Bottlehead Forum
Bottlehead Finished Products => Legacy Products => Bottlehead DAC => Topic started by: Doc B. on October 07, 2014, 03:36:18 PM
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After three years of prototyping, listening, tweaking, nudging, renudging, re-prototyping, re-listening, and repackaging, we have a DAC! These are images of our functional prototype. Like all Bottlehead products the emphasis is on performance and the packaging uses the philosophy of form follows function.
We had initially planned to do this as a kit. However the main board is very sophisticated and very expensive to manufacture. We decided that we didn't want to raise our customers' blood pressure (or ours!) with scary proposition of having to buy a many hundreds of dollars replacement board in the event of an assembly mistake. So we will be offering the DAC in finished form. There will be a future battery supply upgrade that will be in kit form.
The front is very simple, with a smoked acrylic panel holding a power switch, input selector switch and the ubiquitous likeness of Doc B. Behind the panel stands an old school seven segment red LED display that indicates the sample rate of the file being played - which is set automatically each time a new song is started, up to 384kHz via USB.
The back panel has an HDMI socket which will be used for future added features, RCA output jacks (nominal output is 2V) and a power inlet across the top row and USB, TOSLINK and COAX S/PDIF inlets across the lower row.
As those who have been following the long development of this project know there is a LOT more cool stuff going on inside, and those who have heard it know that it is quite a special piece of gear. I am here late at the office tonight just to get these pics up. I will add more info about the DAC and how we plan to crowdfund the first production run over the next couple of days.
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HOLY DAC!!!
What's the name? My son calls it "The King of the DACs." Yes, I've been talking it up to him. He's six.
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Congrats team! I'll give one a home as soon as you can get it to me ;)
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If the Big Pre sells before the crowdfunding I'll buy three for the HT. Now, how does that sound?!
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Don't want to ruin your crowdfunding plan but +1 for the pre sell. You already got my cc number.
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Thanks, we are most happy to hear from those who want one! We are crowdfunding just to be sure that we can swing the first run OK. I checked my wallet and I am completely out of $30,000 bills. So we are going to need 20 people to commit to do this thing. I will be working on the setup starting tomorrow and will get something together ASAP.
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Not sure if I have the cash to purchase (new roof about to go on the house) but wish you all the best with the project and am looking forward to seeing the Dac up on Kick Starter.
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Looks great! Looking forward to it!
Debra
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So many questions... and its so tiny!
Sign me up, i'm ready and waiting.
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Yeah, baby!
I'm a definite maybe.
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Did I miss it? The price? Not that it will change my decision. ;D
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The price will be $1550. I'm putting together details about the DAC and how it functions. Should be together in a couple days. We have also been working on dressing up the final appearance a little bit.
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Smart move keeping the price as originally announced but saving the battery for later upgrade. I think that's a fair trade-off. Definitely interested, but funds are low... Here's hoping the crowd sourcing is successful!
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Doc can you give me some info on the power requirements, AC or DC and voltage?
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Going to have to sell some more stuff now. ;)
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Doc can you give me some info on the power requirements, AC or DC and voltage?
We will supply a universal wall wart with the DAC. The DC voltage can be between 6V and 9V DC, power consumption is pretty low, something like ~400mA (Swenson is going to pop on here and correct all this I'm sure!).
-PB
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Thanks Paul, that's enough for me to stew over for the time being. I will have plenty of questions for John when he comes along so i'll start a separate thread to discuss further...
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Did I miss what chip you are using? Will that be in the details for the crowd sharing?
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Here is a rendering of my plan for the front panel shape. More details and specs are sitting in a PDF at the moment, and John is pouring over them to be sure nothing is missing.
-PB
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That looks much better Paul. Have we lost the ability to switch between filter modes?
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That looks much better Paul. Have we lost the ability to switch between filter modes?
Yes, John's filter is the only one you want! ;)
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Nice. I like the direction this is heading.
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Found on another forum but wanted to confirm, is the chip in this DAC the PCM5102/5142?
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PCM5142. In terms of the digtal to analog conversion that's just one part of this DAC. John has reassigned some of what that chip usually does to the FPGA that is, as John puts it, the brains of the thing. I am hoping to put a detailed description up tomorrow, just adding the finishing touches to it.
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Any rough idea about the enclosure size?
The picture looks like a narrow, taller unit.
Here is a rendering of my plan for the front panel shape. More details and specs are sitting in a PDF at the moment, and John is pouring over them to be sure nothing is missing.
-PB
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We have also been working on dressing up the final appearance a little bit.
A good idea. :-)
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The shape of the rendering is nice! Any chance you all might consider offering a more pedestrian color scheme/option for those of us who are constantly dancing around WAF aesthetics issues? To preserve marital harmony, I would happily pay a surcharge for a clear coat aluminum enclosure with minimal white lettering and a cutout for the led display. Totally understand if that isn't possible but figured I would at least ask.
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The price will be $1550. I'm putting together details about the DAC and how it functions.
