XP-10 verses RLD-1 2012 Platinum Edition

Well, someone asked me which one won!

The background to this BLOG is I purchased an PASS LABS XP-10 and felt it was too thin on the bass compared to my MAP-1 unit slipped into my Vandersteen Quatro system. I sold my Quatro's and MAP-1 with the DNA-225 and replaced them with C4 II signatures and kept the XP-10. The C4's still sounded thinner with the XP-10 than my liking, but better than with the Quatros. I assumed the preamp had to go, so I purchased an RDL-1 and sent it to SMc Audio for the full platinum mod. That took six months and in the mean time, I bought two Velodyne DD10+ subs for the C4's that REALLY opened up the basement! I finally got the RDL-1 from SMc Audio and that started the comparisons of these two units on C4’s with stereo subs. I have skin in the game times two want BOTH to win. But, there has to be a winner, to my ears.

For me, short term listening session tend to bring out the good points in a unit, and the longer you listen, the bad points surface. I used a CD-R to keep all the source material the same, and have about ninety minutes of uninterrupted music.

These two units still live at each end of the electronic world. The XP-10 is a solid state unit in spades, where the RLD-1 platinum is like a solid state tube unit. More explaining to do…

The RLD-1 pulls everything together to create a huge soundstage, but at the expense of each instrument surviving on it’s own. Each instrument gives up something of itself to “smooth” out the left to right image. This also tends to close in the expanse behind each instrument. The RLD-1 is super smooth and just doesn’t bite unless severely provoked. This sounds like tubes (conrad johnson ET3 SE I listened to at home at length) doesn’t it? Yep, the lows and highs are softer but the mids are very good on simpler music. But, the more complex the music, the harder it is to keep the open expanse around each instrument intact. This can create a matte from which the music is displayed verses an infinite backdrop around each instrument. When the music is interlaced, the openness around each instrument goes away, there isn’t “room” from which to place each unique instrument in space. But, the solidity of the central image is SOLID. Whichever instrument is loudest takes charge of where the image is. For the RDL-1, the simpler the music the better. It imparts a warmer even tone to everything. Bass is fuller and is to be more heard verses feel. All the sharp edges that might be sonically dangerous seem to be burred off. The more technical the music, the more it seems to smooth over. If you like tubes, this is a must listen to pre-amp. No one would say it doesn’t sound nice.

The XP-10 is about as opposite as you get. It’s a solid sate unit through and through. Micro dynamics, inner detail, utter blackness around each instrument is simply stunning. But, since each instrument is on it’s own, the image is a sole effort from each instrument so the sound stage is smaller around each instrument. However, the EXACT placement of every sound is dead nuts. The openness is extraordinary, as there is elbowroom around each instrument or voice. No matter how crowded it gets, the XP-10 still keeps every sound in its place. The dynamic range is more powerful in quickness and decay. Nothing seems to sneak by this pre-amp without faithful amplification. It is FAST. Oh yes, that can be hell on some material, too. But more on that later.

The deal breaker was the addition of the Velodyne DD10+ stereo subs to the C4’s. With the subs, the once thin sounding XP-10 simply took off. The bass is deep and visceral (like solid state!) and you could cut blocks from it and build a fort. This is not tube bass. If you don’t like your insides rearranged…solid state isn’t where you want to go! The weak point of the XP-10 was 100% vanquished with subs but without them, it sounded thinner than my liking. The change with subs was totally unexpected in its magnitude of improvement. But there was more…

The relaxed nature of my MONO KISMET amps comes through in spades with the hi-pass sub option. They are relieved of bass below 80 Hz so I have 6 dB or more of headroom. The amps are just not working too hard. What did this do? It took the edge off the midrange when I ran the C4’s full range. Yep, the KISMETS are not “big” amps (about 325 watts into 4-ohms) but not small either. That’s the problem, though. You tend to really overdrive them on dynamics and things get pinched and strident when SS amps do that. But, they are MUCH better running the C4’s 80 Hz and up. The XP-10 is just way better at telling you the amp isn’t happy than the RLD-1. It also doesn't hurt that as driver go higher in frequency, ones that move less sound better. Those two eight-inch C4 drivers are really calmed down with 80 Hz and below stripped away.

