Amp to power 4 Ohm speakers


New member
Username: Dharris

Post Number: 2
Registered: 02-2004
Not looking to spend much money. I also don't want to buy crap. What is a good amp that can power a 4 ohm speaker without going over 700.00?

Bronze Member
Username: Rick_b

Post Number: 15
Registered: 12-2003
My previous post would cover this question as well.

Silver Member
Username: Hawk

Post Number: 317
Registered: 12-2003

What kind of amp? I know you may think this is very obvious to you, but we aren't there to see what you want it for and many people post the same question, but it turns out they may mean a stereo receiver, a HT receiver, a stereo integrated amp, or maybe just a two channel amp to add to a HT system or for stereo application. Rather than having us guess, please clarify.

New member
Username: Dharris

Post Number: 4
Registered: 02-2004
Sorry for the lack of information. Actually I'm looking for the best for the money. I have an older Denon A/V receiver that has pre outs. I love home theater as much as the next guy, but I love to listen to two channel music more. From what I have read, 4 ohm speakers are hard to drive with budget amps / av receivers. You think that my Denon AVR-1800 has enough power formy MB Quart speakers,
My Denon spec sheet says
Power amplifier Rated output is,
75w + 75w 8 ohms, 20Hz ~ 20kHz with 0.05% T.H.D
110w + 110w 6 ohms, 1kHz with 0.7 T.H.D

Dynamic power:
100 W X 2ch 8 ohms
145 w X 2ch 4 ohms
170 w X 2ch 2 ohms

Silver Member
Username: Hawk

Post Number: 320
Registered: 12-2003

OK--I think I can help here. First off, realize your Denon doesn't get anywhere near its rated output when driving five speakers. The Dynamic Power rating is only when driving two channels )a typical method by the large audio companies), so figure your actual power as something on the order of 30 wpc.

Additionally, it helps to know you have MB Quart speakers, a very fine German brand that is very detailed and somewhat bright sounding. Thus, you need an amp that not only will drive 4 ohm speakers, but can help tame slight exaggeration in the upper midrange of the Quarts just a bit (so that they do not sound "edgy"), while maintaining their superb detail.

I would suggest a B & K 125.3 amp. This is a true 125 wpc separate amp with 3 separate channels (for 4 ohm loads it is 185wpc x 3). This will allow you to use the B & K for the front three speakers with gobs of power and allow your internal receiver amps to power the rears. By relieveing the receiver's power supply of having to drive all five channels, you will get a much cleaner and more powerful signal for your rear speakers when you use it for 5 channel sound. Also, by using a three channel amp, you will get a uniform signal for the front three speakers, making it easier to get the sound balanced. I have priced this amp at $695 here:

It is an excellent amp and I highly recommend it.

Now, if you are a little hesitant to spend that much money, then I recommend a two channel NAD C270, rated at 120 wpc x 2 (340 wpc dynamic power into 4 ohms), which can be had for $399 from Saturday Audio Exchange (, as this model is being closed out for a new model. This amp will allow you to use the outboard amp for your mains thus relieving your receiver's power supply of two channels (which power can be redirected to the center and rear speakers). Again, you will hear real sonic benefits from this arrangement. It is a superb amp.

Both the B & K and the NAD are well built amps that are warm sounding, highly detailed, and very clean sounding (much less distortion than your Denon). Neither will have any trouble with the 4 ohm load of the Quarts and will have an overall sound that will compliment the MB Quarts, beautifully.

Good luck!

New member
Username: Amir

Post Number: 1
Registered: 02-2004
krell 300il

New member
Username: Hawk

Post Number: 5
Registered: 02-2004

Are you suggesting you know where to get a Krell 300 for under $700? If so, let me know. I will order one now.

Silver Member
Username: Gman

Post Number: 235
Registered: 12-2003
You could probably get a Krell 300 for under $700 if it has been dropped off a 10 story building onto a concrete street:=)

Bronze Member
Username: Heff

Post Number: 70
Registered: 12-2003
Have you considered used Hafler equipment? Specifically the Hafler DH-500 Amplifier comes to mind. It's a sleeping giant at 255 Watts @ 8ohms. (375 wpc x 2 into 4 ohms)

The older Haflers are revered by many owners who were fond of David Hafler's work (Dynaco, Ortofon, Hafler). Note: the new stuff bears his name, but David Hafler has no direct involvement with the company. (see RIP)

While many of these vintage units have been pampered by audiophiles, others have been used as workhorses in recording studios, DJ equipment, PA systems, you name it, so YMMV when shopping in the used market.

IMO for($300-$575) a used Hafler DH-500 Amplifier would do an excellent job.

Check out these Links
29 reviews available from Audioreview

Unregistered guest
Im looking for info on Bose 901 series IV. I have just purchased a pair and I am having problems powering them. I have been through about 4 amps, and just havent had that rich warm sound I remember.
I have just bought two monoblock BK st140 power amps and a Yamaha c-2 preamp. I havent recieved the preamp yet but was just wondering if this will be enough, or should I look for more power?

Silver Member
Username: Project6

Post Number: 531
Registered: Dec-03
don't look for more power. You are probably looking into the problem at the wrong perspective. I also thought that the problem is not having the right amp...I was using Hafler, Carver, SAE and Soundcraftsman on my previous 901s back in the early '80s. You have excellent power supplies and it will drive the most demanding of speakers. Anyway, it turned out, i was using the wrong speakers, so I promptly sold them after hearing a couple of Boston Acoustics and the older Klipsch speakers.
So, bring your receiver to a reputable dealer and try out one of their speakers...maybe a set of Paradigms and B&Ws. Just a suggestion, from a former Bose 901 owner.
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