Interesting post. For the nubie Acoustat owner, could you please explain in a little more detail what you are talking about? Where is this PCB, on the panel or in the interface? Are you referring to the numorous wires that connect the panel to the interface?
Thank you for your help.
Any explanation as to why Moscode 300 went into thermal shutdown with Acoustat 3s?
Hi All:
Thank you for those who responded to my Monster wire swap/replacement in the interfaces. And thank you Andy and tyu regarding replacing important (old) parts and possible mods/non-mods. (I've read through most of the pages of this thread regarding parts replacement and possible mods but was hoping that there might be something like a sticky thread with the basic parts to be replaced and possible links to current suppliers. Yes, I know, Google search is where it's at nowadays.
)
Back again with more questions. Was trying out my Moscode 300 connected to my, new to me, Acoustat 3s. After the first to second cuts in Linda Ronstadt's 'What New' album, the sound started to sputter and cut in an out. I powered off the amp and double checked the connections and they were okay. I left it powered off until after dinner. After powering it back on, again, after the first to second cut, the sound started to sputter and cut in an out. I played the rest of the album but the sound deteriorated and before the end of the album, the amp went into thermal shutdown. The heat sinks were very hot after the thermal shutdown. The speaker fuses in the Moscode had been bypassed by the previous owner. The fast blow fuses mounted on the circuit board did not short/trip at all and there does not appear to be any burn smell nor burnt parts.
Prior to trying out the Moscode, I was using a Joilda SJ502 (with KT120s - Jolida indicated the transformers were sufficient for these tubes) and did not have the issue the Moscode exhibited. The only issue with the Jolida is that it does not have enough power when the volume is increased beyond a level (when distortion sets in).
The Moscode did not exhibit this issue when driving a pair of Magnepan SMGs (but the SMG is a more benign/steady load).
Any ideas? I was thinking that the Acoutstats may be too reactive a load for the Moscode or that the Moscode may need to be looked at by a technician or at the worst, replaced with another amp.
If I am to replace the Moscode, any suggestions? The Moscode is a very good sounding unit and can be checked and made better sounding by George Kaye or Stephen Sank but I'm not really wanting incur the expense of shipping it to the US especially when the Canadian dollar is not doing so well again the US dollar. Budget is $1000. (It has been discussed in this thread and others that the Hafler TransNova series, Acoustat TNTs, and Meitners are good candidates. I have had an Hafler DH220 and a pair of Meitner 100W units in the past but not driving the Acoustats. I believe the Moscode is a better sounding unit than both of them.)
Thank you again fro your insightful answers!
Sincerely,
Kingsley.
Hi All:
Thank you for those who responded to my Monster wire swap/replacement in the interfaces. And thank you Andy and tyu regarding replacing important (old) parts and possible mods/non-mods. (I've read through most of the pages of this thread regarding parts replacement and possible mods but was hoping that there might be something like a sticky thread with the basic parts to be replaced and possible links to current suppliers. Yes, I know, Google search is where it's at nowadays.
)Back again with more questions. Was trying out my Moscode 300 connected to my, new to me, Acoustat 3s. After the first to second cuts in Linda Ronstadt's 'What New' album, the sound started to sputter and cut in an out. I powered off the amp and double checked the connections and they were okay. I left it powered off until after dinner. After powering it back on, again, after the first to second cut, the sound started to sputter and cut in an out. I played the rest of the album but the sound deteriorated and before the end of the album, the amp went into thermal shutdown. The heat sinks were very hot after the thermal shutdown. The speaker fuses in the Moscode had been bypassed by the previous owner. The fast blow fuses mounted on the circuit board did not short/trip at all and there does not appear to be any burn smell nor burnt parts.
Prior to trying out the Moscode, I was using a Joilda SJ502 (with KT120s - Jolida indicated the transformers were sufficient for these tubes) and did not have the issue the Moscode exhibited. The only issue with the Jolida is that it does not have enough power when the volume is increased beyond a level (when distortion sets in).
The Moscode did not exhibit this issue when driving a pair of Magnepan SMGs (but the SMG is a more benign/steady load).
