Amp specs for Acoustat Spectra 22

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So I'm very new to the diy audio, and am still very knowledgeable with many of the raw electronics and inner workings.

So I was given a Spectra 22 system with everything except an amplifier (expected) and I can't seem to find anywhere the specifications needed in an amplifier for these speakers (the some of the manuals are missing etc). if any of you would be so generous as to stoop to my knowledge level and educate me in the subject I would be very grateful.
 
Hi
I would use an amplifier over 100 watts that is capable of driving a difficult load as the impedance of the Spectra 22 drops to a couple of ohms.
I have used an Adcom GFA555 and that seems to work OK. You may also want to look a the Acoustat and Hafler Transnova amplifiers that were designed for the Acoustat speakers .Some higher powered tube amps also work well with the Acoustats
Hope that helps
Andrew
 
I'm driving my Acoustat Spectra 22's with a Sunfire 300 X2 and they sound great. I have another on the way and I intend to set each of them up as "Parallel-mono". This should provide 600wpc@8ohms, 1200WPC@4ohms and 2400Wpc into a 2ohm load.

My question is that the broucher state a minimum Power rating of "100wpc or greater" but doesn't establish and upper end. Do I risk damage with the output of a Mono Sunfire 300? I know, be carefull with the volume control, but that isn't always how I roll... I like concert levels!!! :D

And who here is familiar with Sunfire's "Parallel-Mono"? I don't believe it is "Bridging" but I wonder if I'm imparting some level of distortion.

Advise anyone?

From an Acoustat Newbie!!! ;)
 

tyu

Member
2009-07-18 8:16 pm
I have Acoustat 33.........one Sunfire 300 well put 600 watts into 4ohms ...
If you feel that the 22s need more output than you get with that...you may need diff speakers....an yes you can damage the 22s interfaces with more power.
As for the "Parallel-mono".............you better look at the Sunfire 300 manual...
Don't Parallel any SS amps outputs!......you may kill the Amps an the Speakers!... I think your talking bi-wire.
good luck
 
I have Acoustat 33.........one Sunfire 300 well put 600 watts into 4ohms ...
If you feel that the 22s need more output than you get with that...you may need diff speakers....an yes you can damage the 22s interfaces with more power.
As for the "Parallel-mono".............you better look at the Sunfire 300 manual...
Don't Parallel any SS amps outputs!......you may kill the Amps an the Speakers!... I think your talking bi-wire.
good luck

Hi Tyu...

Thanks for the feedback. Now, you state "you can damage the 22s interfaces with more power." Is this from experience and what were you running?

From what I have read, the more the merrier with Stats and like I pointed out, Acoustat doesn't specify the upper end. AcoustatMan, where are you?

Oh, and this is Parallel Mono via Sunfire. They do support doing this so I think I'm good there...

ParallelMonoOperation_zpsbad05945.jpg
 

tyu

Member
2009-07-18 8:16 pm
Right on the Parallel Mono .... Bob put the 1ohm res. in the output of the sunfire Current outputs ....ONLY....
Don't do it with the other Volt output or anyother SS Amp.

you state "you can damage the 22s interfaces with more power."
Is this from experience and what were you running?...........yes!

I have ran Acoustats with Amps like... Sunfire300s 600s.Krell ksa 150-250,Thresholds s/a500, Jadis defy7 tube amps, Halfer transNova
QSC pro amps.....that sound as good driving ESL as any amp I have ever owend...........

Look the 22 are at about 4ohms..........one great Sounding Sunfire 300 well putout real power... .600 watt is not needed for full output of any Acoustat!..............the mono well give each speaker it owen power supply..
thats a good thing....should sound great....go for it...
It not the amp only......if the 5k bias is low that feeds the panels....as the 10-15 pr of Acoustat interfaces I have seen were.........or the humidity is high!.....you can dump a lot of power into the Acoustat interfaces.........an cook the parts...an transfourmers...you cant just call Acoustat an get new parts....these speaker are 25 years old...........
If we were taken Big SoundLab ESL....you could use the power you well have...
An well work great with the Acoustats....it just not needed...I dout youll ever get 200 watts into the 22s.......have fun
 
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any of Ed Meitner's amplifiers (the STR50,55 and the MTR100,101) were designed with the Acoustat as the in house reference loudspeaker. All are mosfet output with dual diff fet input designs very similar to the best of the Luxman designs such as the L48a, L58a and the L68a which were the best amps Luxman has built imo. A STR50 or 55 sounds wonderful on the Acoustat.

all Meitner and Museatex equipment can be upgraded and serviced by Mr. John Wright who was part of Ed's design team and who now owns Museatex Audio.
http://www.museatex.com/
 
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Right on the Parallel Mono .... Bob put the 1ohm res. in the output of the sunfire Current outputs ....ONLY....
Don't do it with the other Volt output or anyother SS Amp.

you state "you can damage the 22s interfaces with more power."
Is this from experience and what were you running?...........yes!

