I owned an A&S (branded ZMF) Pendant for some time. I really liked it, but it didn’t pair quite as well with my Utopia as some other amps, largely because of a slight, but perceptible noise floor. However, I haven’t heard A&S’ higher-end offerings which would be more in line with the Stratus or Stellaris, so my experience with the Pendant isn’t really fair.
Just FWIW, I own the forge (32/300) currently. It unfortunately does hiss with HD800S (and I suspect would with anything ZMF as well) but Utopia are dead silent (though I havent tried the no music crank the vol yet now that I think about it). Not sure why that is as I usually find it goes the other way but
What does the rectifier switch do and how much was the upgrade?
The amp, as “standard” is optimized for a 5U4G, which is directly heated rectifier. You can put in some indirectly heated rectifiers, even without a switch, but it’s not optimized, particularly in terms of noise floor. I used a GZ34 in the demo Stratus (no switch), and it sounded amazing. With the switch, the amp can also operate optimally for indirectly heated rectifiers.
From Donald himself: “Yes, I can add a switch which allows you to switch between directly heated rectifiers and your favorite indirectly heated type. Keep in mind this alternate setting could only be optimized for rectifiers with the cathode tied to pin 2 (GZ34/GZ37) or to pin 8 (422A)”
I paid $300 for this upgrade.
I’m very happy I got the switch in my stratus as the Mullard 5ar4 has become my favorite tube with warmer geared headphones. They seem to synergize well.
I fav parings are 5ar4 with Aeolus.
And both 5u4g/5ar4 with Verites and Auteurs.
Edit: that’s with the very neutral leaning EML Solid plates. I look forward to trying either or with the Acmes I’m getting soon.
SO I checked this a couple days ago and there is hum on utopia on the Forge 32 ohm port if the volume is cranked but none at listening levels (even with a silent “track” playing)
BTW, I scanned the thread and didnt see it mentioned. Any experience with any of the decware stuff? EDIT: NVM. Found that you havent had one at the beginning of the thread
@andris You’re a genius. I bought an MZ3 at CanJam and it’s the only amp I’ve been using for the past few weeks because I love it so much. Today was the first time I compared it to my Nautilus and imagine my surprise when the Nautilus sounds vivid, with more weight in comparison.
I’ve been going back and forth all morning, trying to reconcile the differences and then I remembered your review. You absolutely nailed it. As you say, the MZ3 isn’t soft or veiled, but the edges are just a bit “feathered” and I never noticed that until I compared to the Nautilus, which puts it all out there, warts and all, in vivid technicolor.
One isn’t necessarily better than the other, and your brain quickly adapts to the sound of the amp, so unless you generally listen to music a minute at a time before switching amps, music sounds wonderful both ways.
Super pumped to hear you had a similar experience! I 100% agree that both amps are very different, but each incredibly enjoyable in their own way.
There are options, if it has balanced inputs it adds a chunk to the price, and I’m pretty sure the only one I’ve seen used had that option.
The most expensive version with silver transformers is about 2x what those other amps run, though I believe the number in actual customer hands is low single digits, so the chances of seeing one used are close to 0,