Minimum Power Needed to Drive Klipsch Cornwall IVs? - Considering Erhard_Audio Ray


I'm new to the the hifi world but have taken up the hobby with alacrity. I recently purchased a pair of Cornwall IVs to go with my Rogue Audio Cronus Magnum 2. At the time I purchased the speakers I had no idea what speaker sensitivity is. Now that I do, I realize that I have a lot of interesting options when choosing an amp. I have been toying with the idea of getting an Erhard-Audio Single-Ended Ray along with their Aretha pre-amp. The amp is only 4W/channel. I'm highly skeptical but I've been told that 4W is plenty to drive a 102db speaker and that the sound of an SE amp is amazing.

Wondering if anyone has experience driving Klipsch Cornwall IVs (or other high sensitivity speakers) with a low wattage amp. I'm also interested in experience with SE amps.

My system consists of the following:

Technics 1200G
VAS Nova cartridge
Rogue Audio Triton 2 phono pre-amp
Bluesound Node
Musican Pegasus DAC
Rogue Audio Cronus Magnum 2

My room is 15' x 30' with 14' ceilings. It's a photo studio in an old mill. I'm often moving around so I need the sound to fill the space. BUT I've gotten noise complaints from my neighbors so...

Musical preference is all over the place. Today I'm listening to Dire Straits, Sturgill Simpson, Paul Simon, Miles Davis, Tycho, Post Malone, Taylor Swift, Michelle Gurevich etc.


I would go with a tube amp. The heritage line loves tubes. Or a class A amp.

For example, I have an ARC75se, 75W/ch, with klipsch forteIII, and at roughly 5-6 watts, it is plenty loud and sweet.

I have a lot of seat time w buddy Cornwall i restored / updated. He uses a 300 B Toolshed integrated ….. sounds lovely. When i was working on them a MC240 really made them sing….

Is there something you don’t like with the Magnum combo? Just asking because it’s on my list for the same speakers. Always heard that the Cronus Magnum had some warmth. It had some balls as well. Kinda what I’m lookin for. 

i heard the ones I bought at the seller with an Ayon I think Triton 3 . It was real good. Different room etc but Ayon is on my list as well. 

I have the Ray in a secondary system driving Omega monitors in a larger room and it has plenty of punch. I never felt it lacking in wattage or limited in that regard.  

I use the built in passive pre and have done some upgrades with Miflex coupling caps and upgraded binding posts/RCA's.

This is a beautiful little chunk of an amp.  Louis at Omega finished my monitors beautifully in Padauck to perfectly match the cabinet of the Ray.  As you know the Ray uses very high quality Lindahl transformers.  It's sound is very neutral.  It is not slow, does dynamics well, images beautifully and has good "color saturation" if you follow my analogy.  Many affordable tube choices.  Highly recommended.

For 102 dB sensistive speakers, one watt will give you 102 dB of volume at one meter in front of the speaker. The volume at your listening position further back is a bit trickier since that depends on the size of the room and how it is furnished. Using two speakers (stereo) to the equation will add a couple more dB to what you hear.

Question -- have you bothered to buy a sound level meter or add a sound level app to your phone?  One's person's "loud" is another's "medium" volume, so its a lot better to get a meter and find out for yourself just how loud you like to listen.  These days I find 85 dB in my room about as loud as I want to listen so I'd find 4 watts with a 102 dB sensitive speaker way more than enough. Still plenty of power left for peaks.

@katokaelin 4 Watts won't be enough to really fill that space.

Here's another problem: if you want to really hear what an SET does, you really don't want to drive it past 20-25% of full power, else distortion causes the amplifier to sound 'dynamic' due to how our ears interpret that distortion. That distortion (higher ordered harmonics) also causes the SET to sound louder than it really is- the mark of a really good system is that it won't sound loud when it really is.

So that means with 4 Watts you really only have 1 good one. For this reason and the size of your space, I'd consider a lower powered PP amp since 15-20 Watts probably will be enough, and most PP tube amps have at least 90% usable power rather than only 20-25%.

