Stepped Attenuators

There's something to be said about keeping things simple in audio. Sometimes less is more–less in the signal path means less to degrade the sound. I found this to be the case with Scott Endler's excellent, nude, stepped, passive volume attenuators. These simple devices, available either single-ended or balanced, plug straight into the inputs of the amplifier and can accommodate only one source, with no provisions for remote control. Between the male and female connectors is a ring of 24 resistors, one for each of the 24 volume settings. On top of the ring of resistors is a high-quality Elma rotary switch. Endler chose Yageo metal film resistors over the highly regarded Vishay-Dales, which he feels sound opaque and rolled off in the highs. The pair of 24-step 4K shotgun attenuators I received for review cost a measly $160.

I've read much praise of passive preamps. They are said to provide the most transparent, neutral, and uncolored sound you can achieve, but I have tried a few passive line stages in my system and found them less than stellar. The first passive I tried was a friend's $299 Channel Island VPC-1. While it certainly was transparent, it sounded thin, cold, lifeless, and entirely lacking in bass in my system. The second one I tried was the highly regarded $1595 Placette. This unit failed miserably in my system. The third passive was the Stevens & Billington transformer-based Bent TX102. This unit was a gigantic improvement over the previous two. It not only had improved drive, detail, and musicality, but was also more transparent than my Aragon Aurum line stage, though it could not match the weight and dynamic slam of the Aragon. Passives, unlike active line stages, are more finicky of interconnect capacitance, output voltage of the source, and speaker sensitivity. It is possible that the systems in which I had tried those passive preamps were not optimized for them.

Why would I try another passive if two of the three I had already tried proved to be unsuccessful? I must either be a glut for punishment, or maybe I am just curious. Actually, I have learned that not judging a book by its cover is applicable to audio. Not all tube and solid-state equipment is created equal, and the same applies to passive preamps. I always believe that it is best to try something in my own system.

In addition to the passives I have already mentioned, the list of other preamplifiers that I have tried in my system includes the following, in addition to the Aragon: the Adcom GFP-565, Rogue Magnum 99, IRD Purist, Simaudio Celeste P-5003, Wright Sound WLA12A, Eastern Electric Minimax, Odyssey Stratos, and the beta version of the Modwright SWL-1. In A/B comparisons with all of these active units, the Aurum was quieter. As expected, the solid-state line stages exhibited lower noise levels than their tubed counterparts, but the Aurum was the only one that delivered dynamics with realistic weight and authority. It was the most extended, detailed, and textured of the bunch. Some of the tube line stages had more midrange presence, warmth, and bloom, and the passives had more air and transparency, but none were able to present music with the balance and neutrality of the Aurum.

Enter the $160 Endler Attenuators. After replacing my Aragon preamp with them, I fired up my system with Chris Isaak's Heart Shaped World, not expecting much. Only a few seconds into the first track, I knew that they were special, and unlike any of my previous experiences with passive or active preamps. This was the most neutral, uncolored sound I had experienced in my system. I was taken aback by the superior transparency and musicality. There was no loss in drive and dynamics compared to my active line stage! Disc after disc and track after track, with music ranging from Metallica to Mozart, I could not believe my ears. These $160 volume controls did what no line stage under $2000 I had heard in my system had done—it beat my Aragon line stage in nearly every single sonic category. The Endler attenuators were so far superior to the Aurum in transparency, neutrality, openness, and musicality that that I found it impossible to go back to listening to the Aragon. Its highs sounded congested and opaque in comparison. The Aurum's grain in the upper midrange band was gone. On Kasey Chambers' Wayward Angel, Kasey's voice had always had a certain raspy quality that I had attributed to either the recording or her voice. Now, the grain had all but vanished.

While the Aurum is not refined in the mids and highs, its bass slam, weight, and control had always impressed me. The Endler attenuators easily matched the Aragon in dynamics and slam, as long as the average volume was set at 75dB and higher. Only when the volume dropped below 75dB did dynamics suffer, though only barely. To top it off, they were driving my 86dB Thiel CS2.2s, which are not a friendly load. I had never encountered a passive preamp that could compete with an active one in the dynamics department, driving an easier load than the Thiels, but as the saying goes, never say never! The only areas in which the attenuators fell a bit short were in soundstage depth, separation, and imaging. Images were not as tightly focused or as solidly anchored. The soundstage was more two-dimensional and lost some depth.

What amazes me is the ridiculously low price that Scott Endler is charging for these. They sound nearly identical to the $350/pair EVS Ultimate Nude Attenuators that a friend owns.

As good as the Endler attenuators sound, they will not be ideal for everyone. First, to make volume adjustment possible, your amp or amps need to be located out in the open, with the inputs exposed and easily accessible. If you have more than one source, the Endler attenuators may be too inconvenient, since they only accommodate one source at a time. If you like to go back and forth between vinyl and digital, you will be spending a lot of time bent over your amplifier. Also, if you are an armchair audiophile who does not want to get out of a comfy chair to make volume adjustments, these will not be for you. Another scenario in which these may not be ideal is with speakers of less than 84dB sensitivity in a large room. Since all the volume is coming from the source and amplifier, the maximum volume setting may not be loud enough. Also, these attenuators are far from being pieces of audio jewelry, which may be an issue for you or your significant other.

Finally, the Endler attenuators will not color the sound in a euphonic way. If you are looking for coloration, you had better look elsewhere. But if you are a person who likes to keep your two-channel system simple, and you only run one source, this just might be the ultimate volume control for the money. These are the most accurate, neutral, revealing, transparent, and dynamic volume controls I have encountered for under $2500. Yes, they have tradeoffs, but I am happy to accept the compromises given the benefits. I guess there is something to be said for keeping things simple. I've decided to purchase the review samples! Fown-Ming Tien

Endler Audio
web address: http://mysite.verizon.net/vze4c5pt