[Skylab]

Thanks for your kind words. First of all, I firmly believe lossless is just that - lossless. apple lossless is just as lossless as anything else

I also believe that a flash-drive based front end like iPad or iPhone/iPod Touch/Nano is idea for playing back digital data; better in fact that playing CD's.. The Pure is also just as effective IMO as any of the new digital docks in getting the bits off an iDevice.

 

[mwilson]

My two weeks with the RWA AE
 
I promised I'd post back once I had a chance to spend some time with the RWA AE, especially once I put a Mullard tube to replace the so-so JJ standard issue tube. Right off the bat, and I've mentioned in a previous post, the JJ doesn't do the amp any justice. It's the equivalent of filling up your high-performance car with regular instead of premium - the car set you back so much money, why get cheap on a trivial expense. I say trivial in context - a $95 Mullard will offer so much more it's a no-brainer. All of the notes below are taking into consideration the better tube.
 
The amp is competent. It does what it's supposed to do; effortlessly, expeditiously and unobtrusively. There's bass, of both quality and quantity, there are mids and there are highs, more than I've ever heard on my LCD-2 rev. 2. The highs are the first place where I realized this amp is rather unapologetic in its presentation of the source material. It doesn't mince detail - if the recording is poor, so will be the output. It takes good input to produce glorious output ("glorious" by the way is an affectionate nod to Jack Wu's description of sonic characteristics in his amps). For such material, I opted for the oft-referenced Jazz at the Pawnshop, the 24k Gold Ultimate Collector's Disc. I've heard things I've never noticed before; it's as if the entire audio chain took a backseat to an extremely transparent, in-person listening experience. There was a certain three-dimensionality present that impressed me to no end. I listened over and over again trying to pick any weaknesses of the RWA AE. There weren't any that I could detect, and that's a first for me. At the risk of repeating myself, the immersion in the material aspect was second to no amp I've ever had the pleasure to audition. And that's when I had an interesting revelation - the sound reproduction became poorer if the DAC was switched to upsample mode. Highs became a bit shrill, mids a bit harsh, and the soundstage got rather distorted. Switching back to NOS was a welcome change; back to the dimly-lit, smoke-filled venue where the recording took place, and where the RWA ultimately had transported me.
 
Next up was a decent, but by no means stellar recording - Diana Krall's "All For You". The material on this album sounded better with the DAC set to upsample - the soundstage widened, subtle treble details were extracted and the bass became tighter and deeper than when set to NOS. I was instantly taken aback, especially coming from a very captivating audition of the Jazz at the Pawnshop album. It was at this point that I started missing my WA22, which gave a very intimate, personal reproduction of her voice and piano playing. One clear advantage my WA22 had over the RWA is the ability to take input from an external DAC, and my Wyred DAC-2 has never ceased to amaze me with its ability to render a detailed-yet-effortlessly-swet presentation of the source material.
 
Another recording I used for evaluation is Kraftwerk's remastered Techno Pop album, part of their German "Der Katalog" box set. The RWA rendered the kick slams with no problem, clearly maintaining proper separation between the various drum machines used - a scenario where bass, while deep and plenty, can become a bit muddied with lesser equipment.
 
I also listened to two tracks fom Gino Vannelli's "Powerful People" album: "Lady" and "JoJo". On the first track, the organ shines on pure tube amps, and it showed the hybrid aspect of the RWA - the sound was good, but not memorable. On the second track, the acoustic guitar solo was rendered crisp yet mellow, approaching the sound I seek for that song.
 
In the end, the RWA AE is a very good amp. This was the second amp I tested in my quest for the best sound for my LCD-2. Next up are Cavalli's Liquid Fire and Leben CS-300XS, which Skylab seems so fond of and got me intrigued. A note to Rob if you're reading this - I had better like the Leben, or it will be abandoned in a basket, anonymously, by your doorstep with nothing but a bottle of formula and a toy.
 
As to what my plans for the RWA AE are... hard to say. At the moment, I have it listed on the FS forum, but may as well withdraw it and decide to keep it for myself. With stellar material, it shines. With average and poor recordings, it does, well, average and poorly. To make an analogy with photography, another hobby of mine, the RWA AE is a tack-sharp lens - think Canon's EF 100mm f/2.8L IS macro lens. Tack sharp is good, if the subject calls for it. But it can also expose blemishes in the source material. The WA22 is more like a soft-focus portrait lens - flattering output, regardless of the material. But if the material happens to shine, the RWA beats it.
 
