BEHRINGER A500 AMPS / 2nd FOLLOW UP!

[mtrycrafts]

Hey guys,

Thanks for all the excellent responses. It really helps to know that this is (fairly) normal behavior.

I'm very new to the world of audio equipment so it's hard for me to give a quality review of the hardware. I just purchased the 3805, the A500 and a pair of Dynaudio 72 SE's within a month. My previous setup was an OLD denon receiver with JBL S38 bookshelves. I can definetly say that the A500 provided an improvement to the dynamic qualities of the speakers compared to using the 3805 (which is not designed for 4 ohm loads).

I don't even have a proper equipment rack! I'm currently using Jenga pieces underneath the feet of the A500 to give it some breathing room from the 3805

When I get home tonight, I will try to determine if I have a ground loop in my system and report back.

Yep, you are amplifying the thermal noise in the amp in this method.
What if any noise do you hear when you play music? That is what matters.

 

[WmAx]

Ok, so I'm back to report. First off, the cheater plug didn't do anything to reduce the hiss in the amp. I think the static hiss I heard is probably within normal operating parameters for this amp. I was probably just over reacting.

But you said earlier: "Btw, if I disconnect the Amp from the receiver and crank the gain on the amp, I don't hear anything so it doens't have to do with something internal in the A500..."

In fact, if this is the case, then the hiss noise is the noise from your reciever's preamplifier section being amplified.

The A500 I would compare as being VERY smooth in the highs, unfortunately this is true to a fault and you find yourself wishing the highs were more pronounced. The Rotel on the other hand gives you tons of detail but its almost sibilant and grainy in chacteristic. The nice thing about the rotel is that you get the feeling turning up the volume, that you have tons of head room, it just gets louder and louder, nothing really starts to get unbalanced or out of control. With the A500 you start to hear the mids get out of wack with everything else and the bass is out of control and undynamic.

This is invalid comparision, as it was probably done without level-matched conditions, nor was it a blinded test.

I'm at the point where I might need to go to an even better rotel amp to get the clean highs that I want.

From what you have said so far, your problem is a noisey preamplifier.

-Chris

 

[mtrycrafts]

In short I would say that the A500 was not a good match for my setup, .

This is due to your method of comparing components. Bias is a big factor in evaluations, unless you controlled for it by implementing blind and double blind protocols. Then, you'd have to level match components to a very tight tolerance, 0.1 dB spl that requires a voltmeter capable of measuring .01V differences, or so. Then, you can start and see how well you are able to identify components.

 

[ExtraCheese]

In fact, if this is the case, then the hiss noise is the noise from your reciever's preamplifier section being amplified.

Yes, that's what I'm saying. There's nothing abnormal, I wanted to make sure what I was hearing is similar to what others experienced with this product. Clearly it is.

This is invalid comparision, as it was probably done without level-matched conditions, nor was it a blinded test.

Definetly. My subjective bias going into the listening sessions effected my conclusions to some extent. My super unscientific methods also had part. I don't want to represent that my experience was scientific or conclusive in anyway. It's just my opinion, surely I'm entitled to it.

On the same line of thought, to what extent can you reasonably defend the A500? At some point you would have to concede (i would think) that there is a difference in the quality of the parts and the design compared to more expensive amps. I'm saying that I think I hear a clear difference between the A500 and the Rotel 1070. No reason to coldly dismiss my opinion as bull.

From what you have said so far, your problem is a noisey preamplifier.

What makes you say that? I just confirmed that the hiss I experienced is in-line with what others experience with the A500. Besides I was saying that I wanted cleaner highs compared to the Rotel 1070. Which provides everything I want except perhaps the sound is a bit grating. I would think that grating highs is not a property of too much interference coming through on the signal.

Well, I certainly don't want to start a flame war. Believe me there was no-one that wanted the A500 to be good more than me and I will admit that the A500 did an admirable job driving my old JBL S38 bookshelves.

 

[WmAx]

Yes, that's what I'm saying. There's nothing abnormal, I wanted to make sure what I was hearing is similar to what others experienced with this product. Clearly it is.

So, you have personally confirmed that the A500 itself is not producing any of the noise.

On the same line of thought, to what extent can you reasonably defend the A500? At some point you would have to concede (i would think) that there is a difference in the quality of the parts and the design compared to more expensive amps.

I will defend only from a verified and credible 3rd party measurement point of view. Ironically, the A500 measured better in some important ways as compared to a much more expensive Bryson amplifier, by the same review magazine. This mainly extends to the A500's handleing of varying loads, the A500 is basicaly rock steady stabile regardless of load properties.

I'm saying that I think I hear a clear difference between the A500 and the Rotel 1070. No reason to coldly dismiss my opinion as bull.

Besides the noise, which is apparently a gain difference factor, there is no reason to suspect any other differences that are audible. The A500 is a transparent amplifier based on it's measured parameters.

What makes you say that? I just confirmed that the hiss I experienced is in-line with what others experience with the A500.