Two questions.
1. Should I add UK excise duty to that price?
2. What music players are recommended to get the high upsampling rates?
Thanks in anticipation . . .
Dave
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Two questions.
1. Should I add UK excise duty to that price?
2. What music players are recommended to get the high upsampling rates?
Thanks in anticipation . . .
Dave
Ouch I had forgotten about that :( don't forget to add the Royal mails parcel force ransom fee, err I mean handling fee either!
I wonder if DHL or FEDEX might be a cost effective option? At least there should not then be the rip of handling fee our UK end.
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The shape of the rendering is nice! Any chance you all might consider offering a more pedestrian color scheme/option for those of us who are constantly dancing around WAF aesthetics issues? To preserve marital harmony, I would happily pay a surcharge for a clear coat aluminum enclosure with minimal white lettering and a cutout for the led display. Totally understand if that isn't possible but figured I would at least ask.
This DAC is not particularly large, I'd address the WAF issue by tucking it away where it can't be seen. (It's black anyway...?)
The enclosure we are using isn't available in anodized aluminum. A 1-off aluminum box would take design time and several prototypes. Even if the aluminum enclosure was only $800 (which would be a reasonable estimate for something that looks better in aluminum than what we have now), I would need to make a few to work out the bugs, and spend the time to develop them, so the 1-off $800 enclosure is more like $2400-3200, plus the cost of the DAC.
-PB
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I'm afraid of that too, if it gets caught by customs it will cost me another €352 :'(
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I'm afraid of that too, if it gets caught by customs it will cost me another €352 :'(
At some point it'd be easier to fly someone over to pick them up ;)
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€650 return trip. With half a dozen UK based buyers that would actually start to work out.
I suspect running pack mule services may raise a few eye brows with the TSA :o
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We will look into other shippers. iI you guys have an idea of a more economical solution let us know.
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From buying stuff on eBay anything sent USPS International Priority, or UPS is guaranteed to be seized by customs. The only one i know of that can sneak through is USPS First Class Mail International, but i dont know how it scales in terms of shipping insurance.
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USPS First Class has insurance to $400. Though it is inexpensive and may squeak by customs, it may spend 4-8 weeks in the mail doing so :-\
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Hey vs Bottlehead time that's nothing :P I've never had an issue with USPS but for something this valuable i would be more comfortable with it fully insured.
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If all goes well in the next few days, we will have an updated image that is much, much closer to the rendering I put up earlier.
-PB
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Anyone have some good recommendations for a fair priced, excellent transport companion fir this dac? I am not computer driven yet.
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I am a big fan of the Oppo 103. Not cheap but not pricey either. It bested my Meridian :)
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A Mac Mini is a great way to go.
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OK, here's where the cabinet design stands as of Friday night, after a really looooong and productive week.
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Is the transport really of much importance to the final sonic result? Why not put a CD into a cheap DVD player and feed it to this DAC?
$1500 would stretch me (and no doubt others) a little, but that would be less of an issue if the source unit for the music is not of major importance. In other words, the DAC would be the real "front end", in a way. The price becomes trivial over long service - my current main CD player has been in constant use for 15 years, so the original purchase price has turned out to be modest in the long run.
DocB's comment reminds me that I actually have a Mac mini, too, sitting in a cupboard for the last year since I built a Hackintosh. If I could use it without a monitor, controlled from an ipod touch (no iPhone), it would be nice to bring it back into service. Is that possible?
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Is the transport really of much importance to the final sonic result? Why not put a CD into a cheap DVD player and feed it to this DAC?
$1500 would stretch me (and no doubt others) a little, but that would be less of an issue if the source unit for the music is not of major importance. In other words, the DAC would be the real "front end", in a way. The price becomes trivial over long service - my current main CD player has been in constant use for 15 years, so the original purchase price has turned out to be modest in the long run.
DocB's comment reminds me that I actually have a Mac mini, too, sitting in a cupboard for the last year since I built a Hackintosh. If I could use it without a monitor, controlled from an ipod touch (no iPhone), it would be nice to bring it back into service. Is that possible?
From my listening to it the S/PDIF inputs (coax or optical) are fairly immune to source differences. They are not completely immune, but pretty close. Everything I have tried has sounded very good, the best sounding ones are only slightly better sounding than the worst. So yes you can get very good results with pretty much anything you plug into it.
The USB input seems to have a bit more variability than the S/PDIF inputs. The BEST USB is a bit better than the best S/PDIF. But again it is not huge.
The BEST sound from this DAC seems to be with the USB input with a good USB cable (the Supra is superb) and a computer that has been tricked out for audio use, JUST audio use, scripts that turn off unnecessary stuff, audiophile player etc.
Note that NO configuration sounds bad, the lowest SQ out if this is still superb, it's just that if you really want to get into it you can wring a little bit more.
Going with the upcoming battery supply will probably be the biggest improvement.
John S.
