FM Acoustics 268 preamp - the debate around its Linearizer

[docvale]

Wizard,

in your audioblog you've just uploaded some picks of electronics by YS Sound. They look like clones of FMA... what about them?

 

[A.wayne]

So after all these years , spectral could'nt get one of their amplifiers tested, ahhh yes ..


Also could not find any on FMA , I wish the few magazines who still test would start using the power cube to test amplifiers ..

 

[A.wayne]

Uh, what speakers do you need in order for them to be "appropiate" for Spectral amps??

8ohm high efficiency .... Speakers ...

 

[mep]

8ohm high efficiency .... Speakers ...

So you are saying that all Spectral amps can't handle impedance loads lower than 8 ohms? Oh Terry...

 

[ack]

8ohm high efficiency .... Speakers ...

Agree with mep. Don't even go there. You are WAY off. Just look at my speakers, 1 ohm. If you don't know enough about the product line, there are plenty of threads and comments on Spectral over here.

 

[A.wayne]

Agree with mep. Don't even go there. You are WAY off. Just look at my speakers, 1 ohm. If you don't know enough about the product line, there are plenty of threads and comments on Spectral over here.

Lol ,

Sorry i have to disagree with you, Spectral's output stage and small heatsink cannot drive a 1 ohm load , also Those ML's are not one ohm load speakers they are 1 ohm at high frequencies only(20k) , at a point where power demand is non existent nor demanding on amplifiers .

Connect it to a 1 ohm apogee and call MEP ..



Regards...

 

[A.wayne]

So you are saying that all Spectral amps can't handle impedance loads lower than 8 ohms? Oh Terry...

Additional info ,

You will find and using the Spectral as used by Ack as an example , that amplifiers will sound better if used in there quiescent power range which in this case appears to be 2 amps /ch ..

Hence my recommendation for the Spectral to Be used on high efficiency 8 ohm speakers , this is not to say it cannot be used on anything else as you implied with your usual specious argument ..

As simplistic as possible ,

You see SS AMPS. Tend to suffer thermal drift and designs are made to compensate for such , dependent on usage , it's for such reason Pass uses such high bias and temperature control , as he forces the amp to stay into its thermal sweet spot before drifting changing sonics. Some choose another approach prefering to use cooler operation , as that spectral heats up and operates out of its quiescent region distortion increases , yes you may like it sonIcally , when steaming along , just means you are in favor of its distortion signature and others may not ..

This is why there's no consensus in audio or very rarely , so stop knocking and start enjoying ..

Regards ,

 

[FrantzM]

Lol ,

Sorry i have to disagree with you, Spectral's output stage and small heatsink cannot drive a 1 ohm load , also Those ML's are not one ohm load speakers they are 1 ohm at high frequencies only(20k) , at a point where power demand is non existent nor demanding on amplifiers .

Connect it to a 1 ohm apogee and call MEP ..



Regards...

8ohm high efficiency .... Speakers ...

Inside of the Spectral DMA-180 Stereo amplifer, note the size of the heat sinks ...



The specs:
Power Output:
(continuous)

@ 8 ohms - 200 Watts RMS
@ 4 ohms - 400 Watts RMS
@ 2 ohms - 683 Watts RMS


Inside of the 411 Note the size of the heat sink


The specs

160 W RMS into 8 Ohms
290 W RMS into 4 Ohms
500 W RMS into 2 Ohms

SHould we assume by the same logic that (small Spectral heatsink, etc) that the FMA Resolution 411 can't drive 1 Ohm? Just asking ...

 

[A.wayne]

Inside of the Spectral DMA-180 Stereo amplifer, note the size of the heat sinks ...

View attachment 5580

The specs:
Power Output:
(continuous)

@ 8 ohms - 200 Watts RMS
@ 4 ohms - 400 Watts RMS
@ 2 ohms - 683 Watts RMS


Inside of the 411 Note the size of the heat sink

View attachment 5581
The specs

160 W RMS into 8 Ohms
290 W RMS into 4 Ohms
500 W RMS into 2 Ohms

SHould we assume by the same logic that (small Spectral heatsink, etc) that the FMA Resolution 411 can't drive 1 Ohm? Just asking ...

Frantz,

We were discussing another Spectral model , I would say both amps would have to be fan cooled to handle 1 ohm based on What I'm seeing , in the pictures posted. The FMA is using 4pr outputs per channel which will have to put out 20 amps/ ch to sink 400 watts into 1ohm , that's 5 amps per output /half and I'm not sure what FMA is using for outputs , but it seems likely to exceed SOA for 1 ohm operation , I would like to see at least 6Pr At a min for 1 ohm operation , preferably 8 pr/ ch ..

