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

[tomchr]

I seem to recall the 1k pricing on TI's website being about the same as for the LME49720MA, so you can probably expect the Mouser pricing for the two amps to be similar. That'd be my guess.

OPA1656 is preproduction (POPA1656). You can get samples from TI. There's no MOQ. They'll give you up to five samples for free. Beyond that, I think they want money.

Tom

 

[tomchr]

I encourage those of you who are on Facebook and would like to stay up to date on my retail product developments to follow and 'like' my Tom Christiansen Audio page: www.facebook.com/tomchrAudio

It's a skeleton page, but I'll add content as events happen. It could be a nice opportunity to follow the birth of a new product line (or company, depending on how you look at it) and get a little insight into the day-to-day operations.

The HP-1 successor is coming together. Attached are pictures of a "proof-of-concept" amp. It performs rather well, so I'm pressing on with an actual prototype. I hope to have a small collection of hand-assembled prototypes with me to RMAF in September.
The final version will use the bigger ALPS RK271 ("Blue Velvet") volume pot, feature an RCA input (as well as XLR), have two gain settings, and also have an on-board power supply.
The production PCB colour scheme will be red solder mask with white silk screen. The PCB will be designed, manufactured, and assembled in Canada. The chassis will likely come from Japan. As a minimum, I'll offer a black chassis. I might make a silver (or silver with black hardware) chassis available. I'll send out a survey before I order 100s of these.

I won't promise anything related to specs until I've seen the measurements of the next prototype. I plan to open up for preorders by mid-September with a nice discount for early birds. I hope to be able to start shipping before US Thanksgiving (i.e. mid/late November). I'm targeting a price around the $500-600 mark. I don't have all the numbers yet, so that is subject to change, however.

Tom

 

[Azeia]

I encourage those of you who are on Facebook and would like to stay up to date on my retail product developments to follow and 'like' my Tom Christiansen Audio page: www.facebook.com/tomchrAudio

It's a skeleton page, but I'll add content as events happen. It could be a nice opportunity to follow the birth of a new product line (or company, depending on how you look at it) and get a little insight into the day-to-day operations.

The HP-1 successor is coming together. Attached are pictures of a "proof-of-concept" amp. It performs rather well, so I'm pressing on with an actual prototype. I hope to have a small collection of hand-assembled prototypes with me to RMAF in September.
The final version will use the bigger ALPS RK271 ("Blue Velvet") volume pot, feature an RCA input (as well as XLR), have two gain settings, and also have an on-board power supply.
The production PCB colour scheme will be red solder mask with white silk screen. The PCB will be designed, manufactured, and assembled in Canada. The chassis will likely come from Japan. As a minimum, I'll offer a black chassis. I might make a silver (or silver with black hardware) chassis available. I'll send out a survey before I order 100s of these.

I won't promise anything related to specs until I've seen the measurements of the next prototype. I plan to open up for preorders by mid-September with a nice discount for early birds. I hope to be able to start shipping before US Thanksgiving (i.e. mid/late November). I'm targeting a price around the $500-600 mark. I don't have all the numbers yet, so that is subject to change, however.

Tom

Wow, this is pretty cool, I was randomly checking to see if there was any news on the HP-1 successor and this was the first place I thought to look. What're the odds that I'd look only around half an hour after you posted? XD

I've been looking forward to this ever since I found out about the HP-1; by the time I did though, it was already gone so I've had my eye on the forums for news of the successor. Good to hear that it's coming together. I'm also in Canada so it's nice to see a locally engineered product like this. =)

Out of curiosity, do you have a twitter, or just facebook?

 

[amirm]

I won't promise anything related to specs until I've seen the measurements of the next prototype.

That's awfully cute! BTW, for those of us who don't use facebook, it would be good to get regular updates here.

 

[Azeia]

Prototype for the first product under the Tom Christiansen Audio brand name: HPA-1 ultra-high end headphone amplifier.

Sorry for posting a second time, but I just visited the facebook page and noticed this line; does this mean you're ditching the "Neurochrome" brand for this product? because I always thought that name was pretty cool

 

[DouglasteR]

Also checking in.

Can´t wait to amirm to test it.

 

[invaderzim]

Sorry for posting a second time, but I just visited the facebook page and noticed this line; does this mean you're ditching the "Neurochrome" brand for this product? because I always thought that name was pretty cool

Neurochrome sounds great to us nerdy types but Tom Christiansen Audio does have a classy sound.

 

[tomchr]

Wow, this is pretty cool, I was randomly checking to see if there was any news on the HP-1 successor and this was the first place I thought to look. What're the odds that I'd look only around half an hour after you posted? XD

Nice timing that.

Out of curiosity, do you have a twitter, or just facebook?

No twitter for me. Farcebook sucks enough life out of me. I may have to get more active on Instagram if I'm to reach the younger generations, though. Or Pintrest.

Sorry for posting a second time, but I just visited the facebook page and noticed this line; does this mean you're ditching the "Neurochrome" brand for this product? because I always thought that name was pretty cool

No, I'm not ditching Neurochrome. What I'm aiming to do is to create some separation between the DIY side of Neurochrome and the retail product side of Neurochrome.
Many perceive DIY as cheap - or at least inexpensive (inexpensive = low price; cheap = low price and low quality). It's hard to sell a premium product at a premium price when your brand is perceived as cheap. Now, I'm not suggesting that Neurochrome is perceived as cheap, but DIY is. And Neurochrome is associated with DIY. Neurochrome is also associated with good engineering, good customer service, good value for the money, etc. say my market analyses, but yet I find I have a hard time getting away from under the DIY = cheap/inexpensive umbrella.
I learned a lot from the Neurochrome HP-1 and used those learnings in the TCA HPA-1 (the HP-1 successor). Many of the learnings dealt with 'business' stuff, such as positioning within a market and branding.

