[mikechai]

http://www.6moons.com/audioreviews/b...rk/dac1_3.html

Quote:

Let me put it differently. I'm an unapologetic Zanden and Audio Aero man. In that vein, I'd rather live with the very affordable Eastern Electric MiniMax than the stock Benchmark even though the latter is clearly more resolved. I would, however, much prefer the modified Benchmark to the MiniMax in my big rig since it ups the Eastern Electric's resolving power without undoing what makes it so special in the first place. Getting there without tubes in a tiny box that also adds two headphone outputs? In my book, that's a very appealing proposition indeed.

I wonder the mod can be done at a much cheaper cost...

 

[Jazper]

Dan (aka Blorton) asked me in an email what he could do to upgrade his dac1, here is my answer:
(note JSR = modified jung super regulator)

> In order of ease:
>
> 1. put a ferrite bead on the wires coming out of the transformer (this
> will drop RF noise going into the dac) you can get split beads from
> radio shack that will just clip on.
>
> 2. Upgrade all caps from surface mount crap to cerafine or better, be
> careful of mounting and values (you may have to mount them on their
> sides)
>
> 3. The diodes - I can't see the diodes on the picture (probably due to
> the image quality), but there'll be rectifier diodes in that. Change
> them to the RHRP860s that I mentioned earlier - you may need to do
> some lead bending for that. I'm guessing they use UF4004s or something
> similar, which aren't good as they make a lot of high frequency noise

(note they are clearly visible in the picture in the provided link - I was referring to a picture Dan took)

>
> 4. there are opamps there, change them up to ad8066 or ad8065s
> depending on whether they're singles or doubles.
>
> 5. Change the film caps for orange drops (maybe with lead bending,
> value is not critical, but size is. Use polyprop if you plan to do
> this.
>
> 6. The regulators. I'm guessing due to size they use crappy LM78xx
> regulators, changing these to LM338T or LM317T regulators with
> appropriate support passives (eg 2 resistors to set the voltage) will
> be better. If the voltage going in is 5V above you might consider
> using a jung regulator instead... that would be even lower noise, but
> the voltage MUST be 5v above (at least) and this will take up
> significantly more space. You will have to check voltages in and out
> of the regulators to do this. PA has a JSR that is surface mount (the
> jsr02 I think) which would fit better than the through hole version.
> Also, jsrs will cost more.
>
> 7. A shielded cover for the transformer would work well, you'd use
> sheet metal and ground it to the earth input.
>
> Beyond that you'll be looking at reclocking options.. which is
> definately more advanced. A cheap way of looking at it would be to
> have a look at the clock crystal(the silver covered thing that looks
> like a square) and looking up the specs, then (potentially) finding a
> more accurate one - you can get these from mouser.

Most of these (dare I say all?) could be done easily for under $1k

 

[ephemere]

Let me pull up an old post by John Siau, Director of Engineering at Benchmark, that warns against changing the op amps...

John Siau's post

 

[Jazper]

Quote:

Originally Posted by ephemere Let me pull up an old post by John Siau, Director of Engineering at Benchmark, that warns against changing the op amps... John Siau's post

I still don't see the problem here - the 8066 is a very very highly specced opamp that is a good performer - better than the 2134 mentioned..

 

[Distroyed]

Well he's kind of wrong about having two headphone outputs (from the Dac-1). The Benchmark isnt a great headphone amp, and when you throw two phones at it the volume is halved since they share the same power source. The Benchmark really isnt anything special.

 

[WK446]

There is another company doing the mods for this DAC as well - Empirical Audio ... It seems all companies are charging about the same amount of money. Unfortunately the mods cost as much (or more!) then the unit itself. When you consider how much time, engineering and research has gone into the creation of the original DAC itself, the number of people that worked on it from design concept to production, I guess you have to ask yourself whether or not the mods are worth it?

I suppose I liken it to buying a high performance automobile - if modifications to the car cost more than the car itself, would it be worth doing it in the first place?


Quote:

Originally Posted by mikechai http://www.6moons.com/audioreviews/b...rk/dac1_3.html I wonder the mod can be done at a much cheaper cost...

 

[Hello]

Quote:

I supoose I liken it to buying a high performance automobile - if modifications to the car cost more than the car itself, would it be worth doing it in the first place?

I think the answer to this question is absolutely! The question in any purchase is does the marginal benefit justify the marginal cost? So, if 1k worth of mods make the 1k Dac-1 outclass all 2k dac's, then it could definitely be a great choice to get the modded Dac-1.

The hesitation should come from the loss of warranty, how much the mod's improve the sound, and are there drawbacks to the mod's.

As a side note, I've seen a lot of mod's of the 25$ T-amp that are in the range of 200$. Here, the mod's are 800 % of the orginal cost!

 

[audioengr]

Quote:

Originally Posted by ephemere Let me pull up an old post by John Siau, Director of Engineering at Benchmark, that warns against changing the op amps... John Siau's post

An attempt to scare us into not trying it, IMO. There is nothing magical I can find about the design. It sounds better with different op-amps, given that the power delivery is improved at the same time.

 

[gongos]

At least $500 worth of the reviewed DAC's mods are bybee filters. Seems to me, there could be a more cost effective way to improve the unit than solder in bybees all over the place.

 

[audioengr]

Quote:

Originally Posted by gongos At least $500 worth of the reviewed DAC's mods are bybee filters. Seems to me, there could be a more cost effective way to improve the unit than solder in bybees all over the place.

More cost effective? You can certainly put some black gates in place of the SMT caps, but the improvement will not be significant.

The significant improvements come from much more complex labor-intensive rework to the board, including lots of expensive parts. The Bybee filters can certainly help, but my version has none. My mod is expensive because it takes days of rework to finish it.

I believe there is an Empirical Audio modded DAC-1 at the Summer Meet of the SoCal group this weekend. This one has extensive redesign, including new op-amps, DC coupling, a modded Superclock3 etc... There should be some feedback on this link:
SoCal meet

 

[Kurt]

Quote:

Originally Posted by audioengr There should be some feedback on this link: SoCal meet

Wrong subforum, Steve. That is the announcement thread. Here is the right one.

http://www5.head-fi.org/forums/showthread.php?t=132247

 

[audioengr]

Quote:

Originally Posted by Kurt Wrong subforum, Steve. That is the announcement thread. Here is the right one. http://www5.head-fi.org/forums/showthread.php?t=132247

Thanks, I was wondering why the posting stopped....