So no I would say both would have issues running continuously at 1 ohm ....

Regards ,

 

[mep]

Hopefully Terry will speak-up and tell his thoughts on what type of speakers Spectral amps are capable of driving. Personally, I don’t think they are limited to “efficient” speakers.

post edited

 

[mep]

Frantz,

We were discussing another Spectral model , I would say both amps would have to be fan cooled to handle 1 ohm based on What I'm seeing , in the pictures posted. The FMA is using 4pr outputs per channel which represents 4 amps per output half and I'm not sure what FMA is using for outputs , but it may exceed SOA for 1 ohm operation .

So no I would say both would have issues running continuously at 1 ohm ....

Regards ,

How did we go from you saying that Spectral was best suited for 8 ohm loads to discussing 1 ohm loads? Few amps can run continuously into a 1 ohm load.

 

[A.wayne]

Also , both above examples were starting to current limit going into 2 ohm , I would believe the bigger FMA model to be the most appropriate one for low impedance operation . That aside if you listen at pretty moderate levels , both of the above Amps may have no issues driving an 1 ohm load , if stability is not an issue ..


Since we were discussing in absolute terms then no , after all this is the best of the best forum ...

 

[FrantzM]

Frantz,

We were discussing another Spectral model , I would say both amps would have to be fan cooled to handle 1 ohm based on What I'm seeing , in the pictures posted. The FMA is using 4pr outputs per channel which will have to put out 20 amps/ ch to sink 400 watts into 1ohm , that's 5 amps per output /half and I'm not sure what FMA is using for outputs , but it seems likely to exceed SOA for 1 ohm operation , I would like to see at least 6Pr At a min for 1 ohm operation , preferably 8 pr/ ch ..

So no I would say both would have issues running continuously at 1 ohm ....

Regards ,

So the FMA amplifers also would prefer to paraphrase you , 8 ohms, high efficiency speakers.. I had thought that to you that was a weakness of Spectral amps, those with small heatsink and that are unusually sensitive to thermal drift. May I ask you is it is a fact or a simple opinion? How do you know they (Spectral) are sensitive to thermal drift and how do you know the FMA aren't? You assert those points, can you prove them or show us some reference that would help? Also do you have any idea of how the linearizer works and how well it compares to other solution or PEQ?

 

[A.wayne]

So the FMA amplifers also would prefer to paraphrase you , 8 ohms, high efficiency speakers.. I had thought that to you that was a weakness of Spectral amps, those with small heatsink and unusually sensitive to thermal drift. May I ask you is it is a fact or a simple opinion? How do you know they are(Spectral) are sensitive to thermal drift and how do you know the FMA aren't? You assert those points, can you prove them or show us some reference that would help? Also do you have any idea of how the linearizer works and how well it compares to other solution or PEQ?

Hello Frantz,

No,

but I see theirs a word game at play, so have to thread carefully ..

I never meant to say nor imply spectral amp had an weakness , I had suggested what my speaker preference would be if i was running spectral equipment ..as to thermal drift all ab amplifiers suffer from it , class - a and to the other extreme class-d Dance's around it..

Regards ,

 

[A.wayne]

Franz,

I have no clue as to how FMA is doing their EQ , I was not able to find any technical details on it ...

Regards ,

 

[Steve Williams]

Posts edited and others deleted

I am going to suggest you both take a time out. While you do please read our TOS as name calling isn't tolerated here

Thanking you both in advance that we can happily keep this thread moving along. Challenge the post, not the poster

 

[A.wayne]

Franz,

Here's a beast ....

http://www.krellonline.com/evolution402e.html

Regards,

 

[mullard88]

The Spectral linestage in post #41 is not a DMC 20 but is one of the iterations of the DMC 30 series.

 

[XV-1]

Do you believe in equalization?
Why would anyone risk their reputation by putting an equalizer in a high end component? Or are we missing something?

Seems Dan D is putting his reputation up for ridicule for including tone controls on his long awaited Momentum pre amp debuting at CES.

Myself, looking forward to how it sounds with tone controls bypassed and used.

 

[FrantzM]

Seems Dan D is putting his reputation up for ridicule for including tone controls on his long awaited Momentum pre amp debuting at CES.

Myself, looking forward to how it sounds with tone controls bypassed and used.

Well the way I see things going, why not? After all we have very expensive, thus well respected cables with "Articulation Poles' so why not change the sound before the amp? Tone Control by any other names? Will we see a return of the graphic EQ of the 70's?