Preamp levels versus Amp input attenuation

jbeckva

jbeckva

Admin/Server Dude MAA Guy
Staff member
Joined
Jun 11, 2010
Messages
6,894
Location
Powhatan, Virginia, United States
Tagline
WassupYa Mang?
As one thing to broaden my audio knowledge, I think this is a great question to pose.

As a general rule, how should the amp's input attenuators be set in respect to the incoming signal level from the preamp? I would imagine there are quite a few factors to consider like S/N of amp versus S/N of preamp... interconnect length/noise susceptibility.. ideal preamp "operating output level"??

What's a good procedure or rule of thumb to follow here?
 
I use my preamp to control. My amps have no controls. Take it to where it sounds the best. Let it be. If that is full blast so be it. That is just me.
 
If yhe amp has input controls I usually set them to 3/4 the way. You can experiment with different settings, i have never found the sound quality to vary much, but I usually adjust so my preamp volume knob has a little more latitude between to quiet to hear and to damn loud. That way I hopefully can set the voulme to a level that I like without it beeing a touch too quiet or a touch too loud. The call those controls the anti x-amp controls.
 
Lee and I set them to 11 and don't worry about it. Actually, you can use the potentiometers on the PL700 amplifier as "Gain" controls (you should only have one "Volume" and that is on the preamplifier). To set and forget the gain, turn the amplifier "gain" all the way down, then increase the preamp "volume" to the maximum (fully CW). Then, bring up the amplifier "gain" until: a) your speakers are at the limit of their capacity, b) you hear distortion, or c) you sense pain. Then quickly turn down the preamp "volume" and note that you have set the amplifier "gain" for the range that you can comfortably listen to and not worry about your speakers blowing up when the phone rings and you wife jumps up to turn the volume "down" just as you walk into the kitchen to get another beer. Don't ask me any more about this...
 
Last edited:
Jer, trust your ears, I know they know what up Homey!! Most of my amps have an output level pot, I run the Yamaha at half mast...12 '0 clock with the AR's, the Logans liked them at about 4 '0 clock, or 5/8ths on the level, big bad ass current lovers, Man I miss them :love9:.

This all goes back to the synergy thang, the amp/speaker load, cables add another dimension, and so does the room...I digress. I always thought a great amp that was well designed sounds better loaded down, running a bit hot, rails sagging just a bit..Yep! That's it!

Have ya pushed the little Sanyo intergrated amp to it's limits with a demanding load yet? I'd love to see a scope of the square waves on it loaded down.
 
Still waiting for one to be delivered someday by Louise the FedEx lady. Someday, my pre will come.
 
Power amps all the way up Jer.

Preamp has all the control. Beyond the input attenuator pot , the power amp is running at a fixed and max gain of 26dB anyway. There is no variable gain in the amp itself. The pots just add noise.
 
Just like everything else in audio. You ask a question and you will get a different answer from everyone. Jerry I look at it this way. I try things a lot of different ways. Trust me if you goof you will know pretty quickly.
 
I always have my amps at full gain. No reason not to and if you can leave a pot out of the audio path, so much the quieter. Pot is a gateway...........to noise!
 
God I love this place......Ya'll put a BIG smile on my face!!!
 
i think component synergy can play a roll and the best results are sometimes going to be equipment and or room dependent. case in point, my bedroom rig, AR91 speakers, Yamaha C-2a pre and Yamaha M-2 big iron amp. even with the bias dialed back to 3 o'clock (about 3/4ths full gain) spl's are too much for the room before i get to 9 o'clock on the volume knob of the pre. dialing back the gain controls to 12 o'clock (1/2 full gain) i have better control with the pre and the volume adjustment is more incremental. now i dont overload the room with the slightest nudge of the volume knob and can dial in that sweet spot with much greater precision. in this case that makes for better sound.
 
BrawHahahahah!!! Synergy, that's it, everything is the same until it's different, right? Who Dat?? :tongue10:

I have Sunday off, and will play around with the Yamaha's pots. I always thought they were output devices, so are they really input signal from the pre-amp levels??
 
On my Yamaha M-85 I always ran the pots at full bore, let the pre-amp set the volume level
 
They are acting as gains. Like Dingus said. I turn the volume to where I am going to listen then dial the gains in to what sounds good. Usually it is full bore. I get a more full bodied sound. I go back a little I lose my mids. Every amp I have owned has been that way. To me anyway.
 
The human ear is sensitive in the range from 20 Hz to 20,000 Hz but the perception of the intensity (we call it loudness) across that spectrum is not flat. The majority of people have ears "tuned" by genetics to hear best in the range of the human voice - 100 Hz to 10,000 Hz. An attempt to overcome this was "A-weighting." A-weighting began with work by Fletcher and Munson which resulted in their publication, in 1933, of a set of equal-loudness contours. Unfortunately, much of this work was done in laboratories with pure tones, not "noise" which is much closer to the mixture of frequencies and tones present in music. A-weighting is only really valid for relatively quiet sounds and for pure tones.

When more than one frequency band is stimulated in the ear, the outputs of the various bands are "summed" by the brain to produce an impression of loudness. For these reasons equal-loudness curves derived using noise bands show an upwards tilt above 1 kHz and a downward tilt below 1 kHz when compared to the curves derived using pure tones. This has resulted in the recent acceptance of a new set of curves standardized as ISO 226:2003 from a study coordinated by the Research Institute of Electrical Communication, Tokyo University, Japan. Today, the old B- and D-frequency-weightings have fallen into disuse, but many sound level meters provide for C frequency-weighting and its fitting is mandated — at least for testing purposes — to precision (Class one) sound level meters to measure noise (music) and not pure tones.

So it's not just you.
 
You must log in or register to reply here.
Back
Top