Stereo Amplification

[MPS1975]

I am wondering if there are any opinions out there on a good mid-range stereo amplifier. I currently have an Onkyo TX-SR706 rated at 100W/Ch.x7. I obviously do not need the extra channels. I also think (assumption) I might need more power (based on the following). Right now, running only 3.1 channels, I have to keep the volume at near 80% of capacity for the sound even to be heard. So, I might be doing something wrong as well. I am reasonably sure that the house power is not running at full 120V, which will have an effect. Any ideas?

 

[Midcow2]

What speakers are you using ?

I am wondering if there are any opinions out there on a good mid-range stereo amplifier. I currently have an Onkyo TX-SR706 rated at 100W/Ch.x7. I obviously do not need the extra channels. I also think (assumption) I might need more power (based on the following). Right now, running only 3.1 channels, I have to keep the volume at near 80% of capacity for the sound even to be heard. So, I might be doing something wrong as well. I am reasonably sure that the house power is not running at full 120V, which will have an effect. Any ideas?

What speakers are you using ? If they are 4 or 66 ohms and /or low sensitivity (less than 90 dB) that could be the reason.


Emotivia is having a sale on power amps right now:
http://forums.audioholics.com/forums/showthread.php?t=52138

Also the Behringer EP2500 is a good power amp.


Good Luck,

MidCow2

 

[j_garcia]

Have you run the receiver's auto calibration? Even with just a 3.1 setup, you still need to run it. What speakers? Do you have them set to large or small?

 

[MPS1975]

I have run the receiver's auto calibration. The speakers I am running are JBL S36, and they are set to full band. Part of the problem (I have finally discovered) is that the Onkyo runs 100W at 6 ohms, and my speakers are 8 ohms.

 

[WmAx]

The recommended Behringer EP2500 is a superb amplifier. In reality, it's build quality inside is superior to most 'entry level' audiophile amplifiers, and it will easily outperform most of them. In addition, the EP2500 can handle any load with ease. Real measured output, with extreme low distortion, is about 450 x 2 into 8 ohms, 630-650 into 4 ohms, and 1000-1100 into 2 Ohms, both channels driven.

But, if you get the EP2500, there are some issues to address.

(1) The cooling fan is loud. There is a specific Matsushita fan that has been found to be extremely quiet and is a drop in replacement. It's a 10-15 minute operation - and the same as changing the fan in your computer case.

(2) The device is designed for pro voltage input levels - that are many times higher than standard consumer line level out of RCA jacks. To match it up, you need a $40-$50 device such as the Samson S-Convert. This will cleanly change the level and give adapter jacks as well.

The benefit, of course, is you will have a superb amplifier that can handle just about any speaker in existence without effort.

-Chris

 

[MPS1975]

I might, perhaps, need to open my mind, but I am not convinced about using a live power amplifer. Its price point is excellent. Would I not also need to convert the inputs as well as the output connectors? And further, would I simply use my current receiver as the pre-amp, or do I need a separate pre-amp that would be better suited to the Behringer?

 

[WmAx]

I might, perhaps, need to open my mind, but I am not convinced about using a live power amplifer. Its price point is excellent. Would I not also need to convert the inputs as well as the output connectors? And further, would I simply use my current receiver as the pre-amp, or do I need a separate pre-amp that would be better suited to the Behringer?

Why don't you search my posts. I am have been engineering the highest possible fidelity loudspeaker systems for quite some time. I now use Yamaha pro amps in my main system - and I used to use all McIntosh. If I thought, that even 1% of sound quality was sacrificed, I would not be using pro amps. Fact is, in many cases, the pro amps perform as good or better, and at a far better price. There is no difference except for the input signal requirements. I do understand that audiophiles often like to make up imaginary things that are based on no credible method of comparison - and this useless banter will often cause people to have preconceived notions when reading this audiophile rubbish on an audiophile forum. 99.9% of audiophiles would be fortunate to have a system that can compare to mine. Most 'audiophile' systems are far below my standards. Yet I use those 'dirty' pro amps.....hmm.....

I used to be an audiophile some years ago. I'm glad I was able to actually learn what counts.

The input must be converted because pro gear operates on line signal levels much higher voltage than consumer RCA line level signals. You 'can' feed without conversion - but the result will usually be audible hiss or noise because the consumer gear is feeding such a low voltage that it is not enough to push the pro amp noise floor low. The pro amps expect a much higher voltage - it's as simple as that. The Samson S-Convert is designed to account for this, and will boost the consumer signal to pro signal levels so that no noise is present and that full power can be obtained from the pro amp. It is no problem to simply use the S-Convert between your reciever's pre-amps and the pro amp inputs.

I don't use the converters, but this is because I use a digital DSP crossover system/processor between my pre-amp and amps - and this DSP unit automatically converts between consumer and pro voltages on the input side.

-Chris

 

[Rickster71]

I have to keep the volume at near 80% of capacity for the sound even to be heard. So, I might be doing something wrong as well. I am reasonably sure that the house power is not running at full 120V, which will have an effect.

