An Xciter Journey!
When Dennis Had, the mad scientist and owner of Cary Audio, told me they were designing a new Xciter line of products to include a very versatile Headphone Amp, A Dac and later a Transport, to say I was excited, was an understatement. The Cary Audio Cad 300SEI Integrated/Headphone Amp has long been my reference headphone amp. It is my all time favorite single ended dynamic headphone amp. The 300B tube is God's gift to the audiophile. The magic it can provide the listener is breathtaking but that is a whole other topic to be discussed. Today I would like to talk about the Xciter Amp and a journey I have taken and will continue to take as time passes with a complement of different tubes and how these tubes match up with different brands of headphones.
You would think that a 5 watt channel amp would easily crumble under the strain of a pair of speakers, but during our review multiple speakers at different sensitivities were used. The amp never fluttered. An increase to 10 watts per channel is accomplished with the swap of the 6L6 tube to a KT88. The amp is self-biasing and multiple power tube options are available. 6L6, EL34, 5881, 6550, KT88 and any other power tube with a matching pin arrangement. The input tubes can be 12ax7, 5751, ecc803 or ecc83
Now on to the headphone/tube journey. I assembled quite a stash of tubes to play with, and these are just the cusp of what is available. I tried as many different tubes with different headphones possible to find some matching combination. While I would not use this as a cut and dry direction of which tube to use with each headphone it at least provides a starting place for experimentation. Here is a list of the tubes I have acquired in no particular order and average prices.
Power Tubes
EAT KT88: Beam Tetroid KT88 Diamond w/gold pins matched Quad : $7-900 Matched Pair
Genalex – KT88 Gold Lion brand. $149.95 Matched Pair
Cary Audio Stock 6L6 Free they come with the amp
Electro-Harmonix KT88 EH $49.95 Matched Pair
Tung-Sol 6L6G New Production $49.95 Matched Pair
Tung-Sol 6L6 STR New Production $29.95 Matched Pair
NOS Sylvania 6L6WGB / 5881 $69.95 Matched Pair
NOS Jan Philips 6L6WGB / 5881 $69.95 Matched Pair
Input tubes:
COOL VALVE ECC 803S twin triode with Cool Damper attached Diamond version: : $450 Matched Pair
Cary Audio Stock 6L6 Free they come with the amp
NOS GE 5751 ?
NOS Sylvania 12ax7 $59.95 Single Tube
NOS Jan Philips 12ax7 $49.95 Single Tube
Lets get this out of the way quickly and then we can move on. Bar none, the EAT tubes blow the competition away. Plain and simple. If you can afford these, buy them. There is not a phone on the planet they don't like. They were effortless with everything I could throw at them. No wonder they cost so much. I would easily take these over any super expensive NOS tube. EuroAudio Team did their homework. So for the most part for each phone I will start with the runner up tube.
Because there would be a million variations of input tubes and power tubes I found in most cases after the EAT tube that I liked the GE 5751 tube the best so my reviews of the power tubes will be with this tube.
Sennheiser HD650 Headphone.
I find the HD650 to be the darkest, laid back, lush sounding headphone ever made. Of course I am not heavily susceptible to high frequencies. I always use silver based conductor cables with these to lift the veil and bring them out of the darkness. I see why classical music lovers are the biggest fans of this phone. It does wonderful things with pianos. So in sticking with that thought I found I really liked 2 power tubes the best. The Senn is a harder load to drive and really needs a KT88 style tube to drive them in a demanding load. Thus the Gold Lion sound the best with this phone. In some demanding passages the other tubes seem to crumble a little. However in quiet listening situations I really like the Tung-Sol 6L6 STR tube. It is very clean and I imagine this a cheaper tube. I found this tube to be the best bang for the buck aftermarket tube in a lot of combinations. It was better than it's bigger brother the Tung-Sol 6L6G with these phones.
AKG K701/702 Headphones.
The K701 or K702 are the most neutral of what I call the big three headphones: Grado, AKG and Sennheiser. The Sennheiser is the most laid back. The Grado is the most forward and the AKG is somewhere in the middle. It is a great headphone for all around listening. It is not incredible sounding in any one music type and nether is it awful in any one spot. It is neutral and natural sounding with not a lot of coloration. I always recommend it to folks who don't flow in one direction musically. It is a great all around performer. Where it lacks is in weight. It does not provide a big impact. I liked the Tung-Sol 6L6G big boy tube with this phone it has a bottom heavy type of quality that is not a bad thing. While the KT88s add more power they did not help to add some fatness to the lower end. Thus this was a good choice for this phone.
Grado GS1000 Headphone.
When Dennis designed the Xciter, this was his main reference phone of choice to tune the circuit. And you can tell, because the amp really sings with the Grado line up. And I think this is why the 6L6 tube is the best choice with the Grado's. This is the stock tube Cary decided to go with and label the chassis with. I love the NOS Sylvania 6L6WGB and have used them for years in a Mac MC240 and so this was the first tube I stuck in the Xciter amp when I first received it. It wonderfully matches the Grado sound. Grado's, more so with the RS-1 on down, are very upfront sounding just like study monitors. Very detailed and crisp and RIGHT THERE. The GS1000 is a little more relaxed due to the fact the drivers are farther away from your head. But regardless it is still a very detailed phone. The Sylvania works well to round this out a little and take some of the rough edge off. I found the clean sound of the Tung-Sol 6L6 STR tube to much with this phone. Some of you that are solid state folks, but would like to own a tube amp too, may like the combination of this tube with a Grado.
Audio Technica ATH W5000.
The W5000 is one of my favorite phones. It is loaded with detail and in my opinion is better matched with tube amps than solid state. I have heard some solid state amps that work well with these, but for the most part they can make the sound edgy and too bright. I always recable these with a big fat copper cable like the Black Dragon. That being said the KT88 Gold Lion was my favorite match with these phones. The W5000 is not a hard phone to drive but there was tones of impact with this tube headphone combination. This reissue tube is my favorite in the KT66/88 power tube section. Just great sound is all I have to say....
Beyerdynamic DT880.
The DT880 is my favorite of the Beyer line up. Like the AKG it is a great all around performer and I would put it between the AKG and HD650 on a neutral to darkness scale. This phone can be easy or hard to drive based on which version you pick. By the way the 32ohm, 250ohm and 600ohm are no finally available in the US. Thank God. As the 600 is my favorite version. And because of the load a KT88 is required in my mind. Thus the Gold line is the must have in a 250 version which I did not spend a lot of time with I liked, the Tung-Sol 6L6 STR.
Well obviously this is not all the phones in my stable but this is a start and as I play some more with different phones and tubes I will update this thread. Bottom line the Xciter amp has made it very easy to tailor tubes to different signature and load conditions. It is a very flexible amp and the fact that it auto Bias's is very nice. Please not warm up times are longer because of this. KT88 tubes can take up to 3 minutes to dial in and get it up to speed so make sure to warm the unit up after changing tubes.
Cary Audio Xciter - Integrated Amp / Headphone Amp (NEW)