Going with a higher powered SET really isn't practical. Above about 7 Watts total output, bandwidth really starts to be a problem because that's the Achilles heel of output transformers for SETs, plus the price goes up exponentially and we're talking about a 45 Watt SET to keep up with a 15 Watt PP amp (again, if you really want to hear the best of the SET).

You might not be able to play your system at very high volume levels, but, for the VAST majority of the time, 4 watts will be plenty.  Most of the time you will not be playing above a quarter to half a watt, and even if you occasionally push toward the 4 watt level, this would probably be only on peaks, and if there is some distortion or compression, that is just one of the compromises one makes with ANY component choice; none are absolutely the best under all circumstances and conditions. 

I personally like the sound of 6L6 tubes, although I have never heard them used as a single ended triode tubes.  Given the low price of the amp, it would not be easy to find other higher power alternatives to recommend.  I have not heard the amp you are considering so I don't know how it would compare with your Cronus amp.

Even if you have little skills at building gear, you could probably build an Elekit 300B amp; the kit comes with very good instructions and you can learn basic assembly skills on Youtube.  The amp would cost a bit more than $3,000 once you add in the price of the 300B tubes (the kit comes without tubes), but, I've heard that amp and it is pretty good, and puts out a little bit more power than the amp you are considering.

Wow. Thanks for all the responses.

@skids - my experience with the Cronus has been great so I intend on sticking with tubes. That ARC75se looks sweet!

@tomic601 - First I’m hearing of Toolshed Amps - very cool stuff.

@mofojo - I like the Cronus with the Cornwalls. I would describe the sound as warm, but it is highly influenced by the center driver tube. Tube rolling has made the Cronus very fun to own. And as far as power goes, I like my music on the loud side and have never had the dial past 11 o’clock. I was considering sending it in to have it upgraded to the latest Dark version, but then started wondering what else my money could get me, if there was a more interesting pairing for the Cornwalls... I will likely keep the amp for my living room at home, that how much I like it. And, I’ve had a number of conversations with the guys at Rogue Audio. Their customer service is top notch.

@corelli - It’s nice to hear feedback from someone that has direct experience with the Ray. There isn’t a lot of info online about the amp. I’ve been in touch with Holger, who builds the amps in Montana, and he has been really nice to work with. I’m looking forward to giving him my business. I like your "color saturation" analogy!

@mlsstl - I just downloaded a db meter for my phone. It looks like my typical volume is between 65-85db at 20’ and between 70-90db at 3’. If I’m understanding you correctly it sounds like the 4W should be enough.

@atmasphere - Very interesting. If I decide to pass on the Ray I’ll likely go for Erhard-Audio’s Saturn, which is a 15W PP...

Very interesting. If I decide to pass on the Ray I’ll likely go for Erhard-Audio’s Saturn, which is a 15W PP...

@katokaelin Too bad there's not more information on their site- that amps sounds interesting!

The cleaner the amp is, the more you'll turn up the volume control without really thinking about it. That's because an amp with less distortion won't sound as loud and so you'll naturally use the power.

I'm very curious about Erhard's stuff.

Some SIT amps could be very nice, too.

I agree with @atmasphere 

I drove Cornwall IVs with an SE amp using EL34s, about 10 wpc. That worked great. I am now driving Lascala IIs with a 300B, also a great match. I would have concerns with 4 watts in a room as large as yours.

@katokaelin -- just running back of the envelope numbers, if the loud end of your listening is 90 dB at one meter, you're looking at about one-eighth of a watt to achieve that.  The four watts would get you to 108 dB peaks.   So, from my perspective, the Erhard's power is not a problem for the listening levels you gave. The bigger issue will be whether you prefer the sound quality of the Erhard or like a different sonic signature.  If the seller has a return policy it would certainly seem worth a trial.

@mlsstl If a PP amp was being considered, what you say just above would be correct- but with no headroom. SETs, as I mentioned earlier, need to be used such that you only use about 20-25% of full power if you really want to hear what the amp is all about. Also as I mentioned earlier, if you push the amp past that level, distortion will cause the amp to sound 'dynamic'.

Once you know that, it messes with you a bit because you can make out the distortion (which is appearing on the musical transients).

Big rooms need power.   My 300b is working in it’s comfort zone driving my Forte in a 13 X 15 X 8 room     It will fall apart if I play it loud.  

