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Gain?


JoeJoeThe3rd

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8 hours ago, JoeJoeThe3rd said:

What is the ideal position for the gain knob on the back of my power amp for my speaker? Which I run a parasound a31 and a pair of rf7iii and the rc64iii for my center.

From my understanding, amp gain controls are used to better match the output voltage of your preamp.  Determine the preamps output voltage and adjust the amps gain accordingly.

 

From the Parasound A31 Manual

 

When to Set the Gain Control Knobs Above or Below Normal You can increase loudness by turning the Gain control knobs clockwise if your system will not play loud enough with the Gain control knobs set at Normal. This could be the case if your A 31 is driven from the pre-out jacks of an AV receiver (as opposed to an AV processor). We recommend advancing the gain as little as possible past Normal. As you increase gain settings you increase the chance of hearing a “hiss” sound from your speakers. You also run the risk of damaging your speakers (not to mention your hearing) if the volume level is too high. The primary reason to reduce the gain below Normal would be if your speakers’ efficiency is extremely high and your listening position is close to your speakers. Reducing the gain would reduce audible “hiss” from your speakers. Don’t worry about setting the A 31 Gain control to exactly the same levels for all channels because you can always balance the channel volume using the speaker level calibration in your home theater AV receiver or AV processor’s setup menu. Note: We recommend re-calibrating your AV receiver or processor’s speaker levels after adjusting the A 31 gain controls.

 

Bill

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10 hours ago, willland said:

From my understanding, amp gain controls are used to better match the output voltage of your preamp.  Determine the preamps output voltage and adjust the amps gain accordingly.

 

From the Parasound A31 Manual

 

When to Set the Gain Control Knobs Above or Below Normal You can increase loudness by turning the Gain control knobs clockwise if your system will not play loud enough with the Gain control knobs set at Normal. This could be the case if your A 31 is driven from the pre-out jacks of an AV receiver (as opposed to an AV processor). We recommend advancing the gain as little as possible past Normal. As you increase gain settings you increase the chance of hearing a “hiss” sound from your speakers. You also run the risk of damaging your speakers (not to mention your hearing) if the volume level is too high. The primary reason to reduce the gain below Normal would be if your speakers’ efficiency is extremely high and your listening position is close to your speakers. Reducing the gain would reduce audible “hiss” from your speakers. Don’t worry about setting the A 31 Gain control to exactly the same levels for all channels because you can always balance the channel volume using the speaker level calibration in your home theater AV receiver or AV processor’s setup menu. Note: We recommend re-calibrating your AV receiver or processor’s speaker levels after adjusting the A 31 gain controls.

 

Bill

Yeah read the manual but that doesn’t say what it is which had to do with voltage between the two. I wonder what the optimal position for the gain with my rf7iii and rc64iii and anthem mrx720.

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2 hours ago, JoeJoeThe3rd said:

Yeah read the manual but that doesn’t say what it is which had to do with voltage between the two. I wonder what the optimal position for the gain with my rf7iii and rc64iii and anthem mrx720.

Trial and error.  You may have to experiment a bit.

 

Bill

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I had some Parasound amps with my 4 La Scalas.  I had to turn down the input gain to the amps so I could run my pre/pro at higher gain and control hiss.  That is the only purpose for the input gain on the power amp.  There is NO ideal position.  There is no point in looking for one.  Any of the possible settings that allows the preamp and amp to reach the loudness you desire, is a good setting. 

 

You will never be able to tolerate the full power of that amp driving RF-7s. 

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  • 9 months later...
On 10/16/2020 at 7:55 PM, JoeJoeThe3rd said:

What is the ideal position for the gain knob on the back of my power amp for my speaker?

 

Answer

As low as possible, such that your system is just able to achieve the maximum volume you want to hear.

 

Background

Your playback system will sound better if you set the "gains" correctly.

 

This is more accurately called optimizing "gain structure" of an audio system.

 

Well designed electrical audio components output two things, (a) noise, and (b) signal. Noise is bad and at a fixed and low level, the signal is the good thing, the music. The signal is not fixed in level and can be very low (near the noise) or very high - it can even be so high that it starts distorting. The goal is to run the signal as high as possible so that the distance between the noise and signal is greatest.

 

Example 1: Some people say you should set your amplifier gain at maximum for it to sound best. This is false because it forces you to turn down the downstream components, such as your preamp, to achieve the listening level you want. By turning the preamp signal down, you just pushed the music closer to the noise floor.

 

Example 2: Turn the amp gain way down so that you have to turn your downstream components at or near their maximums to hear a low sound level out of the loudspeakers. If that sounds distorted, turn down each downstream component until the distortion goes away, then turn them up again until you find the "just beginning" to distort volume settings. During normal listening, you should be close to those maximum volume settings. THE LAST STEP is to turn up your amp gains so that you get the sound volume you want out of your loudspeakers. This is the ideal.

 

Example 3: If you're into measuring things, this is how you optimize gain structure with little monetary investment.

 

God bless you and your precious family - Langston

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In my setup, I have a preamp hooked up to an integrated amp.  So instead of having an amp with adjustable gain, I have an amp with a volume control but no gain adjustment.  Would the steps be the same in this case?  First turn the amp volume down and then turn the volume of the preamp up.  Then adjust the volume of the amp only as high as you care to listen to?

 

In case you are wondering, my "preamp" is an OPPO 105D.  I use it as a preamp because it has a remote volume control.  My integrated amp does not.

 

Mark

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7 hours ago, Marks said:

Would the steps be the same in this case?

 

Never lose sight of audio's Prime Directive: If it sounds good, it is good. : )

 

Short Answer: I don't know. Try it both ways and if you can't tell a difference that is in favor of the inconvenient method, carry on with the remote control! : )

 

The technical aspects in your case lend toward setting the OPPO at its maximum and using your integrated amp for volume control. The OPPO uses digital gain control and the integrated amp probably uses analog gain control. Reducing digital gain causes a reduction in bit depth (resolution) of 1 bit per 6dB of volume reduction, which can be a greater compromise than reducing the analog signal to noise ratio by turning down your integrated amp's volume.

 

Nevertheless, in most cases you will probably find that the controlling volume in the digital domain sounds better than doing so in the analog domain, i.e., keep doing it the way you're doing it, but try it both ways to convince yourself.

 

A final thought is that digital audio playback software like Roon and JRiver Media Center process volume control at 64bit resolution, thus losing 1bit per 6dB gain reduction is not going to compromise 16bit or 24bit music playback. Here's some testing a guy did last year with Roon's volume control that demonstrated this.

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Yes, my amp has an analog volume control.  I just did a quick Google search on the OPPO 105 volume control and it seems that it is 32-bit.  So I am probably not goofing up the sound too bad by using it.  🙂

 

Thanks.

 

Mark

 

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