[poseidonsvoice]

Jim Hagerman,

This message is basically in reference to the comments you had posted under DIY DACs linked here: http://www.audiocircle.com/index.php?topic=21246

I would like to make a few clarifications and I will plainly state that I am a DIY'er who has built a passive version of the RAKK dac. Of course, I find the unit to be excellent. I usually don't pounce on blanket statements made on these forums, but when it comes from a manufacturer about another manufacturer I believe clarification is in order so as to minimize confusion and misinformation.

Jim, I consider you one of the 'good guys' in Audio. I believe you provide your products at a just price and you are an excellent supporter of DIY. Your efforts are greatly appreciated.

(1) You stated: "but uses a segmented sigma-delta converter (PCM1794), instead of the more expensive multi-bit type (PCM1704)"

This is partially true. The PCM 1794 in the RAKK dac was chosen by Dave Davenport and Kevin Carter (the co designers of the RAKK dac) after exhausting a number of options including the PCM 1704 which they were impressed with initially. The PCM 1794 is actually a hybrid dac, and employs both the qualities of a delta sigma converter and a multibit dac chip. This was independently verified through an e-mail to Thorsten Loesch as well as Texas Instruments/Burr-Brown. Although I do agree with you that most multibit chips sound signficantly better than 1 bit/delta sigma/timeslicing dacs...in this particular case, it seems that Burr-Brown did their homework. This is truly an excellent dac chip. Moreover, on the Burr-Brown website the costs of both the 1704 and 1794 dacs are quite similar. About $13 from what I have read. The only difference is you'll need two 1704 dacs instead of one 1794 dac when designing.

(2) You stated: "Rakk ($250) + Tent ($250) + Output ($500) + Supply ($250) + Transformer ($150) = $1400. And that doesn't include a chassis. A full-blown CHIME (with chassis) will cost you about $925 DIY."

I am not sure what you are exactly trying to differentiate here because you are really comparing apples to oranges. Although the RAKK dac and Tent Labs Clock are similar in price to your HagDac ($500) with similar technological criteria (i.e 24 bit architecture, playback of CD's only, reclocking, etc...), the similarities actually end there. The active output of the RAKK dac ($500) and the power supply ($250) are of a very, very different design than yours. We are comparing a differential bridged parafeed circuit with single ended AND balanced output options to a single ended common cathode cascaded to a cathode follower design (ChimeDac output section). Moreover, the power supply for this design is a shunt regulated Minimal Reactance design using vacuum tube rectification, and film capacitors instead of electrolytic capacitors. Correct me if I am wrong, but it looks like from the schematic that the power supply for the analog output stage of the Chime Dac is a CRC design with vacuum tube rectification. Finally, the RAKK dac active output stage and power supply use state of the art passive parts (Mills resistors, Auricap capacitors, Kiwame resistors, etc...).

I beg to differ but I don't think that's very fair (or was it an oversight?).

Let's compare two phono stages in your line up. The Cornet phono stage and the Trumpet phono stage. One might ask why the Trumpet phono stage is much more expensive. Since the Trumpet is only available in an assembled version, we'll have to compare an assembled version of the Cornet phono stage to it. $999 vs. $1999. The reason for the price difference is plainly obvious. The Trumpet has a much more sophisticated power supply and analog architecture as well as more expensive passive parts. In technical terms the Trumpet is fully choke regulated, with a choke regulated dc heater supply, employing class A differential long-tailed gain pairs, current source loaded cathode follower outputs, passive shunt power supply regulation, split RC equalization, etc....The Cornet is a much simpler design. Apples to Oranges. Balanced vs. Single ended. And so on and so forth.

To put it simply, the RAKK dac is an extremely flexible design (see www.raleighaudio.com to see all the configurations). You can build it in one of many options. The cheapest option is just the RAKK dac, Passive output stage, and Minimal reactance power supply. This will set you back $607.  The next step up would be adding a Tent Labs XO-DAC reclocking unit which adds about $250. These options and others are listed below:

(I) RAKK dac ($249) + Passive output ($279) + associated power supply including transformer ($79) = $607.