You could put a simple in-line attenuator between the pre-amp and amp, to reduce the noise from your pre-amp that is being amplified by the Behringer.

-Chris

 

[mtrycrafts]

Definetly. My subjective bias going into the listening sessions effected my conclusions to some extent. My super unscientific methods also had part. I don't want to represent that my experience was scientific or conclusive in anyway. It's just my opinion, surely I'm entitled to it.

Yes, everyone is entitled to opinions. But, it must be pointed out that it is based on flawed observations so others can judge that opinion accordingly.

On the same line of thought, to what extent can you reasonably defend the A500?

On the objective tests of that component.

At some point you would have to concede (i would think) that there is a difference in the quality of the parts and the design compared to more expensive amps.

Why? What is the evidence that the parts in that amp is causing it not to be transparent??? The objective data would show us this. It doesn't. And, if the design was poor, that too would show up on the objective testing. It doesn't.

I'm saying that I think I hear a clear difference between the A500 and the Rotel 1070. No reason to coldly dismiss my opinion as bull.

Why not??? After all, the listing protocol, by your own admission, was rather weak.

I just confirmed that the hiss I experienced is in-line with what others experience with the A500.

But you had another component connected to the A500. Perhaps that is the hiss generator, not the A500? And, I bet others did the same way, with another component, a preamp, connected to it. So, it is not the A500 at fault, at least that was not demonstrated.

Besides I was saying that I wanted cleaner highs compared to the Rotel 1070. Which provides everything I want except perhaps the sound is a bit grating. I would think that grating highs is not a property of too much interference coming through on the signal.

Without a proper listening protocol, you will never know where the issues are, if there are any at all.

 

[ExtraCheese]

Man.. ok. Yes I know that the hiss is from the receiver ouputs. I just wanted to get a gauge to see if the amount of hiss I was getting is similar to other users. Obviously, for you guys, you think it is more than I should be hearing. For others they say it's similar.

I'm saying that I think I hear a clear difference between the A500 and the Rotel 1070. No reason to coldly dismiss my opinion as bull.

Why not??? After all, the listing protocol, by your own admission, was rather weak.

Uhh..how many different ways can I say this? It's just an observation. I guess I should stop speculating to the causes of what is going on, it clearly offends you. I guess some people can't handle a little friendly conversation. This is a forum right? Or did I misunderstand what this place is supposed to be? Apparently the gods of audioholics.com have deemed the A500 as worthy. Any other opinion is heresy and must be dealt with accordingly.

Anyways, let's just leave it at this.

[OPINION] the A500 did not work with my current setup. [/END OPINION]

Edit: Ok, I can't resist adding this last thing I just remembered. wMax mentioned that high frequency attenuation could be an issue with this amp. Since my main complaint with this amp was the fact that the highs seemed weak. Maybe this is my problem? (I'm sure mtrycrafts will jump all over me again for the high crime of conjecture without proper scientific evidence but... hey).

 

[pearsall001]

ExtraCheese

Man oh man just calm down. I've found the info on this forum has been very straight forward & very good. Sorry to hear things didn't work out for you. But congrats to you for giving it a try. I'll bet there's a lot of folks that post their opinions without ever using the product, just speculation. You did the right thing & actually purchased & tried the unit. I respect your comments & opinions. If you try something else please post back. Don't lose faith, this is a great forum.

 

[Korg]

Would like to add I have two A500s and they are silent even when gain at 100%.

I have run them quite hard bridged with PA speakers I built myself (15 inch woofer and horn tweets, 500 watts rms, efficiency 98 db (I was a bass player and need more power!!!)) and they have sounded solid and very detailed. However, I run them with professional equipment and use the balanced TRS inputs (never tried the others).

As others have pointed out, if the amp is not making noise turned up and not connected (and mine don't) it is another component making the noise or a ground loop, simple as that. If a component is making noise obviously the more power you add to the noise will make it louder, I think this is the real issue.

It seems that everyone is trying hard to knock Behringer without even really trying their stuff. However, I will add that all is not rosy with Behringer as the first A500 I received had one channel screwed up right out of the box. That one side had the clip light on as soon as I turned the channel up, sounded like a radio and the side heatsink was so hot on that side that you could not put your hand on it. Normally, the heatsinks are cool unless you run them close to clipping in bridged mode.

My two cents.

 

[Johnny Canuck]

I have the Behringer 2500 combined with the Denon 3805, running Polk RTI 12's with straps on, full..

I too get a hiss at about 1 -2 feet from my towers. Kind of more of a slight hum. I tried every combinantion and narrowed it down to the amp. It wasn't there before before I bought the Behringer.

It was however much much worse before I attached an isolation transformer attached to my cable vision wire from the wall. Very loud hum. Got rid of 95% of it. One of the disadvantages I guess but I also have this enormous amp running my towers at a fraction of the price.

My RTI12's have awoken with this baby. Highly recommend getting a Behringer. My fan modification has helped out enormously, no issues at all..cool as ice.