All this threw the equation to the XP-10. As much as I like the RLD-1 on material, I’m a solid-state kind of guy. I can’t give-up the dynamics, the blackness around each instrument and the vocal textures…both micro and macro. The C4’s / DD10+ combination are revealing to an extreme and seem to quietly go about telling you what’s hooked up to them. When I got to the end of the CD-R for a possible third round, I asked myself which unit I would have used…the XP-10. Which unit would I use as the “main” pre-amp…the XP-10.

Can you find a music source to say I’m wrong? Yes, you can. So can I. But in the end the XP-10 got a shot of double hi-fi VIAGRA with the subs. They got bass and a smoother voicing at the same time. This took an also ran and ran away with the contest. I was actually surprised.

The XP-10 needs BASS (if you don’t have it, you’ll know!) and PLENTY of clean power to sound right. Given those two ingredients and I can finally hear the following this unit has. It isn’t perfect. It is still too “winter” or cool sounding at times and can be sometimes so detailed your brain aches taking it all in.

For speaker auditions, be VERY careful of electronics. The C4’s sounded like two different speakers with the change in electronics. Two people would review them vastly different and the speaker isn’t changed any at all! My experience with modern hi-fi components drive this point home to the point of making it hard to decide WHAT I’m listening to during an audition. A speaker of the caliber of the C4’s, and there are many, are being spoken for by the electronics in a BIG way least we forget. I would change electronics on purpose to see what voice it is you’re hearing, and what the ultimate potential of the speaker really is.
Rower, that's a very interesting read. Thanks. I have Pass XA.5 amps and the
XP-20. The paragraph in which you describe the sound of the XP-10 with
pinpoint location of each instrument, black backgrounds and isolated space
between the instruments, say a lack of sound fill in the staging or voids in the
spaces, is exactly what I heard with the XP-20. Until recently that is.

I just upgraded my analog source to a massive suspended turntable with a
12" arm. I don't know much about digital, but this upgrade resulted in
major improvements in exactly that weak area of the XP-20 soundstaging
characteristic. There is so much more harmonic information and density of
sound around the instruments that the space between the instruments is now
filled and continuous. It is much more believable.

I now conclude that this was not a characteristic of the XP-20, but rather a
shortcoming of my former turntable. The XP is so transparent and neutral
that I find whatever musical information is reproduced at the source simply
passes through the Pass electronics on its way to the speakers.

Also that lack of bass you describe, that was a shortcoming of the analogue
source too, not the pre amp in my experience. I find it difficult to criticize
these pre amps.

Congratulations, the XP is a superb product.
The XP-10 isn’t perfect, like I said. But yes it is hard to characterize the sound. I agree that the extreme detail can be almost too much, but my ear is happier there than too smoothed over where dynamics and individual expressions of each sound are a "group" affair. Again, this is my ear's preference. I like my music capitalistic where every sound is it's own effort, not socialistic where it's all a group effort.

As far as bass, the XP-10 can be can indeed be thin compared to ANY other pre-amp I've used, and with the same source material. That is until I added the DD10+ subs, something happened there that was a big surprise. I have no clue why the bass IS INDEED thin with the C4's full range. It was thin with my Quatro, too, and they have powered subs. But, I call it like I hear it with the subs on the C4's. The bass is crisp, fast and detailed. It is still a hard-hitting physical bass, however.

But I 100% agree that the XP-10 lacks harmonics between the space around each instrument that adds the "timber" to music. This is what makes it sound hard at times. No, I didn't say it has none, it is just weakest here. Piano's can sound too thin and lack body, for instance.

Playing with preamps has been fun. It's also discouraging, as I know how hard it is to really get one right, and how important it is. At an affordable price point, you have to align your ear’s preferences to a "place" that makes you happy knowing full well the trade-offs. To that end, I at least try to characterize the pieces I've used to allow people to center them up to what best fits their ear.
My only point is that the characteristics that you ascribe to the XP-10 in your system I heard also in my system with the XP-20. I had thought it was a characteristic of the pre amp. I was very mistaken. What I thought were shortcomings in the XP-20 were eliminated completely when I upgraded my front end. Therefore, I concluded that the XP-20 is actually quite neutral and transparent as changes upstream were easily heard and identified. Of course, I may have reached the wrong conclusion, and it seems not to be consistent with your findings.

What happens to the sound of your XP-10 when you switch cartridge or arm or turntable? Does it still repress harmonics and does it still sound thin?
Oh yes, the XP-10 is consistently thinner sounding than other pre-amps with ALL sources. I think you description is right,though, that the haromonics off of the main fundamental is where the XP-10 may be weak when it comes to proper blending. Piano's can sound less full than they should.

