Best High Current amplifiers stable into low impedances

Luxman 10-x advertises great current into 2 ohms and lower loads. I spent a couple hours with one. I have to admit I was really disappointed… too dry and un-musical for me. I had high hopes… just from their reputation. If you are into dry detail… check it out.

Pass X350.8… real high current design. I owned a x350 for a decade. Great amp, but not a tube amp… which once I got an Audio Research amp completely turned me off to solid state amps. It is a great map though.

Odyssey Audio 

REGA OSIRIS 

Most Class A amps can do that as they typically have robust power supplies. Sanders Magtech, maybe Krell, Bryston, Parasound, Coda, McCormack etc.. I’d guess that most amps that near double into 4 Ohms would likely also handle a 2 Ohm load.

Perreaux 2150B - 340/680/920 wpc @ 8/4/2 ohms. Can be found on eBay for under $1K. I have one! 

When you get down to the 2 ohm range, it's best to talk to the manufacturer and tell them what loudspeaker you are trying to drive. Specs don't tell the whole story and I would not put a lot of faith in them. 

Gryphon Diablo 300. 950W/channel into 2ohm!!!!

I went through the 2 Ohm dance with my now sold Thiel CS3.7 speakers. I thought newer speakers were easier to drive.

The amp I am likely going to get for my Livingroom is the KRELL KSA i400. It is 400 watts of Class A (depending on demand) at 8 Ohm. It doubles down to 800, and then 1600 watts. It is supposed to be able to double again to 3200 if your power source can provide the current.

I do not think that 400 watts of Class A will double, nor half. I remember an interview with the designer where he said it stays at 400 watts of Class A when it is doubling.

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I have the KRELL Dou 175XD that has similar tech as this new amp. I love the 175XD, which I use as a headphone amp (’ear speaker amp’).

The CODA #16 also doubles into 8 - 4 - 2. It is a great sounding amp.

pass / threshold / usher

gryphon

sanders

krell

classe

coda

bryston

odyssey

top parasound, musical fidelity, mccormack

upper ayre, hegel, plinius, perreaux

On the used market, Innersound Electrostatic amplifier. Or Sanders or Coda.

These amplifiers share a common design approach - numerous transistors that can dump gigantic amounts of current into any load. Here’s something I clipped from the enjoy the music review of the Innersound amp:

The InnerSound Electrostatic Amplifier ("ESL amp") solves this problem by using a massive output stage. Each output transistor is capable of delivering 250 watts -- and there are eighteen of these per channel. As a result, it can deliver a staggering 135 amps of current with a combined power rating of 4,500 watts per channel! The output impedance of an amplifier must be lower than the impedance of the speaker, or current clipping will result. With so many output devices, the output impedance of the ESL amplifier is virtually zero. Current clipping simply is no longer an issue.

This amp does not sound dry. It sounds beautiful. Like music. I’ve emphasized it here because I’ve owned one. A tremendous piece of gear. A tremendous value. The Sanders amplifiers are evolutions of this design and are extremely good value. Same with Coda. Mind-boggling approach. Totally cool.

There are lots of brands that are "stable" at 2 ohms.  Implying they can deal with it for short stretches but they aren't comfortable at 2 ohms. 

I recommend Naim.  Naim is designed to pair with Focal and it thrives at 2 ohms.  Any of their power amps will do extremely well.  Focal speakers tend to have relatively low impedances and require high current amps but not much in the way of top line power.  

Sanders Magtech

Magnus Audio-any of the four power amps.

Sunfire amps can work with any load stable.

Anybody know what the status of the second iteration of Purifi amps. These new ones are supposed to be much more powerful than the 200 watt first version.

Seems like several of the boutique Purifi builders, Apollon, Rouge, VTV, March, are using the new module, but none of the big boys have come out with a new model yet, AFAIK.

I just checked the VTV site and the specs are not too bad.

950W @ 2Ω

500W @ 4Ω

250W @ 8Ω

(2) Bruno strikes again. Purifi 1ET7040SA VTV Amplifier. Sinad 109. 950 watts. - YouTube

I think I I need to give one of these amps a try before I buy an old school amp for my Livingroom. I love the sound of the Benchmark AHB2 (that is no sound). Though the AHB2's power in 2 Ohm is lacking in stereo and definitely  in mono.

