Very efficient speakers (100 dB), how important is amplifier power?

[Flavio]

It matters because some amps are much quieter than others. There's no such thing as "no hiss". Just degrees. It's measurable just like everything else.

True, but it seems that the quieter amps are also the more powerful ones (and more expensive) so it is a question of finding the right balance.

 

[fpitas]

True, but it seems that the quieter amps are also the more powerful ones (and more expensive) so it is a question of finding the right balance.

Not always. My J2 for example is very quiet indeed, suitable for direct connection to 111db/W horns. Yet it's only rated at 25W. It's true that the latest class D offerings are also very good in that regard.

 

[Bob from Florida]

It matters because some amps are much quieter than others. There's no such thing as "no hiss". Just degrees. It's measurable just like everything else.

The OP says he has hiss with what he believes are 100 db sensitivity speakers. A lot of posting ensues about whether the speakers really are 100 db. It doesn't matter whether they are really 100 db - they have audible hiss through his current amplifier. Changing to a "quiet, non-hissing amp" will solve the problem. I am making the assumption the OP isolated the amp as the hiss source. Perhaps changing "non-hissing to whisper-hiss" will satisfy your thinking. My posting was pointing out that a discussion about actual numbers for the speaker changes nothing. A different amp is required.

 

[fpitas]

The OP says he has hiss with what he believes are 100 db sensitivity speakers. A lot of posting ensues about whether the speakers really are 100 db. It doesn't matter whether they are really 100 db - they have audible hiss through his current amplifier. Changing to a "quiet, non-hissing amp" will solve the problem. I am making the assumption the OP isolated the amp as the hiss source. Perhaps changing "non-hissing to whisper-hiss" will satisfy your thinking. My posting was pointing out that a discussion about actual numbers for the speaker changes nothing. A different amp is required.

You're still missing the point. There is no such thing as a no-hissing amplifier! One that is for example quiet on his speakers may sound like a waterfall hooked to my horns.

 

[Bob from Florida]

You're still missing the point. There is no such thing as a no-hissing amplifier! One that is for example quiet on his speakers may sound like a waterfall hooked to my horns.

I did say whisper-hiss to be more accurate a couple of sentences later. Should that not show understanding on my part?

 

[kipman725]

I use EXTRON XPA 2004 amplifiers with 100dB/1w speakers can only hear hiss with my ear next to the speaker in a silent room. These are cheap second hand.

 

[fpitas]

I did say whisper-hiss to be more accurate a couple of sentences later. Should that not show understanding on my part?

OK, fine. But these things are measured in voltage at the amp output, and any decent amp has that listed in the specs. You then have to work through the speaker sensitivity to see how much noise acoustic output you can expect.

 

[voodooless]

I am making the assumption the OP isolated the amp as the hiss source.

That’s a good point! But can/should we make that assumption? Better to ask and confirm, otherwise you might end up chasing ghosts.

So first only connect the amp to the speakers, and short the input. That way, all you’ll hear is the amps noise. If there is no hiss that way, the source is somewhere else.

 

[Bob from Florida]

OK, fine. But these things are measured in voltage at the amp output, and any decent amp has that listed in the specs. You then have to work through the speaker sensitivity to see how much noise acoustic output you can expect.

You can go by specs, better yet measurement confirmed - and run the numbers through the speaker specs, also better confirmed by measurements(speaker OEM's frequently cherry pick numbers or outright lie). You can do these things and think you are done. Then the OCD kicks in with the "audiophile" getting his ear close enough to the tweeter that he still hears "something". Me, if I can't hear it at the couch - I am happy.
Your high-sensitivity horns present a challenge to many amplifiers. Fortunately, you don't need high power and an amp with less overall gain helps a lot in keeping things quiet. Quicksilver has their Horn Mono 25 watt tube amps that lower the amp sensitivity - 9 volts in for full-power - and increase feedback to make them quiet in the milliwatt outputs needed for sensitive horns. I bet your system is very "dynamic"!

 

[fpitas]

You can go by specs, better yet measurement confirmed - and run the numbers through the speaker specs, also better confirmed by measurements(speaker OEM's frequently cherry pick numbers or outright lie). You can do these things and think you are done. Then the OCD kicks in with the "audiophile" getting his ear close enough to the tweeter that he still hears "something". Me, if I can't hear it at the couch - I am happy.
Your high-sensitivity horns present a challenge to many amplifiers. Fortunately, you don't need high power and an amp with less overall gain helps a lot in keeping things quiet. Quicksilver has their Horn Mono 25 watt tube amps that lower the amp sensitivity - 9 volts in for full-power - and increase feedback to make them quiet in the milliwatt outputs needed for sensitive horns. I bet your system is very "dynamic"!

A lot of vintage horn guys do use tube amps. I was going for a more up-to-date approach, using a SOTA driver by TAD and a 25W class A SS amp, the J2. As you mentioned earlier, the quietest power amp does no good if you are feeding noise to its input, so I resorted to a 14dB pad from the DSP unit. If I put my ear to the horn I can just barely hear hiss when nothing in the house is making noise, so I'm satisfied. And yes, it is dynamic, and gives a presentation somewhat like listening to headphones.

 

[Flavio]

That’s a good point! But can/should we make that assumption? Better to ask and confirm, otherwise you might end up chasing ghosts.

So first only connect the amp to the speakers, and short the input. That way, all you’ll hear is the amps noise. If there is no hiss that way, the source is somewhere else.

Oops, I am embarrassed to admit that my diagnosis was wrong.

