Benchmark DAC-1 Get The Most Out Of Your DAC-1

Like all other reviewers I like the DAC-1's transparent and neutral sound, but many people may not have got the maximum potential from their DAC-1.

In the past 6 years I've owned all versions from the original DAC-1 to the USB/PRE/HDR, and have tried different configurations in different systems from tube to solid state to active monitors to headphones.

In all cases I found it sounds MUCH better if you:
(1) Use XLR output instead of RCA
(2) Set the XLR output jumpers at "0 dB"
(3) Set the headphone jumpers to "+10 dB gain"
(4) Set the output to "Calibrated" instead of "Variable"

A few notes and explanations:
(1) The DAC-1 was originally designed for professional audio where XLRs are more popular than RCA. I've owned a Cary 306 whose XLR performance is very close to RCA, and I know there are superb sounding DACs out there which only have RCA, so I am not against RCA, but the XLR on the DAC-1 is WAY BETTER than its RCA. To take this advantage, you need fully balanced, differential pre/pwr amps to work with the DAC-1.

(2) When the XLR output jumpers are set at "0 dB", the output voltage can reach a max of 10 volt, which satuates a lot of preamps especially tube preamps. If you hear noise that means your preamp's input stage can not handle it. If you decrease the output voltage, the output impedence goes up and the sound becomes less transparent/direct. Again, 10 volt is for pro audio, not Hi-Fi, Hi-Fi sources normally output 2~4 volt on XLR.

(3) The headphone gain jumpers works pretty much like the XLR gain jumpers. When you use "+10 dB", the sound is more dynamic and transparent than "0 dB". Of course you have to turn the volume knob down to get the same listening level. DAC-1's headphone amp fits low-impedance headphones (~30 Ohm Denon or Audio technica) better than high- (300~600 Ohm Senn or Beyer).

(4) Assume you have an High-end balanced preamp, the DAC-1 sounds better as a DAC with calibrated output. But if your preamp is not top notch, running DAC-1 directly into a power amp may give you pros and cons. There are many threads about preamp v.s. preamp-less sound.

(5) Over the years DAC-1 has received some revisions and the newer units sounds smoother and less agressive than the old. But if you don't need the analog input, DAC-1 USB sounds slightly better than DAC-1 Pre/HDR due to simpler circuits. The HDR sounds different especially when you use variable output -- it's got a different potentiometer. Whether you like the difference is up to personal taste and system match, but after trying all models, I've sold the HDR and will stick with DAC-1 USB as a DAC only (with external preamp).

(6) DAC-1's USB v.s. other USB/SPDIF converters: I found DAC-1's own USB input to be very good, adding another USB/SPDIF converter could lead to plus or minus. I have tried Logitech Transport, Halide Bridge, Stello U2, and a friend of mine tried M2Tech Hi-face Evo. We found while one maybe superior than the other, each device adds its own signature to the sound. Stello U2 by far is the most natural sounding device and Halide Bridge condenses the sound which you may or may not prefer.

Overall, DAC-1 is a superb DAC at an affordable price. When setup right, the DAC-1 can compete with high-end digital front end. You may not like DAC-1 if your personal taste leans towards a forgiving, laid-back presentation with somewhat recessed treble and sweetened midrange.

The DAC-1's pro audio heritage may give you some trouble choosing the right preamp, but as a plus, try DAC-1 directly into a quality studio monitor, which is what DAC-1 is designed for. Even a moderate Dynaudio BM5A Mk-II may surprise you. Cheap studio monitors will not sound as refined as your Hi-Fi, but there are something foundamentally "honest" and "right" in the music.

Enjoy your DAC-1!
There are several other things you can do to help out: vibration control, change out the fuses, power chords, ICs and of course the USB cable. Just my 10 cents!

Also upgrade the fuse and BDR cones, no. 4, unsure the unit really make it shine. Add a shunyata python alpha Vx and plug it into a shunyata v-Ray and it ain't that much less than my Berkeley dac.
Yingtonggao - Benchmark DAC1 had two problems at the very beginning:

- thin sounding Signetics/Philips NE5532 OpAmps
- high output impedance on unbalanced (RCA) out.

Texas Instruments bought NE5532 license, after Philips factory burned down in 2000/2001, redesigned die (making it larger) and produced fuller sounding OpAmp used now in DAC1 (recognizable by TI logo - map of Texas).

Unbalanced output impedance was so high that many users elected to use headphones output instead. It was fixed in one of early revisions. Balanced outputs' impedance is lowest at 0dB but -10dB is worse than -20dB. Newer DAC1 PRE or DAC1 USB use stronger output amp (LM4562) and lower impedance divider.

My DAC1 is rev. G and is free from mentioned problems. I use it as a preamp with balanced outputs set to 0dB (I don't have any analog sources). It places volume control in the signal path but according to Benchmark this path is identical (doubled) with or without volume control. The only issue I can see is small inexpensive volume potentiometer but in return I gain some quality (and money) by using only one set of ICs.

This tiny pot. tracks very well (even close to 0) but develops static over time (dust) that goes away after turning pot few times - coming back again next day. Solution to this problem is to lift one corner of the pot's back cover with fingernail or needle (just a needle thickness to avoid breaking) and spray contact cleaner inside (a lot) - then rotate pot few times. I used one designed for fader lubrication:

You're right about unforgiving nature of DAC1. Benchmark technical director John Siau said once that Benchmark was designed not to sound warm but rather "natural". I had it with unforgiving/revealing class D amp and Paradigm Studio/60 speakers with revealing tweeter. It was very transparent but unpleasant with a lot of unnatural sibilants (energy in 8-11kHz range). I replaced speakers with warm sounding Hyperion HPS-938 and now it is really nice and musical. Sibilants are still there quite strong but very clean and natural. New speakers have soft dome tweeters vs. aluminum dome on Paradigms but are also in different class/price range.
My DAC1 is rev. G and is free from mentioned problems.

