Question Driving 4 ohm speakers

MaryWhitehouse

Well-known Member
Theoretical question for the moment.

Expecting some Dynaudio Audience 42’s in the post tomorrow. For now the system will run with my passive pre feeding (kind of as it’s what I’ve got) the power section of an old but top of the range Pioneer AVR.
Now I read that these speakers are excellent but can be hard to drive at 4 ohms. I’ve been looking at power amps up to about £250 (very, very much max) and a seller advised that Cyrus for example hate driving 4 ohms. I’ve also read a generalisation in spec is that an amp that drives 4 ohm at double the watts of 8 ohms should have decent current. The Dynaudios seem to like around 100w.
Any thoughts and recommendations?
 

Orobas

Well-known Member
Realistically... for dynaudio you will need something in the region of what i have with the Roksan or a Musical Fidelity or a higher rated Arcam amp like the SA10 or SA20. These are the ideal amps

Lower priced stuff....
Rega Brio will power them low to mid volume levels very well as will something like a PS Sprout.

in terms of power amps.. at that price.. i would be looking Rotel Amplifier RB-06 or Arcam Alpha 10P though.. Roksan poweramps tend to start at the 400 mark second hand...
 
Last edited:

MaryWhitehouse

Well-known Member
Thanks. Only looking at power amps and how to read the specs to have any chance of success.
From my reading and logic so far an Avr that can operate as a power might work well if it has a big power supply.
 

Orobas

Well-known Member
Thanks. Only looking at power amps and how to read the specs to have any chance of success.
From my reading and logic so far an Avr that can operate as a power might work well if it has a big power supply.
I updated my answer since you last saw it so please do check again!
 

MaryWhitehouse

Well-known Member
The rb-06 specs are an example of unhelpful. Showing power in stereo at 8 ohms but bridged at 4 ohms but not vice versa.
 

Orobas

Well-known Member
Your other option is not something alot of people tend to think of.. and thats get a "disco" power amp.... and feed them that way
 

MaryWhitehouse

Well-known Member
Your other option is not something alot of people tend to think of.. and thats get a "disco" power amp.... and feed them that way

Hah have been looking at those. Particularly Alesis RA’s and Behringer A500/A800.
 

Orobas

Well-known Member
Hah have been looking at those. Particularly Alesis RA’s and Behringer A500/A800.
Both of those are almost monitor grade.. half decent sound.. too...
 

MaryWhitehouse

Well-known Member
Any experience with the a800? Just as I think that’s still available new.
 

Orobas

Well-known Member
Any experience with the a800? Just as I think that’s still available new.
The A800 is a nice amp but there are several issues to note..

1. it is pretty flat response to about 15khz.. then there is a pronounce lift and gain in the tope end of the treble.. this is a bright top end amp
2. Its noisy with distortion running around 66db.. this should be down at the mid to high 70's ideally...
3. Works best off a balanced input which not alot of amps give on their output.. it's ok with a normal input but balanced is better...
4.. Best used with the Neutik speaker connectors as opposed to the bare wire terminals..
5.. Hard to get a -3db peak input signal into it (0db is nominal.. anything higher is distortion being fed in)

but at £190 .... you dont expect much at this price... so i cant fault it really
 

MaryWhitehouse

Well-known Member
Cheers. The disco amps are right up there at the moment. At least I can try and return.
 

Orobas

Well-known Member
Cheers. The disco amps are right up there at the moment. At least I can try and return.
Dynaudio thrive on power... but quality power.. they also are very unforgiving of their source.. they are quite excitable speakers as it is with a pronounced top end... You feed them bright they will make your ears bleed.. you feed them poor.. they will make you cringe...

Be warned on this.. this is not to be taken lightly.. your older pioneer will be quite bass thumpy with not much mid... this will amplify through the beringher and increase that top end on the dynaudio also...

You will need quite a bit of experimentation here and may need a few trials till you find the right sound
 

MaryWhitehouse

Well-known Member
Be warned on this.. this is not to be taken lightly.. your older pioneer will be quite bass thumpy with not much mid... this will amplify through the beringher and increase that top end on the dynaudio also.

I hear what you say about the Pioneer but that won’t be in the chain. Sources are good.
 

Paul7777x

Distinguished Member
This will drive the Dynaudios all day without even noticing.

 

MaryWhitehouse

Well-known Member
Ta. Wouldn’t a 8 ohm power of 100w with only a 50% increase at 4 ohms suggest a small power supply?
 

Paul7777x

Distinguished Member
The 8000p was tested a couple of times with upwards of 130W into 8Ohms.

And the power supply, which counts most, is huge.

I seem to recall reading that it can swing 40 amps.

Which, unless you plan to weld supertankers with the Dynaudios, is massive.

I’d say you’d be catching a high speed driver before the Audiolab raised a sweat.
 

MaryWhitehouse

Well-known Member
Added to the list. Thanks a lot.
 

