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Author Topic: Here's the rundown on the DAC  (Read 17246 times)

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Offline Doc B.

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Re: Here's the rundown on the DAC
« Reply #30 on: October 16, 2014, 02:01:43 PM »
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.
Dan "Doc B." Schmalle
President For Life
Bottlehead Corp.

Offline kumasan

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Re: Here's the rundown on the DAC
« Reply #31 on: October 16, 2014, 08:41:05 PM »
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 ;)

Offline Doc B.

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Re: Here's the rundown on the DAC
« Reply #32 on: October 17, 2014, 05:52:50 AM »
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!"
Dan "Doc B." Schmalle
President For Life
Bottlehead Corp.

Offline skypig

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Re: Here's the rundown on the DAC
« Reply #33 on: October 18, 2014, 02:24:02 AM »
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 :) 
« Last Edit: October 20, 2014, 05:34:56 AM by skypig »

Offline elcraigo

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Re: Here's the rundown on the DAC
« Reply #34 on: October 19, 2014, 04:30:27 AM »
"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.
Craig Lewis (elcraigo is a nickname a good friend who grew up in Mexico gave me)

Offline Doc B.

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Re: Here's the rundown on the DAC
« Reply #35 on: October 31, 2014, 02:20:04 PM »
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.
Dan "Doc B." Schmalle
President For Life
Bottlehead Corp.

Offline Grainger49

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Re: Here's the rundown on the DAC
« Reply #36 on: October 31, 2014, 02:54:07 PM »
I know the sinking feeling.  Glad you are back to normal.

Offline kumasan

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Re: Here's the rundown on the DAC
« Reply #37 on: January 04, 2015, 01:34:26 AM »
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?

Offline Paul Birkeland

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Re: Here's the rundown on the DAC
« Reply #38 on: January 04, 2015, 12:39:28 PM »
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.
Paul "PB" Birkeland

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Offline Hank Murrow

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Re: Here's the rundown on the DAC
« Reply #39 on: January 04, 2015, 03:19:36 PM »
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

Offline Paul Birkeland

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Re: Here's the rundown on the DAC
« Reply #40 on: January 05, 2015, 06:57:11 AM »
Yes, the DAC will drive your TVC's nicely.

-PB
Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man