• The move to the new server is done. There are some software and database maintenance updates in process. This has us passing the hat around to help out. We appreciate any donations. Seriously, even a dollar helps. The payment page may be found here - https://www.audiokarma.org/support.html

Really Basic Power Amp/Preamp Question

R

rswojo

AK Subscriber
I just got a power amp and preamp. The power amp has a R and L level control. I know I control volume with the preamp. Where should I set the power amp level controls for the best sound, 1/4, 1/2, 3/4, full?

What I like about vintage gear is I can afford stuff now that I could only drool over when I was young. I am glad my wife told me I needed a hobby. :D:D:D Those words are the anvil for my hammer.:D
 
Register to hide this ad
It seems like some trial and error would be in order to find out what would be the best or better for your set up. I would assume with your stuff, like mine; the controls act differently at different settings. In other words not linear.
Give it a couple of hours with different sources, and see what you like!
Mike
 
rswojo said:
I just got a power amp and preamp. The power amp has a R and L level control. I know I control volume with the preamp. Where should I set the power amp level controls for the best sound, 1/4, 1/2, 3/4, full?

What I like about vintage gear is I can afford stuff now that I could only drool over when I was young. I am glad my wife told me I needed a hobby. :D:D:D Those words are the anvil for my hammer.:D
Click to expand...

Run the amp low and the preamp high. You want to use as much of the preamp's volume control range and output voltage as possible.

Normally I set the amp very low so as not to be really loud for the next step, then turn up the preamp volume control until I hear distortion and back off until it's clean (or hit the end of the volume control travel, whichever comes first). Once I reach that point then turn up the amp gains until it's as loud as you want to go or just a bit more for cushion. Now the gain structure is set properly and you run the system with the volume knob, but you'll have to turn it further than you're probably use to. This method gives the best control over the system and the best signal to noise ratio.

Some don't like it though because they're use to systems where you're blowing out the windows at a volume setting of 3 of 10 so it seems like the system adjusted as above isn't as powerful.
 
Last edited:
whoaru99 said:
Run the amp low and the preamp high. You want to use as much of the preamp's volume control range and output voltage as possible.

Normally I set the amp very low so as not to be really loud for the next step, then turn up the preamp volume control until I hear distortion and back off until it's clean (or hit the end of the volume control travel, whichever comes first). Once I reach that point then turn up the amp gains until it's as loud as you want to go or just a bit more for cushion. Now the gain structure is set properly and you run the system with the volume knob, but you'll have to turn it further than you're probably use to. This method gives the best control over the system and the best signal to noise ratio.

Some don't like it though because they're use to systems where you're blowing out the windows at a volume setting of 3 of 10 so it seems like the system adjusted as above isn't as powerful.
Click to expand...

This makes sense - I'll have to give it a try.
 
whoaru99 said:
Run the amp low and the preamp high. You want to use as much of the preamp's volume control range and output voltage as possible.

Normally I set the amp very low so as not to be really loud for the next step, then turn up the preamp volume control until I hear distortion and back off until it's clean (or hit the end of the volume control travel, whichever comes first). Once I reach that point then turn up the amp gains until it's as loud as you want to go or just a bit more for cushion. Now the gain structure is set properly and you run the system with the volume knob, but you'll have to turn it further than you're probably use to. This method gives the best control over the system and the best signal to noise ratio.

Some don't like it though because they're use to systems where you're blowing out the windows at a volume setting of 3 of 10 so it seems like the system adjusted as above isn't as powerful.
Click to expand...

I can relate to that, on a receiver 1/4 is enough. They are out of rotation now but will be back in next.
 
If you use the 'Loudness' function in the preamp, you will want to set power amp gain for the most natural sounding results as the preamp volume control is advanced into the region where loudness compensation tapers off. Ideally, you shouldn't hear any shift in tonal balance.
 
I've been running seperate's for year's, and usually find the power amp level control's all the way up for published spec's, unless two of them bridged, then about 12-0-clock. Keep in mind, many power amp's have no level control's, and run at full gain. These control's are really just for direct connection of an input source(such as a CD player) without using a preamp. As "Mike" mentioned, if desiring the low level bass boost loudness feature of some preamp's, usually past 10-0-clock on the pre level, it's dialed out.
 
Renzor213 said:
These control's are really just for direct connection of an input source(such as a CD player) without using a preamp.
Click to expand...

I disagree. They're to provide adjustment to system gain structure.

That some amps have no gain controls is irrelevant in regard to those that do, IMO.
 
Power amp gets turned up all the way . Preamp is used to adjust the volume. Often in the manuals it may mention about adjusting the gain controls on your amp to match your preamp, but others say turn it all the way up . I have played around with it at times and always came back to just turning it all the way up for the full 1v
 
Last edited:
In car audio I always set my systems up by adjusting the amps input gain as low as possible yet allowing enough for the amp to begin clipping with the preamp volume set to around 80%. This kept the noise floor at a lower level and allowed a little extra room for recordings that were recorded at a lower level (Peter Gabriel's Security was a really quiet disc) I'd assume this would apply to home audio also
 
Last edited:
I understand the point of having the pre high and the amp low. But, it doesn't make any sense technically? One is just amping the signal with the pre only to have it attenuated at the amps input again. If the amp is set at full power, then usually the signal goes straight through the pot without another attenuator in the signal path?
 
rswojo said:
I just got a power amp and preamp. The power amp has a R and L level control. I know I control volume with the preamp. Where should I set the power amp level controls for the best sound, 1/4, 1/2, 3/4, full?
Click to expand...

In part it might depend on your setup.

I also have an active crossover in my setup and it evidently works better with the input maximized. With 109db speakers, I can assure you that you don't want to be in the same room with them with the intput of the crossover maximized!

My system is now always changing.

