FM Acoustics 245

ack

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I enjoyed the review; one comment:

Many audiophiles say FM Acoustics components sound very fast - fast songs sound faster. [...] The length of the song does not change, but the impression is that it sounds faster. I believe this is due to the incredibly fast rise times of FM Acoustics pre and power amps.

Indeed. This is one of those things that differentiate really fast circuits from all others. I hear this false "faster" tempo with the Spectrals too.
 

FrantzM

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Apr 20, 2010
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Hi

A friend of mine had an FMA amp and stupidly sold it ... He is regretting it to this day after maybe 20 years ...

Concerning the "speed" of FMA.. From the specs nothing tells me they are any faster than say, Spectral or some Krell. The bandwidth is inline with decent SS and I didn't nore anything particular about these IMO. Spectral is Wideband , some Krell are wideband they go to MHz, so does Goldmund but what I see from the FMA is not exactly "wideband"
For example for the 411 MKII amp those are the specs:

Bandwidth including Input Filter:
Less than 1 Hz to 60 kHz;
if required, internally settable to any frequency between 1 kHz and 60 kHz (Low-Pass) and
1 Hz to 1 kHz (High-Pass).

Risetime at Full Power: 3 us

Good but nothing close to Spectal 3 Mhz bandwidth at -3dB ... or rise time of 400 nanoseconds .. 7 times faster than the FMA ....

I find the FMA numbers good but noting exceptional.. THose of Spectral defintely are ...
As for the sound .. Don't know .. I haven't head one for 15 years so ... But the last I heard was superb...
 

ack

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It's great stuff regardless. Next question... Up until the advent of the Spectral 30SS preamp with its presumably ultra-exotic volume pot, both of these lines were using a conductive plastic pot. I believe FMA still does? What can you tell us about it?
 

ack

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docvale

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... I find the FMA numbers good but noting exceptional.. THose of Spectral defintely are ...
As for the sound .. Don't know .. I haven't head one for 15 years so ... But the last I heard was superb...

So, the only FMA encounter I had was with a 122 phono preamp (don't know which generation, it was 2006 and it was new, though), linking a Basis+Lyra analog front end to Spectral amplification and Magico Mini speakers.
The sound was truly amazing! :eek:

Once I read on an Italian forum: "If you look inside an FMA preamp or power amp you'll have the impression that the construction level is not impressive at all, but the sound is fantastic, addictive".

Wizard, congrats for your system! :)
It's for sure at the level of a TWBAS ;)
 

Steve Williams

Site Founder, Site Owner, Administrator
So, the only FMA encounter I had was with a 122 phono preamp (don't know which generation, it was 2006 and it was new, though), linking a Basis+Lyra analog front end to Spectral amplification and Magico Mini speakers.
The sound was truly amazing! :eek:

Once I read on an Italian forum: "If you look inside an FMA preamp or power amp you'll have the impression that the construction level is not impressive at all, but the sound is fantastic, addictive".

Wizard, congrats for your system! :)
It's for sure at the level of a TWBAS ;)

I agree

I would love to see photos of the system as a whole
 

mep

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I thought it was odd that a reviewer who has some dirt cheap components in his system and couldn't tell hiss from brushes on a drum or cymbal would be given gear at this level to insert and review in his system. And everyone who says when you look at the inside of FM gear and you won't be impressed, they are right.
 

flez007

Member Sponsor
Aug 31, 2010
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I already hate you wizard! :D (jokes aside...I stand next to Steve on the pics request!)
 

garylkoh

WBF Technical Expert (Speakers & Audio Equipment)
Sep 6, 2010
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What makes it so famous?

The two most difficult things for an audio attenuator to do are inter-channel tracking and log tracking (let's not go into the 'sound' which cannot be adequately measured to satisfy the objectivists).

1) Inter-channel tracking means that at any one position on the dial, one channel tracks the next channel. For example, 3dB to -40dB. This means that at any one position from -40dB to 0dB, the channels are within 3dB of each other. Unfortunately, at -40dB you are still plenty loud. So, at low listening levels, your left channel could be more than 3dB louder than the right channel. Ideally, you will want 0.5dB at -100dB - but I haven't found a pot that does that. I don't think that any exist.

2) Our ears hear exponentially, and hence for a volume to be twice as loud, you have to have a 10x increase in power. For a volume pot, you need a log taper, and not a linear taper. Log taper that accurately tracks the log curve is hard to do. When the pot taper doesn't track the log curve, you get strange shifts in volume when you turn the knob. What's worse, if the pot doesn't accurately track the log curve, it is doubly hard for it to match the other channel.

The "Blue Velvet" or RK27 has one of the best specs of the above two measurements. (Interestingly, the RK27 while sold as "log taper" does not curve-fit to real log but it sounds "correct" and the curve track is very smooth - not two linear in parallel which some manufacturers use to approximate log.)

I am not surprised to see the RK27 pot in the FM245 because it's a single-ended preamp with balanced outputs. However, I am very surprised to hear that the motorized version is used in the 268. This is because the RK27 pot is only manufactured for 2-channel. For a true balanced preamp, you need a 4-channel attenuator - left +ve and -ve, right +ve and -ve.

Also, just because you see "ALPS" on the pot does not mean that it's good. Alps makes a wide variety of pots, from the truly excellent RK27 to what I would consider to be junk.

Sorry ack, long reply to a very short question.
 

ack

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Thanks for the excellent and detailed response. Next - how does this pot measure when it comes to channel cross-talk?
 

nirodha

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Aug 11, 2010
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All those "open" shots of components...it is almost audio porn haha ;)
Unfortunately I have never been able to listen to FM acoustics. Which of course makes me curious ánd suspicious. Curious, because I always want to hear things that are reputedly "the best". Suspicious, because a company can hide itself from real criticism by not giving their products to professional reviewers. There is one specific question concerning FM acoustics. I hope some of the owners here can shed a light on this. On the one hand the amps are labelled: fast, no overhang, uncoloured. On the other hand though, the loudspeakers are called: sleep inducing, mild, relaxing. So....what does FM acoustics stand for? Please note, this is not a FM Acoustics bashing, just curiosity. :p
 

nirodha

Well-Known Member
Aug 11, 2010
679
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All those "open" shots of components...it is almost audio porn haha ;)
Unfortunately I have never been able to listen to FM acoustics. Which of course makes me curious ánd suspicious. Curious, because I always want to hear things that are reputedly "the best". Suspicious, because a company can hide itself from real criticism by not giving their products to professional reviewers. There is one specific question concerning FM acoustics. I hope some of the owners here can shed a light on this. On the one hand the amps are labelled: fast, no overhang, uncoloured. On the other hand though, the loudspeakers are called: sleep inducing, mild, relaxing. So....what does FM acoustics stand for? Please note, this is not a FM Acoustics bashing, just curiosity. :p

No one? Wow...
 

mep

Member Sponsor & WBF Founding Member
Apr 20, 2010
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Odd that it has 4 sets of unbalanced RCA inputs (5 if you include the tape input) and only one set of main outputs which are balanced. This appears to be an older entry level looking preamp, but I'm sure it cost a gazillion dollars and sounds better than live music.
 

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