The harmonic structure off nthe main fundamental seems to be hard to get right. No, it isn't the same as the initial tone (the RLD-1 platinum is very good here) but the energy that comes off of that.

My ear is a stickler for opennness and an a vast expanse of blackness in the soundstage and micro dynamics that make sound seem more real. I can get along with deficiencies, but not so much in those area areas.
Rower, I'm not aware that I suggested "that the harmonics off of the main
fundamental is where the XP-10 may be weak when it comes to proper
blending." I barely understand what that means. I'm sorry if I was not
clear. I tried to convey that in the case of my XP-20, I don't hear the deficiency
that you attribute to your XP-10. In fact, the reproduction of harmonics changed
dramatically when I improved my source component leading me to conclude that
the XP-20 is very transparent and able to reproduce harmonics. Whether or not
there are other pre amps that are more transparent or able to reproduce more of
the harmonic content of the original signal as it comes off the CD or LP, I can not
say. The Pass unit is the best, out of just a few, that I've heard in my system.

When you say piano can sound thin, with the XP-10 in your system, I believe the problem is a "choke point" or synergy issue in your system.
Your speakers are among the best available, IMO. Your Oppo
is admired by many experienced members of this site.
I am not familiar with your amps.
I know exactly what your saying when you say the detail level can be hell on some material!
I have a greatest hits CD of John Lenon. My favorite track is "#9 Dream". This track was poorly recorded on this CD.
With my Pass X1 preamp, the track was listenable. With my XP-10, it became marginal. With my XP-20 in the system,
it is now just unpleasant to listen to.
As the resolution of my system went up, poorly recorded CDs became worse. But some (many) of the best recordings now shine.
A prime example of this is "Tidal" by Fiona Apple. "Pale September" is now my reference track I use anytime I make a change in my system. There is so much detail in this song, and it is recorded so well, I can quickly assess any change I make in my system (power cable, interconnect, etc.).
Many others point out that the XP-10 can be thin at times, so it isn't just to my ears. More so with the balanced outs verses RCA's. My stereo DD10+ subs really help the XP-10 bass where the it was way too shy previously running the C4's full range(that synergy thing again). Bass is not a big issue anymore. I do love powered subs, every system I've gotten to be "right" has had them. DQ-10 with DQ-1W subs, Quatro's (built-in), and now the C4's with Stereo Velodyne DD10+ subs.

To say I don't like the XP-10 pre-amp is not the case, however. To say my system has synergy problems? Hell yes, what system doesn't? The room, the electronics you name it. SOMETHING is always "there" in the way.

What I do know, is that the two preamps present an entirely different approach to sound. It's like two different speakers if you didn't know I changed pre amps. Half will like one and half will like the other. The RLD-1 platinum is getting better with break-in, but it is never going to be as brutally revealing as the XP-10. What it will be is so SMOOTH and easy going.

So yes, the C4's are brutally able to reveal what your downstream electronics and speakers can do. I am more and more impressed with this preamps engaging sound (and the KISMET MONO amps and C4's resolution). True, many don't like the level of detail that I hear in the XP-10, and like a softer approach (the RLD-1 paltinum excels here). Me, my ear keeps coming back to the XP-10.

And let's not forget, some recording, like you mentioned, are indeed terrible! That's not the preamps fault. Run the vinyl Cat Stevens albums through once, they are all fantastic. Then try the two Carol King vinyl albums. One is great, the other is muffled and poorly done.

The fact that the XP-10 shows a much wider window of sound quality through the C4's to me is a big plus. Yes, the crappy stuff bugs you, but the good stuff is really good. Isn't that the idea, anyway? To go as far as your system can take you. The XP-10 seems to get everything much farther along to what my ear yearns to hear. I like to hear the mechanical "hit" on a stringed instrument as well as the overtones after it resonance. The XP-10 does this effortlessly, and so do the C4's if your electronics gets it to them!

So the question is, what takes the XP-10 to the next level in a preamp? And I do mean in it's general sound pallet; fast and firm, low noise, dynamics and micro detail.
I don't quite understand your last question: "...what takes the XP-10 to the next level in a preamp?" Do you want to modify somehow your XP-10 so it goes to the next level (adding isolation, power cord etc), or do you want the next level of preamp that retains the qualities of the XP-10 that you like? If it is the latter, I would suggest the XP-20 or even better, the XP-30.

