Power Amp Question

Question: how to match a power amp to my system using an integrated amp as a preamp.


Triad Gold LCR In-Room Speakers 4-OHM 100-400 watt

Audio Tecnica AT-OC9XL Dual MC cartridge

NAD C356 integrated amp

Rega Aria MK3 (recently added)


Thank You




Hey there,

You have a nice combination already.  I'd suggest a subwoofer and room treatment are better options than a new amplifier from where you are. 


No.  Just...no.  IME the preamp is more important than the power amp, assuming the power amp is up to the task.  Don’t half-ass it.  Sell your current stuff and buy a better integrated or separate pre and amp.  Preamps are crucial to getting the best performance out of your system.  Underestimate it at your peril. 

#1 problem w integrated, even the great ones… ( like an Aesthetix Mimas ) are the loooooooooong speaker wires….


     IF your question is how to use your NAD integrated as a preamp only: there should be two links (rectangular, black plastic covered) between the C356's rear PRE OUT 2 and MAIN IN RCA jacks.

     Remove those and simply plug a pair of interconnects, between the PRE OUT 2 jacks and your new amp's input jacks.

     If your desire is to add a second amp: use interconnects from PRE OUT 1, to that amp and leave the PRE OUT 2/MAIN IN links alone.

@rodman99999  I understand much better now, thanks.  If I go with the C356 and a power amp or a preamp upgrade and power amp, how do I match my speakers?


Right now I need more power IMO. 


 Speakers 100 - 450W - 4 ohm and the C356 80 watts is too little. I am not sure.


Depends on how loud you listen.

This little monster should do ya.

That's as much as I would spend before getting a better pre.

@bop333 -

     Supposedly: your current speakers are fairly sensitive, at 92 dB/1W/1M.   

     Many SS amps will safely double their 8 Ohm output wattage ratings, into a 4 Ohm (nominal) load, which your speakers will present.

     According to the specs: your NAD doesn't, staying at 80 WPC, into both 8 and 4 Ohms.

     You might try a 200 WPC @8 Ohm amp, that you've confirmed will safely handle 4 Ohms (preferably: double it's output), with your Triads and see if they satisfy, prior to making any other leaps.      

                        If not: more efficient speakers may be your ticket. 

@bop333 -

     btw: Are you dissatisfied with your system's SPL output, with all sources, or- only with your analog setup?

     I've been trying to find the voltage output for your AT MC cartridge, but: guess that's a company secret.

     The output levels of many MC carts are too low for some systems.    In those instances: additional gain devices (ie: a transformer or higher gain phono pre) may be needed.

     Just thinking your system may not have enough gain, to step up the cart's output to satisfying levels, as a possibility.

Why do you believe you need more power? (maybe you do, its just that there is no evidence or explanation here......)

You realize the relationship between power and volume is roughly logarithmic? so doubling it makes a very small difference.....

BTW if you do wish to upgrade i tend to agree that a better ovrall integrated would be a better choice - the signal is a chain and only as good as the weakest link after all.

#1 Move all the stuff from in front of your speakers. #2 Use very heavy gauge speaker wire, at least 10 to 12 gauge. #3 The more power the better, 200 watts/channel minimum. I would also agree that you may want to go with separates eventually, but the NAD should work fine for now. I do not agree with the comment that a preamp is as important as the power amp, speakers #1, power amp #2. Good luck.

I must agree with @fiesta75 that moving the stuff from in between your speakers would likely result in a real improvement. But given the size of your room the biggest gain would be in the preamp. A good preamp is the heart and soul of a system like yours… as well as the phono stage. I would invest in that way before a new amp.


I have been pursuing high end sound for fifty years. I started with very modest components. The first big step up was from owning a great preamp, the second a great phonostage, and finally and amp. It would be easy to overload the sound in that small room and make you think you need more power and bass… you will probably want bass traps in the corners to help stop overloading the space. That lets the contrast of nothing to strong sound increase. Also, after removing the stuff between the speakers a thick wall hanging to absorb sound and one on the wall opposite the speakers should help. Corner traps would prolly help (small).

@ghdprentice @rodman99999 @fiesta75 

I greatly appreciate all the valuable insights and suggestions.

I will think about adding a 200 watt power amp.

The phono preamp is a few days into the system.

There is a lot to think about.





+1 soix4. Look for a used pre and power amp. If your speakers are 92db sensitive you won't need 200wpc unless you have a truly large room or are a headbanger.

Yes, for me, buying a very good preamp was the mightiest game changer. The signal is so small and delicate...screw it up here and it won't matter much how good the amp is.

Buying a better amp is usually a modest upgrade. 

Want to make a big difference? Preamp and phono amp: get the very best you can afford.

OK I am confused. How does using separate amp or pre-amp or an integrated change the length of a speaker wire. Or did I miss the joke!

@randym860 you can put dual mono power amps right next to the speakers so the speaker wires are short.

True. But then you will probably need longer cables to connect them to your pre-amp so I guess there is some give and take. As they say there is no free lunch.