I have ran Acoustats with Amps like... Sunfire300s 600s.Krell ksa 150-250,Thresholds s/a500, Jadis defy7 tube amps, Halfer transNova
QSC pro amps.....that sound as good driving ESL as any amp I have ever owend...........

Look the 22 are at about 4ohms..........one great Sounding Sunfire 300 well putout real power... .600 watt is not needed for full output of any Acoustat!..............the mono well give each speaker it owen power supply..
thats a good thing....should sound great....go for it...
It not the amp only......if the 5k bias is low that feeds the panels....as the 10-15 pr of Acoustat interfaces I have seen were.........or the humidity is high!.....you can dump a lot of power into the Acoustat interfaces.........an cook the parts...an transfourmers...you cant just call Acoustat an get new parts....these speaker are 25 years old...........
If we were taken Big SoundLab ESL....you could use the power you well have...
An well work great with the Acoustats....it just not needed...I dout youll ever get 200 watts into the 22s.......have fun

Thanks Tyu!!! You are saying it's over kill and I need to be careful!!! Got it!!!

I see your point about the Bias settings... I haven't really had these interfaces checked out, so I don't know for sure where they are set. And yes, your point about not having spares if I do "cook" something is a point well taken.

Guess I'll use the other Sunfire as a spare for now. Not like I can't sell it someday! And I will heed your advise and only run them off the single amp! :thmbsp:
 

tyu

Member
2009-07-18 8:16 pm
I well say out of all the Sand amps I have owned.....I was in the Audio sales in the 1980-90....we sold Carver ...I never cared for any of Bobs magic T amps....
But then came the Lite Star....Wow...
I think the Sunfire 300-600..Are some of the Best sounding Amp ever made.........An drive ESL like thay were 500lb Amps....but thay come in at about 40lbs.....Sweet sounding an real power.....an run cool....I like the sound of the ones with the fixet power cord..........

To day after I saw you post I pull my Acoustat setup out ....an just ran two panels per side...
An yes Any two panel Acoustat only always left me need More.....I think it well be the same for you...one more panel per side an the output gos up 3db more...
I love the sound of these speakers...
justsaying
 
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I well say out of all the Sand amps I have owned.....I was in the Audio sales in the 1980-90....we sold Carver ...I never cared for any of Bobs magic T amps....
But then came the Lite Star....Wow...
I think the Sunfire 300-600..Are some of the Best sounding Amp ever made.........An drive ESL like thay were 500lb Amps....but thay come in at about 40lbs.....Sweet sounding an real power.....an run cool....I like the sound of the ones with the fixet power cord..........

To day after I saw you post I pull my Acoustat setup out ....an just ran two panels per side...
An yes Any two panel Acoustat only always left me need More.....I think it well be the same for you...one more panel per side an the output gos up 3db more...
I love the sound of these speakers...
justsaying

Good input Tyu... I had a McCormack DNA-1 Deluxe driving these (185W@8ohms, 300W@4ohms and 500W@2ohms), but when I switched in the Sunfire 300, the Acoustats really opened up nicely! :p

I was just thinking mono-blocks might go another step further. But I do worry about frying them.

I may still try it and tread lightly. If the sound really improves then I can hopefully control my passion for +100db. Otherwise, if the sound doesn't improve much, I'll error on the side of caution and just run them off a single amp.

And yeah... I wish I had room for Spectra 33's... maybe someday! ;)
 
Acoustat recommended a minimum of 100 watts per channel for most of their models, but never specified a maximum power. This is somewhat analogous to saying there is no such thing as a car with too much horsepower, because in real-world driving, you can only use so much due to other limiting factors like competing traffic and speed limit laws.

That being said, I feel there isn't much advantage to using more than 250-wpc (8-ohm rating) for any of the models. You do want enough power to produce loud peaks without clipping, but there is a limit to how much the speaker can handle on average. One needs to be conscious of, and listen for, signs of distress from the speaker, like diaphragm rattling or obvious compression. Therefore, 250-wpc is a good maximum, used with some caution and prudence, because that much power CAN damage the speaker.

Also keep in mind that the stock 5-amp slow-blow fuse should not be relied upon to protect the speaker from ordinary over-driving conditions: its value was chosen to protect against catastrophic conditions.

Acoustat always recommended against the used of bridged amplifiers, since in that configuration, each half of the bridged amp effectively 'sees' only half the load impedance. Since the Acoustat's impedance can dip rather low to begin with, only half of that value that can give trouble to some amps, and won't deliver that much extra power anyway.

So, I would recommend sticking with a stereo amplifier (or true, non-bridged monoblocks) with a maximum of 250-wpc. This is definitely a case where quality of power is far more important than quantity of power.
 
So, I would recommend sticking with a stereo amplifier (or true, non-bridged monoblocks) with a maximum of 250-wpc. This is definitely a case where quality of power is far more important than quantity of power.