I have come to the view that a good preamp should only restrict to a greater or lesser extent what it is being fed by the source component. Your attributes of "fast and firm, low noise, dynamics and micro detail", in my system are qualities that are retrieved from the LP grooves by a good cartridge/arm/table and passed through to the electronics. At that point, the electronics shouldn't add any of those qualities, they should just not reduce them by much. This is what I refer to as transparency. The XP-20 reduces them slightly less than does the XP-10. But they are not generated by the preamp, IMO. If that is what you hear through the XP-10, I believe they are being reproduced by the source or produced (created) by the speakers, like the bass with your subs in this case.

More colored electronics can indeed impart some flavor or character to the sound, but I don't get the sense that that is what you want from your preamp.
Oh how right you are! The XP-10 has me spoiled since it is much better than I thought it was, and so are the C4's! Once you shoot a gun, a knife just won't do anymore.

The XP-10 and C4's get sounds (human voices) to be almost "real", which is a feat in itself. Nothing else I've owned did it to the degree that this system does. Digital verses LP? LP's are good at harmonic detail, but lose out on micro detail (too much background noise) and dynamics. Still, on not too dynamic or complicated music they are superior (think Cat Stevens, Bruce Cockburn or similar vocal presentations) to digital. I like the sound of records more often that digital. The "real" quality of the human voice exceeds digitals attributes so far. Doesn't have to be that way, as 24-bit hi-def should be the "standard" for digital sound. It is so much better than the 16-bit we are forced to buy.

No, I don't mean modify the XP-10, I mean alternative pre-amps that capture what the XP-10 does (brutally resolving to what the source material is, and NOT the pre-amp). Yep, that can be bad on crappy digital or poor LP's but, I've realized that making everything sound homoginized to a "colored" sound isn't satisfying at all. The C4's get neutered before they can run.

Wire? No, I'm not in that mystic camp. If I don't hear it blind, I don't buy it. I've done blind test over and over during the last thirty years and NEVER "heard" a power cord. Quality high-impedance leads (Belden 1694A with Gold RCA's) have held away everything I've "blind" tried (have a friend swap them in and out). An amp input stage is a (should be) high enough impedance as to be virtually voltage driven only. So, consistently low capacitanc is key. Your lead is a first-order low-pass filter with a -3 dB frequency limit based on the total capacitance.

Speaker leads just need not be too long as the major attribute(mine are 18")to not inductively load the power amp, as you have a nasty back EMF from the speakers to the amp. Hook a VOM to you speaker terminals and push the woofer in and out. Yep, that's there going the wrong direction to your amp. Add high inductance leads and you have issues. So SHORT good cords will always be better than longer cords, even "superior" longer cords. Bad just gets worse the longer they are.

You tube guys don't really have a complete "output stage" as it is completed with the leads to the pre amp and likewise the speakers from a tube power amp. So leads are indeed a problem for you more so than SS electronics. Some newer tube units use J-FET's to isolate the output from the leads like SS.

The RLD-1 and XP-10 "sound" is fully appreciated with the SAME interconnect cords. The cords pass massive detail with the right electronics and source material. If I "hear" better, I'll use it. So far, thousands in cords changes my bank account more than the sound.

I read the 6 Moons review on your amps, this morning.
Your amps are single ended, but they do have "balanced"
inputs. These inputs are just converted back to single ended, within the amps. That's why the RCA inputs on your amps sound better - they are more direct.
If you try the XP-10 in your system with fully balanced amps, you'll be using the preamp to it's full potential.
I agree with Danielk, If you want to know what the XP-10 is really capable of, try it in full balanced mode with a Pass amp.
Yep, but I ran out of MONEY. Remember, this is C4's on a budget. I'm really impressed where these speakers are with the electronics I have right now. Some say that the XP-10 is more lean with balanced than single ended. Don't know. What I do know, is I tend to like the PASS sound. Fast and detailed. It seems to follow the music so effortlessly you forget it is there. I guess I'm just not a romantic sound kind of listener. I keep edging back to full, rich, deatiled and tight sounding products.

The C4's aren't nice to play with, though. If you take home something really nice, you better be able to buy it because these speakers will let it be known what's good and what's not. So far their capability seems to keep going and going and going...