Focusing on speaker wire length is just plain anal (and irrelevant) when in comes to answering the OP's question.  Feel free to experiment with (probably class D) more powerful amps, but you may find that they don't give you significantly better (only different) sound than your NAD.

@fatdaddy2 @randym860 @pennpencil @pennpencil 

Thanks for your input. I feel much more informed as I go forward. Looking forward to being an active part of the forum.


I once owned the NAD C256BEE. Regarding needing a more powerful amp I have two questions. What is your room size and at what position is the volume knob when listening at loudest levels. In my experience when volume knob for this amp is at the 12:00 o'clock position the gain from the preamp stage is driving the amp as hard as I feel comfortable (for amps sake).  

I do not post much, but - the NAD should be powerful enough to give you hearing damage in under 10 minutes with that setup. Before you go and spend a bunch of money, in my opinion it would be a good idea to verify all your components are working according to specification.

I took a look at your picture of your listening room - it is not very large, and the NAD with those speakers at 92db 1w/1m, according to the specs should be able to drive  them to 110db at 64 watts at 1m, and depending on where you are sitting (you will lose 6db at double the distance); so - 104db at 2m. 104-110 db is quite loud - as in, rock concert - hearing damage loud (supposedly hearing loss will start in about 7 minutes at those levels). You need 128 watts to get to 107-113+ db (Double the Power Rule-When you double the power, there will be a 3db gain in SPL)  and you would need a 256 watt amp to get to 110-116db.

The NAD has 220watts of dynamic power at 4 ohms, so I am surprised it is not powerful enough, especially in that small room.

This makes me wonder if your input to the NAD is high enough to allow you to get to full output (the NAD specs says its sensitivity is 500mv). Is the NAD loud enough when using the CD player? If it is, and your analog setup is not loud enough, then something is not right with your analog setup. The AT-OC9XL is a 0.4mv output, so into the Aria at 63db gain at the MC inputs, should get you to 400-500mv into the NAD, which should be enough to get the NAD to full output.

I suggest you download the Decibel X app for your phone (or a similar decibel meter for your phone) and find out how loud your system is now when using the CD player in your room. If it is not at 104db or better when the NAD is maxed out, something is not right. 



Do some research before you make the same mistake others do. WATTS per channel equate to a very small part of the power equation of audio gear. I can show you an amp with 500 watts per channel that wont drive your speakers. Then I can show you an amp with 5 watts per channel that will blow you out of the room. Just make sure you have all the right information when evaluating what you reference is “need more power”! They did not name a company First Watt because they thought it was catchy. They did so because the First Watt is the most important one when done right!

I would agree on the Class D Audio GaN amp. I bought one, and it continues to amaze me. I use it just to give my 3C24 tube amp a break.

Another thing I agree on is how important a great preamp is. I never realized how much difference one could make until I bought a Herron VTSP 3/A 360 preamp some weeks back. it's brought the SQ of my system way beyond what it was before it came into my system.

So, get the best one you can afford. If you have to save your money until you can afford one. It'll make a difference you wouldn't think was possible.



@sgreg1 Thank you for the information.

I have a question which will help me understand.

My reasoning for more  power is to not have to turn up the volume to 11/12 to get a full soundstage. 

I will look into your suggestions.






My long term goal is a tube amp and a preamp.In the meantime I am learning more about my current setup. 

(BTW myaudio/video system will be posted soon. The Triads were part of that system)




Hi George -

A couple of things - 

1. I think @sgreg1 is absolutely correct - not all amps are created equal. If you are turning up the knob to super high sound levels to get the full sound stage, then I think something is not working well for that 'first watt' as sgreg1 put it. A "better" amp, or better synergy between components will give you that full sound stage at lower levels.

2. The position of the volume control with an analog potentiometer like the NAD has, is an attenuator for the source (eg: the CD player or the turntable) - the preamp itself may have gain too, but I have found that at the 12 to 1 o'clock position is usually where unity gain is (meaning no gain, no reduction to the input signal); so, if the input signal is below the amplifier sensitivity level, you will not get full amp output at that point. Then there are digital volume controls which have no 12  o'clock necessarily - they just spin a number representing the attenuation - sometimes in db.

I think this video does a pretty good job of explaining the "volume control" -



@bop333 Said,

My reasoning for more  power is to not have to turn up the volume to 11/12 to get a full soundstage. 

In my opinion: That is more of an issue with the speakers then the amp. Speakers that have efficiency  > 1 % and a impedance > 8 Ohm, do not need a lot of juice to get a full soundstage or to sound good at low volume. Also amplifiers produce more distortion in lower impedances then higher impedances. That has been my experience.








Now that you have read many contributors comment about your preamp, amp, speakers, system, etc., I would like to comment on your original question.

"how to match a power amp to my system using an integrated amp as a preamp."

As a general rule of thumb, you should try to have the input impedance of the power amp be at least 10x the output impedance of the preamp. Or the output impedance of the preamp section of your integrated amp in this case.