[tomb]

Quote:

 
...And what DACs are you comparing the Pup to?
 
I'll be able to compare it to the Gamma-1/2 and GrubDAC, so I'll definitely be posting my impressions.

A couple of things here, and I know you meant no malicious intent.

  It was my fault for making such a strong statement, but I am excited about the design.

 
I typically frown away from direct comparisons between genuine, DIY-based designs.  That's because we're all operating on a shoe-string budget most of the time (me for sure, anyway) and we are in this business because we enjoy it.  My wife often jokes with me about Beezar - at least it self-sustains my hobby ... for a change.  However, nothing that you mention is really an absolute, direct comparison.  I have no issue with stating un-categorically, pupDAC >> grubDAC (much greater than for you non-math types).  They are both designed by cobaltmute for different purposes, though - the grubDAC being perhaps the best available in the 1" x 2" form factor (and perhaps better than some bigger than that).  Cobaltmute will need to correct me if I get this wrong, but I think the pupDAC competes against the pinnacle in a USB-powered DAC, without an added extensive feature set (more options, connectibility, etc.).  PupDAC and grubDAC each fill two distinct market niches and will have a definite price differential commensurate with their performance.  They will also have a huge difference in difficulty of construction.
 
As for the Gamma 1/2, both have a superior feature set to either the grubDAC or pupDAC,  plus - if I'm not mistaken, they were specifically designed to minimize the non-through-hole parts.  So they don't really directly compete (IMHO).
 
For me personally, I won't say what I've heard and what I haven't heard.  Suffice to say that I admitted in that same earlier post that I'm biased.

 

[forsakenrider]

Hot damn! If I didnt miss out then count me in!!

 

[tomb]

OK - everyone's accounted for, including an alternate.

  I'll try to send out the payment requests tonight through a Head-Fi PM.

 

[tomb]

PM's sent requesting payment.  I will update you through your Paypal e-mails from now on.

 

[tomb]

Wow - thanks a lot, everyone!  You've all paid already!
 
I'm embarassed to continue to ask for your patience.  I will do my best to get the PCB's and other stuff shipped out by Friday.
 
I'll either e-mail the BOM or have it posted by then, too.

 

[Mullet]

No worries man. Glad to be a part of the prototype phase. No malicious intent by the way. I was just fishing for a comparison in terms of sound signature and not feature set. A Gamma 1/2 or fully built Buffalo 3 would win any day in the features dept. If we were to closely compare this DAC in terms of what it sets out to do then I'd compare it to the Pico DAC. Both have similar outputs and is USB powered and should be about the same size. It differs in that the Pico uses a Wolfson 8740 as its DAC chip and isn't DIY. I have no idea if it has bypass caps on the output. That's where the comparisons could be made.
 
We're all into DIY for different reasons... some for the challenge, some for "thinking" they're saving money, and some because we have nothing better to do. I'm in it for all three. I can see why we wouldn't want to compare for the reason of avoiding pissing contests or bias. It's hard to detach yourself from things sometimes.

 

[scootsit]

The chip on the pup is not oversampling, right?

 

[Mullet]

Here are a few questions...
 
Because there are both RCA and 3.5mm connections... Is it safe to assume you can supply two amps at the same time?
 
What's the RMS of this DAC?
 
Also, I'm in for trying to figure out measurements for a Front Panels Express order. Anyone else interested? I'd say they would cost between $40-50 for a set of two.

 

[cobaltmute]

The chip on the pup is not oversampling, right?

The PCM1794A is a oversampling chip.

 

[cobaltmute]

Here are a few questions...

Because there are both RCA and 3.5mm connections... Is it safe to assume you can supply two amps at the same time?

What's the RMS of this DAC?

Also, I'm in for trying to figure out measurements for a Front Panels Express order. Anyone else interested? I'd say they would cost between $40-50 for a set of two.

There is both connections, but I wouldn't necessarily drive both at the same time. Depending upon cables and pots in the amp, you could end up loading the output stage a little heavily.