If I'm listening to the evening news or background music or something like that, I'll turn the gains on my amps (Crown K2's) down to below 50%. This allows me to maximize the input to my crossover, yet not blow my ear drums.

If I'm in another part of the house or outside (working with open windows or doing an outdoor movie) I might want more volume. Rather than crank my preamp any higher, all I need to do now is change the gains on my amps and they're ready to deliver.

Mine are not 'set & forget'. I change/alter them every couple days, depending on what's happening.

Does your preamp have right/left gains as well? (you didn't mention it so I presume not)

If it DOES, then my understanding is, the best way to give you the most resolution there is to turn the gains to zero. Next, turn the volume to 100% (with your amps set wherever you want to use/keep them) and then turn the gains on your preamp up until you hit the maximum listening level you think you will be using.

This will give you the most control (resolution) through your preamp and you'll always have more 'horsepower' available to you if you need, by turning up the gains on your amps.
 
ev13wt said:
I understand the point of having the pre high and the amp low. But, it doesn't make any sense technically? One is just amping the signal with the pre only to have it attenuated at the amps input again. If the amp is set at full power, then usually the signal goes straight through the pot without another attenuator in the signal path?
Click to expand...

First have to clarify that the gain/level controls are not power controls. They do not limit the output of the amp, they only change the ratio of output to input (gain).

It makes perfect technical sense. By doing this you get better signal to noise ratio as the signal is proportionally stronger than the noise floor of the preamp the higher you turn the volume control.

Here's a crude example that I think works...

Just for example, say the noise floor of your amp is equivalent to 0.01V and you have the gain structure set so that you're only turning up the preamp to 1V output. This means that 1% of your output is the noise floor of the preamp.

Now let's say that with the same preamp you've changed the gain structure so that you need 4 volts out of the preamp. The noise floor is still 0.01V, but now that represents only 1/4% of the output signal. So, the amplifier is now amplifying a signal with better signal to noise ratio and you end up with a quieter (noise wise) system.
 
Last edited:
whoaru99 said:
First have to clarify that the gain/level controls are not power controls. They do not limit the output of the amp, they only change the ratio of output to input (gain).

It makes perfect technical sense. By doing this you get better signal to noise ratio as the signal is proportionally stronger than the noise floor of the preamp the higher you turn the volume control.

Here's a crude example that I think works...

Just for example, say the noise floor of your amp is equivalent to 0.01V and you have the gain structure set so that you're only turning up the preamp to 1V output. This means that 1% of your output is the noise floor of the preamp.

Now let's say that with the same preamp you've changed the gain structure so that you need 4 volts out of the preamp. The noise floor is still 0.01V, but now that represents only 1/4% of the output signal. So, the amplifier is now amplifying a signal with better signal to noise ratio and you end up with a quieter (noise wise) system.
Click to expand...

Thats a very clear explanation......nicely put........:thmbsp:
 
whoaru99 said:
First have to clarify that the gain/level controls are not power controls. They do not limit the output of the amp, they only change the ratio of output to input (gain).

It makes perfect technical sense. By doing this you get better signal to noise ratio as the signal is proportionally stronger than the noise floor of the preamp the higher you turn the volume control.

Here's a crude example that I think works...

Just for example, say the noise floor of your amp is equivalent to 0.01V and you have the gain structure set so that you're only turning up the preamp to 1V output. This means that 1% of your output is the noise floor of the preamp.


Now let's say that with the same preamp you've changed the gain structure so that you need 4 volts out of the preamp. The noise floor is still 0.01V, but now that represents only 1/4% of the output signal. So, the amplifier is now amplifying a signal with better signal to noise ratio and you end up with a quieter (noise wise) system.
Click to expand...

This makes sense. However, it would seem more logical to set the amp at a certain level and then just use one knob (volume on the preamp) to control loudness rather than two on the amp.

The gear we are talking about is a Sony TA 3200F amp and a Sony TA 2000F preamp. Two level controls on the amp, one volume control, no separate level controls, no loudness switch on the preamp. My first ever separates.
 
donberry said:
Power amp gets turned up all the way . Preamp is used to adjust the volume. Often in the manuals it may mention about adjusting the gain controls on your amp to match your preamp, but others say turn it all the way up . I have played around with it at times and always came back to just turning it all the way up for the full 1v
Click to expand...

I would've said the same thing 2 months ago, but I recently picked up a Parasound preamp. The manual indicated that the amp should be adjusted so that normal listening levels on the pre should be around 12 o'clock, and several reviews, both owners and magazine reviewers, noted that the sound quality was better at this setting than by running the amp "wide open" and running the pre at 9:00 like most everybody does.

From a technical standpoint, if the volume control on the pre is adjacent to the INPUTS, then you are maximizing the signal-to-noise ratio by using the highest volume setting. The noise floor of the pre is fixed, and by running the pre "wide open" your signal is as large as possible vs. the noise floor.

If the volume pot is just upstream of the OUTPUT of the preamp, then it doesn't matter quite as much because the volume control is attenuating the noise flloor as well as the signal. However, it's still best to run the pre's volume higher than lower.

The gain controls (volume controls) on the power amp are ALWAYS adjacent to the INPUTS, meaning the noise floor is what it is and the best thing you can do for the sound quality is feed as clean a signal in as you can by having the best S/N ratio coming out of the pre.
 
rswojo said:
This makes sense. However, it would seem more logical to set the amp at a certain level and then just use one knob (volume on the preamp) to control loudness rather than two on the amp.
Click to expand...

Yes. Use just the volume control on the preamp in day-to-day use. Setting/adjusting the amp gain/level controls is part of the dialing in process to get the gain structure set up. After that there isn't usually any need to adjust them on a regular basis.
 
You must log in or register to reply here.
Back
Top Bottom