Bought an Audio Research Amp


I feel like i should preface this with a basic rundown of my system up til now:

 

Pre: ARC LS25 MKII

Amp: Legacy High Current Amplifier (rebadged CODA Stage 3.2)

Dac: SMSL M400

Transports: Auralic Aries Femto/Sony DVP-S7000

Speakers: LSA-10 Signature

Subwoofer: Recapped Velodyne Servo-1200

 

Anyhow, as the story goes, I recently acquired an old Yamaha RX-770 on the cheap, figured maybe I’d gift it to a friend. When I inserted it into my system to test it, I was shocked by how good it sounded. It sounded really close to my separates. Worse yet, the Yamaha actually made much better bass through my speakers (sub was off). It was louder, faster, and better controlled sounding. This was extremely distressing. 

I thought maybe this was due to the age of my CODA, but the yamaha is actually about ten years older, so that didn’t make sense. The best I could come up with was just a poor match for my preamp. I can’t recall the figures off the top of my head, but i did some math when I bought the amp to ascertain if matching them was appropriate, in terms of both input sensitivity and impedance, and recall that both were  toward the bare minimum.

Having read numerous times that the increase in synergy is substantial between ARC components, I started casually shopping online for an ARC amp. I briefly entertained a VT100 MKIII which seemed a good deal, but the price of retubing it currently is around $1000, and i just don’t think right now is the time for me to jump into tube amplification with the soaring prices of tubes.

A 300.2 caught my eye, but I couldn’t find any information online that convinced me that a Tripath class-d design of ten years ago would better a solid class a/b design, and I can’t really afford to buy an amp just to find out.

Fortunately, I came across a craigslist ad a week ago for a D400 located only an hour away from me, at a price that was a fair bit lower than similar models had sold for recently (as per Hifishark). Awesome. 

I spoke with the gentleman who had listed the amp, and it turned out that he was the proprietor of a stereo service center, and was selling it for a longtime customer who had been using it, along with 2 D200’s and a D300, to power an eloborate horn speaker setup, but who had, due to the onset of Alzheimer’s, become unable to manage the complexity of his own system. This is, I have to say, extremely tragic. The store’s owner told me the amp was in great shape, had been well cared for, and due to being used in a high efficiency setup, had never been run hard.

Needless to say I was extremely excited at the prospect of owning a D400. Wasn’t able to uncover much in the way of reviews, but I was able to find that it shared circuit-design lineage with the extremely well-regarded d240 MKII, as well as reports from other users who’d paired it with an LS25 and reported extremely positive results.

So I made an appointment to bring my preamp down and auidition the amp. When I arrived, the store owner was extremely friendly, more than happy to take the time to talk audio with me,  show me his personal system (Threshold/Altec VoTT), and all the amazing gear he had on hand, even though I showed up shortly before his usual closing time. 

And the Amp? I really wasn’t prepared for how colossally huge it was… it really is a monolith, just beastly.As far as the sound goes, well, let’s just say that by the time I’d been listening to it for 5m, I already knew i was going to buy it!

Once i got it home (nearly destroyed my back getting it out of the trunk), and into my system, it sounded even better! Compared to the CODA, highs were more sharply focused, I gained more of a sense of instruments existing in specific “space”, and the bass/mid bass had tightened up considerably while also increasing considerably in terms of volume and impact. Overall, I’d say the sound is   less on the warm side than the CODA, which I think is better for my speakers  which have a pretty laid back character.

I will, say that the amp runs pretty hot, even at Idle. I don’t know if it’s biased pretty hard into class a, or what. Also, it does does take 2-3 hours of warm up before it sounds at it’s best. I’ve taken to power it up the night before if I’m intending to do a lot of listening the following day.

Really, I couldn’t be more ecstatic; I really feel like I took a big step toward being  “there” with my system. Of course that just leads me to thinking about what I need to start agonizing over upgrading next, ha ha!

Big shout out to Kevin at The Stereo Workshop in Eugene, OR for being such a gracious host and giving me such a fair shake.

rfnoise

OP,

I had a reluctance to tube amps for a very long time. The idea of retubing. But a few years ago I went ahead. I immediately realized my mistake. It was false economy to me. My system took on a realism and natural musicality (ARC) I never imagined possible (although I had briefly experienced it here and there). But living with it. I will never go back regardless of retuning cost. Realistically when I was working… retubing would be necessary less than once every 5 years. You only live once. I personally wish I had done it sooner.

Thats right rfnoise they were the 67000uf ps caps.As i started thinking about it ARC might have told me that what they found as replacement would not fit into the amp and that they were trying to figure out a way to retro fit these into the amp.I don't know the dimensions of those Cornell Dublier caps you mentioned if they would have been the same dimensions.

@ghdprentice 

Everything I do in this hobby I have to do on a pretty tight budget. My friends all think I’ve lost my mind when they hear how much I’ve invested in my meager system. Having said that, you’re kind of making me wish I’d taken a chance on that VT100…

@mmarch 

You know, as I was turning this capacitor quandary over in my head, it did occur to me that perhaps it was the specific dimensions that was the issue. I did a little more digging last night (when I should have been sleeping) and came up with a spec sheet for Cornell Dublier capacitors wherein it lists a number of capacitors that meet the required spec in a variety of dimensions, in regards to both case size as well as terminal spacing.
 

Unfortunately I only have the ARC part number for the stock caps in my unit, which doesn’t get me anywhere in terms of determining their dimensions.

Losing sleep whilst obsessing over finding a replacement for a capacitor that for all I know is functioning fine. Whoo this hobby is a blast lol.

@rfnoise 

Yes, I’ve had that crazy moniker on audio for nearly my whole adult life. Even when my system was very modest… but was not modest compared to my meager income.