There was a tour on Super-Best Audio Friends. It ran until the end and the amp was forwarded to a reviewer who ended up liking it so much that he bought it. If you were part of that tour but didn't get to hear the amp, that's clearly a mistake. Sorry about that. I didn't organize the tour so I took a rather hands-off approach to it.
You can find a customer review of the HP-1 on my website: https://www.neurochrome.com/product/hp-1-ultra-high-end-headphone-amp-2/#reviews. There's quite a bit of chatter about it on Head-Fi and SBAF as well.
Tom
You can find a customer review of the HP-1 on my website: https://www.neurochrome.com/product/hp-1-ultra-high-end-headphone-amp-2/#reviews. There's quite a bit of chatter about it on Head-Fi and SBAF as well.
Tom
Most customer reviews can usually be taken with the proverbial "grain of salt" since it's still only one individual's opinion/experience with the product.
If that particular sample was purchased by someone, why not send another one out for those people that didn't get to listen to it?
After all..."hearing is believing!"
Shoot, I'll even sign up for that if you decide to send another one out on tour.
In addition, since XRK is now selling his creations on etsy.com for about 1/4th the cost of your HP-1, don't you kinda feel a little obligated to letting your potentially toughest competitor hear the HP-1 in action?
Now...let's bust out the whiskey and the soldering iron and build something!
Agree wholeheartedly. It is a rather thorough review, though. As I also pointed out, there are plenty of reviews elsewhere (Head-Fi, SBAF, etc.)
Because samples cost time and money to build. It takes me a full workday to assemble and test one of these amps and the parts cost alone is a significant chunk of the sales price, which means I'm floating most of a month's rent during the loaner program. I need to work up enough operating capital to be able to afford another loaner. Sorry. That's life in a small business world.
If there is enough interest in a North American tour, I can arrange one. I need to get some sort of sign-up system going.
In addition, since XRK is now selling his creations on etsy.com for about 1/4th the cost of your HP-1, don't you kinda feel a little obligated to letting your potentially toughest competitor hear the HP-1 in action?
Other vendors can sell their wares at whatever price they choose. As I stated earlier the parts cost alone is a significant chunk of the selling price of the HP-1. Cutting my prices to 1/4 of the current selling price means I pay for the customers to buy my amp. That's not a sustainable business model.
I don't feel obligated to do anything that doesn't drive business results. Neurochrome is my only source of income - by choice. I cannot afford to run it like a hobby. I need to eat periodically. I provide state-of-the-art products and my prices are more than fair. You're free to disagree.
Tom
Do we say well done Texas Instruments or well done Tom, who designed the amp? What makes it high-end. Sorry I am not being derogatory but so many claims are made as high-end, what does it mean?
Tom, I'm not asking you or anyone else to lower their prices or not "eat periodically". Please...give me a break.
I clearly understand that you have a lot time and money invested in one of these amps from earlier posts in this same thread. If not, then I never will.
The point of my previous post was to have a little fun with you and 'ole XRK as potential "competitors". Nothing more.
@XRK, I realize that the 2 amps are as different as night and day. Like Tom, I prefer AC-coupled op-amp designs for their simplicity(even though Tom's design is FAR from a simple op-amp design), where you obviously prefer discrete, FET DC-coupled designs.
Knowing the point of my previous post now, hopefully you can "lighten up" a little Tom.
BUT...should you ever decide to send another unit out for a audition tour, I still would like to get on board.
Now...let's bust out the whiskey and the soldering iron and build something!
Do we say well done Texas Instruments or well done Tom, who designed the amp? What makes it high-end. Sorry I am not being derogatory but so many claims are made as high-end, what does it mean?
I think in the case of the HP-1, you would have to say "well done" to Tom for the design first and foremost and to T.I. second for manufacturing the ICs for it.
"High-end" is a term that I personally stay away from.
Someone else hear will have to answer what a qualifies a product/design to be "high-end".
Both. National Semiconductor designed the LME49600. Excellent buffer. The folks at the former Burr-Brown designed the OPA1611. Excellent opamp, though the phase wobble above a few MHz causes some serious compensation challenges in composite amps. OPA2140. Awesome opamp for DC servo use. Good work TI!
I designed the HP-1. The guys at National Semiconductor designed an LME49720+LME49600 headphone amp. I improved on this by changing the LME49720 to an OPA1611. This required significant changes to the compensation of the composite amp formed by the LME49600 and OPA1611. I also added a DC servo which actually works (unlike the one shown in the LME49600 data sheet). I further optimized the DC servo to not have any sonic impact as measured by the THD at 20 Hz. I then proceeded to add a protection circuit, gain adjustment, differential input, and supply regulators with its own protection that shuts down the supply if one of the rails fails. I then added an SMPS and output filter which was optimized to ensure the lowest supply impedance possible within the audio band while still providing good attenuation at the switching frequency. I backed this up by a comprehensive set of measurements quantifying the state of the art performance. The measurements are on my website for those who wish to see for themselves. Good work Tom!