Sounds like you should check into your other suspicions before spending more money. The Behringer EP2500 is nice; but lets check some basics first.

The fact that you have to turn the volume control up to 80% for the sound to be heard is reason to keep searching.
Unless you're trying to fill a very large room.

Are you sure the speakers are hooked to 'Front left & Front right' , and not hooked to the surround speaker outputs, and the AVR is set to output stereo ?
Do you have the speaker wires out of phase? Check to see that the wires to the +plus and -minus (red and black) are the same on the speaker as the Onkyo's speaker outputs.

In the set-up menu it should have a choice between - "4 ohms–16 ohms or 6 ohms–16 ohms" Set it for 6 ohms–16 ohms, since your speakers are 8 ohms and 90 dB.

 

[MPS1975]

Sounds like you should check into your other suspicions before spending more money. The Behringer EP2500 is nice; but lets check some basics first.

The fact that you have to turn the volume control up to 80% for the sound to be heard is reason to keep searching.
Unless you're trying to fill a very large room.

Are you sure the speakers are hooked to 'Front left & Front right' , and not hooked to the surround speaker outputs, and the AVR is set to output stereo ?
Do you have the speaker wires out of phase? Check to see that the wires to the +plus and -minus (red and black) are the same on the speaker as the Onkyo's speaker outputs.

In the set-up menu it should have a choice between - "4 ohms–16 ohms or 6 ohms–16 ohms" Set it for 6 ohms–16 ohms, since your speakers are 8 ohms and 90 dB.

The speakers are definitely connected to FR/FL, and I did check their phase, and they are in-phase (in fact, that was the very first thing I checked). The option on the menu is set to 6 ohms. I have them running at full band with double bass in the subwoofer, and performance is still quite weak.

The room size is 22 x 16. Main opening is on a 16' wall. Walls are drywall with some wood millwork, floor is carpeted. The speakers are sitting on shelves near to the front approximately 5' off center of a 22' wall, elevated 4'.

 

[MPS1975]

The input must be converted because pro gear operates on line signal levels much higher voltage than consumer RCA line level signals. You 'can' feed without conversion - but the result will usually be audible hiss or noise because the consumer gear is feeding such a low voltage that it is not enough to push the pro amp noise floor low. The pro amps expect a much higher voltage - it's as simple as that. The Samson S-Convert is designed to account for this, and will boost the consumer signal to pro signal levels so that no noise is present and that full power can be obtained from the pro amp. It is no problem to simply use the S-Convert between your reciever's pre-amps and the pro amp inputs.

It is all about the sound (not the box). As far as the pre-amp goes, if I am reading correctly, your feeling is that I should I just use the Onkyo, with the S-Convert? Or should I purchase a dedicated non-receiver (more "pure") unit?

 

[WmAx]

It is all about the sound (not the box). As far as the pre-amp goes, if I am reading correctly, your feeling is that I should I just use the Onkyo, with the S-Convert? Or should I purchase a dedicated non-receiver (more "pure") unit?

I have never used your Onkyo. I don't know anything about it. But if it's pre-outs are noise free - it will work fine. I don't about 'more pure'... what is more pure? Receivers can have pre-amp stages that measure better than many dedicated pre-amps. It's product dependent. I now use a Yamaha RX-V2600 as my stereo preamp. I used to use a Stereophile recommended 'audiophile' pre-amp, and I can't tell one iota of difference in SQ. But the V2600 is much more useful to me - with digital dB volume display, etc. - so upon Gene's(admin of this site) measurements and comments about the extremely high grade pre-amp stage used in the RX-V2600, I decided to get one for my two channel main system.

-Chris

 

[MPS1975]

But if it's pre-outs are noise free - it will work fine...But the V2600 is much more useful to me - with digital dB volume display, etc.

This is perhaps my naivete, but how would I be able to hear noise on the pre-outs? Is there a test that can be performed? Right now I have a powered subwoofer which uses a pre-out, so would it be advisable to listen to this single channel at increasing volume to determine whether there is noise being produced?

Second...if the signal is being carried from input through the receiver's pre-amp to a pre-out to the amplifier, and then to the speakers, are you able to control the volume? I thought (probably incorrectly) that volume was controlled by the amplifier.

 

[WmAx]

This is perhaps my naivete, but how would I be able to hear noise on the pre-outs? Is there a test that can be performed? Right now I have a powered subwoofer which uses a pre-out, so would it be advisable to listen to this single channel at increasing volume to determine whether there is noise being produced?

Second...if the signal is being carried from input through the receiver's pre-amp to a pre-out to the amplifier, and then to the speakers, are you able to control the volume? I thought (probably incorrectly) that volume was controlled by the amplifier.

Sub can not be used to detect the noise, because the sub will low pass all of the mid and high frequency noise which is most audible.

The pre-amp is what controls the volume of the system. The amplifier operates at a fixed gain, and you adjust the line level voltage using the pre-amplifier.