(II) RAKK dac ($249) + Passive output ($279) + associated power supply including transformer  ($79) + Tent Labs XO-DAC ($249) = $856.

(III) RAKK dac ($249) + Active output ($499) + associated power supply ($249) = $997.

(IV) RAKK dac ($249) + Active output ($499) + associated power supply ($249) + Tent Labs XO-DAC ($249)  = $1246.

(V)  RAKK dac ($249) + Active output ($499) + associated power supply ($249) + Combo input ($369) = $1366. This provides a combination of the DAC plus a preamplifier supporting both balanced and unbalanced line level inputs.

(VI) RAKK dac ($249) + Active output ($499) + associated power supply ($249) + Tent Labs XO-DAC ($249)  + Combo input ($369)  = $1615.

Now options III through VI don't include a power transformer. The consumer can purchase either a Lundahl Transformer or source a cheaper one.  For all of these options,  I've been told an enclosure will be available this fall.

Don't get me wrong. I believe the Chime Dac to be an excellent design and I am actually planning on building one in the future. I think making price comparisons of the two DAC's without considering the monumental differences in analog architecture and power supply is foolhardy.  Misinformation can be dangerous to both the consumer as well as the designer. I realize this is your forum and you may conduct it as you like. However, I felt clarification was in order. But if we are truly wanting to compare from a price standpoint, you can with the RAKK dac. Options (I) and (II) listed above would be my choice if comparing it to the Chime Dac. I don't know who would come out ahead but am sure willing to try in the Chime Dac US tour that you are conducting.

Sorry about the long thread. For the record, I would do the same for you if I noted any degree of misinformation regarding a product that you designed as well. Its with that premise that I considered writing this thread.

Best,
Anand.

(Disclaimer: I have absolutely no relationship with K&K Audio or Raleigh Audio, other than being a satisfied consumer).

[hagtech]

Anand,

Thank you for your post!  I don't mind the clarification at all.  Indeed, the two units have differences, as each designer applies their own choices and preferences to topology and components.  That is the beauty of high-end audio.  There are many roads to take.  My apologies if it sounded like I implied the two DACs were exactly the same.  The point I was trying to make was that there are very few DIY projects that attempt to hit the state-of-the-art performance of top commercial units (Wadia, Meridian, emm, etc.).  In that respect, both the RAKK and CHIME use reclocking, 24 bit conversion, passive I-V, and tube output stages.  That is how they are similar and the basis for my comparison.  I am including the RAKK in a very elite group.

Regarding the PCM1794, it is indeed less expensive, as you have to include the DF1704 into the calculation.  That makes the PCM1704 version about 3x more costly.  When I started this project, not too much was known about the 1794.  It's new hybrid architecture left me worried, so I went the safe route by sticking to the acclaimed 1704.  I also wanted the ability to separate the digital section from analog as much as possible, which you cannot do in the 1794.  However, as you now inform us, perhaps the 1794 does achieve the same great sonic performance as the 1704, and at a much lower price point.  

jh

[poseidonsvoice]

Thanks for the vote of confidence! Jim, when you do have some time on your hands (you look like you are just inundated with work), do try the 1794, its a nice piece   .

In the future, I am planning on using a modified version of your Clarinet preamp (6SN7's, shunted PEC volume control , LC power supply, and selector) with your HagDac, to make an all in one dac/preamp just for kicks. One thing I do like about your HagDac is that the reclocking and dac circuitry are all on one board. Depends on if you want the flexibility of having a nice reclocker or not. Indeed its nice to have choices, and that's what you pay for. In the DIY world, I don't think consumers realize how lucky they are to have such a nice group of designers do all the R&D. That takes a ton of time and money. Patience is a virtue   . There aren't many Hagtech's and K&K Audio companies around. Need to support them as much as we can   .

Best regards,
Anand.