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Review and Measurements of Neurochrome HP-1 High-Performance Amp

restorer-john

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#21
and such a small pot. Probably should have gone for an RK27 instead of an RK097.
Totally agree. Those small Alps pots are terrible in terms of longevity. I replace them all the time in consumer level gear as they fracture, separate and get torn off the boards. Often the aluminium rivets in the corners split the plastic. I sincerely hope there is a nut and washer under that little knob.

The balanced headphone jack should have countersunk screws that match the other screws as a bare minimum.

The 6.35mm PCB mount headphone socket appears to eschew any type of physical mounting other than the PCB solder joints and perhaps some plastic spigots through the board? It's designed to utilize a nut to hold it to a metal sub chassis, behind the front panel- is there one? Bear in mind, those sockets get a hammering and dry joints will happen without adequately secured sockets. I know, I fix them all the time.

The PCB mount toggles are relying 100% on the solder joints for mechanical support (un-threaded collars and no nuts) and will fracture down the track. The single solder pin 'anchor' point at the front of those switches is manifestly inadequate IMO, the number of them I see loose in PCBs on modern gear- especially PbFree, makes me angry.

All these criticisms are justified. It is marketed and reviewed here as a USD$1249 retail product, let's not forget that.
 
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tomchr

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#23
While the measurements may be exemplary, it's hard to take a product of this level seriously with such a small volume knob.
That along with the "feel" of the knob (whatever that means) were the most surprising criticisms of the HP-1. Live and learn.

As for the aesthetics of the enclosure: I designed the HP-1 as a DIY projects. Many liked it and after a loaner round on SBAF quite a few wanted one. They just didn't want to build their own. So the completed amps started selling. As one reviewer said, "it looks like a DIY project" ... because it is a DIY project, albeit a quite nice one if you ask me. :)
As far as I'm aware, there is nothing that competes with the HP-1 on performance in the DIY space.

There's no way that a small fry like me will ever be able to compete on price with the Best Buys (or Massdrops) of the world. That's just reality. I have to compete on something else.

Tom
 

restorer-john

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#24
That along with the "feel" of the knob (whatever that means)
The weight, surface texture and finish of the knob, the viscous silicone damping on the pot shaft collar and the overall way it operates.

This area the Japanese absolutely nailed decades ago. They worked out that how something looked and 'felt' in you hand or touch was most important.

The Alps RK27 (motorized or not) with a heavy knob recessed into the front panel was pretty much a standard on gear with pretensions to high end for many years.
 

helloworld

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#25
That along with the "feel" of the knob (whatever that means) were the most surprising criticisms of the HP-1. Live and learn.

As for the aesthetics of the enclosure: I designed the HP-1 as a DIY projects. Many liked it and after a loaner round on SBAF quite a few wanted one. They just didn't want to build their own. So the completed amps started selling. As one reviewer said, "it looks like a DIY project" ... because it is a DIY project, albeit a quite nice one if you ask me. :)
As far as I'm aware, there is nothing that competes with the HP-1 on performance in the DIY space.

There's no way that a small fry like me will ever be able to compete on price with the Best Buys (or Massdrops) of the world. That's just reality. I have to compete on something else.

Tom
Have you ever thought of finding a factory in China to deal with the production so that you got more units sold while we got affordable price..... In this case I guess you could lower the price to half at least.
 

tomchr

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#26
Totally agree. Those small Alps pots are terrible in terms of longevity.
It's been a bit over two years since I launched the HP-1. To date, I know of one pot that has gone scratchy. That's rather disappointing of course, but it's not exactly a high failure rate. The RK097 has pins that latch in place whereas the RK271 has regular solder pins. I'd be a bit surprised if the RK271 is more rugged than the RK097.

The C&K switches have two anchoring pins that are soldered to the PCB. They fit quite tightly in the front panel, so you won't get that much torque on them. Some, of course, but not a lot.

I appreciate your insights, though. I definitely want my products to last as long as possible.

Tom
 

tomchr

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#27
Have you ever thought of finding a factory in China to deal with the production so that you got more units sold while we got affordable price..... In this case I guess you could lower the price to half at least.
I'd rather handle the production in North America, to be honest. In part because I have greater trust in NA production (and I have more control over it), but also because my customers tell me that they perceived "Made in Canada" as of higher value than "Made in China".

I'm gradually pulling back all my circuit board production to North America. My Modulus-186, 286, and 686 are all Made in Canada from start to finish. Except the electronic components. They're made all over the place - the ICs in the US, for example. My PCBs are made in Ontario and assembled right here in Calgary - a 15-minute drive from my house. The assembly place specializes in low-volume orders, hence offer competitive prices for me. They're also able to build the full assembly for me should I need it.

Fact of the matter is that the HP-1 is an expensive amp to produce. I didn't hold back on the component cost, that's for sure. Even at QTY 10k, I wouldn't get enough of a bulk discount to produce the HP-1 for a sale price of $350. As I said a few posts back... Live and learn. :)

I'd like to take the opportunity to ask you folks here: If I was able to make a headphone amp available in a prettier case, with a volume knob that felt right, and that would provide the same performance (except likely lower output power) for around $500-600, would you be interested?

Or let's say I went the other way and wanted to make an amp for the $5-10k space. What features, performance, etc. would you expect?

Tom
 

restorer-john

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#28
The RK097 has pins that latch in place whereas the RK271 has regular solder pins. I'd be a bit surprised if the RK271 is more rugged than the RK097.
I've only ever replaced two full size Alps blues in 30 years IIRC. Both blues were for shafts being snapped off. Maybe a dozen Alps black beauties (stepped resistor laser trimmed on substrate) as the substrates can go bad and wipers can dig in.

