Here's the rundown on the DAC

[Doc B]

This DAC may very well upset some conventional notions. I don't think that you will see John or me the least bit upset if it does. As I explain in the description we had assumed - when the DAC project was initiated with a very different design using a very different DAC chip - that there would be a tube output stage.  When this design was put together it was put up against earlier tube output designs and it was a clear winner in terms of weight, dynamics, extension, noise floor and imaging.

A few other commercial DACs have been brought by during the listening stages of this project and there was some disparity in quality levels that made it difficult to relate the two. My hope is to head to our studio in the next couple of weeks so that we can compare against a Pacific Microsonics Model2 and hopefully some other studio grade gear.

I would offer that there may be many other things that are different between your DAC and this one besides the filter. Even if there was a way to emulate the filter that is just one component of the design and I don't think you could really get a full sense of what this DAC might sound like by emulating that one element.

We are hoping to do some demos of the DAC in the near future. I don't know where or when yet, but we will certainly announce any opportunity here on the forum.

 

[tsingle999]

Theres a lot of questions flying around and rightly so at the size of the investment but i also know if Doc et al spent 4 years developing it that it will sound amazing and still be a bargain! Taran

 

[Doc B]

Thanks Taran, and thanks for being one of the first to commit. Thank you too Dave, your fearless support of us the minute we release a new product is really special to us! You guys rock!
I've been absolutely buried trying to get everything lined up today, so I'll just post here before I get to the official post,

the crowdfund has started

here's a link -

http://bottlehead.com/product/bottlehead-dac/

 

[Paul Birkeland]

Did you experience any disadvantages at all by not using an output stage or did you find it better in general but not necessarily in every aspect?

Having built several of the prototypes (including the last one with a tube output stage), I can say that there was a distinct disadvantage in the case of this DAC when adding any of the tube output stages we tried. 

This was not the case with the earliest prototypes that required an output stage of some sort to function. 

Owning a NOS DAC without digital filtering I'm interested to know if I can emulate the sound your DAC is providing by running a test on some converted files using your filter.

I can't speak for Doc and John, but this isn't an open source project, and a request like this comes across strangely. 

 

[Rob181]

I am in Australia...sending the DAC back for unsoldering one chip & upgrading or inserting a replacement would be an expensive, inconvenient & the least preferred option.

Is the a Plan B for OS sales...Thanks

 

[Paul Birkeland]

I am in Australia...sending the DAC back for unsoldering one chip & upgrading or inserting a replacement would be an expensive, inconvenient & the least preferred option.

It's about $60 each way to ship.  That is expensive, but not incredibly so. 

This still boils down to wanting to maintain your warranty.  If something happens and your DAC board is damaged in the upgrade process, you really want that to be our responsibility, not yours! 

 

[JamieMcC]

It's about $60 each way to ship.  That is expensive, but not incredibly so. 

This still boils down to wanting to maintain your warranty.  If something happens and your DAC board is damaged in the upgrade process, you really want that to be our responsibility, not yours!

I would be nervous about getting stung for a second lot of import duty on it return! Not sure how that works if anyone can clarify the procedure of shipping a purchased item from the UK for warranty/service/upgrade work for customs and receiving it back it would be appreciated.

 

[Paul Birkeland]

Yeah, we can slip an invoice in with the shipping paperwork.  This has come up when we've retubed and serviced our Tape Repro amps internationally, and so far there haven't been any problems. 

-PB

 

[mcandmar]

I got hit with that before when i sent a DAC back to a manufacturer in California.  The return shipping label clearly said "returned from warranty repair", $0 value, and $500 insured value so some wise ass in customs charged me duty on the $500 + shipping + handling charge + vat, and i had to go the depot to collect it myself.  I had a colorful vocabulary that day.

I got a refund in the end after submitting a claim, had to get a letter from the manufacturer to verify it was a warranty repair with a copy of the original invoice to prove i owned it. Two months later i got a cheque in the post refunding the cost - the handling charge

The worst part is every single package i have received from the US since then has been sezied and had duty charged on it. As the postman in my local depot put it "your on somebodys shit list!"

 

[Paul Birkeland]

The worst part is every single package i have received from the US since then has been sezied and had duty charged on it. As the postman in my local depot put it "your on somebodys shit list!"