If you think the HP-1 is just a "typical application" schematic from a data sheet you're deeply mistaken.
I get asked for free stuff all the time. It's getting old. I didn't perceive any sarcasm in your post. That doesn't mean that none was intended only that I wasn't keyed into the same stream of consciousness as you were were when you wrote. That's all.
Fair enough.
Once I have another demo unit available and a sign-up system set up, I'll post here. You'll be welcome to join. There'll be another demo tour. Just not right this moment.
Tom
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Glad we're on the same page, Tom.
My sense of humor can be misinterpreted and my "to the point" opinions have gotten me in more than my share of trouble with the moderators.
Tom, out of all the bipolar op-amps available, what did you find so magical about the OPA1611?
Also, without you thinking I'm trying to steal any of your ideas or designs, can you shed some light on the PS section of your amp?
Things like type of regulators(shunt or series), type of rectifier diodes and capacitance.
I'm in search of a suitable dual PS for simple, low-gain(6dB) op-amp line stage circuits.
Can you give me some pointers and/or recommendations?
My sense of humor can be misinterpreted and my "to the point" opinions have gotten me in more than my share of trouble with the moderators.
Tom, out of all the bipolar op-amps available, what did you find so magical about the OPA1611?
Also, without you thinking I'm trying to steal any of your ideas or designs, can you shed some light on the PS section of your amp?
Things like type of regulators(shunt or series), type of rectifier diodes and capacitance.
I'm in search of a suitable dual PS for simple, low-gain(6dB) op-amp line stage circuits.
Can you give me some pointers and/or recommendations?
With the various cultural differences, language barriers, etc. it doesn't take much for communication to go sideways. Then you add the fact that it's written communication as opposed to face-to-face with a delay time on the order of hours if not days and you have a real mess. No worries man.
Low THD, low IMD, high AVOL, low Vos, low noise (including 1/f noise), high bandwidth (relevant for AVOL @ 20 kHz). The only drawback is the input bias current (hence the DC servo).
I suggest reading Douglas Self's line-level books (e.g. his Small Signal Audio Design) if you're looking to design line-level circuits. You'll find many good pointers about power supplies there.
I (nearly) always prefer series over shunt. Designing a shunt regulator that can deliver enough peak current for the four LME49600s in the HP-1 while still maintaining regulation would burn about 36 W of quiescent power. It would need a heat sink similar in size to those used on many 100 W class AB amplifiers. That's not a production solution for a headphone amp.
I use an SMPS.
I might offer something like that in the future.
Tom
I thought I was signed up - I had contacted you via email and you informed Nathan at SBAF to put me on the list. This was back on Jan 6.
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Argh! Bummer. Sorry about that.
therefore i´d like to ask, how the entire sound chain looks like
You can find the full block diagram on my website: https://www.neurochrome.com/hp-1-ultra-high-end-headphone-amp/
When you find out what "high end", "transparent", and other audiophile verbiage means would you kindly let me know?
Some may consider hand crafted components (cardboard tubes with charcoal dust resistors anyone?) and other bling to be "high-end". I disagree with that definition.
I define high-end based on measurements. Lowest THD, lowest IMD, low noise, etc. Basically "high-end" is pushing the design as hard against the boundaries of what physics and current devices will allow and backing this up with a comprehensive set of measurements.
As far as the electronics being dirt cheap.... Yeah. A ±0.5 % tolerance metal film SMD resistor is $0.12. That's pretty cheap. Some of the opamps are in the $5-10 range. That's pricy for an opamp but pretty cheap in the grand scheme of things. The trouble arises when you put a bunch of them into an enclosure. Then the cost adds up pretty fast. There're over $250 worth of just electronic parts in the HP-1. That does NOT include the PCB or chassis. The PCB is pretty pricy as it's a large 4-layer board. The chassis is custom made in low quantities, hence relatively pricey. So while each individual component is relatively inexpensive, the total cost is significant.
No offence taken. Just stating facts.
It's high-end because he's selling them, silly
There's something to that for sure. It's high-end because I said it is!
There's also a fair bit of consumer psychology around the pricing. I'd have no issues selling the HP-1 at 2-3x the current cost in a sexier chassis backed up by some audiophile verbiage by a well-known reviewer. It's all perception. A $100 amp is cheap. The same amp with a $10k price tag is exclusive and will sound better - even if the only difference is the price tag. Floyd E. Toole and Sean Olive published some research on this from Harman a while back. Actual research. Ya know. Significant sample size, blind testing, controlled experiment, statistical analysis applied, etc.
Tom
As I said electronic components costs nothing especially surface mount, therefor the cost mainly consists of your labour. That is perfectly fine Tom, you work to make money and no one can dictate the asking price.
All I am after is what is "ultra high-end" if fact even explaining high end would be a nice start.
All I am after is what is "ultra high-end" if fact even explaining high end would be a nice start.
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