Thanks AcoustatMan, you've convinced me to stick with a single Sunfire 300!!! Man, the Spectra 22's sound nice being driven with that amp!
 
I think the Sunfire 300-600..Are some of the Best sounding Amp ever made....

Hi Tyu.... have you ever tried a Trans-Nova 200 and how would you compare that to the Sunfire? I've found one available, and realize they were built to drive the Acoustat ESL's. But I'm wondering if the Sunfire with the tracking down converter design might be a better option.

Thoughts about the two?
 

tyu

Member
2009-07-18 8:16 pm
No...not the old 200....
But I have 3ea of the later Last Hafler P7000 Transnova pro amps.375 watt per ch..mosfet outputs...
an as for how thay drive the Acoustats.....vary good..
but sound wizes....little to dark souning for me..... Sunfire sound vary hard to beat...vary good at driving any speaker....an a better topend than any mosfet amp I have had...in the current output.....
But I have move to amps with flat frequency response....as you know the Sunfire an Pass, krell,an most other high end amps are what I call Eq,ed...colored..little dark......in some ways......now in most speakers ....this can be a good thing with there dome or ribbon tweeter...that can get a little hot on the top...with mosfet sound... are the Eqing well forgive some of that.....but with ESLs...I don't find this to be needed....I like pro amps ...Like QSC....thay give a flater top end on my ML an Acoustats.....400 watts pr ch.. to drive with........only down side is thay have fans....but I feel that when I drive my ESLs hard...these fans are needed....I find the high end amps when driving Esls hard.... even get more colored the hoter thay get............ in my setup the sound of QSC even pushet out the sunfire...well I say the sound was as good....thats saying a hell of a lot....hands down I find the sunfire hard to beat..... it runs cool....I think that has a lot to do with the sound..like the fans............justsaying

The preamp I use most to day is a tube old hhscott 355....with tone controls..hehe
if I feel I need any Eqing I well be the one to do it....but with Esls I dont
all this is just one mans finding..........an one mans ears

Now have you ran your sunfire on the Vot output.....what do you think about the sound?........... diff in the current output...
an don't for get if you don't go......you wont know!
.thanks
 
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Now have you ran your sunfire on the Vot output.....what do you think about the sound?........... diff in the current output...
an don't for get if you don't go......you wont know!
.thanks

Thanks Tyu... I guess I'll pass on a Trans-Nova I saw for sale. I think you're right, the Sunfire is probably hard to beat for driving the ESL's!!! But I am looking for a Lightstar!!!

And no, I haven't tried the "Voltage Out" yet. I'm running "Lab In' and "Current Out"... The system is sounding nice! :yes:
 

tyu

Member
2009-07-18 8:16 pm
"Voltage Out"......well the lightstar....litesunfire...you only have to run the vot out..to hear what you well have with the star-amps.....you know not to run the Vot out if your running mono!.....Look I get your need to build "your"... ear sound memory....if don't go you wont know....I am all for it...

One thing to keep in mind.....from the transnova to the lite star an sunfire....all well need to be recapet..soon.....there all over 20years old....I sure you have seen this on others sites.....
I have found some time the stock sound changes when reworked..........my diy work on tube amps... has let me hear... that just a cap changes....can kill the sweet Stock sound...
Bob had a tek out west for years ....that rework the lightstar-sunfire.....but thay may be out of stock boards....If I were starting over to day...one of my frist amps would be some of Jeff Rowland .....some of the best of the best...if you like the sound...... but in the end... it the speakers......good luck on your quest...have fun
 
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One thing to keep in mind.....from the transnova to the lite star an sunfire....all well need to be recapet..soon.....there all over 20years old....I sure you have seen this on others sites.....
I have found some time the stock sound changes when reworked..........my diy work on tube amps... has let me hear... that just a cap changes....can kill the sweet Stock sound...
Bob had a tek out west for years ....that rework the lightstar-sunfire.....but thay may be out of stock boards....If I were starting over to day...one of my frist amps would be some of Jeff Rowland .....some of the best of the best...if you like the sound...... but in the end... it the speakers......good luck on your quest...have fun

I hear ya Tyu... there's a shop in Gresham, OR that I am going to have work on my "now" spare Sunfire to do all you are suggesting. They have a "Cabinet Refresh" option that basically goes through everything with a fine toothed comb. On the list of ToDo's along with a rebuild of the Interfaces by Roy! ;)

PS; and I will compare the Voltage out to the Current out! :yes:
 

tyu

Member
2009-07-18 8:16 pm
Do give your thinking on the sound of Voltage output........after haveing that big 50watt 1 ohm res an some eq-ing caps on the Sunfires current output....an the other one ohm res...in the input of the Acoustats 22.123 interfaces... there well be a diff.....
the Voltage output never inpresst me......after living with the current output on any speaker......But the QSC H output amps...there vary stabel......Just matches up with the tranfourms on these ESLs....great tone..........................Weird..even too me...... I have tride not to like there sound......hehe..........
thanks
 
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