Not so Easy to Skip the Preamp?

I have just tried to assemble a system for a third office, using a Behringer A500 in stereo.

I have tried a Hagtech USB interface to output SPDIF ito an Audio Research DAC5 and both the optical and RCA outputs of a Behringer interface.

As I am only using one input (the PC) I hoped to skip a preamp and any extra sets of cables.

In all three cases as above, however, the sound was pretty bad - congested, veiled and distorted almost as if the speakers were blown.

Is this because neither an interface box or the ARC DAC would have sufficient gain to drive a power amp correctly?

This was not immediately obvious to me because there is sufficient volumn and the VU meters on the amp are well below clipping - it just sounds bad.

Thanks for any ideas - maybe a cheapo Parasound preamp would help for these types of "systems".
What are you using a volume attenuator? The DAC5 only has 20 bit resolution and a digital one may throw bits away? Or it may just be that there is a impedance mismatch between them. Although my DAC has plenty of drive (Weiss DAC2 -50 ohm), with my present rig I am using a TVC. There is a small sacrifice in dynamics, but has added body and weight. YMMV, and probably will.
Do you want SS only? Otherwise I really like the Cary preamps. I am especially fond of the AES AE-3 which I think you can still buy new although hotrodded a bit at Upscale Audio for about $1200-
I don't know if you can still buy the Parasound Z-pre?

The other really cool solution is a custom made pre by Mapltree Audio in Canada. He has standard models for about $500-600 IIRC, but if you tell Prof. Peppard what you need he can make it work for you. In general he is very reasonable. Check out his website. They are all tube however.
I assume you have tested all of the components individually in other systems and they are all working properly? If so, then what computer type are you using and what playback program? Have you checked that the computer output to the Hagtech, and the Hagtech to the DAC are all configured with compatible bit depths and sample rates? If you are using a Mac and iTunes, you must restart iTunes after changing the parameters in Audio Midi Setup.

As someone mentioned above, if you are sending 16 or 20 bits, you may also be throwing a lot of bits away. Is the volume in iTunes (or whatever your playback program is) set very low? If so, you may want to get a couple of passive attenuators and put them between the DAC and amp. They should have enough attenuation so that you playback program is near full volume at normal listening levels. You can get decent ones from Parts Express for about $25, or "audiophile grade" ones from Rothwell or elsewhere.


One of the reasons I thought I could get away with no preamp is because the Behringer has volume controls for each channel.


Yes, it sounded so bad that I switched out the monitors, then made sure I was using the same cables and everything was fine.

Also, the DAC has sounded great in another application.

Re computer program, I use Windows XP and I am not an expert, but the OS usually recognizes whatever I plug in and it works fine.

For playback, I am using lots of different things, but Foobar and WAV files whenever I am testing, and in this case to discover how bad it sounded.

Re "sending" 16 or 20 bits or whatever.....not sure how to change those settings, but I think in "preferences" in Foobar.

But I am not talking about splitting hairs - I am talking about really pretty bad, muffled, veiled, distorted sound compared to the same amp and the same speakers and the same cables in another desktop system.

Everything is the same, other than the fact that the good sounding desktop signal first goes through a Behringer DEQ2496 which functions as a preamp of sorts.

So I would guess either an "impedance mismatch" of some sort, or insufficient gain, but again, a bit puzzling and appreciate all suggestions.

Oh...full disclosure....

As I was hoping to A/B compare this system with a leaner, meaner (?) Hagtech interface straight into the Audio Research DAC, I did not switch out the Behringer amp as that is what I am using in my other desktop system.

So I suppose there is a greater than 0% chance that the amp is defective or needs repair?

But I have a few of them and have generally had 0 sound or reliability issues with them.

So still a bit puzzled why it wouuld sound surprisingly bad, when all my other Behringer desktop systems have sounded surprisingly good.
I'm a little confused. Is your setup like this?:


If so, what role does the DEQ2496 play?
Better check the amp. You may have been lucky with the A500s, but I was not. For me, 3 out of 5 were bad, one within a month, two straight out of the box. I also found that the volume controls are not good¬óbest to leave them at full output.

Main desktop system:

Computer USB to USB hub > Behringer Interface Box > Interface optical out to DEQ24 > Also, analogue out from Cablevision HDTV box to DEQ2496 > 2x Behringer A500 (in mono) > ATC SCM 7's and/or Epos ELS3's

In this case, I use the DEQ2496 as a "preamp" of sorts to switch between computer and HDTV. Sometimes, I also experiment with the RTA and equalize the speakers.

I was curious to see how much better the computer audio might sound if

a) I was using the Hagtech and SPDIF instead of the USB hub and optical cable and

b) I was using the ARC DAC instead of the Behringer DAC. (In this configuration, I am not using the 2496).

As I have spare ATCs and Behringer amps, I was otherwise hoping to "A/B" the demo, and was surprised when it sounded terrible.

Perhaps Ojgalli is correct and it is simply a bad amp. I have generally had much better luck however, using another pair of A500s since 2007, which I leave on 24/7 and use every day for both HDYV and computer...

Thank you, everyone, for all of your help and thoughts and Happy New Year.


OK so I checked the Behringer and it was perfectly fine, and sounded surprisingly good.

In fact, I did another A/B vs a Bryston amp and at least at pre clipping levels, there was no obvious winner. Thanks God I paid < $500 for the Bryston on Ebay and not the $1895 MSRP.

Then, I reconnected everything using the Hagtech USB to SPDIF, into the Audio Research DAC, and straight into the Behringer.

This time, for some reason, everything worked fine.

So, in fact, it was easy to skip the preamp, so I will consider using these amps for desktop applications with small monitors.