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Will new Class D trump a vintage Class A/AB?

After 6 years on a shelf, I finally got a 1986 VSP Labs TransMOS 150 power amp fixed. Back in its heydey, the Gold Edition of this amp was one of J. Gordon Holt's favorite amps for neturality and musicality. It's fairly heavily biased into Class A, as the VSPs run on the warm side. They weigh a ton--50-60 lbs depending on whether you have the 150wpc or 200wpc version. They are stable all the way down to 0 ohms, have a really high damping factor, and have deep, extended, tightly controlled bass. It's one of the first MOSFET transconductance amps--it's a solid state implementation of tube amp topology. I remember it being fairly fast, but especially liquid.

Now, I haven't heard a VSP in years (even though I have 4 of 'em--most needed recaps or something).

Anyway, in a fit of impulse-buying, I ordered an Onkyo A-9555 class D integrated amp, which has been enthusiastically reviewed and recommended by both Absolute Sound and Stereophile.

So whaddaya all think? Has amplifier development come far enough in the past 22 years that a high quality MIJ class D integrated could give a handmade boutique old school AB amp from the '80s a run for the money? I know I'll find out in a couple of weeks, but which way do you think it'll go?
johnnyb53
johnnyb53 OP
3,510 posts
 
08-27-08: Mapman
What's the rest of your system that the Onkyo will be synergizing with?
Source is a Technics SL1210 M5G with KAB fluid damper, Oracle Groove Isolator sorbothane mat, and Audio-Technica AT150MLX MM cart mounted on an LPGear Zupreme headshell. Although the Onkyo has a well-reviewed phono section, I plan to continue to use my outboard Cambridge Audio 640P phono stage. Most interconnects are solid core AudioQuest PSC conductors. Speakers are bi-wired Mirage OMD-15 floorstanders.

Boy I tell you, right now, the current rig using an Outlaw 950 purely for its analog line stage feeding a 22-year-old Amber Series 70 power amp is going to be hard to beat. I don't know what happened but it seems like the current system has popped into focus in the last few days.

The more I listen to this humble little Amber, the more I wonder how that amp didn't end up re-defining the state of the art for affordable 70 wpc SS amplification. Its balance of linearity, neutrality, and musicality is extraordinary. It's so good it should influence one's choice of speakers instead of the other way around. Stereophile ranked the Outlaw RR150 as a class C integrated amp/receiver, and it doesn't deserve to be mentioned in the same breath as the Amber. If a new product at $1800 came out that sounded exactly like the Amber, I wonder where S'phile would rate it.

The Onkyo is going to have to be something else to beat it.
mapman's avatar
mapman
22,464 posts
 
I think the result will come down to taste and preference more than anything else.

Isn't the thing still humming though?

The Onkyo Class D was a very savvy choice for trying to improve at reasonable cost though. In that the Mirages are larger floor standers and rated 6 ohm I believe ( a somewhat more difficult than average load to drive I would suspect), I think there is a very good chance the Onkyo will work out. The main difference I would predict would be in the low end in terms of perhaps providing a fuller and tight bottom end that adds meat to the sound and helps balance things out.

LEt us know.

Cheers!
kijanki's avatar
kijanki
4,432 posts
 
Johnnyb53 - It is difficult to compare different amps without setting price range and even then it migh be not easy. Compare 2x200W class A design to my Rowland 102 (class D) I paid $1500 for. There is no such class A amps for $1500. Class D beats many class AB designs within the same price range.

I picked Rowland since it was $100 cheaper than Bel Canto S300 and had Rowland's reputation behind (no bad product in 20 years). I don't think Onkyo was available then.

Get Continuum 500 and don't worry about home equity. One can live without a home but not without great Audio Gear.
johnnyb53 OP
3,510 posts
 
08-27-08: Mapman
I think the result will come down to taste and preference more than anything else.

Isn't the thing still humming though?
It's the VSP Labs TransMOS 150 that hums and it's back in the shop for them to fix it right for the $144 I paid them. The Amber Series 70 currently in my analog rig does not hum. The VSP is rated at 150/300 wpc into 8/4 ohms. Rather high class A bias and very high current. Amber has a single pair of output transistors per side and is rated at 70 wpc into 8 ohms. Don't know its 4 ohm rating.

The Onkyo is similar to the Amber in power--85/170 wpc into 8/4 ohms. Rather low damping factor (25), but I wonder if that isn't just one of those bugaboos when using conventional test methods on class D amps. Plus, I don't know that the Mirage's little 5.5" woofers will need a really high damping factor.

What I'm looking to get in the Onkyo is clarity, speed, and transparency beyond what was attainable in 1986, but without sacrificing musicality, coherence, harmonic rightness.

It's scheduled for delivery Tues. Sept. 2. We shall see.
ostemo8
21 posts
 
I agree about the prowess of the Amber 70. I have been using one against a worthy Muse 100 amp and the Amber has so much more character and depth- great soundstage- seemed to have trouble pushing an old Fried Beta set with Sub, but seems ok with my DQ-8's which are demanding- does well with my Spica TC-50's...always wondered what they sound like in Mono pairs-just one old review claimed they were too bright in that config..hmm, that's my 2 cents
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