Any ideas? I was thinking that the Acoutstats may be too reactive a load for the Moscode or that the Moscode may need to be looked at by a technician or at the worst, replaced with another amp.
If I am to replace the Moscode, any suggestions? The Moscode is a very good sounding unit and can be checked and made better sounding by George Kaye or Stephen Sank but I'm not really wanting incur the expense of shipping it to the US especially when the Canadian dollar is not doing so well again the US dollar. Budget is $1000. (It has been discussed in this thread and others that the Hafler TransNova series, Acoustat TNTs, and Meitners are good candidates. I have had an Hafler DH220 and a pair of Meitner 100W units in the past but not driving the Acoustats. I believe the Moscode is a better sounding unit than both of them.)
Thank you again fro your insightful answers!
Sincerely,
Kingsley.
Thank you for your post Tyu. I have read this entire thread plus lots else on the net but most of it is Acoustat experts discussing things amongst themselves that a guy who hasn't even taken down the grill cloth on his first pair can't follow. Just wanted some clarification on the last post to check my new to me Spectra 22s that I am struggling a bit with. Appreciate any help I can get from you guys.
This May Sound funny to some.....But if a Amp Dose not have a fan in it... I would never use it with my Acoustats. are other ESLs....
I have owned Minny amps from Krell...all older class a type....MDA 300...500....theses Amps well drive any thing!.. an any othere. Amps from A-Z....OTLs Mosfets.. U name it.that would Drive..Ribbons Maggys .B&W ..........what ever but these Acoustat can take a lot of clean power.... Proamps Like QSC, An the Hafler Trans•nova dimond....7000 are great....
An thay have fans..An can hold there owen up agenst some Big $$ amps sound wise..thay let you push the amps with out cooking old Acoustat parts in the inter faces....an amps themselfs...
But my old ears lov the sound of the ESLs low THD....an I just cant get a Nuff....it me that's defected...more than the speakers...hehe.....But with my lov of Tube sound...An help from people like Bob Carver I got some tube Amp MODS... that let me get 80-90% of the ESL sound out of theses old Apogee Ribbons An old Maggys...To make me happy.....Have fun ...Long live Acoustats....
All just one mans findings
I have owned Minny amps from Krell...all older class a type....MDA 300...500....theses Amps well drive any thing!.. an any othere. Amps from A-Z....OTLs Mosfets.. U name it.that would Drive..Ribbons Maggys .B&W ..........what ever but these Acoustat can take a lot of clean power.... Proamps Like QSC, An the Hafler Trans•nova dimond....7000 are great....
An thay have fans..An can hold there owen up agenst some Big $$ amps sound wise..thay let you push the amps with out cooking old Acoustat parts in the inter faces....an amps themselfs...
But my old ears lov the sound of the ESLs low THD....an I just cant get a Nuff....it me that's defected...more than the speakers...hehe.....But with my lov of Tube sound...An help from people like Bob Carver I got some tube Amp MODS... that let me get 80-90% of the ESL sound out of theses old Apogee Ribbons An old Maggys...To make me happy.....Have fun ...Long live Acoustats....
All just one mans findings
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Audiobasic, How big is your room, I've had pretty much all of the older models of Acoustat, a lot of people think these need high current amps, Myself I've had more problems with high current amps, I use mostly high voltage output and so far they have worked well, in other words output on amp to have higher v than c. My Treshold S300 has 3 sets of speakers on it, in paralel , 2+2's, Apogee Stages, and Infinity QLS-1 and it don't complain at all. Al
Small by most standards, approx. 10x11. Not anything like your cavernous room!. Quarter round bass traps in all four corners, one half-round trap against the wall behind the rack in center between M3s and one in the center against the wall behind the listening position. I get fair volume with the Jolida but only up to a certain point before the distortion level sets in. The brief moment with the Moscode 300 provided some insight as to the loudness level/dynamics achievable with the higher power rating. I don't listen at rock levels and never will as I like to protect my hearing. Seems like I might be in a similar boat to what Mendel is experiencing in regards to volume/dynamics levels (although his room slightly larger than mine). And no, I don't know Mendel at all, just figured he was the one who bought the Spectra that were listed on CAM shortly after the M3s were listed. Thanks for asking, Delta Star.
