Noisy amps with high sensitivity speaker systems

[bracurrie]

I finally have a system that seems to my ear to be be as true to reproduction as I have ever heard. So now I think I want to attack the noise and hiss at low volume. I am using a Faital HF200 16 ohm on Fastrac 400 horns. At listening position I can hear the noise at quiet times or in between songs and I wonder if I can get better. When the joyfull noise erupts its a non issue, but there are some classical and jazz numbers where it becomes a distraction. Is this what I have to put up given high sensitivity speakers?

Brad

[russ69]

You have a gain mismatch between some of your gear. Put a 3 or 6db pad between your pre and amp. That should do the trick.

http://www.parts-express.com/pe/showdetl.cfm?partnumber=266-242

[Dr Morbius]

bracurrie, I also have a system that seems to my ear to be be as true to reproduction as I have ever heard. I have a Scott 299D tube amp hooked to Cornscala's and a very good dedicated Marantz CD player. The problem I feel you're having is the same as mine. I believe it has to do with how the CD's are mastered. I have a Stowkowski remastered cd that was highly rated by Amazon critics and I hear hiss at the beginning and end of each Beethoven piece (orig. recorded in 1957) I put up with it because the music itself is of a very high quality. On the other hand my #1 test cd for showing off my speakers is Bernard Herrmann's "Mysterious Island" cd which was recorded just a few years ago and is super quiet before and after each song. { Fabulous recording, by the way } so, to sum up, the older recordings will have a bit of hiss where the newer ones , if they are good, will not.

Another example of a different kind is I purchased, again on the advice of Amazon critics a recording of Chopin's Nocturnes by M. Paolini (i think that's how you spell it) and when I popped it in, I heard a fairly nice recording of Chopin, except that next to the pianist it sounded like Dennis Hopper from "Blue Velvet" was sitting next to him breathing through his emphysema/asthma machine at full blast! Not Good! I suppose it was a bad placement of a microphone. I now see that some new Amazon critics since I purchased it have said pretty much the same thing - they must be owners of Klipsch speakers!

[DrWho]

What gear are you currently using in your system?

[bracurrie]

Thanks Doc. But I hear noise when nothing is playing either. I have a good digital black test track and the problem exists. Some recordings are just noisy and that is compounded when you have horn systems, but its really a good problem because I love the detail like hearing horn players breathe.

[bracurrie]

What gear are you currently using in your system?

AR sp6 preamp miniDSP Audio by Van Alstine Synergy 240 for low end and Psvane TS66 Integrated Tube Amplifier for HF using ?Faital HF200 16ohm on Fastrac 400 horns.

[bracurrie]

Thanks for the suggestion. I unplugged the input to the amp and the noise is still there.

Brad

[Don Richard]

If turning the volume control on the integrated amp does not affect the noise there is either something wrong with the amp, maybe a noisy tube, or the amp may just be noisy by design. There are amps that do not do that in bi-amped systems, you may need another amp that suits your purposes better.

[mark1101]

It's nice to have an amp with gain controls so you can minimize the noise among other things.

[LarryC]

If turning the volume control on the integrated amp does not affect the noise there is either something wrong with the amp, maybe a noisy tube, or the amp may just be noisy by design.

Not necessarily and perhaps not even likely -- someone suggsted a gain-matching issue, and that's my thought too -- There may be too much gain in the amp, and you are hearing magnified PRE-AMP noise. IOW, I don't think it's amp noise.

I prefer low-gain amps for that reason, say on the order of 2 or 2.5 v. for full power out. Too many amps require only 0.5 or 1.0 v for FP, and that's too much gain EDIT: for very high efficiency speakers. Mark was on the right track in suggesting the advantage of volume controls on the amps.

[bracurrie]

If turning the volume control on the integrated amp does not affect the noise there is either something wrong with the amp, maybe a noisy tube, or the amp may just be noisy by design. There are amps that do not do that in bi-amped systems, you may need another amp that suits your purposes better.