Maybe we can mail it to your neighbor instead?  (Or to your work address?)

 

[Doc B]

Is the a Plan B for OS sales...Thanks

Off the top of my head I don't see any way that would be cheaper. If we ask customers too attempt it themselves, they run the risk of roaching a $750 main board. We are trying to make it so the cost difference between DIYing the update and us doing it is minimal.

 

[kumasan]

I can't speak for Doc and John, but this isn't an open source project, and a request like this comes across strangely.

Well it's a question you can choose to answer or not. Anyway I ordered a bh dac and are looking forward to hear how it compares to my modern nos dac

 

[Doc B]

Thanks so much for your support! Since we are licensing the digital side of this project from John, it's completely up to him when it comes to a decision about sharing his IP. Apologies if we came off a little abrupt there. I think we're all just a bit wound up from finally getting this project out of the lab and onto the street. As you guys know it's been quite a long haul while everyone else is showing great enthusiasm with their questions our perspective tends to lean a bit towards

"Auughh! No more changes! We have to deliver this thing!"

 

[skypig]

I currently use a Cambridge NP30 to play digital files from a USB memory or NAS (all a bit new, and slightly mysterious to me.)
I run this into a "Tubemagic D1" DAC, upgraded OpAmps, NOS output tube  (via Optical)

Then though my amp/old favorite speakers
Or
For a more "revealing" listen, through my BH Crack/speedball and Senheiser HD650s

Listening to FLAC files this way sounds superb to me. [some 44.1/16bit, up to 96/24bit (max for current streamer and DAC)]
I also enjoy vinyl.

I don't think I'm a terribly "sensitive" listener. Too much exposure to helicopters, motorbikes and rock music, maybe.

Anyone care to offer an opinion on how audible an upgrade to the new BH DAC would likely be for me?
Just comments/suggestions/opinions sought. Not guarantees  

 

[elcraigo]

"Auughh! No more changes! We have to deliver this thing!"

I understand this statement completely Doc --- draw the line in the sand, FPGA in this case, and move on.

 

[Doc B]

Well my blood presure is back to normal this afternoon. This morning I put the DAC prototype back in the system. It had been sitting in my office for the past week or two as we had been so busy with sales that there was not really any time to listen. Thinking I would put on a little music today and relax a bit, I plugged the DAC in and it started acting very strangely. It wouldn't autoselect the sample rate, the display was a little buggy and the sound was distorted. Oh My God!!! We've started production and this thing is broken!!!

Peebs comes in to work a little later and says -"You know, that's not the right power supply. It's way too puny". He goes downstairs and grabs the proper, beefy power supply and it starts right up, beautifully. It was very nice to listen to some really fine sound to calm my nerves. TGIF.

 

[Grainger49]

I know the sinking feeling.  Glad you are back to normal.

 

[kumasan]

When this design was put together it was put up against earlier tube output designs and it was a clear winner in terms of weight, dynamics, extension, noise floor and imaging.

Did you experience this with an active pre amp as the Beepre or also when using a passive pre amp?

I'm thinking that an active pre amp might work like an active output stage and adding an active stage ahead of an active pre amp will just be an extra stage not doing anything but smearing the signal. I'm using a transformer based attenuator so an output stage might be beneficial in my system?

 

[Paul Birkeland]

Did you experience this with an active pre amp as the Beepre or also when using a passive pre amp?

Both.

I'm thinking that an active pre amp might work like an active output stage and adding an active stage ahead of an active pre amp will just be an extra stage not doing anything but smearing the signal. I'm using a transformer based attenuator so an output stage might be beneficial in my system?

In our earlier design, with a different DAC chip, gain after the DAC output was essential to the DAC functioning.  In the new design, sufficient voltage output and low output impedance are available right at the output of the DAC chips themselves.  When adding an active stage, generally the reasons are to increase the gain or decrease the output impedance. 

A transformer based attenuator in general is a pretty low impedance load, so the focus is most often on low output impedance of sources beyond all else.

 

[Hank Murrow]

Dear Paul; I imagine that your last comment in the previous post means that running the DAC out of my OPPO and into the TVC's fronting my BH linestage will be optimum?

Cheers, Hank