What is recommended volume level for Source, Preamp and Power amp?

[Kannan]

It is a wonderful device to match your source with your power amplifier. It has a volume control and has a unity gain.

Buffer is not always necessary unless your components are a bit vintage or you have some tube gear.
Most modern amps have pretty high input impedance of 100K and above (150k is quite common now). Most modern DACs n pres have output impedance at less than 500ohms.
If you are above 20/30 times of input impedance on the power stage, that is good enough.

It is quite a hard bargain between the dynamics of active pre and the transparency of the passive pre.
With good gain on modern sources, high gain active preamps are now redundant.

 

[Bloom@83]

This is not a simple question and the answer to your question is not simple too. Gain and volume are different animals. Simplistically, gain is a load at the input while volume affects the output. What is the output impedance of your pre? Your manufacturer should be able to tell you that. Based on that, your amp manufacturer should be able to tell you what the ideal gain setting should be kept at the amp.
The volume pot is a resistive element so the more it is opened up the better the sound. So once the gain on the amp is determined and fixed, you don't play around with that any more. You play around with the pre volume and the source volume to determine what is best sounding for YOU!

Edit: I see Joshua beat me to it.

Precisely.

 

[keith_correa]

@Kannan you're right, I have checked with the power amp designer as well and he suggested the same.
The volume attenuator provided is useful while directly connecting source without pre amp.
Though I will try both settings.

You should also try connecting the source directly to the power amp which I understand has a volume pot in addition to a gain switch. Who knows, you may like a passive preamp better than an active.

 

[adas]

@vbutani from the specs, I see that the amp has input sensitivity settings of 0.5 V and 1.5V.
The volume control on this power amp it is only an attenuator, to be used only if you do not have a dedicated preamp.
Since you have a dedicated preamp, set it to full (no brainer here).

Of course put the digital output full on your LG source aswell.
Try both 0.5 and 1.5 volt sensitivity on the power amp.

Go with the sensitivity that offers a wider bandwidth on the volume pot of the preamp. I guess with modern DACs pushing out 2 volts, 0.5 should be good enough on the power amp, but try both settings

What kannan is saying is absolutely correct , the amp volume is to be kept at 100% and the adjustments are to be made on the preamp side and as the preamp can push out 2V it's best to keep the gain at low setting.

Regards
Aniket Das

 

[bornfi]

Power amp and dac at 100% and control the volume using preamp. This is one of the reasons why one buys a preamp. Sorry, I couldn’t read the entire post but this is what I have on my system.

 

[Yelamanchili manohar]

One could take a KT88 valve, which is a power amplyfing valve, bias the voltage to make it output 8 watts at 0.1% THD. And one could bias the same valve to output 12 watts at a lot more percentage of THD. As we increase the gain, we increase the distortion.

Usually solid state power amps don't have adjustable gain. They are set at factory to output a particular gain. And makers qoute thd vs watts figures for the same, at that particular gain. Which to be honesr is at the upper limits of a power amps ability.

Whereas many tube amps come with adjustable gain. So that one can choose to run their tube amps easy at a lower gain setting, with the preamp running at full pelt. But the preamp, though working at lower 2V voltages is also struggling with a 2V load. So an ideal balance has to be found between preamp volume and poweramp gain.

In my own system, I use a passive preamp at 2 o'clock volume position, with my power amp gain at 80% gain. And not to mention, that in the best interest of prolonging tube life, I run the tubes at below their recommended bias voltages.

So there is no one hard and fast rule governing this in my humble opinion. So one has to experiment and find balance. And if the poweramp comes with a gain knob, then there are sonic benefits to be had, by not running it at 100% gain.

 

[Kannan]

@vbutani Please check the possibility with @adas Aniket and see if the attenutor on the power amp can be bypassed. In my opinion you will benefot from it if you are using a dedicated preamp.
It is just a matter of couple wires that you need to desolder and rewire to take the potentiometer from the circuit.

 

[adas]

@vbutani Please check the possibility with @adas Aniket and see if the attenutor on the power amp can be bypassed. In my opinion you will benefot from it if you are using a dedicated preamp.
It is just a matter of couple wires that you need to desolder and rewire to take the potentiometer from the circuit.

Keeping the volume at 100% is essentially Bypassing the attenuator , because the center leg of the potentiometer touches the other end when it's at 100% there by essentially Bypassing it.

Regards
Aniket Das

 

[vbutani]

You should also try connecting the source directly to the power amp which I understand has a volume pot in addition to a gain switch. Who knows, you may like a passive preamp better than an active.

I was using power amp directly connected to source and it sounds good.
I wanted to try tube based sound as never heard it before.
After introducing tube pre amp in my setup, I really liked the sound! Vocal became more natural!
I tried very old Gujarati folk song and it sounded very natural to me! The vocal details mesmerized me!
It also improved overall sound and pre amp disappeared in the setup.

Thanks to all dear forum members, it was really a good learning experience!

I tried multiple combinations and found following volume levels sound good to my ears:-
Source (mobile) volume 15 out of 75 >> Pre amp 40-50% volume >> power amp in low gain mode (volume 100%)

I think my source amp is powerful so I may try to get line output by using digital usb c not sure much in this but fingers crossed!

