Neurochrome HP-1

Did you stick with 0805 to keep it within the realm of sane DIY? How small could this amp feasibly be if you had it all done at an assembly house?

 

I kept it at 0805 for human solderability. The board is limited by the size of the connectors on the rear and by the length of the power supply bricks in the other direction. You wouldn't really save anything by going with smaller passives. Also note that some area is required to keep the LME49600s running cool. The board acts as a heat sink for those.

Tom

 

Apologies if you saw this as an attack on you for inflating the shipping price or something, I was merely referring to how much awesome stuff we miss out on being isolated on this little island. (especially loudspeaker DIY kits from Madisound, the BK-20 pair kit was $600 to ship, though I know some cabinetmakers who could put together the box based on blueprints!)

 

No worries. I'm just letting everybody know where I come from and how the shipping calculated. That's all. There are some things that are within my control. The shipping rates is not one of them. That's life.

Tom

 

CanadaPost shipping rates are just terrible for anything going out of country if you want anything with speed/tracking. I've sent parcels out the cheap way before, but you'll be waiting in limbo for months.

 

Just in case any of you are trying to visit my website to check out the HP-1 (or anything else I offer): My site is bouncing in and out of service right now. Thankfully, it's mostly up, though sometimes it takes a nap. It's been going on for a few days now. Grr... Joy of small business ownership. I have a trouble ticket in with my web host. I expect to have the issue fixed within a few days.

Sorry. That's not up to my usual quality standards.

Tom

 

Man, wish I'd got in on the chassis before you adjusted the prices. The prices as a whole make more sense now, though (if there is such a thing). I'll probably succumb at some point anyway.

 

Yeah, sorry... There were enough questions about the pricing of chassis+board vs fully assembled that it became a distraction that needed to go away.

In the interest of transparency, the current introductory sale runs until Christmas. I am putting the final touches on a couple of circuit tweaks and expect to have the final revision ready by the end of this month. I'll have bare boards in stock by then. The fully assembled boards and products are assembled by hand, so expect 1-2 week lead time.

Tom

 

The amp is getting quite a bit of attraction. One of the local audio stores, The Audio Room, hosted the North American rep as well as the Frenh rep of Focal for a dedicated headphone demo. My amp was primarily demoed with the Utopia, but on occasion the Elear would be substituted in. I received lots of praise for the amp - in particular for its transparency, detail, dynamic range, and exceptionally low noise. Both Focal reps had a good long listen after the show had wound down and really liked the amp.

The event was quite successful. We probably had 50-60 people milling through and a good chunk of those jumped at the opportunity to hear the HP-1 with the Focal Utopia.

Tom

 

Oh man, I wish the Focal guys had a better amp here in Winnipeg when they did their headphone event. They were using a Naim unit which I don't think was doing them any favours.

 

I think they used the same Naim unit here last night. I didn't listen to it. I was busy talking about the HP-1.

Tom

 

Allow me to offer a super brief 5 minute review as written in the style of today's post-millenial generation-Z...

So clean.
Much wow.
Very music.

That is all.

 

Is this for real? Looking forward to building one and hearing it through Utopes!!

 

The HP-1 is in Winnipeg for the weekend for the Head-Fi meet. Sounds like it made the trip OK. Thanks to the organizers and coordinators for making that happen.

Tom

 

Ah, great. Look forward to further impressions. Gen-Z, Gen-X or otherwise.

 

Alas, even with a new Furman unit chugging away at cleaning up the power (it's better than before), the noise floor is too high to use with IEMs. Granted, it's still better than every other mains powered amp I've got plugged in at the moment, so that's something.

edit: to clarity, this is my mains power issue, not the amp

 

At what level does residual mains hum need to be for IEM usage?

 

I suppose it depends on the IEM, though in my case I'd like at least another -12dB on my mains power. I'm curious if a fully balanced output stage would alleviate my problems, or if the dirty ground sneaks into everything.

 

I tried with my Etymotic ER-4. I can't hear the 1.0 uV of the HP-1. Once the noise gets up in the 5-10 uV range I start to be able to reliably detect the noise in the phones. All numbers: A-weighted, 20 Hz - 20 kHz.

Tom

 

I edited my earlier posts to clarify. This is really just an issue with my power, not the amp itself. I was kinda hoping that something magical would happen in the amp psu to clean things up, but alas my household electricity is just cursed.