The Purifi modules are supposed to be almost as good as the AHB2 but with better power specs at 2 Ohm.

@audiojan 

”Gryphon Diablo 300. 950W/channel into 2ohm!!!!”
And a lot of current; 238 ampere !!! according to measurements in a Swedish HiFi-mag.

I may have misinterpreted the OP's question. I believe there is a difference between HIGH CURRENT vs WATTS. Can anyone set me straight on that. I am considering the excellent 150 watt CODA #16 (which is supposed to be high current) vs some other amps that have a lot more watts. Are there scenarios where the CODA #16 could be considered a better match for a 2 Ohm hard to drive speaker vs an amp with more watts?

CODA #16 specs

Maximum current: 100 amperes per channel

Power supply: 3KVA  power transformer/ Dual independent rectification and 280,000 of power supply filter capacitance

“Watt is the measure of power. Volt is the measure of electric potential. Ampere is the measure of current.”

The point is that current is the number of electrons available. Watts is a combined term.

Since output in amps is not generally stated. You get a rough guide by looking at the relationship between watts into different resistance. An amp has lots of current if the number of watts doubles 16 ohms -> 8 ohms -> 4 ohms -> 2 ohms -> 1 ohm. As resistance disappears the amount of current needed to maintain the flow requires a lot more current.

agree w @ghdprentice 

from a practical p-o-v for users sorting through amp choices, the best indicator is if the maker clearly states the amp is able to double wattage from 8 to 4 to 2 ohms... another indicator, less good than the first, is if the amp (at least traditional class a or ab ones) are big and heavy with substantial power transformers and heat sinks - delivering consistently high current flow into low impedance loads generates mucho heat

@jjss49 

Yes. Goes back to the seemingly silly assertion that the heavier the amp, the better it sounds (well actually all audiophile equipment). You need huge power supplies to   Supply current. 
 

After college I was an electrical / mechanical engineer for a while. I welded… low voltage and 5 amps. My first Threshold amp 3.5 amps. Then I got my second top of the line amp A Pass x350. The same amperage as a welder! That is power.

Accuphase A-75 - Class A amplifier.  It is stable down to 1 ohm.  See below:

You would better off if you get a class A amp, the class A/b amps don’t always have enough heat sinking to drive a 2ohm load at higher volumes for extended periods. 

....or you could get a properly designed speaker.

Just a quick note. The above technical comments are a useful reminder of what the OP was really asking about. And there are many solid suggestions for fine products, too.

So, IMHO this becomes a question of value. Bang for the buck. "We know what we want. Now, where to get it at the best possible price."

Which brings me back to the Innersound Electrostatic amp. Or one of Roger Sanders fine amplifiers. Reviews of theses amplifiers consistently refer to their beautiful sound, rivaling in many ways the finest tube amplifiers, but with tremendous, prodigious, useful power. Hence, my ongoing praise of these products. 

Of course you can also get very nice amplifiers with excellent performance like we are discussing if you are willing to spend a ton of money. Lots of money makes it easier to solve many problems. But as my mother used to say, "what's the fun in that?" 

Here is another new amp that doubles down in Class A and is not big and heavy.

Rei | WestminsterLab

It uses similar tech as the new KRELL iBias way of doing Class A. Not real Class A as stated by companies like Gryphon.

@secretguy So a classic speaker like the Thiel CS3.7 is really improperly designed?

what is so wrong about just designing a stable 8-ohm load for any amp?

There are a lot of 90's amps that can provide high current.

A bunch have been mentioned. Krell, Parasound, McCormack...

Aragon is also one that can supply high-current loads. I sold my 8008BB to a guy who had some Martin Logans, and he loved what that amp did for his speakers.

Personally, I am using Aragon Palladium 2's paired with a tube preamp to drive a set of Magnepans.

Not mentioned are spectral amps.  Had the studio model and drove anything including Maggie panels.   Sold the system when I downsized.  Lack of dealers, slow and picky customer service were the reason not to go back to the brand

we can talk amps that can deliver gobs of current into low impedance loads (op's query asks for what's best in terms of 'stability into 2 or 4 ohm loads')

but separately we can also talk about amps that sound terrific doing so

b is very much a subset of a, let’s not mistake that

speakers like thiels maggies etc need the power/current but they are also very revealing of the sonic quality of what is being fed to them

solving for a does not necessarily solve for b, for best performance, need both

@jasonbourne52  Perreaux 2150B - 340/680/920 wpc @ 8/4/2 ohms.