I'm pretty sure it was Alpine's need for extremely small pots for car audio in the 1970s/1980s (multiple stacked controls on concentric shafts) that created that form factor (parent company Alps). I first saw them on flexible substrate ribbon style looms that went back to the main PCB back then. Essentially, they haven't changed a bit, except they are being soldered direct to PCBs with no nuts to hold them in a lot of gear.
 

tomchr

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#29

restorer-john

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#30
I'd like to take the opportunity to ask you folks here: If I was able to make a headphone amp available in a prettier case, with a volume knob that felt right, and that would provide the same performance (except likely lower output power) for around $500-600, would you be interested?
I think you would sell a lot more, definitely.

Design the casework and controls to look and feel like something really special. Make it beautiful. Make it so people want to touch it, take it home and show it to their wife.

Then design the PCB and associated peripheral parts placement to fit that design, not the other way around. Otherwise, it looks like all the other DIY style or Chinese PCBs stuffed into whatever box they can fit in in.

I bet you there's some industrial/creative designers on this board that would do it for fun.

You have the performance part absolutely nailed. :)
 

tomchr

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#31
I think you would sell a lot more, definitely.

Design the casework and controls to look and feel like something really special. Make it beautiful. Make it so people want to touch it, take it home and show it to their wife.

Then design the PCB and associated peripheral parts placement to fit that design, not the other way around. Otherwise, it looks like all the other DIY style or Chinese PCBs stuffed into whatever box they can fit in in.

I bet you there's some industrial/creative designers on this board that would do it for fun.

You have the performance part absolutely nailed. :)
Thank you. Yeah... The HP-1 is a bit more "make the ultimate PCB, then fit a case around it" rather than "make the ultimate case and fit a PCB around it (within a budget)". Industrial design is definitely an area where I need to develop some skill.

Tom
 

Sythrix

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#32
I'll definitely be looking to build one eventually, from a bare board. I can't afford it right now, but consider me a likely future DIY customer of this and your other projects.

Positive proof that the critics of DIY designers (who insist that only large teams can produce an effective amp) are just masters of conjecture.

I hope we see more of your stuff soon :D.
 

Johnb

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#33
Amir, you are getting more and more confident with your new analyzer! So fitting to have two essentially flawless amps at precisely this moment to test your skills. Wow. State of the art stuff.
 

Johnb

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#34
DIY designers aren't "hobbyists" if they have a wealth of experience in design. Still, what Tom has done is really exceptional. Everyone benefits from having a team helping out, if only to point out things that go unnoticed. It's a lot of hats to wear- designer, buyer, project scheduler, builder, marketer. Color me impressed.
 
OP
amirm

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Thread Starter #35
I am totally stoked to see the FFT of the 1 kHz tone (yes, I'm really that much of a geek!) Would you mind running the FFT separately? I'd like to see 1 kHz @ 400 mW into 300 Ω with 1M point FFT, 8 averages. Pretty please. :)
Here you go:

1542684137431.png
 
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amirm

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Thread Starter #36
1 million point FFT is brutal in the way it digs deep to find even the tiniest hints of distortion/spurious response. Here is the same measurement as above but with Audio Precision APx555 measuring itself in loopback mode:

1542684422867.png


Power supply noise spike is at near -150 dB. Distortion spikes are even lower than that.

The FFT in the dashboard uses 32K points so quite a bit less resolving (but still far better than many traditional methods).
 

jsmiller58

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#37
I'd rather handle the production in North America, to be honest. In part because I have greater trust in NA production (and I have more control over it), but also because my customers tell me that they perceived "Made in Canada" as of higher value than "Made in China".

I'm gradually pulling back all my circuit board production to North America. My Modulus-186, 286, and 686 are all Made in Canada from start to finish. Except the electronic components. They're made all over the place - the ICs in the US, for example. My PCBs are made in Ontario and assembled right here in Calgary - a 15-minute drive from my house. The assembly place specializes in low-volume orders, hence offer competitive prices for me. They're also able to build the full assembly for me should I need it.

Fact of the matter is that the HP-1 is an expensive amp to produce. I didn't hold back on the component cost, that's for sure. Even at QTY 10k, I wouldn't get enough of a bulk discount to produce the HP-1 for a sale price of $350. As I said a few posts back... Live and learn. :)

I'd like to take the opportunity to ask you folks here: If I was able to make a headphone amp available in a prettier case, with a volume knob that felt right, and that would provide the same performance (except likely lower output power) for around $500-600, would you be interested?

Or let's say I went the other way and wanted to make an amp for the $5-10k space. What features, performance, etc. would you expect?

Tom
If there was a way you could make compromises that reduce the cost, while not compromising your principles or the product, AND at the same time improve design...

Given competitive options available, for a product this good, and add in excellent ergonomics/design, I would put down up to $700 USD. I would like to say more, but then I would have to get the CFO (aka the MUCH better half) involved...

Extraordinary product you have designed there!
 
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amirm

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Thread Starter #38
And here is the Massdrop THX 789 using the same input level but with 1/3 the power at 168 milliwatts (can't do 400 mwatts @ 300 ohm):

1542685000501.png
 

maxxevv

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#39
Have you ever thought of finding a factory in China to deal with the production so that you got more units sold while we got affordable price..... In this case I guess you could lower the price to half at least.
I would say outsource the non-critical stuff such as the case work to some China factory where they have a competitive cost advantage and you don't have too much to worry about the quality of them as they either fit or don't at assembly( and you don't have to worry about customer recourse due to some electronics quality issues that were not spotted at shipping that need a round-trip to China to claim for costs) .

And then assemble the complete system in Canada.
 

Mad_Economist

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#40
While we're asking for FFTs, would an FFT of the HP1 (and if possible the THX 789) driving a 16 or 32 ohm load for, say, 1-2Vrms be possible?
 
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