Cheers,
Nick

 

[Skylab]

No doubt, The RWA does very little editorializing, when using the "Hi-Res" DAC. It's very transparent and neutral. That isn't always what people, including me, want to hear. The Leben is a little more musical, but it's not as neutral. You pays your money and you makes your choice, as they say. I like the RWA with the LCD-2 and the Leben with the R-10, and that's how I have settled.

 

[WarriorAnt]

Nice write up Nick!  Don't be too hard on Skylab if you don't like the Leben. He's got so many amps it would be a burden for him to have to feed and care for another one. Me on the other hand, I'm making a special space on my mostly empty table right now to care and feed that poor Leben, or Liquid Fire if the case may be. I'll raise either one of them up properly in a good home.  You won't even have to leave a toy or formula.

 

[Skylab]

LOL at you both

 

[OzarkTom]

 
 

 

[OzarkTom]

I guess that is why I stay away from tube amps with transformers. They are not as accurate.

 

[OzarkTom]

RWA sounds like my kind of amp that I prefer.
 
Have any of you put 500-600 hours on the RWA yet? Most DACS takes that long to burn in properly. 
 

 

[Skylab]

I guess that is why I stay away from tube amps with transformers. They are not as accurate.

I know that seems to be your personal belief, and you are entitled to it. But like everything in life, there are no absolutes, and in this case there is a very real trade off. An OTL tube amp, in every case I have ever seen measurements on in almost 20 years of adding Stereophile and studying John Atkinson's measurements, will introduce very noticeable frequency response swings in response to an actual load. The occurs due to a mismatch between the output impedance of the amp, and the load impedance of the speaker or headphone, since the output impedance of an OTL tube amp is determined by the inherent impedance of the output tube itself. The purpose of an output transformer is to provide a more linear frequency response into a real speaker (or headphone) load which in almost all cases will have the impedance vary with frequency (the notable exception being something like the LCD-2 or HE-6 planar headphones) by fixing that mismatch between the output impedance of the amp and the impedance of the load.

The issue with output transformers is they have a sound. And cheap ones sound bad. You need a good output transformer for it to be transparent. But there is no doubt that, electrically, a well made transformer coupled tube amp is going to measure much better than any OTL tube amp ever possibly could, and PRECISELY in terms of "accuracy" in the frequency domain.

 

[tmarshl]

Nick,
 
Thanks for your review.  I  particularly appreciated your evaluation using different source material.
 
I just put in an order for the RWA "Audeze Edition", and am looking forward to receiving it.  I plan to give it a good long burn-in period before making a judgement, as I have made unfortunate snap-judgements in the past with Stax 007, Sennheiser 650 and others. 
 
In fact my AKG K1000s sat in a closet for years until I read the 6Moons review which recommended recabling and a dedicated First Watt F1 amplifier.  What had been a lackluster set of "earspeakers" became the best I have heard to date. 
 
It will be interesting to see how the RWA "Audeze Edition" stacks up with good cabling and a good DAC/AMP combo.
 
Thanks again for your review.  I will be interested to see if you hang onto the combo for a while.
 
Regards,
 
Tom

 

[mwilson]

Tom,
 
In the end, I parted with the RWA AE. Here are a few considerations for you:
 
1. Don't bother with the stock JJ tube. It's the consensus among all of us who have reviewed the AE that it's a mediocre tube at best. Skylab and I both used a NOS Mullard tube ($95, readily available on ebay, or I can sell you mine at a discount since I have no use for it now - PM me)
 
2. I feel that the ALO cable included in the package drives the combo price to an unnecessary level. This isn't to say it's a bad cable, but there are better and less expensive alternatives. A lot of us already have good aftermarket cables. For instance, I prefer the Q Audio cable over the ALO any day - to my ears it's more musical, manifests virtually no microphony, whereas the ALO is very stiff by comparison and any rub against clothes is instantly audible. If, however, you desire a bright presentation, the ALO will do the job.
 
3. The AE shines with stellar material. I find it rather impeccable in its rendition. But if you're like me, said material represents a minority of the music library, and for the rest the AE will constantly remind you of their imperfections. I found this aspect so distracting, that I just couldn't get lost in the music.
 
4. Lack of analog inputs. One day you may get an external DAC, and will find yourself stuck with the ones in the AE. Don't get me wrong, they're good, but you're limited to them. 
 
Bottom line, if money were no object, I would have kept the AE as a secondary amp just for my best recording - Vinnie designed a very good amp. But since my money printer is low on ink, my best compromise is a euphonic yet detailed amp that will gloss over mediocre material while still offer a good presentation of the better.
 
Please post back once you've gotten a chance to audition it for yourself; I'm interested to read your take on it.