Upon further investigation the noise is coming from my Anthem and/or LG projector.
I found out when I did not hear the noise when my LG was switched off.
It only occurs when the Anthem and LG are both on and connected with HDMI.
I am still investigating what the cause is.

Anyway, I have learnt some new things from this thread and I am still going to swap out the amps. I will get a pair of Hypex NC500 based amps on Saturday. They are supposedly the prototypes for the Taiko Audio Kodo amps.
Members here will not be surprised that these amps (basically a stock NC500/SMPS 1200A700 build looking at the inside) retailed for EUR 4.000 each!

Taiko Audio Kodo

€4000 Ultimate Audiophile Performance Class D Power Amplifier based on the Hypex Ncore NC500 amplifier module...

wizard-highend.blogspot.com

I was not swayed by the fancy language about the design, but by the low price I could get them for.

 

[kemmler3D]

It's always good news when you can definitively track down a problem! The Taiko amps look really sweet, but as you note they've got the same guts as a lot of other NC500 kit. If my experience is any guide you'll be quite happy with them.

 

[daftcombo]

Hypex S500NC from Audiophonics produce no hiss in my Focal speakers.
Genelec 8030C are very noisy in comparison.

 

[benanders]

Oops, I am embarrassed to admit that my diagnosis was wrong.

Upon further investigation the noise is coming from my Anthem and/or LG projector.
I found out when I did not hear the noise when my LG was switched off.
It only occurs when the Anthem and LG are both on and connected with HDMI.
I am still investigating what the cause is.

Anyway, I have learnt some new things from this thread and I am still going to swap out the amps. I will get a pair of Hypex NC500 based amps on Saturday. They are supposedly the prototypes for the Taiko Audio Kodo amps.
Members here will not be surprised that these amps (basically a stock NC500/SMPS 1200A700 build looking at the inside) retailed for EUR 4.000 each!

Taiko Audio Kodo

€4000 Ultimate Audiophile Performance Class D Power Amplifier based on the Hypex Ncore NC500 amplifier module...

wizard-highend.blogspot.com

I was not swayed by the fancy language about the design, but by the low price I could get them for.

They’re supposedly the prototypes… based on what? That seems like a dice roll, if based on the wording

 

[Bob from Florida]

Oops, I am embarrassed to admit that my diagnosis was wrong.

Upon further investigation the noise is coming from my Anthem and/or LG projector.
I found out when I did not hear the noise when my LG was switched off.
It only occurs when the Anthem and LG are both on and connected with HDMI.
I am still investigating what the cause is.

Anyway, I have learnt some new things from this thread and I am still going to swap out the amps. I will get a pair of Hypex NC500 based amps on Saturday. They are supposedly the prototypes for the Taiko Audio Kodo amps.
Members here will not be surprised that these amps (basically a stock NC500/SMPS 1200A700 build looking at the inside) retailed for EUR 4.000 each!

Taiko Audio Kodo

€4000 Ultimate Audiophile Performance Class D Power Amplifier based on the Hypex Ncore NC500 amplifier module...

wizard-highend.blogspot.com

I was not swayed by the fancy language about the design, but by the low price I could get them for.

Henceforth the first question will be "What makes you think the hiss is from the amp?".

Regarding your Anthem and LG - you are likely getting a different kind of ground loop. We usually think of ground loops a 60 Hertz hum but when we put switching power supplies in our equipment you sometimes get a switching "hiss" kind of ground loop.

 

[mhardy6647]

You're still missing the point. There is no such thing as a no-hissing amplifier! One that is for example quiet on his speakers may sound like a waterfall hooked to my horns.

[emphasis added]
Not to be repetitiously redundant but I want to repeatingly reiterate this yet again for the third time!
Pretty much true by definition -- 'cause if some silly engineer or technician tries to measure a component with zero noise on a dB (i.e., logarithmic) scale, the universe as we know it will collapse instantaneously into a singularity, and -- well -- that'll be that.

 

[fpitas]

[emphasis added]
Not to be repetitiously redundant but I want to repeatingly reiterate this yet again for the third time!
Pretty much true by definition -- 'cause if some silly engineer or technician tries to measure a component with zero noise on a dB (i.e., logarithmic) scale, the universe as we know it will collapse instantaneously into a singularity, and -- well -- that'll be that.

I've tried. Lord knows I've tried. And not just to collapse the universe!

 

[Flavio]

They’re supposedly the prototypes… based on what? That seems like a dice roll, if based on the wording

Based on the what the person I bought them from said to me. he claims his brother in law built the amps for Taiko Audio.
I am just treating them like a pair of regular NC500 builds.

 

[Flavio]

Well, I got the NC500 mono amps this evening, hooked them up, and no more ground loop noise?! The system is absolutely silent.
So it appears the Sabaj amps were the issue after all? I can't explain it though.

Also the levels in the Anthem can be set to normal levels now.

So I am a happy camper now and going to enjoy my system over the weekend.

Thank you all for the advice.

 

[Bob from Florida]

Well, I got the NC500 mono amps this evening, hooked them up, and no more ground loop noise?! The system is absolutely silent.
So it appears the Sabaj amps were the issue after all? I can't explain it though.

Also the levels in the Anthem can be set to normal levels now.

So I am a happy camper now and going to enjoy my system over the weekend.

Thank you all for the advice.

Congratulations on your amps.

The simplest way to break a ground loop is to not have a ground connection in your power cord. Double insulated components do this the right way. Strangely, when I visited the Taiko Audio site, this product is nowhere to be found. Taiko seems to be primarily involved with out of this world priced music servers.

Taiko Audio – High End Music Servers: Taiko Extreme. Vibration Control Platforms.

taikoaudio.com