Mendel, the PCB is in the interface. There are three connectors on the PCB - two are threaded knobs that clamp the panel stators (blue and white connectors), and the middle red pin is the bias. The two blue and white connections are your stators and for three wire panels you have two stators and teh bias wire. The Blue stator wires are connected together and the White stator wires are connected together. Make sure they are all connected to the hook that goes in the clamp.
Make sure there is no power to the interface, then pull the red bias pin and touch both blue and while connector posts before doing anything - you should hear a nice crack that indicates the discharge voltage from the panels. Do this a couple time until you no longer hear the discharge. And do this before touching anything in interface. You will get a nice shock otherwise...
Make sure there is no power to the interface, then pull the red bias pin and touch both blue and while connector posts before doing anything - you should hear a nice crack that indicates the discharge voltage from the panels. Do this a couple time until you no longer hear the discharge. And do this before touching anything in interface. You will get a nice shock otherwise...
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I would first check that the MK121 interfaces haven't had one of the unholy modifications being touted around, like removing the 1ohm resistor from the LF transformer primary, not to mention various mods to the HF filter, like going full range on it which will saturate the transformer core at high output and lead to countless problems.
Power supply section of the interface - aged ceramic caps? Only way to know is to measure and for that you need a 20-50x voltage divider probes for your multimeter, and fresh underwear...
It's cheap, quick and easy to replace the caps and diodes in the voltage multiplier, maybe that should be done no matter what.
While you are it, for the ultimate in interface impedance stability you want the MK121-C interface upgrade ("Medallion" transformers are not a necessity). Schematic is somewhere in this thread. Much less impedance variation and easier to drive than any of the old Maggies. If you cannot find the schematic, shout and I'll email you.
Next, I would check / change the speaker cables. Some amps cannot stand the capacitance buildup.
Finally, maybe it's all in Linda Ronstadt's voice...?
As to the welding-machine Class-A current-on-tap type amps vs. current-on-demand amps (class A/B and higher), honestly, it more than anything else depends on the quality of the amp and that is entirely dependant on who designed it.
I had zero issues driving many different ESLs (Model-3 included) with class-A amps and I prefer them, sonically speaking.
Currently enjoying Oregon's "Roots in the sky" LP playback via DIY valve preamp with high-ish output voltage, driving a standard DIY Pass F5 (25wpc in class-A) and Spectra-44s. Much more beautiful SPL than my ears can handle in a 36m2/120m3 room.
DeltaStar, you perked my interest - of course, I might have misunderstood what you wrote. Do you drive three pairs of different speakers, in parallel, at the same time? In the same room?
Thank you fdlsys. Won't be able to check the ceramic caps since I don't have 20-50x voltage divider probes (only a cheap DVM from Canadian Tire) but can check the resistors. Will probably replace the ceramic caps and voltage multiplier network after gathering the requisite parts. I think I saved a schematic of the Medallion C from one of the pages in this thread. (I might be safer wearing rubber coveralls. )
The speaker cables are Cardas Golden Five that have been with me many years throughout systems upgrades/changes so I don't think they will be swapped.
Yea, Linda Ronstadt can sure belt out the songs!
Wow DeltaStar...gotta get one 'em Thresholds S300s.
Thanks fellas.
)The speaker cables are Cardas Golden Five that have been with me many years throughout systems upgrades/changes so I don't think they will be swapped.
Yea, Linda Ronstadt can sure belt out the songs!
Wow DeltaStar...gotta get one 'em Thresholds S300s.
Thanks fellas.
Thanks John for the detailed explanation. I will check this out when I get home the interfaces will have been unplugged for 5 days so should be safe to work with. Has anyone tried a contact enhancer on the connectors between the panels and interfaces (walker SST)? Works very well for speaker cable and interconnect. At the least I intend to clean all contacts with Deoxit and alcohol.
And the socks will be coming down.
Subwoofer out question
If you use the crossover in the Spectra 22 to remove 100hz and lower to the panels, is the output to the subwoffer out binding posts only sub 100 hrz frequencies or is it full range? Thinking of hooking my old speakers up to the sub outputs as sub woofers. They are bi-wired would I only hook up the woofer posts?
