Extremely low S/N ratio amp choices? - AVS Forum
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post #1 of 39 Old 04-10-2010, 07:32 AM - Thread Starter
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I have some new DIY speakers (waveguide designs), The tweeters have 105dB sensitivity with normal amps and decent S/N ratios there is a hiss (when there is no content) this is about 60dB 1" from the throat of the tweeter.

I need to know if there are some extremely low S/N choices out there so that I can reduce the hiss by 10dB. I can do it with an Lpad but that is just wasting power.


EDIT: Sorry, I mean higher S/N ratios.

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post #2 of 39 Old 04-10-2010, 08:17 AM
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Anthem PVA series.
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post #3 of 39 Old 04-10-2010, 08:27 AM
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Correct me if I am wrong, but did you mean higher S/N ratios?
I always thought amps or receivers with lower S/N numbers are the ones that induce more background noise. For example: amp A with S/N 115 db would be quieter than Amp B with S/N of 105 db. Taking into account if both amps are 150 watts per channel (RMS 20-20K), having a THD of .007 percent and other factors are the same, would you choose Amp A? Please enlighten me, maybe I am missing something here.
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post #4 of 39 Old 04-10-2010, 08:47 AM
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Quote:
Originally Posted by cyphrex View Post

Correct me if I am wrong, but did you mean higher S/N ratios?
I always thought amps or receivers with lower S/N numbers are the ones that induce more background noise. For example: amp A with S/N 115 db would be quieter than Amp B with S/N of 105 db. Taking into account if both amps are 150 watts per channel (RMS 20-20K), having a THD of .007 percent and other factors are the same, would you choose Amp A? Please enlighten me, maybe I am missing something here.

He clearly meant "low noise" which equals higher S/N and simply "misspoke."
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post #5 of 39 Old 04-10-2010, 09:00 AM
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i recently picked up a ati 3006 amp to use with my JTR Quintuple speakers, i had some hiss with my emotiva that could be heard from a few feet away, with the new amp i had to put my ear up to the tweeter to hear anything at all. still some noise, but tons of improvement. there are lots of people that say dead quiet, but i do wonder about that especially with the highly sensitive tweeters.
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post #6 of 39 Old 04-10-2010, 09:08 AM
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Quote:
Originally Posted by rto View Post

He clearly meant "low noise" which equals higher S/N and simply "misspoke."

I figured as much and +1 to your Anthem PVA suggestion.
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post #7 of 39 Old 04-10-2010, 11:19 AM - Thread Starter
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yep, sleepy confusion and a bad explanation of my needs.

Thanks for the correction...

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post #8 of 39 Old 04-10-2010, 11:22 AM - Thread Starter
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FWIW, My current amps are the Outlaw M2200 and they have these specs

Outlaw M2220
THD Signal to Noise: 112 dB "A" weighted


I not sure if its accurate.

Thanks guys for suggestions! Yes the Emotiva's have a similar noise level to the Outlaw amps. I had the XPA-5 with my ribbon tweeters and I remember the hiss there too.

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post #9 of 39 Old 04-10-2010, 11:26 AM - Thread Starter
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Anthem PVA 4 is 122 db, A-weighted, nice!

Down side is no XLR inputs. Sorry I didnt mention that I require amps with balanced inputs.

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post #10 of 39 Old 04-10-2010, 11:38 AM
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The ATI 3000 series has XLR inputs, it's s/n ratio is greater then 120db below the rated full bandwidth power of 300@8ohms and 450@4ohms.
the ATI 2000 series has XLR inputs and same ratio and is rated for 200/300.

They can be found decently cheap, and they make amps for earthquake, adcom, outlaw and quite a few others.
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post #11 of 39 Old 04-10-2010, 12:12 PM - Thread Starter
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Very cool, I will have too keep looking for a good used price.

I only need about 75Watts since these Compression drivers are insanely loud to start with.

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post #12 of 39 Old 04-10-2010, 12:23 PM - Thread Starter
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I wonder if those ratings are full power?

I noticed Emotiva gives S/N at 1 Watt

Quote:


• Signal to Noise Ratio:
1 watt: >89db
Full Power: >117db


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post #13 of 39 Old 04-10-2010, 02:08 PM
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Hai,

All i can say is that my denon avp / poa combo is silent when there is no audio signal period. I can put my ear as close as i can get. Its the first combo (for me) that has this effect and ive seen several reviewers also comment on this. I guess no-noise on no-audio is like blacklevels on a projector its something you notice once you hear/see it.

Daniel.

