A/B Test: SR-71 vs MPX3

[gregeas]

I received my SR-71 on Monday and have since burned it in for about 100 hours. So tonight I put it head to head against my maxed MPX3 (with EH 6sn7 tubes).

I connected both amps to my Arcam CD33 upsampling player, which thankfully has two sets of outputs. The Arcam resolves just about everything and is known as a smooth player. I connected the MPX3 to the Arcam with Silver Dragon ICs, but I had to use a cheap Monster Cable mini-to-RCA adapter for the SR-71. For cans I used my HD650s with the Silver Dragon cable. The Arcam and the Singlepower amp were connected to separate Ultimate Outlets for power conditioning.

I used three test CDs: Ben Harper’s Fight for Your Mind; Wilco’s Ghost Is Born; and Steve Earle’s Train a Comin’. Each of these has plenty of air and separation between mainly acoustic instruments.

The result surprised me: the SR-71 held its own, revealing only subtle shortcomings compared to the Singlepower amp (which is about 20x bigger in volume). In fact it took many minutes of listening to hear any differences. Eventually I noted that the Singlepower had a bit more impact, with a more enveloping sound. The high ends were comparable, while the MPX3 seemed better at fleshing out the mid-range. That said, the SR-71 had a surprising amount of tight bass and produced a full-range sound that was very satisfying.

Overall, I’d say the SR-71 has the goods to perform as a home amp with excellent sources and cans. The problems with home use are that the SR-71 only takes batteries and lacks RCA inputs. But the quality is way up there, especially considering its diminutive size. In my system the SR-71 did very well against the MPX3, even with a crappy Monster ICs to the CD player.

One more note: I also connected the SR-71 to a laptop with an Echo Indigo soundcard (playing lossless APE files via ASIO). For the first time I heard the Indigo’s flaws, including an under-layer of digital hiss, Slight, but definitely noticeable, Next week I’ll listen to the SR-71 at work, with my RME DigiPAD card.

 

[raaj]

WOW !! Is the praise for the blackbird ever going to end?? Now, it sounds as good as a MAXED MPX3, eh?

I'd really love to try it out, but the lack of AC power capability really, REALLY puts me off. I am sure Ray had a very good reason for this design decision, but if it could run off of AC power, I would have ordered it in a heartbeat..

I wish Ray figures out a way to include that ability without making noticeable sacrifices to performance..

 

[james__bean]

I figured the reason he didn't include one was to keep the size of the unit down. This amp is stricly portable, if you want a transportable amp that can be used at home go with the XP-7.

 

[stryker]

There was a big step up in resolution, speed, and tighter bass with the addition of good NOS tubes in my MPX3. I find the EHs are a nice start, but no contest when good tubes are put in.

I really need to hear these Ray Samuels amps, but I am a firm believer that the sound of the Singlepower amps are of a totally different flavor and soundstage than solid state.

 

[raaj]

Having to confine such a wonderful sounding amp to portable use would be a shame.. given the lack of any truly great sounding portable sources (at least worthy of a Maxed MPX3 or by implication, the SR-71)..

IMHO, getting the SR-71 for portable use alone would be an extreme overkill affordable only to a well-padded wallet..If it truly performs very similar to a maxed out MPX3, it should have been designed to be suited for home use too.. If Xin could accomodate AC power input into an amp the size of a matchbox, Ray could have accomodated the AC power input in the blackbird, given its dimensions. So, I guess the sacrifice of the AC power input must have had a bigger reason than smaller intended form factor..

The reason that sounds logical to me is similar to what Ack! dAck! designer Chris claims - 'relying on battery power eliminates any adverse effect the variations in AC power might have on the sonic performance'.

Maybe, only Ray can shed some light on this design choice..

 

[Budley007]

I was bummed out to hear about the Echo Indigo. I was considering the SR-71 for a portable/home rig till I can afford a better amp. I carry and Indigo for my laptop. Any ideas as to where the hiss was coming from? If you get a chance to explore this in the future, I'd be glad to hear your conclusions. Thanks for the review.

 

[oneeyedhobbit]

When you say "Maxed out" MPX3, do you mean all three Solen upgrades, the Goildpoint attenuator, all the paper and oil thingimajobers (forget the name), etc, with a HUGE price increase?