-Chris

 

[MPS1975]

Sub can not be used to detect the noise, because the sub will low pass all of the mid and high frequency noise which is most audible.

The pre-amp is what controls the volume of the system. The amplifier operates at a fixed gain, and you adjust the line level voltage using the pre-amplifier.

-Chris

Considering the cost of the EP2500, I think it is worth trying with my Onkyo as a pre-amp (and if that does not work, I can try an old Pioneer).

Is there anything I need to watch for if/when I implement the EP2500 as the power amp? For example, are there any known speaker pairs that do not play nicely with the EP2500 (because eventually I would like to purchase a new set of speakers as well).

 

[JerryLove]

Is there anything I need to watch for if/when I implement the EP2500 as the power amp? For example, are there any known speaker pairs that do not play nicely with the EP2500 (because eventually I would like to purchase a new set of speakers as well).

The 2500 is a very well-built, professional amp capable of driving a 2O load. The only way you would run into trouble, is if you found a speaker demanding more power than this could provide and tried to run it. No such speaker comes to mind: perhaps a large planar speaker or one of Chris's low-cabinet-volume, high-spl, low frequency units.

Even then, you could double your power by buying a second 2500 and running each bridged.

 

[MidnightSensi]

Sub can not be used to detect the noise, because the sub will low pass all of the mid and high frequency noise which is most audible.

The pre-amp is what controls the volume of the system. The amplifier operates at a fixed gain, and you adjust the line level voltage using the pre-amplifier.

-Chris

The amplifier should still be operated with its input attentuators set to where the amplifier and the pre-amp clip at the same point.

 

[MPS1975]

Okay...from my current surround receiver, now acting as a pre-amp, I run RCA out to the Samson S-Converter, which increases the voltage of the signal. I have to then run XLR from the s-converter to the Behringer EP2500. If I want to continue to run a powered subwoofer, I would need to continue to run it from the pre-amp rather than the Behringer, right?

 

[KEW]

I currently have an Onkyo TX-SR706 rated at 100W/Ch.x7.
Right now, running only 3.1 channels, I have to keep the volume at near 80% of capacity for the sound even to be heard.
I am reasonably sure that the house power is not running at full 120V, which will have an effect. Any ideas?

I don't get it. The amp recommendations are good ones; but an Onkyo running 100 Watts into 90dB speakers should be plenty loud at a below 50% setting.
Something is wrong. Maybe the amp section of your Onkyo is messed up and a new amp will fix it, but if the problem is in the preamp, the new amp won't help at all!

When you say 80% to even be heard, do you mean to fill the room, or literally to be able to hear and identify the music?
What are you using as a source?
Have you tried other sources such as the radio?
Is there an attenuation option that could be on?
What about muting?
Are you sure the speakers are set to "A".
What you are describing, if taken literally, sounds like you are hearing the crosstalk of a signal which has electronically been turned off!
How is the headphone volume level?
Check your manual and see how to reset the receiver. This should wipe all settings back to a standard configuration and eliminate any settings which you or someone else may have accidentally engaged.

Two more questions. Is it new? has it always been this way?

 

[WmAx]

Okay...from my current surround receiver, now acting as a pre-amp, I run RCA out to the Samson S-Converter, which increases the voltage of the signal. I have to then run XLR from the s-converter to the Behringer EP2500. If I want to continue to run a powered subwoofer, I would need to continue to run it from the pre-amp rather than the Behringer, right?

Yes, you use the sub pre-out jack from the receiver to send to the active subwoofer(s).

-Chris

 

[MPS1975]

When you say 80% to even be heard, do you mean to fill the room, or literally to be able to hear and identify the music?

80% is a bit of an exaggeration...but 50-60 is not. 60 might be ok if the furnace is not active. To fill the room, though, requires 80-85.

What are you using as a source?

An Onkyo CD player via digital coax.

Have you tried other sources such as the radio?

I have not tried the radio, but I have tried DVD, with the same outcome.

Is there an attenuation option that could be on?

I do not believe so. I have checked many of the options in OSD menus, and nothing is turned on.

What about muting?

Not muted. My muting is set to infinite, and the muting does work well when active.

Are you sure the speakers are set to "A".

Yes, I checked that the speakers are set to "A" (or in this case, Zone 1). Zone 2 speaker posts are not even active.

How is the headphone volume level?

I have not checked this lately, but I do remember doing so some time ago. Same problem...lack of volume until at least 50.

Check your manual and see how to reset the receiver. This should wipe all settings back to a standard configuration and eliminate any settings which you or someone else may have accidentally engaged.

I will give that a try. I do not think much will change, since most things have their default values, but perhaps doing so will shake the unit from its slumber.

Two more questions. Is it new? has it always been this way?

It is relatively new (w/in 2 yrs) and it has always been this way.

I know part of the problem is the JBL speakers...as they are bookshelf speakers, they do not produce the necessary bass. However, if I move to full range speakers, most are beyond the capability of the amplifier, which means I will have to change the amp anyway.