My 40 w Quicksilver amps are a much better match if I were to listen loud but I don’t.    

Unlikely that any flea powered amp can give good results in that size room.  Stick with your Rogue for now , get a feel for the Cornwallis , then try a few quality , moderate to higher powered tube amps.   So important to try your next amp with your speakers.   Would be a shame to sell a good amp like the Rogue and make a lateral move.   



Ok. Lots of differing opinions here and I'm realizing that the only way to know for sure if the amp will work in my space, with my listening preferences, is to try it.  I'm willing to take the risk.  I'm putting together a stereo system in my living room at home which is considerably smaller so in the event it doesn't cut it in my studio I'll use it there.

The most extensive review of a flea watt amp with Cornwalls I came across in a Steve Guttenberg video reviewing the combination of Cornwalls with a 2wpc Decware amp.  He raves about the combination...

I will report back with my findings once I receive the amp in a couple months.

Thanks for all the feedback!

In my 460 sq ft room with 8 ft ceilings, 3 watts of high quality SET is not enough, but 8 watts is more than enough and glorious.

@katokaelin Seriously, 2 Watts isn't going to work in your larger space although I'm sure the Decware will sound fine at lower volume levels.

My speakers are 98dB and 16 Ohms; very easy to drive. My space is considerably smaller than yours and I have 50Watts/channel which I've found to be a good amount. Less than that causes the system to be less relaxed- I get a very good 1st Watt from my amps.

Again, the mark of a good setup is it never sounds 'loud'. It should always be relaxed even when playing at 105dB at the listening chair. If it does not, it indicates you have a distortion problem somewhere.

My speakers are only 3dB behind yours and might be easier to drive due to the 16 Ohm impedance. So I could probably work with 25 Watts if I had your speakers (keeping mind I would never push the amps that hard since I want the system to sound musical and effortless), but now consider that your space is considerably larger than mine- and you're trying to make that work with 2 or 4 Watts?? I get the appeal, but an SET is only good for about 20-25% of full power (notwithstanding the remonstrations this comment is likely to get from any SET manufacturer, but if they are being honest they will be forced to agree, since every single one of them have gotten feedback from their customers about how 'dynamic' their amps are considering how little power they have) if you really want to hear what the amp is about.

(Above that power level distortion shows up on the transients in the music, giving it a 'dynamic' quality since the distortion is higher ordered harmonics used by the ear to figure out how loud sounds are. It is true that the smaller SETs sound better because they have more bandwidth, that is why the type 45 power tube has such an ardent following.)

So with 2 Watts total you really have only 0.5Watt of usable power! Not gonna work. Might be nice for some headphones though.


@atmasphere I don't doubt what you're saying one bit.  I am fully anticipating the amp ending up in my living room.  At which point I'll be back here asking for speaker recommendations!  But I do intend on trying the amp at my studio.  It will be fun to test everyone's hypothesis. : )

And, it's worth mentioning, I got another noise complaint today, so maybe the Ray is the throttle I need.  Hahaha.


I run my Cornwall IV’s with Orchard Audio Ultra’s or Black Ice F100’s with KT170 Tubes. Don’t believe the "high efficiency BS that people love to spew about ported Box Klipsches. That 15" Woofer needs a lot of juice to feed your room. While the Tweeter & Midrange allows to to get away with at least 10W or more (they are Horns after all).

Ralph @atmasphere is correct. A pair of his Class D's would work well too ! Just sayin'

@katokaelin   Obviously many diverse opinions here.  One qualifier to my prior comments.  The system I use the Ray in, with my significantly less efficient speakers, provided plenty of juice for all of the music I used that system for BUT when I had full scale works I used my larger system.  I would wager that for the vast majority of your music you would be quite happy.  Also, I did not mention, the amp is very quiet. No hiss or hum in my system.  Lastly, my system is CD based and, via a short pair of IC's,  I was able to bypass the need for a preamp using the optional volume pot.  Just a thought.  If you do go with a separate pre, and find you need more power for that 10% of the time you need to really rock it, you could always get a second PP amp. Variety is the spice of life right?  But SET amps are special and I was shocked how well 4wpc worked for me.