, and since they are not floating about the used market as much as years past, perhaps they are worth the effort and price.
You need a proper amp, and amp appropriate for these speakers to get best results. Fwiw.
You might want to consider repackaging into "model 4s" over the 2+2, unless you have just the right space and room, the 4s will give you max bass, except maybe for Model 6 and 8...
All opinions expressed are not those of the management...
PS. unless the caps in the HV bias multiplier have been replaced, I'd shotgun the lot with new caps, and replace them all - they tend to fail this many years out since they were manufactured... it's an easy replacement. De-solder, insert, re-solder, done.
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Hmmm...I have bought and received new primo film caps to replace all the other caps in my interfaces, but did not buy new ceramic caps for the voltage multiplier, so I might as well replace them too. What value and voltage rating are they? Never mind, I'll check the posted schematics.
I found Vishay/Cera-Mite P/N 615R100GAD33 ceramic disk, 3300pF 10KV $3.47 ea.
615R100GAD33 Vishay / Cera-Mite | Mouser
615R100GAD33 Vishay / Cera-Mite | Mouser
BTW, High Voltage Components Associates has their G10FS (replacement for the P/N they sold to Acoustat):
High voltage rectifiers, high voltage diodes, high current rectifiers, high current bridges, Metal Oxide Varistors, Selenium, full wave bridges & electronic components
Downside is that the minimum order is $100. A couple of guys could get together and place an order - would be good to have a set just in case of a problem down the road.
High voltage rectifiers, high voltage diodes, high current rectifiers, high current bridges, Metal Oxide Varistors, Selenium, full wave bridges & electronic components
Downside is that the minimum order is $100. A couple of guys could get together and place an order - would be good to have a set just in case of a problem down the road.
The ceramic caps are unlikely to be an issue. I'd leave well enough alone and avoid risking the creation of problems where none previously existed.
Sorry, SY, replace the HV caps, they definitely break down. When they do, they trash the diodes too...
HV caps routinely get "paths" through the ceramic over time.
I've had to replace HV caps many many times, in all sorts of multiplier supplies and SMPS HV supplies and in RF applications. Removing the insulating shell inevitably shows "marbling" from the tell-tale tracks (carbon?) through the ceramic. Fresh caps are pure white ceramic.
Replace the caps.
Vishay caps are overkill, standard NPO or even Z5U high voltage ceramics ought to be less expensive and just as good in this application, imo.
_-_-
HV caps routinely get "paths" through the ceramic over time.
I've had to replace HV caps many many times, in all sorts of multiplier supplies and SMPS HV supplies and in RF applications. Removing the insulating shell inevitably shows "marbling" from the tell-tale tracks (carbon?) through the ceramic. Fresh caps are pure white ceramic.
Replace the caps.
Vishay caps are overkill, standard NPO or even Z5U high voltage ceramics ought to be less expensive and just as good in this application, imo.
_-_-
But then you don't get sound.
I've not experienced HV ceramic cap failures, either in Acoustats, Quads, or any of the various ham and laser stuff I've built over the years. Maybe Andy has something to say about it...?
These speakers are rare enough that the market price is really how much people in that area are willing to pay. They are too big to ship so prices can really vary a lot.
I got mine for $600 two years ago, came with cables, nice socks, medallions, c mod.
However, it was the first time I saw a pair pop up on the craigslist in the years I was watching.
If you see some pop up on ebay that are near you, watch the listing; they'll probably not sell as people don't usually ship them. Then, make an offer.
I'd rather pay $1200 for a nice pair 30 miles away than $600 for a set across the country, but again, always keep in mind that there is a good chance that the only person wanting them is you!
If you are worried you paid too much, can you think of another full range esl that cost less used? I can't think of any.
I got mine for $600 two years ago, came with cables, nice socks, medallions, c mod.
However, it was the first time I saw a pair pop up on the craigslist in the years I was watching.
If you see some pop up on ebay that are near you, watch the listing; they'll probably not sell as people don't usually ship them. Then, make an offer.
I'd rather pay $1200 for a nice pair 30 miles away than $600 for a set across the country, but again, always keep in mind that there is a good chance that the only person wanting them is you!
If you are worried you paid too much, can you think of another full range esl that cost less used? I can't think of any.
SY, I've rebuilt a fairly large number of Acoustat multiplier sections, many dead and leaky caps. Best to shotgun it. Cheap, simple, effective and certain.
I've seen many RF caps with the same sort of symptomatic failures. Takes a lot of years, but they die. Ask some hams who do enough work on RF finals, dead ceramic caps are found all over the place.
Also, as I mentioned in HV supplies.
_-_-
I've seen many RF caps with the same sort of symptomatic failures. Takes a lot of years, but they die. Ask some hams who do enough work on RF finals, dead ceramic caps are found all over the place.
Also, as I mentioned in HV supplies.
_-_-
The rectifiers need to be 3kV since they will see twice the peak secondary voltage ( 2*750VAC*1.414= 2,121V). Mouser has Vishay GP02-30 @ $0.45 in quantity 1+.
They also have Murata 3300pF/3.15kV caps.
They also have Murata 3300pF/3.15kV caps.
if i remember correctly the caps in the HV supply dont have to meet the output voltage. only the stage voltage , using 230 volt ? then all above theat will do using 110 ? all above that will do. using an inverted then it has to be able to stand the voltage the inverted puts out, and here you need some headroom becasue with no ballast they can ouput a little bit more then they are rated weird enough.
from this site
DIY Homemade Voltage Multiplier - RMCybernetics
QUOTE
The components you have mentioned should work OK if you are applying a high enough voltage to the input. If you want to be able to adjust your variac (variable transformer) from as low as 10V then it may be better to use diodes rated for lower voltages.
Your componets are only exposed to the stage voltage so if you are only applying 220V AC the components only need to be rated as such. An example diode might be a 1N4007 or something similar in the series. These are only small so if you need to pass higher currents you should select a larger equivalent.
QUOTE
Ofc a bit of overkill cant hurt 🙂 but ive seen many cascades with 250volt rated caps and 1n004 diodes wich are rated for 1000 volt . putting out 5kvolt, so be my guest to buy expensive diodes and capacitors.
it does not hurt to take the diodes a bit overkill they are not expensive ,, input voltage time 3 or 4 will take you there
from this site
DIY Homemade Voltage Multiplier - RMCybernetics
QUOTE
The components you have mentioned should work OK if you are applying a high enough voltage to the input. If you want to be able to adjust your variac (variable transformer) from as low as 10V then it may be better to use diodes rated for lower voltages.
Your componets are only exposed to the stage voltage so if you are only applying 220V AC the components only need to be rated as such. An example diode might be a 1N4007 or something similar in the series. These are only small so if you need to pass higher currents you should select a larger equivalent.
QUOTE
Ofc a bit of overkill cant hurt 🙂 but ive seen many cascades with 250volt rated caps and 1n004 diodes wich are rated for 1000 volt . putting out 5kvolt, so be my guest to buy expensive diodes and capacitors.
it does not hurt to take the diodes a bit overkill they are not expensive ,, input voltage time 3 or 4 will take you there
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