 

[OzarkTom]

Here is a great report on what output  transformers do to the frequencies.
 
http://davidberning.com/technology/comparison

 
Quote:

I know that seems to be your personal belief, and you are entitled to it. But like everything in life, there are no absolutes, and in this case there is a very real trade off. An OTL tube amp, in every case I have ever seen measurements on in almost 20 years of adding Stereophile and studying John Atkinson's measurements, will introduce very noticeable frequency response swings in response to an actual load. The occurs due to a mismatch between the output impedance of the amp, and the load impedance of the speaker or headphone, since the output impedance of an OTL tube amp is determined by the inherent impedance of the output tube itself. The purpose of an output transformer is to provide a more linear frequency response into a real speaker (or headphone) load which in almost all cases will have the impedance vary with frequency (the notable exception being something like the LCD-2 or HE-6 planar headphones) by fixing that mismatch between the output impedance of the amp and the impedance of the load.
The issue with output transformers is they have a sound. And cheap ones sound bad. You need a good output transformer for it to be transparent. But there is no doubt that, electrically, a well made transformer coupled tube amp is going to measure much better than any OTL tube amp ever possibly could, and PRECISELY in terms of "accuracy" in the frequency domain.

 

 

[mwilson]

Oscilloscope captions notwhithstanding, I find it a bit subjective right from the start:
 
"Comparisons between the Berning ZOTL Impedance Converter and a high-quality audio output transformer"
 
Color me sceptic, but a high-quality audio output transformer can mean pretty much anything. If he had given a concrete example, such as
 
"Comparisons between the Berning ZOTL Impedance Converter and Woo Audio XX" or similar, I'd have given it more weight.
 
Quote:

Here is a great report on what output  transformers do to the frequencies.
 
http://davidberning.com/technology/comparison
 

 

 

[Skylab]

Quote:

Here is a great report on what output  transformers do to the frequencies.
 
http://davidberning.com/technology/comparison
 

Propaganda from a purveyor of OTL amps.  His stuff may be great, but it does not contradict one bit of what I said.
 
Anyway, it's totally off topic here, so I won't comment about it further in this thread, and since this is my review thread, I ask you not to as well. 

 

[tmarshl]

Nick,
 
Please see my responses in RED below.
 
Quote:

Tom,
 
In the end, I parted with the RWA AE. Here are a few considerations for you:
 
1. Don't bother with the stock JJ tube. It's the consensus among all of us who have reviewed the AE that it's a mediocre tube at best. Skylab and I both used a NOS Mullard tube ($95, readily available on ebay, or I can sell you mine at a discount since I have no use for it now - PM me)
 
Have sent you a PM.
 
2. I feel that the ALO cable included in the package drives the combo price to an unnecessary level. This isn't to say it's a bad cable, but there are better and less expensive alternatives. A lot of us already have good aftermarket cables. For instance, I prefer the Q Audio cable over the ALO any day - to my ears it's more musical, manifests virtually no microphony, whereas the ALO is very stiff by comparison and any rub against clothes is instantly audible. If, however, you desire a bright presentation, the ALO will do the job.
 
I will listen to the ALO cable and see how it performs.  The Q Audio cable is on my list as an alternative.  Thanks.
 
3. The AE shines with stellar material. I find it rather impeccable in its rendition. But if you're like me, said material represents a minority of the music library, and for the rest the AE will constantly remind you of their imperfections. I found this aspect so distracting, that I just couldn't get lost in the music.
 
This is perhaps the biggest issue.  Fortunately, I have a Weiss Minerva DAC as an alternative, so I may just identify my best source material to run through the RWA Audeze Edition. In particular, I have been experimenting with some of the very high resolution digital offerings now being made available online.  As with anything else in the audiophile domain the price increases exponentially with quality, so I am not yet convinced that the extra resolution is worth it.
 
4. Lack of analog inputs. One day you may get an external DAC, and will find yourself stuck with the ones in the AE. Don't get me wrong, they're good, but you're limited to them. 
 
As mentioned above, I do have a DAC with analog inputs, so I am covered here.
 
Bottom line, if money were no object, I would have kept the AE as a secondary amp just for my best recording - Vinnie designed a very good amp. But since my money printer is low on ink, my best compromise is a euphonic yet detailed amp that will gloss over mediocre material while still offer a good presentation of the better.
 
Money is always a factor. Depending on my listening results with the RWA Audeze Edition, I will make the decision about what equipment to retain.
 
Please post back once you've gotten a chance to audition it for yourself; I'm interested to read your take on it.
 
Thanks again for your thoughts.  I will probably take a bit of time to make my decision to let everything burn in properly.  In the past, I have made some snap decisions which may have been premature.
 
Tom