The Spectras seem to play cleaner without the sub 100 hrz frequencies on the panels.
Thanks in advance for any info.
If you use the crossover in the Spectra 22 to remove 100hz and lower to the panels, is the output to the subwoffer out binding posts only sub 100 hrz frequencies or is it full range? Thinking of hooking my old speakers up to the sub outputs as sub woofers. They are bi-wired would I only hook up the woofer posts?
The Spectras seem to play cleaner without the sub 100 hrz frequencies on the panels.
Thanks in advance for any info.
The subwoofer output on the MK-2123 interface used on the Spectra 22/2200/33/3300 is FULL RANGE. This was done because the system is intended to be used with the Spectra SPW-1 Subwoofer, which contains its own 100-Hz low-pass filter. This is also useful for using other subwoofer systems that contain their own crossover.
Therefore, you'll need some sort of crossover to use your old speaker's woofers, which is probably already present in the cabinet. However, the crossover frequency in your old speakers may be considerably higher than 100 Hz, and may not yield the desired results. But it won't hurt anything to try. You would make connection only to the woofer binding posts of a biwired speaker.
Jason, cap values would be in 100s of uF which is not practical for film caps. You would have to use bipolar electrolytic caps and bypass them with metal-film. If you want to give it a try, download Winisd for Windows or free crossover filter calc. app for Android. Keep in mind that by lowering the crossover point using existing filter topology (1st order I presume - 6db/octave) you will put the panel at risk of over-excursion so a safe(er) option is to opt for at least a 3rd order filter: cap - inductor - cap which will produce the 18db/octave cutoff slope. Furthermore, increased low-Fq current may stress the audio transformer at higher SPL. In short, it is doable but within reason and not as simple as just a cap value change.
Figured it couldn't be easy. It does look like a first order, and I had (albeit briefly) though of the ultimate effect on the transformer, but was wishful none the less. I don't see myself experimenting on good set of spectras and possibly screwing the set up so I guess I will rebuild the controllers with stock valued parts, and live with them as they are.
Really safer to swap out the speakers for my forte 2's or ML Ascents when playing heavy electronic pieces anyways. Also putting it out there, but I am looking for 2-4 9 inch 5 wire panels.
Really safer to swap out the speakers for my forte 2's or ML Ascents when playing heavy electronic pieces anyways. Also putting it out there, but I am looking for 2-4 9 inch 5 wire panels.
Thank you for the info Andy. Some other questions; there is one fuse accessible on the back of the interfaces which is 5 amps I believe. But inside the interface there are 2 other fuses that are accessible. What are the value of these and what purpose do they serve? Does the audio signal go thru them or just power supply?
My Spectras are the early version with captive power cable and no wall wart. Is there any way to test the bias current and adjust it? So far from what I have read it seems that these early Spectras did not have adjustable bias and only by making sure the caps, diode and resistors in the bias voltage supply were in spec could you get the proper voltage. Many of these models eventually went out of spec and one speaker would produce less volume than the other. That is why the adjustable ultra sonic bias supply was introduced to allow user/techs to adjust the bias,
Is this summary true or am I off base? Any info would be very helpful. Very much appreciate your time and insight.
Confused - Isn't the Acoustat Spectra 22/2200/33/3300 panel already able (and doing) full range anyway? That sub out connection on interface just adds LF to existing output of the full range panel, correct?
Whoops, or are we talking Spectra 11 or 1100 here? Sorry....but again, the Spectra panels can do full range anyway...
If you had a 4 ohm sub driver, for 50hz low pass 1st order, you would need 796uf (yikes)....you gonna spend a fortune on film caps (and need a big enclosure) for this passive crossover... for 250hz low pass, you will need 160uf for same 4ohm driver 1st order...
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It's very simple John: -3db point (for example) on the system response curve is very different between 2, 4 or 6 panel system.
The only way of achieving the the same LF SPL response using fever panels is by pushing more power into them.
More power = longer excursion.
Also,
1st order lowpass filter is an inductor, not a cap.
The only way of achieving the the same LF SPL response using fever panels is by pushing more power into them.
More power = longer excursion.
Also,
1st order lowpass filter is an inductor, not a cap.
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