[bluemonkeyflyer]

  thanks

As far as surface mount builds go, this one is easy. The sound quality is simply...excellent. 

 

[baritone]

when you say the sound quality is exellent    but compared to which amplifier ?

 

[Armaegis]

  As far as surface mount builds go, this one is easy.

 
Well you do have three or four QRV08 builds under your belt...

 

[tomchr]

  can anyone
estimate the cost of the parts for the board ?

The parts cost (BOM cost) is right below the spec table on my website.
 
Tom

 

[tomchr]

  when you say the sound quality is exellent    but compared to which amplifier ?

Click on the "Reviews" tab: https://www.neurochrome.com/product/hp-1-ultra-high-end-headphone-amp/
 
Tom

 

[bluemonkeyflyer]

when you say the sound quality is exellent    but compared to which amplifier ?

Compared to other DIY amps I've built and commercial amps I own, in no particular order:

DIY:

Bijou
CK2III (easiest to build)
EHHA Rev A
Kameleon 2
Neurochrome HP-1
QRV-08 (most difficult to build)


Commercial:

CEntrance DACmini
Garage 1217 Project Ember
Liquid Carbon
OPPO HA-1
Single Power MPX3

I like all these amps; different sound quality "flavors."

 

[bluemonkeyflyer]

Well you do have three or four QRV08 builds under your belt... :rolleyes:

Well, 3 but who's counting? I'm a slow learner...but persistent.

 

[strangecargo]

  when you say the sound quality is exellent    but compared to which amplifier ?

 
I find the HP-1 to be more resolving and to have better transducer control than the headphone output of my Chord DAVE. I have not yet heard a GS-X mk2 (hopefully I will sometime in the coming weeks), but it seems to be described in similar terms. I don't have any truly power-hungry cans, but the HP-1 seems to always give you the "best version" of the headphones that I've driven with it. With the HD650, it was like that scene in a high school movie where they take off the bookish girl's glasses, give her a makeover, and you discover that she's been a supermodel the whole time.
 

   
Well you do have three or four QRV08 builds under your belt...

 
As far as SMD things go, I didn't find the HP-1 particularly bad. It had been almost 20 years since I had done any SMD soldering and the only part that I had issues with was the DAP paddles and larger pads (documented in this thread), which turned out to be an issue with my soldering iron not being able to put out enough heat. I think one of the most time-consuming aspects of populating the PCB was actually finding the locations of the components. I think they're numbered in a sort of logical order that makes sense when you look at a schematic, but not in a way that makes any sense when you're staring at the PCB. I think the two most important things to have that I don't think are explicitly mentioned in the documentation are a nice set of tweezers and good, bright task lighting. I used a pair of 130mm Wiha ESD-safe tweezers and I didn't have a decent task lamp, so I spent some amount of time holding diodes under a reading lamp at various angles, trying to figure out which end was which.
 
@tomchr have you considered making a cut-down version of the HP-1 design (HP-2, perhaps)? Maybe an SE-only version without paralleled amplification or selectable gain that fits into a commonly available project case? It seems like popularity of the HP-1 could be helped if there existed a "gateway" design that didn't require as much investment and had a less daunting component count.

 

[tomchr]

  I don't have any truly power-hungry cans, but the HP-1 seems to always give you the "best version" of your headphones. With the HD650, it was like that scene in a high school movie where they take off the bookish girl's glasses, give her a makeover, and you discover that she's been a supermodel the whole time.
 
@tomchr have you considered making a cut-down version of the HP-1 design (HP-2, perhaps)? Maybe an SE-only version without paralleled amplification or selectable gain that fits into a commonly available project case? It seems like popularity of the HP-1 could be helped if there existed a "gateway" design that didn't require as much investment and had a less daunting component count.

I rather like the high school movie analogy.
 
Re. HP-2 (or whatever it'll be called): I've thought about it. I wanted to make a splash when I entered the headphone amp space, and I think I succeeded. An HP-2 could be, as you point out, a version with only one LME49600 output driver per channel, no protection circuit (or maybe a simplified version), single-ended inputs only. The power supply could be simplified as well. I'd still do my own chassis, but it could potentially be smaller, thereby less expensive. The goal would be to reduce the project cost and hopefully not give up too much performance in the process.
 
I have a few other projects to finish first, though.
 
Tom

 

[strangecargo]

 
I have a few other projects to finish first, though.

 
One of those projects wouldn't happen to be a MC phono stage, would it? 

 

[tomchr]

One of those projects wouldn't happen to be a MC phono stage, would it? 

Maybe... Would you be interested?
 
Tom

 

[strangecargo]

  Maybe... Would you be interested?
 

 
Yes. More than a little If the HP-1 is your "statement" headamp, I'd be very interested in seeing the equivalent statement in terms of a MC phono amp.

 

[tomchr]

It'll happen. Once I have a better timeline for that project, I'll post about it in my newsletter.
 
Tom

 

[paradoxper]

Will graphite chassis be available again?

 

[tomchr]

I have six graphite chassis in stock, so plenty of boxes are available. I have plenty of bare boards, connectors, and volume knobs. If you're looking to DIY you're a mouse click away from starting.

I still build the fully assembled versions by hand as the orders come in. Once I get the next order, I'll probably spend a solid 12-14 hours soldering to build three of them so I can have a little inventory. I'll have some inventory ready for the US Thanksgiving and Christmas season for sure.

Tom