RAAL requisite audio SR1a Review: HOLY MOLY! Buy this now!

On Vidar:

So I set up Vidar last night, and while the sound is good, the Vidar by itself is the slowest amp I've heard yet with the SR1a. Again, in the context of SR1a, it's not slow sounding per se, but slower than the NHB-108 and Aegir x2. We are talking about slow in the spectrum of fast. It almost seemed that the Vidar itself (I used a passive pre) slowed things down to the point of being on the level of traditional dynamics, yet with the advantages of client transients.

Note that I found the Vidar and Jot (early-production) combination to be much "faster", but in hindsight, I realized that the OG Jot was contributing its zippy transients the SR1a. Well, to be honest, this was the reason that was given to me for using this combination. I didn't believe it at first, but it's true. The downside (and in hindsight I now realize) the Jot was also contributing its upper midrange forwardness through the Vidar to the SR1a.

The takeaway from this is that the SR1a seems to be greatly affected by amp and source as @Zhanming057 has already confirmed.

Vidar with the passive volume control by itself didn't seem any better than Vidar + Jot (the Jot is also a little bit on the flat side in terms of microdynamics), but I would assume this is because the Vidar is the limiting factor in the chain. (Note the amp blind test thread at the Schiitr where Vidar lagged behind the Rag 2 and Aegir). The warmer, almost thick tone of the Vidar really suites the SR1b which on average has a gentle upward slope in terms of frequency response. I noted that I backed off (or just turned off) the minor EQ curves I applied at 1.8kHz and 7kHz). However, I miss the sheer technicalities, the microdynamics, the resolution, and even the macro-dynamics to a smaller extent, of the Aegir monoblocks and especially the NHB-108. The Vidar isn't horrible as I do plan on using this rig next to my beside in the coming months. It's the economic choice. However, the point is that the SR1a can scale like mad. I don't think we've even touched the surface of what it can do with direct drive amps.

 

I believe that's different. Current amplification doesn't necessarily mean a ton of current. What we are looking for is a amp with low voltage rails, but capable of sustaining an almost short circuit.

 

No chance since this would need a 100W amp, maybe even 150W with tubes since a little higher output impedance compared to solid-state amps. I guess a tube pre might help with deeper soundstage and bloom.

Now a direct drive tube amps with 100:1 OPTs might work, but this will depend upon the popularity of ribbons. Another issue to overcome is the response shaping networks which may be different depending upon implementation. I can see an over-the-ear version requiring different response shaping to the open baffle of the SR1a.

 

Publish DIY specs for your fun exercise

 

So I pulled out the Crest CA2 pro audio amp. Yeah, this works quite well with the SR1a. The CA2 amp is 100W into 8-ohms and 200W into 4-ohms. Now, do I advocate using Class AB pro audio amps? Probably not because of the loud fans. However, what I did was replace the fans with lower speed ones. I looked up the part # inside the case, and simply ordered the slower speed (or higher voltage equivalent to get a slower speed) from Digikey. It's just a little bit of work (no soldering was required). The replacement fans weren't cheap. But a used CA2 is $150 to $200 easily.



So how do I like the sound? I just might stick with this. The CA2 has a bit of veil compared to the others, but it offers a more open and expansive soundstage compared to Vidar. The Vidar is a bit warmer, thicker, and does have better clarity overall. The CA2 frequency response is more even with just as smooth, maybe a bit smoother highs. I think tonally and timbre-wise, this CA2 reminds me more of the Dartzeel, but without the grip, dynamics, and clarity.

So it's poorer technically in many respects to the other amps I've tried so far, yet the expansive soundstage and may I even say even microdynamics and involvement factor may be superior to that of Vidar? There just something about this setup that is enticing. It's not an especially fast sound, in fact, the speed seems more normal and akin to fast dynamics; but as I have already stated, I prefer this. I'm not into fake fast sounding transients.

I may have to go back to compare to Vidar. I suspect that Vidar's closer soundstage can be fixed to a large extent with Saga as an active preamp. (Note that I'm currently using a passive pre).

Now going back to the old adage of transducers first (amplifier next, and source last), what we have here with the CA2 can easily still qualify as "Summit-Fi". $3500 + $200 used pro audio amp + 50 fans x2. And this is what I really wanted to point out. I'm also using a Modi 3, so think what would happen if I were to use a Dangerous Music Convert-2 as the source!

I figured I'd mention this because I saw someone mention that SBAF might sell them on the idea of owning an HD800, but knowing how finicky the HD800 is and the amplifier required to get it up to "Summit-Fi" levels, I figured I may as well throw out this possibility with the SR1a.

I continued to be enamored by the RAAL / Requisite SR1a, to the point where I am listening to headphones (in this case ear monitors) again before I fall asleep in my bed drooling.

 

Probably not optimal. Output impedance from 8-ohm tap is 1-ohm. From 4-ohm tap is 0.5-ohm, however, will be less power output from the 4-ohm tap. The darn thing does 80W into 8-ohms before hitting 1% THD (yeah, the specs are fudged a bit). Not to mention 1-2db rolloff at the extremes. And in Triode mode, even less power. And if Ultralinear mode, why even bother? Just go good solid-state, especially since good ~100Wpc solid-state can be had used below $1000 (pro audio amps, Classe, GAS, Sumo, Linn, etc.)

Now I wished I snagged up @dBel84's reconditioned Linn Klout.

 

Oh yeah! Even better! You are done!

I think I should talk to Danny @ Requisite to see if we can get a special SBAF secret hand sign deal.