Ugg10

Distinguished Member
Keep an eye on these XTZ A2-300, the guy has two listed, you may be lucky but suspect they may go for £300+. Loads of clean power and will drive down to 2ohms, based on Icepower ASX200 boards iirc.

 

MaryWhitehouse

Well-known Member
Thanks a lot. Despite various searches still being shown things I don’t see!
 

MaryWhitehouse

Well-known Member
I suspect they’re for sale on here too.
 

BlueWizard

Distinguished Member
...

Now I read that these speakers are excellent but can be hard to drive at 4 ohms. I’ve been looking at power amps up to about £250 (very, very much max) ....

Let's talk about how 4 ohm speakers work. Lower impedance means more Current Flow for a given setting of the Volume Control (voltage). More Current means more heat, and more chances that the Amp will go into thermal shutdown.

The other factor affecting Current is Volume. The louder the speakers, the higher the applied Voltage and the higher the resulting Current, which in turn mean more heat, which in turn means a greater chance of the Amp shutting down.

So, for an amp to work, you have to stay within its range of Heat Tolerance, and within the Current capability of the Power Supply.

There are lot of consumer grade Amp that are 4 ohm rated, so this is not really a problem. But seeking a good Power Amp for only £250 is (sort of).

About the best you can do in a New Amp is the Crown XLS-1502 Drivecore. Massive Power in a Class-D Studio Amp. Though a bit above budget.


Admittedly above your budget, but it is an amp with 300w/ch to 8 ohms and is rated functional down to 2 ohms.

Oddly, the 300w/ch Amp is less money than the 200w/ch model.


Many Positive Reviews on YouTube for the Crown XLS Amps. Some pretty serious Stereophiles use the Crown as their primary amps.

The Crown also have DSP Crossover control. They have Low-Pass, High-Pass, and Band-Pass filters. The Low-Pass could be used to drive a passive Subwoofer. The High-Pass could be used to filter low frequencies from the Front Speakers, and the low bass then diverted to the Subwoofer. So, very versatile amps.

The Amps also have a Bridged Mode, where the Left and Right Channels can be combined into one large Mono Channel. In Bridge Mode Mono, the XLS-1502 puts out a very solid 1050 watts to 8 ohms. 1550 Watts to 4 ohms.

There are lower cost Class-D Studio Amps available from Behringer. These come in two versions, the "D" with DSP Control, and the non-D which are just straight forward power amps. Reviews are good, but I'm not sure these are in a class with Crown. -

This is the Berhringer NX1000D - DSP version (160w/ch to 8ohms) - £225 -


This is the non-D version - Behringer NX1000 (160w/ch to 8 ohms) - £174 -


Studio Spares is not real clear about the power, but I looked it up on a USA seller, and the standard Power Rating is a more modest 160w/ch relative to the substantially and potentially overpowered Crown.

Here is the USA site, click "Specs" to see the standard 8 ohm rated Power.


Crown is a company with a stellar reputation spanning many decades. Behringer are a newer though well established internationally, and while maintaining quality, represent high value in Audio Equipment.

For your budget in a New Amp, this is about the best you can do.

Steve/bluewizard
 

BlueWizard

Distinguished Member
If you can grab a crown amp it’ll last you forever and drive anything.
Though the Crown is surely the better Amp, both the Crown and the Behringer are able to drive 2 ohm speakers, so driving 4 ohms will be a breeze.

I did check one review on the Behringer NX1000, and they said that the Fan was a bit loud. This owner was going to replace the built in fan with some Quiet Computer fans of the same size.

While the Crown amp has a Fan, the amp monitors the temperature and the fan only comes on, and perhaps speed regulates, based on that Temperature. Z-Reviews on YouTube reviewed the Crown amps and he said the amp never got hot enough for the fan to come on in all the time he used it.

Though I don't know for sure, I suspect the Behringer fans are just on, and not monitoring amp temperature.

Whether that is a problem will depend on how sensitive you are, and where the Amps are placed. It will also depend on what sacrifices you are willing to make to stay within your stated budget.

Steve/bluerwizard
 

Paul7777x

Distinguished Member
I’ve had quite a few ‘pro’ power amps over the years, including some of BK Electronics excellent MFX series and I’ve always simply disconnected the fans.

I’ve never found them to need anything other than convection cooling in domestic situations.

As a rule pro power amps are built very robustly, and designed for work far more vigorous than a uk living room.
 

The latest video from AVForums

Podcast: Sony A90J/A80J OLED details, Best type of Amplification, Film & TV Show News + Reviews
Subscribe to our YouTube channel

Latest News

LG offers best ever OLED prices - for one week only
  • By Andy Bassett
  • Published
Sony launches Bravia XR A80J OLED TVs in Europe
  • By Andy Bassett
  • Published
Tidal streaming service acquired by Twitter/Square's Jack Dorsey
  • By Andy Bassett
  • Published
Netflix adds support for reduced theatrical release window
  • By Andy Bassett
  • Published
Paradigm launches Founder speaker series
  • By Andy Bassett
  • Published
Support AVForums with Patreon

Top Bottom