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post #14 of 39 Old 04-10-2010, 02:19 PM
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i think the sunfire cinemagrand series II--at least the 400X5 model had a reported snr of 118dB and has balanced ins--dont know which sunfire you had before (or still have) but if I remember correctly it was pretty high--my own is dead silent through the 91dB efficient focal 1027be's via a parasound c1. Definitely no where near as sensitive as what you are using though.
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post #15 of 39 Old 04-10-2010, 06:46 PM
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Quote:
Originally Posted by danielo View Post

Hai,

All i can say is that my denon avp / poa combo is silent when there is no audio signal period. I can put my ear as close as i can get. Its the first combo (for me) that has this effect and ive seen several reviewers also comment on this. I guess no-noise on no-audio is like blacklevels on a projector its something you notice once you hear/see it.

Daniel.

just wondering how sensitive your speakers/tweeter is.


i mentioned some noise on mine, but keep in mind that my tweeters are rated for 111db sensitivity, or at least the is what that spec sheet says.
my noise sounds a bit like emi and not hissing.
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post #16 of 39 Old 04-10-2010, 08:11 PM - Thread Starter
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Quote:
Originally Posted by Denophile View Post

i think the sunfire cinemagrand series II--at least the 400X5 model had a reported snr of 118dB and has balanced ins--dont know which sunfire you had before (or still have) but if I remember correctly it was pretty high--my own is dead silent through the 91dB efficient focal 1027be's via a parasound c1. Definitely no where near as sensitive as what you are using though.

I had the sunfire Signature series. There was a hiss with 110dB sensitivity drivers.

I think its important to note that we are not talking about any domes here. My domes are dead silent on my amps.

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post #17 of 39 Old 04-10-2010, 08:15 PM - Thread Starter
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Quote:
Originally Posted by danielo View Post

Hai,

All i can say is that my denon avp / poa combo is silent when there is no audio signal period. I can put my ear as close as i can get. Its the first combo (for me) that has this effect and ive seen several reviewers also comment on this. I guess no-noise on no-audio is like blacklevels on a projector its something you notice once you hear/see it.

Daniel.

do you have > 95dB drivers?

You point about once you hear it is so true. In between songs, turning the system on and before playing content. There is the hiss. First thought is boy is that distortion what will it sound like during playback?

Now in a normal environment at 8 feet it isnt a big deal considering the house will have ambient noise but this is my HT room and its decent room with treatments so the hiss is something Im looking at figuring out.

I can Lpad my designs down 10dB and the hiss is not noticeable. That is still an option but in this thread Im just wondering if there are amps that really have a far better S/N ratio.

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post #18 of 39 Old 04-10-2010, 08:17 PM
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Quote:
Originally Posted by penngray View Post

I wonder if those ratings are full power?

I noticed Emotiva gives S/N at 1 Watt


I wish more manufacturers would do that, give out a S/N rating at 1 watt as well as full power altogether.
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post #19 of 39 Old 04-10-2010, 08:19 PM - Thread Starter
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Quote:
Originally Posted by cyphrex View Post

I wish more manufacturers would do that, give out a S/N rating at 1 watt as well as full power altogether.

In my case, I think I need to know the 1Watt value. Since its only during during min-voltage times that I hear the hiss.

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post #20 of 39 Old 04-10-2010, 08:24 PM
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Of course there is some info that is supposed to help compare some amps that are rated at 1 watt with others that are rated at higher wattage with some formulas to get a better representation. I thought this was useful.

http://www.bcae1.com/sig2nois.htm
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post #21 of 39 Old 04-10-2010, 08:25 PM
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Quote:
Originally Posted by penngray View Post

In my case, I think I need to know the 1Watt value. Since its only during during min-voltage times that I hear the hiss.

That makes more sense and is more realistic.
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post #22 of 39 Old 04-10-2010, 11:57 PM
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Quote:
Originally Posted by penngray View Post

do you have > 95dB drivers?

You point about once you hear it is so true. In between songs, turning the system on and before playing content. There is the hiss. First thought is boy is that distortion what will it sound like during playback?

Now in a normal environment at 8 feet it isnt a big deal considering the house will have ambient noise but this is my HT room and its decent room with treatments so the hiss is something Im looking at figuring out.

I can Lpad my designs down 10dB and the hiss is not noticeable. That is still an option but in this thread Im just wondering if there are amps that really have a far better S/N ratio.

They are only about 91dB so no, but i just did drive them not to 0dB but to the max i can 16.5dB to compensate for you. At that point (that is full blast, never try this with music level). In bridge mode (stereo and pure-direct so 4 amps involved) each channel then has a output of about 400 - 500watts.

In stereo i could now hear a hiss at about 20cm. In pure direct i could now hear a hiss at about 10cm.