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We did a fair amount of comparison with TOSLINK from Mac mini vs TOSLINK from a Pioneer blu ray player. The differences were subtle and probably mostly due to using Amarra as the player on the Mac. I think whatever digital source you have right now will work nicely with the DAC, and that moving to a music server might be a future move made more for the convenience of having all your music in one place. All that said, a used Mac mini is relatively inexpensive.
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Speaking of S/PDIF coax input, you will have noticed from the pictures that the input is BNC not RCA. That means that you will need a cable with a BNC plug. My favorite to use for this is the Blue Jeans Cable digital audio cables. You can get them with RCA on one end and BNC on the other or BNC on both if you have a source that has that.
If you are one of the few that uses AES/EBU you can get transformers that convert to BNC, these will plug right in to the BNC jack.
John S.
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Thanks to you and John for the informative replies. Very encouraging to know, and I hope I can put down for a purchase in the not too distant future. (Currently juggling that with a few other possible BH orders - can't do 'em all at once...)
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Thanks for the responses on the input options.
Checked my denon 3910 and indeed it has rca and optical toslink outputs so i think they should work.
Any variability on various toslink cable types? Thanks for the blue jeans recommendation on rca to bnc. Is the bnc vs the toslink any different in sound quality?
Here is a picture of back of the denon just to ensure i have it right and can in fact use it as the transport.
Thanks again
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Since you won't be playing anything higher than a 96kHz file either coax or TOSLINK will work fine. It's difficult to say if one will be better than the other, as it seems dependent upon the player. My hunch is that a cheap TOSLINK cable might sound better on average than a really cheap coax cable. But if you spring for something like the blue jeans coax cable the difference might be very small.
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I looked at the picture at the back of the amp, but didn't see any obvious connection for the power supply. Am I missing something? Is it proprietary, or something we can mate it to with a commercial umbilical cable connector if we build our own linear PS? Or, would that not be a not good idea and the connect ion should be re-engineered. (As i recall most plugs from wall warts are pretty puny).
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It's top right, DC mini (2.5mm?) jack.
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Is it proprietary, or something we can mate it to with a commercial umbilical cable connector if we build our own linear PS?
It's a very standard connector. None of the linear supplies that we made sounded anywhere close to as good as the battery supply we will be releasing after the DACs start shipping.
Or, would that not be a not good idea and the connect ion should be re-engineered. (As i recall most plugs from wall warts are pretty puny).
The demands on this connection are very low. You are certainly welcome to modify the DAC however you like, but you will forfeit the warranty in the process.
-PB
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Here is a photo of what the production DAC's back panel will look like. It's hard to tell from the camera angle, but those are some very nice gold plated copper and teflon insulator RCA jacks.
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Upgraded sockets are a nice touch. Would it be possible to swap the power switch and input jack positions around? Just thinking it would be a little bit easier to find if its on the outer edge.
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Upgraded sockets are a nice touch. Would it be possible to swap the power switch and input jack positions around? Just thinking it would be a little bit easier to find if its on the outer edge.
The power switch isn't meant to be turned off.
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Yeah, the switch is really there just in case you change power supplies. Other than that you want to keep the DAC on all the time. It makes a big difference in the sonics to keep it warmed up.
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Fair enough. I have an old DAC that subscribes to the same philosophy in that it doesn't even have a power switch, always puzzled me as to why it makes a difference.
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Fair enough. I have an old DAC that subscribes to the same philosophy in that it doesn't even have a power switch, always puzzled me as to why it makes a difference.
Super high precision clocks drift with temperature. Not much, but when you need the precision you notice it. Computers etc. are designed binary so minor errors either don't matter or are checked and weeded out, but it matters for analog.
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Super high precision clocks drift with temperature. Not much, but when you need the precision you notice it. Computers etc. are designed binary so minor errors either don't matter or are checked and weeded out, but it matters for analog.
Temperature change on clocks is an important part, but there is another. DAC chips generate less jitter when they are warm, and I do mean warm as in higher temperature. All chips generate current pulses on their power and ground traces in the die and on the package bond wires. These variation in PS voltages create jitter due to threshold change in the chip. The amplitude of the current pulses a given piece of circuitry depends on how fast that circuit changes state. Total amount of charge transferred stays constant, so if the circuit is faster, the current is higher, which creates more jitter.
It turns out that as CMOS circuits heat up they get slower, thus generate less internal jitter. The hotter it gets the less jitter, up til the speed gets so slow the chip fails to operate. I have done several studies on this and found that hot chips DO sound better. This is part of the reason I design my DACs to be warm, they just plain sound better. Heat can also decrease chip life so there is a tradeoff here. Run a DAC warm but not HOT.
John S.
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Fascinating stuff, thanks for the explanation gents.
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Still waiting, anxious to see the final photo of the back panel Dan. I check every day.
Hank
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The image is about 9 posts above this one.
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Dan: Have you posted the dimensions of the DAC enclosure? Any idea of the size of the Battery Kit?
Thanks