JC

 

[Korg]

Are you running balanced or unbalanced inputs?

 

[Korg]

That was probably a stupid question, I know (I don't know anything about your Denon).

I assume you are using RCA outs to the A500 unbalanced RCA ins. Maybe the inputs used are the real issues with this amp??? I'll have to try the RCAs to see (too late now to do this).

This amp was designed to be used in the studio and any studio would use the XLRs first and the TRS's second and never the RCA's.

 

[tomd51]

I also picked up a bit of hum when relatively close to the speakers (3-4 ft. away) running this with RCA cables unbalanced at approx. 2 o'clock on the gain in stereo mode.

By using an RCA to 1/4" plug adapter (less than $5 at Radio Shack) and utilizing the 1/4" balanced connection, I was able to completely eliminate any hum even at full gain, stereo or bridged mode. This saved quite a bit of money as opposed buying all new balanced to RCA cables.

I'll also attest to this being monsters when it comes to raw, clean power. Running these bridged w/my BA VR3s which are rated at a 93dB sensitivity level at reference level is hardly even pushing them. Incredible value with these... -TD

 

[beppe61]

Dear Sirs,

is anyone using the A500 with xlr cables (run balanced)?
anyone who can report how it sound when connected to an high quality system and run balanced ?
Thank you very much

Kind regards,

beppe

 

[WmAx]

Dear Sirs,

is anyone using the A500 with xlr cables (run balanced)?
anyone who can report how it sound when connected to an high quality system and run balanced ?
Thank you very much

Kind regards,

beppe

I used them balanced from a DCX2496. No noticed noise. However, both my A500s seem to have been defective -- and both distorted high frequencies with a fuzz/crackle noise on things like piano solos, etc.

-Chris

 

[beppe61]

I used them balanced from a DCX2496.
No noticed noise.
However, both my A500s seem to have been defective -- and both distorted high frequencies with a fuzz/crackle noise on things like piano solos, etc.
-Chris

Thank you very much for your kind and valuable reply.
Two units both defective is a bad thing.
I have one and I am getting hum using the RCA inputs.
It seems to me more a problem of loop anyway.
I will try to use it with XLR directly linked to a src2496 that I have also have.
I think that a normal xlr should suffice. I iwll use nothing of exotic I think.

Thanks again and kind regards,

beppe

 

[beppe61]

Well I did it. I set up the following chain:
cheap sony dvd player > behringer dac src2496 > xlr to jack balanced (5 meters) > behringer A500
I can say the hum is completely gone.
Even with the front panel controls at maximum (no input signal) no noise at all.
Now that I think more with the unbalanced rcas the hum is zero at zero volume and increases with the volume.
It seems indeed that the noise comes from the upstream components and is amplified by the A500.

Setting the volume is now a little unpractical but no noise.
Now the search for a cheap but nice balanced preamp is on.
I have already an idea. Behringer has a little mixer-preamp that could work just fine.
Of course kind suggestions would be extremely appreciated and welcome.


Thanks and regards,

beppe

 

[beppe61]

Hello to everyone,

I have disconnected the amp from the electrical grid ground and I like the resulting sound better.
The hum is still present but in lower level.
I have the feeling that the scarce power supply capacitance is one of the thing that holds back the amp performance.
It does not give to the amp that "ommphh" quality (or what is sometimes called "bloom") in the bass that personally I like so much.

Kind regards,

beppe

 

[WmAx]

Now the search for a cheap but nice balanced preamp is on.
I have already an idea. Behringer has a little mixer-preamp that could work just fine.
Of course kind suggestions would be extremely appreciated and welcome.


Thanks and regards,

beppe

I don't know if Behringer has any small mixers with balanced outputs. I have both a Behringe UB 1202 and a Behringer Xenyx 802. While they have several balanced inputs; they only have unbalanced outputs. I think they may only have balanced outputs on the large mixing desk units(?).

You could have a balanced pre-amp made custom for a low cost, however. I have used eletronics course students that I have met by chance online as a way to get custom work done at low cost. If you are in the United States, I could point you in the direction of one.

-Chris

 

[WmAx]

I have the feeling that the scarce power supply capacitance is one of the thing that holds back the amp performance.
It does not give to the amp that "ommphh" quality (or what is sometimes called "bloom") in the bass that personally I like so much.

Kind regards,

beppe

The capacitance is sufficient for the amplifier to work correctly; no issue there. Some more capacitance may yield a 10-15 percent increase in output power at very low frequencies, but nothing of audible significance. Remember, a 100 percent increase in power is required to achieve a 3dB acoustic output gain.

What you may want to do, however, is get a precision DSP equalizer such as a Behringer DEQ2496, or even better, a Behringer DCX2496(this has EQ and very useful DSP xover options). You can get any subjective bass quality that you so desire using such a precision equalizer correctly, assuming your speakers have sufficient extension with low enough distortion in the first place.

-Chris