For the long term, I hope to keep both the DIY and the retail branches going. I need to be very careful about overlap, though. I guarantee that there will be no DIY version of any of my retail products.

That's awfully cute!

I have a bad habit of disclosing data too early. This requires me to backpedal on the specs which never looks good. My current prototype is very bare bones, thus shows the best performance. My goal is to have the production version be as close to this as possible.

What I can say is that if the final version is anywhere close to the prototype on THD, I will have to build a distortion magnifier to measure the THD. You may be interested in buying such distortion magnifier from me too...
I have a design in mind for the distortion magnifier. Basically it's equal parts of Baxandall, Cordell, and Christiansen. Cordell's article in Linear Audio Vol 0 is a good place to start for those interested.

BTW, for those of us who don't use facebook, it would be good to get regular updates here.

Absolutely! Will do.

Can´t wait to amirm to test it.

I can't either.

Tom

 

[tomchr]

Neurochrome sounds great to us nerdy types but Tom Christiansen Audio does have a classy sound.

Thank you. Yeah. That's basically where I landed as well.

Also, with Tom Christiansen Audio, I'm hoping to build a personal brand. I'll probably use my signature (or some derivative thereof) as my logo (though I'm open to suggestions). I want to send the message that I stand 200% behind my stuff and believe in it to the point where I'm willing to sign my name on the front panel.

Tom

 

[Azeia]

I'll probably use my signature (or some derivative thereof) as my logo (though I'm open to suggestions).

Maybe initials? or like "TCA" but in cursive signature-like writing?

 

[invaderzim]

Separating the DIY and the finished products is a great idea and I think it is really good that the DIY stuff will still keep coming.

 

[amirm]

You may be interested in buying such distortion magnifier from me too...

I would indeed!

 

[restorer-john]

Also, with Tom Christiansen Audio, I'm hoping to build a personal brand. I'll probably use my signature (or some derivative thereof) as my logo (though I'm open to suggestions). I want to send the message that I stand 200% behind my stuff and believe in it to the point where I'm willing to sign my name on the front panel.

The Lexus of Toyota, the Infiniti of Nissan or the Esprit of Sony. I like TCA.

What I can say is that if the final version is anywhere close to the prototype on THD, I will have to build a distortion magnifier to measure the THD. You may be interested in buying such distortion magnifier from me too...
I have a design in mind for the distortion magnifier. Basically it's equal parts of Baxandall, Cordell, and Christiansen. Cordell's article in Linear Audio Vol 0 is a good place to start for those interested.

Keep us informed on the DM.

 

[tomchr]

The Lexus of Toyota, the Infiniti of Nissan or the Esprit of Sony. I like TCA.

I like that analogy.

Keep us informed on the DM.

Will do.

Tom

 

[JohnYang1997]

I have a bad habit of disclosing data too early. This requires me to backpedal on the specs which never looks good.

I will have to build a distortion magnifier to measure the THD.

I just did this to myself. Two days ago I just realized that the crosstalk introduced to the input reduced my distortion by 4 times. It's really embarrassing. I'm also trying to getting my measurement improved, small details can affect too much.

 

[Veri]

I just did this to myself. Two days ago I just realized that the crosstalk introduced to the input reduced my distortion by 4 times. It's really embarrassing. I'm also trying to getting my measurement improved, small details can affect too much.

Maybe you and tomchr should collaborate ;p

 

[tomchr]

I just did this to myself. Two days ago I just realized that the crosstalk introduced to the input reduced my distortion by 4 times. It's really embarrassing. I'm also trying to getting my measurement improved, small details can affect too much.

Welcome to precision circuit design.

Tom

 

[JohnYang1997]

I kinda figured it out it's related to grounding issues. But it may be much more embarrassing to see the initial amplifier that I did modification on has the performance I always wanted. And it only uses opa2189 operating at +-7.8V on battery.

 

[kn0ppers]

I'll probably use my signature (or some derivative thereof) as my logo (though I'm open to suggestions). I want to send the message that I stand 200% behind my stuff and believe in it to the point where I'm willing to sign my name on the front panel.

Tom

Have you been inspired by HBOs Silicon Valley and are we going to see the HP-2 Tom Christiansen Signature Edition?

Jokes aside:

Are you planning on having an internal power supply on the new design?

 

[tomchr]

Have you been inspired by HBOs Silicon Valley and are we going to see the HP-2 Tom Christiansen Signature Edition?

LOL! OK, so no signature then?

Are you planning on having an internal power supply on the new design?

It is decidedly so.

I'm not able to find a transformer from a North American vendor that will deliver enough power and work on the global market. There are a few that'll work on 120 V with US plugs, but 230/240 V versions are not available. I considered using an external switching brick, but that would tie me to a single +24 or +48 volt supply. That either means an output cap (which I don't like) or an internal switching supply ... so an SMPS followed by another SMPS. I ran a quick BOM estimate and found it less expensive, easier, and likely better performing to just add two Mean Well switching bricks on the board and call it good. I'll add appropriate filtering.

I dinked around in Fusion 360 earlier... Attached should give you a sense of scale.

Tom