 

[SanVJ]

ter introducing tube pre amp in my setup, I really liked the sound! Vocal became more natural!

Hi @vbutani

Could you tell what preamp you use?

 

[keith_correa]

Hi @vbutani

Could you tell what preamp you use?

What is recommended volume level for Source, Preamp and Power amp?

I recently bought Swara tube preamp and O&B audio SS2150 A/B power amp and trying different combinations of volume levels in all the devices. My setup: LG G8x Mobile to play FLAC/Apple lossless files >> Swara tube preamp >> O&B Power amp >> Dali Blue 6006 Floorstanding speakers I observed that...

www.hifivision.com

 

[SanVJ]

What is recommended volume level for Source, Preamp and Power amp?

I recently bought Swara tube preamp and O&B audio SS2150 A/B power amp and trying different combinations of volume levels in all the devices. My setup: LG G8x Mobile to play FLAC/Apple lossless files >> Swara tube preamp >> O&B Power amp >> Dali Blue 6006 Floorstanding speakers I observed that...

www.hifivision.com

Thankyou...

 

[Sixcies]

You have to start balancing the volume from your pre amp. As SandeepMohan mentioned above, your audible level of music/sounds is somewhere around 40%. Assume when you turn your pre amp volume on all the way to its maximum output, that means it’s 100%. If it is turned on it’s half, it means 50%. So the ideal pre amp volume output level to power amp set up is the middle from zero to 50% (half way) of your pre amp volume knob This depends on the recording level of your input source to the pre amp. Also, the power handing of the floor standing speakers, distance from the set up and from the walls behind the speakers, size of the room, the place you sit to listen and the angle of the speakers to your sitting position ( and more). Generally power amps do not have volume controls but gain controls of the back in most occasions. Once you set up your pre amp level of volume to somewhere around 40% of your full volume open level, then the rest can be adjusted from your gains controls of your power amp. However, this audible sound level can be varied once you apply your loudness functions in both pre and power amps. But still the basic is the 40% of the volume open of your pre amp volume knob. But most importantly make sure to use analog sound input sources to pre amp when possible. If musics are in digital mode use a DCA (digital to analog converter like Rotel DAC) to convert digital to analog and then input to pre amp. Never use Bluetooth mode to connect your storage/ device to DCA > pre amp or directly to pre amp ( if pre amp has Bluetooth connectivity) and use the RCA cables. I won’t use any mobile, laptop or PCs as input devices to my pre amp but directly connected USBs; stored my preferred music to the DAC. Also to get the best quality out of any pre amp/ power amp combination, always use an qualifier between pre and power amp. Then you have lots of controls to fine tune the quality of your sounds. But still the basic is “ Pre amp volume is at the middle of the volume knob from zero to its half open. In other word, quarter of your pre amp volume knob. Hope this helps to set up your master volume.

 

[manek]

Preamp at max, and power amp till where it doesn't distort

I would go with preamp at half way up on the volume and adjust power amp gain accordingly so you do have the control on preamp. But I like the way manohar is telling you to use the preamp as a straight wire.

 

[jenson]

Earlier with my pulz ha400 and thr pulz pre amp... I used to keep the amp at full and adjusted thru pre.

When playing thru mobile, kept volume level in mobile at full and adjusted volume thru pre.

What you can certainly experiment is step by step as most have suggested here. Also, you can try combination of simultaneously adjusting volume between pre and power to come at a noise level where the hiss is minimal, assuming entire chain is otherwise ok

 

[Yelamanchili manohar]

I would go with preamp at half way up on the volume and adjust power amp gain accordingly so you do have the control on preamp. But I like the way manohar is telling you to use the preamp as a straight wire.

It actually depends on a lot of factors which are variable.

1. But generally speaking poweramps are working into a variable load, due to varying impedences, and are thus likely to clip or distort. Where as a preamp is always working into a fixed load, determined by the input sensitivity of the power amp. So they don't clip.

2. The gain induced by a power amp varies from 27 to 32 db depending on design. Where as a preamp is taking a 2V signal and only in case of very hard to drive speakers, will amplify the input 2V to 4 or 6V depending on design.

3. So from the above, it can be seen that there is more danger in running a poweramp at full gain, than running a preamp at full gain,

4. I have a active as well as a passive preamp, and I have tube mono blocks with variable gain. And I infact run the poweramps at close to 50% gain, to prolong my tube life. And preamp at close to 80%. It sounds absolutely sublime.

Just my 2 cents

 

[Dhruv.Arora]

I run my power amp at full gain and adjust preamp and source levels. The logic being that many power amps don’t have gain control so aren’t they by design running at full gain.

 

[arj]

Gain is the most important factor here as @Yelamanchili manohar has written

ideally the power amp gain to be kept at the the min position such that you get you usual listening range in the 30_50% volume of your pre amp. Unduly gain of the power amp at 20_28 db is enough and pre providedes 10 or above.. overall amplifier gain if 30-37 is enough

There is no clear rule here but too much high gain and sound gets saturated and you lose details and low gain means your harmonics go missing and you lose texture of themusic