When looking at the output stage, I originally designed it to swing +-2V,

 

[forsakenrider]

Is this going to fit in the same sized Hammond case as the first? Or is there a different case planned?

 

[cobaltmute]

A couple of things here, and I know you meant no malicious intent.   It was my fault for making such a strong statement, but I am excited about the design.

I typically frown away from direct comparisons between genuine, DIY-based designs.  That's because we're all operating on a shoe-string budget most of the time (me for sure, anyway) and we are in this business because we enjoy it.  My wife often jokes with me about Beezar - at least it self-sustains my hobby ... for a change.  However, nothing that you mention is really an absolute, direct comparison.  I have no issue with stating un-categorically, pupDAC >> grubDAC (much greater than for you non-math types).  They are both designed by cobaltmute for different purposes, though - the grubDAC being perhaps the best available in the 1" x 2" form factor (and perhaps better than some bigger than that).  Cobaltmute will need to correct me if I get this wrong, but I think the pupDAC competes against the pinnacle in a USB-powered DAC, without an added extensive feature set (more options, connectibility, etc.).  PupDAC and grubDAC each fill two distinct market niches and will have a definite price differential commensurate with their performance.  They will also have a huge difference in difficulty of construction.

As for the Gamma 1/2, both have a superior feature set to either the grubDAC or pupDAC,  plus - if I'm not mistaken, they were specifically designed to minimize the non-through-hole parts.  So they don't really directly compete (IMHO).

For me personally, I won't say what I've heard and what I haven't heard.  Suffice to say that I admitted in that same earlier post that I'm biased.

Here is my take on it:

If you want to compare designs, build a grubDAC and a USB-only gamma1. They will have very similar schematics and since they both use Wolfson chips, will have a similar sound characteristic. I have both, and I can hear the differences between them. The choice however between them has to be up to someone's personal preferences.

As for how I think the pupDAC sounds? Let me tell you a story. Over half my life ago, when I was a teenager, I listed to vinyl through HD414's with tone controls engaged with full bass and treble boost. It was cool. It was loud and boomy. As I got older, the tone controls got disengaged and I started to learn that there was detail in the bass. The bass wasn't as fat, but I could hear stuff down there - like the actual notes. As I proceeded to get older, my equipment got better and I could hear more details everywhere through the range. Add a few more years, and better equipment, and I started to hear not just the notes, but the stuff going on between the notes, like the little noises fingers make as they move across the strings. Stuff that is hidden in the background, and it takes good resolution to show through.

That's where I think the pupDAC is. The first generation prototype was pretty darn good about showing you all those details. In fact it was good enough that I did the most un-audiophile thing - I settled on it. I really didn't need or want more. As I said to tomb, I don't know if it was just the layout changes or the RCAs or what, but this second generation prototype (with the LMH6643) seems to resolve just a little bit better. In trying to track down the offset problems in my proto, we tried a different op-amp, the OP2835. It was a step-up in all those things that I like - clear dynamics, clear sound and wonderful resolution.

At this level, personal preference for sound characteristics really starts to take affect.

 

[cobaltmute]

Is this going to fit in the same sized Hammond case as the first? Or is there a different case planned?

Exactly the same case. I toyed with a lot of ideas before doing the revision, but one of the things I had to keep the same was the form factor.

 

[c12mech]

One more thing, can we get an updated schematic along with the BOM. 
 
Now that I have some more parts to play with I plan to do a little experimenting.  I've got a lot on my plate tight now but this will be worked on between other personal projects and some builds I'm being paid to do.

 

[cobaltmute]

Is there an updated BOM or is it all the same parts with just a different layout?

I will be able to compare it to the original prototype and a couple of different Buffalo 3 builds I'm doing.  I know the Buffalo is not a fair fight really but it would be nice to how they compare.

Most of the BOM is the same, but there is some differences. Mostly around the fact that instead of using a crystal, there is an oscillator with dedicated regulator.