Comparacion entre un Rudistor Sistema NX-02 y Jaycar (ampli DIY de Australia)

[mrarroyo]

Rudistor Sistema NX-02 versus Jaycar with JLH and other Mods by AlexK

Recently I purchased a new old stock (NOS) Rudistor Sistema NX-02 headphone amp from Amazon. This amp was sold via the Ultrasone Headphone site as a companion to the Ultrason top of the line PROline 2500 and the PROline 750 (not including the Edition 9 which are an special edition). Its faceplate is blue to match the two headphones listed earlier.

Ultrasone stopped selling NX-02 in early summer of 2008, at the time its MSRP was $875 plus S&H. Currently you can pick up an NOS unit in Amazon for $605.99 plus S&H. This unit has received an slight modification and can be found in Rudi's site (http://www.rudistor.com/NX03-steel.htm) as the NX-03, it retails for 599 Euros (about $775 USD) including worlwide S&H.

On the other hand the Jaycar starts life as a simple kit ofered by Jaycar in Australia (http://www.jaycar.com.au/productView.asp?ID=KC5417&keywords=kc5417&form=KEYWORD) with its corresponding power supply (http://www.jaycar.com.au/productView.asp?ID=KC5418&keywords=KC5418&form=KEYWORD) However various enthusiasts have taken up the challenge of improving upon this offering and have turned a nice unit into a world class single ended headphone amp. A large element of the improvement is due to the addition of the JLH add on power supply/regulation board and the tweaking to find a better sounding op-amp ending with the LM4562. You can get a much better idea of the mods and improvements by visiting Rock Grotto, you will find various threads discussing modifications/improvements, pictures, and cost. Please visit:

http://rockgrotto.proboards39.com/index.cgi?board=chitchat&action=display&thread=3621
http://rockgrotto.proboards39.com/index.cgi?board=chitchat&action=display&thread=3729
http://rockgrotto.proboards39.com/index.cgi?board=chitchat&action=display&thread=3622
http://rockgrotto.proboards39.com/index.cgi?board=chitchat&action=display&thread=3694

For today's comparison I am using Apple Lossless files stored in my Dell PC and played via iTunes 8.02 . I am using a glass optical cable from a Chaintech AV710 to feed a Monarchy Audio NM24 DAC that is receiving its power from a Monarchy Audio AC Regenerator both using a Virtual Dynamics Power Cord 3. The signal leaves the SS DAC portion of the NM24 via a Monster RCA splitter to feed both the NX-02 and the Jaycar amps simultaneously. The NX-02 is being fed via a Blue Jean Cable LC-1 RCAs using a PS Audio Extreme Power Super Punch power cord and the Jaycar via DH Labs Silver Sonic BL-1 RCAs using a Phino 14 gauge shielded power cord.

Following are a few pictures for your viewing pleasure.
















For music I chose various offerings by the Modern Jazz Quartet. Specifically:



For the first listening round I chose the Denon AH-D5000 which have the MarkL Mods and one of his V4 Cups made of Australian Bubinga.







So how do they compare? The first thing that hits you is the bass presentation, the Jaycar has more and deeper. Initially this causes you to think the treble on the Rudistor extends further and is clearer. After spending more time switching between the two amps I realized that they are both very clear, however the NX-02 has an slight edge on the treble extension.

The Jaycar w/ the D5000 has a more compact soundstage than the Rudistor. However this makes for a presentation with a bit more impact and punch. On the other hand the Rudistor's wider soundstage allows for a bit more air between the notes at the cost of less involvement by the listener.

The Jaycar in my opinion exhibits a longer decay of the notes than the Rudistor. Perhaps the longer decay combined with the more compact soundstage accounts for a bit better mid range micro detail over the NX-02. This is very minor and it is only in the mids that I hear it. If I was not using such superb cans as the Denon AH-D5000 w/ the MarkL Mods and V4 Bubinga Cups I do not believe I would have heard this difference.

For my second round I chose a pair of Grado RS-1. This can has been the one I have own the longest and one that surprises me every time I use it. Until now I have always felt that it sounds best with tube amps, however both of these SS amps faired very well with it. Actually they sounded much better than expected.



For some reason the Grado in my opinion fares better with the Jaycar. Perhaps it is that I find the Jaycar to have a warmer and more intemate presentation over the Rudistor. A contributing factor is that Grado's in general are no know for their great soundstage, thus it would not benefit for the slightly wider presentation of the NX-02. Furthermore the Grados tend to have a lot of trebel energy and since the Rudistor has a more extended presentatio it would be to much of a good thing.

By the way I should mention that the above differences are not night and day. At best we are talking about +/-8% difference in each of the parameters I mentioned. The one area where the difference is huge is price, a DIYer could easily build the Jaycar for under $100, under $300 if he/she chose premium parts.

So for this first side by side I give the edge to the Rudistor NX-02 if you are using cans like the Denon AH-D5000 and listen mostly to classical music and some jazz. On the other hand I give the edge to the Jaycar if you are using cans like the Grado RS-1 and listen mostly to upbeat and in your face kind of music like some jazz, rock, and blues. By the way the background is very black on both amps.