The manual says 200 wpc into 8 ohms. Could you confirm that? Could you articulate its sound traits? Its damping factor sounds reasonably high but the continuous current of 10 amperes per channel seems a bit low compared to modern amp. Thx.

@atlvalet  Aragon 8008BB 

Do you know the current spec of this?  Seems not available in the manual.  Again, could you articulate its sound traits?  Thx.

From the user manual of the Pass Labs INT-25 integrated amplifier:

The amplifier is stable into any load which does not dip below 0.5 ohms, but it will protect itself by shutting off any channel which outputs more than 10 amps (200 watts peak into 2 ohms)

Remember, the Pass INT-25 is rated at only 2x25w per channel but its stable down to 200 watts @ 2Ohms :) Not all watts are equal watts

I have often thought Pass Labs XA series would be a great amp to drive a 2 Ohm load, but they don’t publish any specs into a 2 Ohm load. I was ready to jump on a pr of XA 160.8 but was unsure they would drive my Focal Maestro speakers. The Focal’s have a schizophrenic load; it’s all over the place in the upper bass and lower midrange. 
I’m currently running the new Luxman M-10x amplifier. It drives the Focal’s well and sounds good, but there’s a feeling that the Focal’s need more. 

Call Pass and ask them what their 2 Ohm output is.  I’d be surprised if it’s not more than capable given their very robust power supplies. 

@lanx0003,

Not sure on the "current" spec/capacity, but the 8008BB is dual mono rated at 200 watts into 8 ohms and 400 into 4.

It has two torodial transformers, each rated at 1.1 kVa. Each channel has two 35,000µ capacitors...which means each channel can store 171.5 joules of energy.

:)

OP,

Call up Pass or your local dealer. I am absolutely sure they will be able to address your concerns. I have owned Pass amps for well over thirty years and they have always exceeded my expectations in performance…. Especially in driving difficult loads. 
 

Nelson pass addressed this question on the diy forum several years ago, he recommended the x600 monoblocks for the 1ohm apogee scintilla speakers.

Classe Delta Mono, 1kW into 2Ohm

300W / 8Ω
600W / 4Ω
1000W / 2Ω (with AC line held constant)

 

the Delta Stereo can do it too :

250W / 8Ω
500W / 4Ω (with AC line held constant)
350W / 2Ω (with AC line held constant)

 

 

I have one pair of bridged amps that puts out 30 amps (75 peak) into 1 ohm and 500 W into that load (when I bought them they were driving 1 ohm Apogee Scintillas) but they made less than 200 of them so I doubt you could find any.

I have another that I run in stereo that puts out 40 amps continuous (90 peak) and 475 W (if that’s not enough you can bridge them and get 1000 W) but the problem is that it is also a vintage amp and it would be a hunt to find one.

Depends on how patient you can be - they turn up on Audio Mart from time to time and you can check Hifishark to see what past prices have been.

Classe DR3 VHC and Jeff Roland 5. If you go for the larger Rowland 7 there are some for sale right now - pairs of monos for around $4K, which is a bargain price.

See

Bang for the buck, Parasound will do the trick.

McCormack DNA 500 if you can find one. 

I just sold mine a few weeks ago that used to drive Thiel CS5i's with no problem.

BUT, my real message here is that I have shifted to high efficiency speakers with a First watt F7 amp.. Dynamic and alive.

An epiphany for me.

Thanks for listening.

Dsper

..."stable into low impedances" only suggests that the amplifer won’t go into oscillation when presented with a low impedance. It doesn’t offer how much power at what levels of noise and distortion or what qualtiy will be available into low impedances. I don’t suggest trusting off hand remarks about capablities into low impedances unless the manufacturer actually specs it into a given load. Off handed remaks of capabilites are often given to protect sales potential and especially dealer networks. Often times reviewers won’t test into low loads like 2 Ohms unless actually spec’d to do so. Even then we often see stereo amps failing to deliver when only tested into 1 channel. If  you need a certain power level into a given load, seek out manufactures that will will actually spec it as such. If not move on. If it’s backed up by independent testing; all the better.

The Naim NAP 250, 300, 500 and their Statement will all handle 2 ohm loads. 

has anyone compared the VTV and LSA Voyager or Warp 1 power amps?