Best Location for Best Cable

I have an all Benchmark system, DAC3B + HPA4 preamp + AHB2 amp + Benchmark speaker cable. I am using Benchmark StarQuad XLR interconnects on all the above components. The HPA4 + AHB2 is separated by about 15 feet so I have either a 15 foot or 20 foot XLR between them. System sounds excellent.

Today, I received my upgraded Audience AU24SE (some XLR’s and some RCA’s, all short) from Audience AU24 and AU24e. I put the AU24SE XLR between the DAC3B and HPA4 preamp and notice a very slight unveiling of the sound. It sounded even more excellent now. I am not even sure if the Audience cables are burned-in because they are upgrades not new (likely burned in).

I am now wondering where the best bang for the buck improvement in cable sound comes from. Is it the sources connected to the preamp or the preamp connect to the amps? I cannot permanently move my gear around anymore since I have committed to my current setup, which I love. I have a new stereo rack coming next week and it is too big to put between the speakers to have the preamp and amp close to each other. I am also not sure if non-Benchmark XLRs would work great sonically for very long lengths with my gear (cost is also a factor).

I am just curious as to where people put there best cables. This info will be useful to see what I should try.
We subscribe to a top-down philosophy, so typically higher in the signal path provides more improvement. In this scenario, I'd go for the better cable from your source to preamp. 
How long until the phrase "everything matters" enters this discussion to dampen the useful advice above? 3, 2, 1...

But seriously, a good question and all I've heard in addition to the above is that the preamp to amp connection does matter a lot, too. 

The Benchmark StarQuads are very good cables and I would not have looked at anything else except for the fact that I had to get my Audience cables upgraded due to damage of the AU24 and AU24e originals. They are a tiny bit better than the StarQuad on the short run between the DAC and preamp.

My SACD player and 2 FM tuners will get 3 foot AU24SE cables from this upgrade that yielded 5 cables from 1 very long AU24 and 1 short AU24e. I will set this all up next week when my rack arrives. I could sell all of these cables to buy a long XLR between the preamp and amp but it sounds like what I am doing is the next best thing.

One thing that I really should ask Benchmark, and I will when I buy 2 more pieces from them (HPA4 + AHB2), is if their gear works well with long XLR runs and  "non-professional" grade XLR's.  I been bugging them a lot already so I will pace the questions to them  They use the term professional grade vs consumer grade (such as my AU24SE).

Professional balanced interfaces generally operate with much higher signal levels than unbalanced consumer interfaces. This voltage difference gives these balanced interfaces a significant SNR advantage over unbalanced interfaces. Most RCA interfaces operate at a maximum signal level of +8.2 dBu which is 2 Vrms. In contrast, professional balanced interfaces usually operate at a maximum signal level of +24 dBu which is 12.28 Vrms. If you do the math (24 dBu - 8.2 dBu) you can see that the signal level is 15.8 dB higher on the professional-grade balanced interface. If the noise is the same on both interfaces, the balanced interface will provide almost a 16 dB improvement in the interface SNR.

But, balanced interfaces always require dual output buffers and dual input receivers. These additional active devices contribute some noise and this tends to reduce the SNR improvement by about 3 dB. Taking this into consideration, the interface SNR of a professional balanced interface is still about 13 dB better than that of an unbalanced consumer interface.

In addition, balanced interfaces provide rejection of many types of interference. This immunity to interference can provide a 50 to 100 dB reduction in these unwanted noises. This immunity to interference is usually more than enough to keep the interference inaudible.

Professional interfaces are more expensive to build. The high signal levels generally require the use of +/- 18 volt power supplies within the audio product. To save costs and reduce the power consumption, consumer products usually use much lower supply voltages. As a result, it is rare to find consumer audio products with balanced interfaces that can support professional signal levels. These products have dumbed-down balanced interfaces that operate at much lower voltages.


Many high-end consumer products have balanced interfaces, but they operate at a maximum level of 4 Vrms which is + 14.2 dBu. This is 10 dB lower than the level used in professional interfaces. This means that the 13 dB advantage provided by a +24 dBu balanced interface is reduced to just 3 dB when operating at a maximum level of +14.2 dBu. Consumer-grade balanced interfaces are definitely a step better than unbalanced interfaces, but the signal levels are too low for use in very high perfomance systems.

Benchmark D/A converters are equipped with professional-grade +24 dBu outputs. These outputs have 10 dB passive pads that can be engaged in order to drive consumer-grade 4 V balanced inputs. If you find you need these pads, it is a good indication that the downstream device is limiting the SNR performance of your system. Likewise, the AHB2 has a gain setting that supports inputs from 4 Vrms consumer-grade balanced outputs. Again, these consumer-grade devices will be the weak link in the system.

Check the specifications and look for balanced interfaces that support professional signal levels. Consumer-grade balanced interfaces may look like professional interfaces, but they do not provide the same level of performance.

Another vote for closest to source.  I found biggest difference in DAC to pre vs. pre to amp, but as always every system is different. 
They will need some time after the factory SE upgrade to settle. The upgrade involves a new junction between the wire and the XLR plugs and the new plugs which benefit from some time and use as well as a crypt treatment that I in theory affects the molecular alignment of the copper in the wires. I had the factory do this same upgrade on a few pairs of cables in the past. I enjoyed the improvement that it brought after they settled a little. Started a little hot in the treble region. I have subsequently upgraded to the AU24SX balanced cables representing an additional improvement in my system.  I use my best cables at the source and work in from there...
They both matter of course,but differences seem to be easier to hear between dac and pre for better or worse.
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Normally I would replace cable closer to source - in this case DAC to preamp, but in your case you can set both cables at +22dBu (close to +24dBu pro standard) and the most obvious difference is cable length.  IMHO, cable always has negative effect on sound (shouldn't be used as tone control) and this effect (capacitance, dielectric absorption, electrical noise pickup) is proportional to cable length.  Since cable between HPA4 and AHB2 is as long as 20 feet I would replace it first.  
If you are running multiple sources, then: 

#1 for me would be preamp to amp in this case.  Multiple sources benefit.

If you are only running ONE source, then:

#1 would be start at the source cable first.  

Ideal is "both".