Ditto here - mine is a rev. G and out of the box it sounds great - although I have never tried the RCA outs and I run it variable.
I had my DAC-1 modified by Chris Johnson (of Conrad-Johnson fame), in which the mod focused on the RCA outputs. Frankly, it's because I have Kimber Select 1036 interconnects that I didn't feel like replacing with 1136's. So it's Locus Design Cynosure USB into the Benchmark, 1036's out to powered Mackie speakers...also meant for pro audio, FWIW.
Great units, and hard to beat for the money. They are very sensitive to power and power cords too. One will be well rewarded experimenting with one. Lastly, I leave mine set on USB with cable attached to a CPU in so that it stays on avoiding standby.
The Dautch, I believe that Chris Johnson ran Sonic Frontiers not conrad-johnson (the name is not capitalized). Bill Conrad and Lew Johnson started conrad-johnson.
You're right, bad. Got my blasts from the past mixed up.
Thanks to everybody's input to my thread, Regarding vibration control, having spikes underneath might help but I can live with the stock rubber feet. Adding weight on top makes the sound dull and less alive. Unless you have a bright system, the DAC-1 is meant to be a free standing item without weight on top of it. I know this is surprising because common sense tells us light-weight components benefit from weights on top.

I've tried many things including MapleShade heavy hat/foot, vibrapods, various wooden feet, various metal cones, Totem beaks etc. Finally I just let the DAC-1 sit on a 2 inch solid maple board with its original feet.
I had the Chris Johnson mod and just had the opamps of that mod changed by Chris to the Burson discreet op amps. Chris said the change would be "massive" and he was right. All the hardness that was sometimes evident with the DAC and not very good recordings is gone. The sound is more detailed but much, much more natural. I still have the balanced outs with the original chris johnson mod and when I switched from the rca outs with the Bursons to the balanced mod without them, I felt as though I had gone to a shrill sounding low-fi system.
Is there a separate jumper(s) for the headphone gain? I see in the owner's manual there is: p2 Input source select jumper, jp7 coaxial input impedence jumper, p5 p6 p7 p8 xlr output attenuation jumpers.

Again, I don't see any mention of this in my owner's manual. I have DAC1 revision H.
Theduke, yes the headphone gain jumpers are the jumpers close to the headphone jacks. I agree their user manual does not change as fast as their revisions... but you can try the jumpers on the fly... won't hurt anything just don't drop your fingers to create a short circuit!
Yingtonggao - My Benchmark does not have any jumpers close to headphones jacks. Are we talking plain DAC1?
Fine comments, all of which highlight the excellent quality of the DAC1 and, because of its quality, how well it responds to changes and upgrades.

A few more things.
(1) Digital interconnect. Extremely important for the DAC1, or for any dac, is the digital interconnect (if you're not using USB). I found that using the Stereovox XV or especially the Stereolab XV Ultra made a big big difference.

(2) Transport - If you're using a transport, don't follow the idea that the transport doesn't matter because of the DAC1's jitter elimination features. If you're using a cheap DVD player of low-mid CD player as a transport, you're missing plenty. Try a high end transport and you'll be amazed.

(3) Other - As mentioned above, a fine powercord like the Shunyata Python and power conditioner like a Shunyata Hydra make big improvements. A HiFi tuning fuse made a nice improvement.

I use the balanced outs to a Pass X150.5 amp and it sounds superb. Of course, fine interconnects from the DAC1 help greatly too.
Believe or not digital cables do make a difference, and sometimes bigger differences than the transports. You don't have to spend a lot, but organic-sounding digital cables work better with DAC-1. Benchmark's own AES/EBU is cheap and good, and better than Benchmark's RCA/BNC cable, but it's not forgiving, just like the DAC-1 itself.

Kijanki, call Benchmark for the location of jumpers, I have the DAC-1 USB, and every model has different versions, so the circuit board layout may slightly differ.
I'm considering a Krell KAV 250A power amp and using the DAC1 as a preamp. Is there any sound quality difference between the variable and calibrated setting on the DAC1 any noticed? The chain would be Lossless -> USB -> Benchmark DAC1 -> Balanced XLR -> Krell KAV 250A -> Jamo 707s.
Ninjasquirt, According to Benchmark, signal path (calibrated or variable) is the same (two parallel circuits) on basic DAC1. USB version might be different.
Empirical Audio Off-ramp4 (now they have Off-ramp5) is a very good asynchronous USB/SPDIF converter, and better than DAC-1's own synchronous USB, but to hear a significant difference you have to buy battery supply and other upgrades which cost you twice the price of DAC-1.
I've found that Herbie's Tenderfeet work wonders for desktop usage. Simply lifting one side of it up by one finger can provide a hint of what this can do for the sound. It's subtle, but significant enough to be worth the modest cost of the feet. It helped eliminate the bloated, forward bass and edgy highs that I was experiencing with my Denon AH-D2000 headphones playing through the headphone jack.

To be fair, I'm using an older base model that came with the rack-mount face plate (revision g, maybe?) directly next to my laptop on a fairly cheap desk, so maybe newer models on better platforms aren't as susceptible to vibration issues. Worth a shot either way.