[T_Schmidt]

Hey everyone, I know the question has been asked a thousand times which amps and dacs go well with k701s and believe me I've read those threads, (Uncle Erik's post in http://www.head-fi.org/forums/f5/new...7/#post3909767 was very informative), but I'm hoping that some head-fiers can help me out with my specific situation.

My k701s are arriving from Headroom in a couple days, and I am trying to pair them up with a reference-quality Amp and Dac for $1000.

With this setup, I plan on touching up the final mixes to the Dance/Progressive House Music that I produce. Reference Quality is really the key issue, which is why I went with the K701s over, for example, the SA5ks or the D5ks. Also, the "lacking bass" issue of the K701s should be nonexistent if properly amped, and the bass levels I set in my tracks are much more integrated (such as Jody Wisternoff, Adam K, and Freemasons) than dominant.

All tracks I produce are instrumental, so the "warmth" that derives from a Tube amp for lush vocals is much less important. However, I still know that there are terrific tube amps out there that would meet and exceed my above criteria, so I respect all opinions.

I have more experience with DACs over Amps, but not at the quality at which I am now entering. I have previously owned both the MAudio FastTrack Pro USB and the EMU 0404 at a time when those were all I could afford, but found both inferior (obviously) to others that I came across in studios (mainly Digidesign's MBox lineup). I know that there are many more Dac's under the sun than what Digidesign offers, and I don't produce with ProTools, so I'm hoping that I can get some great recommendations to other DACs. 24/192 capability is imperative.

Thanks a lot for the help.

 

[AmanGeorge]

The most neutral K701 amp I've heard is the SPL Auditor, but it would probably eat up too much of that budget. I think if I was working with $1,000, I'd pick up a used PS Audio DLIII (very neutral DAC) for around $500-600 and look for a decent amp with the remaining $$ - a used Gilmore Lite or a Sheer Audio HA-006+ Dynalo might do the trick as far as well-respected and neutral solid state amps go.

I would be looking to buy separate components, as there are very few combo units out there that are supposed to have excellent amp and DAC sections.

 

[T_Schmidt]

thanks for the help, Aman. Those recommendations helped out a lot.

I only have USB output on my laptop here, so USB input for the DAC is essential.

By checking your recommendations, I went "deeper down the rabbit hole" and stumbled upon the Benchmark Dac1 USB. Now I was planning on buying separate components, but this looks like a really nice product. It retails for $1300, so I'm sure I could find one on sale or for sale for $1000 somewhere. It comes with the HPA2 Amp. Have you listened to the HPA2 before? Thanks again.

**Edit: Also, what about the headroom ultra desktop Amp & Dac?? I'm sure that bad boy must have some oomph to it**

 

[AmanGeorge]

Unfortunately, I've never heard either of the components you mentioned for myself. The Benchmark is supposed to be an excellent DAC (and certainly neutral and accurate as you desire), but the built-in headphone amp FWIR is a bit of an underperformer. I don't know anything about the Headroom gear - maybe someone else can help with that.

 

[T_Schmidt]

Can you tell me where you heard that the DAC1s amp was "a bit of an under performer", please? I'd like to possibly get in contact with someone who either owns or has owned the dac1 usb.

I read a review for the benchmark on stereophile, and I found this interesting...Also as supplied, the headphone output had a maximum output of 2.78V. (This can be increased by 10dB by removing internal jumpers adjacent to the jacks.)

I spent some time figuring it out, but if my calculations are correct, then the headphone out route with the 701s should produce 118 dB, realistically approx. 110dB.

This combination would be more than powerful enough for me if a 110dB level, like I calculated, is achieved. I guess hearing first hand accounts from DAC1 USB owners would help out greatly, because I am most definitely not an engineer, and do not have that much confidence in my calculations.

For those who are interested, this is how I calculated the 110dB figure:

from DAC1 USBs spec sheet
Headphone amp output-level range
(@ 0 dBFS into 60 Ohm load): Off-to-+21 dBu

Turning +21 dBu to volts is: v = 1dBu * 10 ^^ (dBu gain/20)
1dBu = .775V
v = .775V * 10 ^^ (21dBu/20dBu) = 8.6942V

Calculating Resistance loss = 1 + (Amp resistance / HP resistance)

loss = 1 + (60 Ohm / 62 Ohm) = 1.9677

**Note: while the headphone jack output for DAC1 USB is actually specced at 0.01 Ohm, the +21dBu output level I used above was with reference to a 60 Ohm load, hence why I used 60 Ohms. This provides a conservative sensitivity rating in the end**

Calculating actual voltage received to headphones is: v = total volts / loss resistance

v = 8.6942V / 1.9677 = 4.4185 V

To calculate the power(in mW): P = (1000mW) * (headphone voltage^2) / headphone resistance

P = (1000mW) * (4.4185V^2) / 62 Ohms = 314.89mW

Calculating voltage sensitivity is: dB = 10log(power)
dB = 10log(314.89mW) = 24.982 dB

jung's link to http://stereo.50webs.com/ in the milliWHAT thread shows that the k701s have a sensitivity of 93dB/mW, therefore:

total sensitivity = headphone sensitivity + voltage sensitivity

total sensitivity = 93dB + 24.982dB = 117.982dB = 118dB.

In reality, it is wise to subtract 10 dB from this level due to unforeseen errors (my calculations, realtime hardware differences, etc) which still leaves this combination with a very respectable 108dB figure.

**addon: If my calculations are incorrect, I'd really appreciate being shown where I went wrong. Like I said before, I am not an engineer in any sense of the word and just wiki'd some basic electrical formulas. I really worked to figure all of that out!! Not sure if that's a good thing.....**

EDIT: I realized that in stereophile review, he says that the maximum voltage for the head out jack is 2.78V, while in my calculations I found and was using 4.4185V. This merely reduces my previous 118dB to 114 dB.

 

[AmanGeorge]

Here are a few threads which touch on the headphone amp section of the Benchmark not being of the same high quality as the DAC (or as other headphone amps):

http://www.head-fi.org/forums/f5/ben...lifier-202017/
http://www.head-fi.org/forums/f5/benchmark-h1-210059/
http://www.head-fi.org/forums/f5/hea...k-dac1-265737/
http://www.head-fi.org/forums/f5/ben...ne-amp-436445/

Take from them what you will - I've never heard a Benchmark myself, but hopefully these links are helpful.