I have used a Hafler, Adcom, Phase Linear and my Van Alstine and they all to some degree or another had audible noise at the listening position. The Psvane TS66 Integrated Tube Amplifier I just acquired is the worst but sounds the best. The amplifier volume attenuation doesn't affect the noise and having no source attached also doesn't change the noise. So how about reasonably priced tube amps with better signal to noise ratios that 66db? Does anyone know the sensitivity of Faital HF200/Fastrac 400 system? Maybe I could make them less efficient. [*-)]

[Don Richard]

There are several amps I know of that are dead silent with horn loudspeakers. The most surprising is a Crown XLS-402 (old style) that I am using now. On stock Khorns I could put my ear in the top horns and they were dead silent. I had an inexpensive Yamaha 2 ch. receiver that was the same way. Same with a Mitsubishi receiver. 27 years ago I had a 300 wpc Yamaha Reference amp that was totally quiet, on the same Khorns. Not at the listening position, right at the speaker.

Now I am using the XLS for a bass amp with 2 Crown Xtis driving the tops in a triamped configuration. I can hear noise from the tops 2 feet away but not at the listening position. The top horn's driver has a 111 dB sensitivity and is directly wired to the amp with no passive crossover or blocking cap.

[mikebse2a3]

I have used a Hafler, Adcom, Phase Linear and my Van Alstine and they all to some degree or another had audible noise at the listening position. The Psvane TS66 Integrated Tube Amplifier I just acquired is the worst but sounds the best. The amplifier volume attenuation doesn't affect the noise and having no source attached also doesn't change the noise.

Something more seems to be going on here. Just in case I will mention that if you are using typical dimmers for light control in the room they can cause radiated noise issues like you describe.

If my experience helps any I can say having used several Hafler amps on Khorns, LaScala and Belles noise was never an issue.

I also have used 2 different 2A3 based single ended amps on my TAD/K402 HF and you have to place your ears at the horns mouth to hear any hiss noise. Likewise my friends 300B amps are just as noise free on his K402/TADs

Don's comments are correct in that if you have no sources connected and your volume control is all the way down look toward amplifier issues or a radiated noise source especially since it seems all the amplifiers are giving you noise at the listening position.

miketn

[bracurrie]

Something more seems to be going on here. Just in case I will mention that if you are using typical dimmers for light control in the room they can cause radiated noise issues like you describe.

Gonna use some short speaker wires to test and have determined I have no dimmers in the building. Do you recall the signal to noise ratio of the amps you mentioned?

[bracurrie]

The most surprising is a Crown XLS-402 (old style) that I am using now. On stock Khorns I could put my ear in the top horns and they were dead silent.

I looked them up and SNR was 100 db, but so was Xtis, so whats different?

[derrickdj1]

Vintage Yamaha amp are dead quiiet. I use M 80 an M 70 amps and you can hear a pin drop between songs. I prefer silent amp with no hiss, hum, ect.

[Don Richard]

I looked them up and SNR was 100 db, but so was Xtis, so whats different?

I hooked them up and listened. I also measured the S/N on the Xti and it was more like 88 dB. The newer XLS amps have switch mode power supplies, the older ones like I have use bulk power supplies with large transformers.

[LarryC]

If my experience helps any I can say having used several Hafler amps on Khorns, LaScala and Belles noise was never an issue.

I also have used 2 different 2A3 based single ended amps on my TAD/K402 HF and you have to place your ears at the horns mouth to hear any hiss noise. Likewise my friends 300B amps are just as noise free on his K402/TADs

Don's comments are correct in that if you have no sources connected and your volume control is all the way down look toward amplifier issues or a radiated noise source especially since it seems all the amplifiers are giving you noise at the listening position.

Mike, what was the gain and sensitivity of those Hafler amps?

I still think mucking around with amp S/N's is off the track -- you are most likely NOT hearing amplifier noise! IMO you are most likely hearing preamp noise magnified by a high amp gain and speaker efficiency. Also, it's preamp noise after the volume control, which means that turning the VC up and down won't affect it.

This means that low-watt SET's should be nearly silent.

[Panacea Engineering]

FWIW - The newer Compact Fluorescents or for that matter, any Fluorescents with Electronic Ballast will put out RF that your Horn Drivers can/will pick up. In some cases, you can get noise without the amp being connected. Also, some types of amps will pick up this signal. There are so many areas that noise can be generated these days, it is really very hard to track the source down. Don't just linit yourself to connections.......you have to look at everything that is related to the listening space.

[bracurrie]

I still think mucking around with amp S/N's is off the track -- you are most likely NOT hearing amplifier noise!

Thanks for chiming in. I do need to point out that the noise is the same whether I have the preamp connected or not. Also, I have turned off all HVAC refrigerators and all lights with no impact. The S/N is 66db for my amp. I thought the volume control on the amp was an attenuator. It has no impact on the noise.