 

[Jester]

Quote:

Originally Posted by raaj Having to confine such a wonderful sounding amp to portable use would be a shame.. given the lack of any truly great sounding portable sources (at least worthy of a Maxed MPX3 or by implication, the SR-71).. IMHO, getting the SR-71 for portable use alone would be an extreme overkill affordable only to a well-padded wallet..If it truly performs very similar to a maxed out MPX3, it should have been designed to be suited for home use too.. If Xin could accomodate AC power input into an amp the size of a matchbox, Ray could have accomodated the AC power input in the blackbird, given its dimensions. So, I guess the sacrifice of the AC power input must have had a bigger reason than smaller intended form factor.. The reason that sounds logical to me is similar to what Ack! dAck! designer Chris claims - 'relying on battery power eliminates any adverse effect the variations in AC power might have on the sonic performance'. Maybe, only Ray can shed some light on this design choice..

The intent of the SR-71 was portability not strickly home use. If you look at the Pocket Reference for example, it faces just the opposite problems. It is big and heavy and lacks the try mobility that the SR-71 offers. Yet it has the features that you are looking for (RCA jacks, AC power) and I think that it misses the mark when it comes to portability. I am not saying that it is a bad amp, but to call it a "Pocket Reference" is a bit missleading.

We have high-end home headphone amps, what is wrong with high-end portable amps? Another thing to consider is that Ray has built the XP-7 or even the HR-2 to fills this role (home amp). Why would he want to build a product that is already in his portfolio? It would not make sense. So getting a Stax system is not EXTREME OVERKILL for a home based headphone systems? Your logic does not make sense Raaj as it relates to the fact that the SR-71 is overkill as a portable unit. He delivered a product that meets a market segment that was lacking in high-end portable audio.

People who view this as both a home and portable rig are right in one aspect, you can use it at home if you would like. The true purpose of the SR-71 is the delivery of quality sound while on the move.

 

[gregeas]

Stryker: Which NOS tubes are you using? Any recs on where to find them? I agree that upgrading the tubes can make a difference with this amp. (I've only had the MPX3 for two months and am a tubes novice.)

I don't have the list of my MPX3 upgrades with me now, but to give you an idea, it cost a little under 2x the basic list price. I'm sure Mikhail could upgrade it further, but not too much.

Regarding the Echo Indigo, I'm saying that it falls short in relation to my home source, which it should given the price difference. The aforementioned hiss might result from its DAC or from its lack of a true line out (the signal gets amplified twice when used with the SR-71). But the Indigo sounds pretty damn good for a "portable" source," and I will continue to use it as such. I consider my laptop a home-quality source that I can carry around with me; I usually use it with SR225s or Ety 4Ss.

I do wonder which portable player can live up to the SR-71's potential. Perhaps the Rio Karma, which can play lossless files and has a line out. I wish someone would design a portable player with true audiofile qualities.

 

[Budley007]

I've been "wowwing" people at work with the Echo Indigo/SR225 combo. The first thing they say is, "I can't believe it sounds so clear". I was just curious about the addition of the SR-71. I'll be purchasing one in about a month and didn't want to be disappointed with the Indigo. Unfortunately, with a laptop, I'm extremely limited in my choices for a "true" line out. Thanks for getting back to me on this.

 

[stryker]

It sounds like you definitely got a nice MPX3.

As for the tubes, there's a good Singlepower tuberolling thread started by Hirsch. It was recently posted to, and a search will easily find it.

You can find tubes by posting a wanted ad in the for sale section or by looking on Audiogon or at tubeseller.com or even Ebay. Buyer beware at the A'gon and Ebay sites, though, so look for reputable sellers. Tom Hankins was selling some 6SN7s on the for sale forum but I think they're all about sold.

Good luck. I know I love my MPX3 and I think about selling it to upgrade, but then quickly change my mind as its hard to top it without spending lots more cash.

 

[gregeas]

When using the Indigo, you need to set two analog volume controls, one for the soundcard and one for the amp. There might be an ideal configuration of volume that reduces the hiss. (Is the Indigo turned up too much?) I tried a quick experiment to still heard some hiss. The other issue is that the hiss could be part of the recording but gets cleaned by the upsampling of the CD33. I'll see what happens tomorrow at work with my RME card and SR-71.

I've never really appreciated "black blacks" until I used the CD33/MPX3/HD650 combo.

 

[Budley007]

Thanks bro. I just wish the Indigo came with a true S/PDIF out. Maybe we'll get luck on their next iteration.

 

[KZEE]

Quote:

Originally Posted by gregeas In my system the SR-71 did very well against the MPX3, even with a crappy Monster ICs to the CD player.

Unless you've had a different experience than I have, I wouldn't be so quick to condemn Monster products. The stuff I've used from Monster has sounded very, very good in my systems, especially when price is factored into the equation.

 

[gregeas]

I've bought many Monster Cables over the years... The mini-to-RCA Y connector I referenced is very low end (~$20), whereas the cable connecting the CD player to the other amp cost about 10x. In this case the Monster Cables seemed to do fine...