Sorry if i can't be of more help, but for a 10 channel amp i consider this very good and like i stated before its the first combi that is this silent for me i am sure there are others i just haven't tried them.

Daniel.

PS: i did put the 0dB limiter back on after the test, having some visitor turn the knob to full blast scared the hell out of me

PS2: if you want i can ask in our owners thread probably someone with more sensitive speakers that can test for you.

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post #23 of 39 Old 04-11-2010, 04:58 AM - Thread Starter
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Quote:
Originally Posted by cyphrex View Post

Of course there is some info that is supposed to help compare some amps that are rated at 1 watt with others that are rated at higher wattage with some formulas to get a better representation. I thought this was useful.

http://www.bcae1.com/sig2nois.htm

Thanks for the link!

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post #24 of 39 Old 04-11-2010, 05:45 AM
 
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Anyone ever compare these monster weight, heavy transformer based units, with one or two of these light weight Class AB, 4 channel, 'newer' design amps:

DCM2004L Features
- Ultra-light 10 lbs
- noise less than -106dB for studio applications
- Ultra-low THD (20-20k Hz 50% power) 0.03%, (20-20k Hz 90% power) 0.1%
- Full 3-year warranty (USA) - Made in the USA

The Manufacturer's price is $529 each.
http://www.carvinguitars.com/product...oduct=DCM2004L

Caveat: there is some conflicting information as to which models are Class AB and which Class D, and this seems to be date dependent.

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post #25 of 39 Old 04-11-2010, 06:12 AM - Thread Starter
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Quote:


Anyone ever compare these monster weight, heavy transformer based units, with one or two of these light weight Class AB, 4 channel, 'newer' design amps:


Yes, they are doing some over in DIY, Carvin, Peavey even Behringer has some lighweight high powered choices on the pro audio side but I will already tell you they are not what Im looking for in this thread.

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post #26 of 39 Old 04-11-2010, 06:17 AM
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Quote:
Originally Posted by iq100 View Post

Anyone ever compare these monster weight, heavy transformer based units, with one or two of these light weight Class AB, 4 channel, 'newer' design amps:

DCM2004L Features
- Ultra-light 10 lbs
- noise less than -106dB for studio applications
- Ultra-low THD (20-20k Hz 50% power) 0.03%, (20-20k Hz 90% power) 0.1%
- Full 3-year warranty (USA) - Made in the USA

The Manufacturer's price is $529 each.
http://www.carvinguitars.com/product...oduct=DCM2004L

Caveat: there is some conflicting information as to which models are Class AB and which Class D, and this seems to be date dependent.

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From specification it is clear that this is Class D amplifier with switched power supply. I do not thing that it is suitable for Hi-Fi audio in any role other than subwoofer amplifier.
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post #27 of 39 Old 04-11-2010, 06:37 AM
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Unfortunately, amp noise can vary substantially among units with the same on-paper specifications. After Audyssey calibration, with the volume control set to 0 db, I have to put my ear right up to a tweeter to hear any hiss from my Marantz AV8003 prepro (105db snr) + MM9000 amp (95db snr). Others report being able to clearly hear hiss at their listening positions when using an AV8003+MM8003 amp (105db snr).

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post #28 of 39 Old 04-11-2010, 06:42 AM
 
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Quote:
Originally Posted by ap1 View Post

From specification it is clear that this is Class D amplifier with switched power supply. I do not thing that it is suitable for Hi-Fi audio in any role other than subwoofer amplifier.

Thanks for looking at this. Carvin pre-sales support told me that some of the DCM...L models are in a process of moving from Class D to AB.
In any case the DCM1540L is clearly Class AB.
http://www.carvinguitars.com/manuals...eries-0709.pdf
So same question, but substitute DCM1540L for DCM2004L.
Do you/anyone think that this is 'suitabled for Hi-Fi audio'?
At least the specs look comparable to the best in breed heavy transformer based units.
But I am looking for hands on testing links, or personal experience.

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post #29 of 39 Old 04-11-2010, 06:58 AM
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Quote:
Originally Posted by iq100 View Post

Do you/anyone think that this is 'suitabled for Hi-Fi audio'?

If you look at pro type equipment, you need to choose devices made for studio use other than for concert application. There are very different requirements for them. Home use is closer to studio rather than to live performance at large venue.
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post #30 of 39 Old 04-11-2010, 07:04 AM
 
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Quote:
Originally Posted by penngray View Post

Yes, they are doing some over in DIY, Carvin, Peavey even Behringer has some lighweight high powered choices on the pro audio side but I will already tell you they are not what Im looking for in this thread.

Would you have a link to this testing?
Thanks,

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