Anthem CD-1 tube upgrade?

I recently got an Anthem CD-1 for use in my office, and I love the sound of this thing. Don;'t know whether it's the tubes, but it just sounds sweet. This has the factory tube in it. Is there a simple, drop-in replacement that wo9uld make this player sound even better?

(Sorry, I dnot even know what model the factory tube is, if that tells you anything :). The rest of the system consists of of a Headroom Max amp and Sennheiser HD-600 headphones. I listen to just about every kind of music, from Classical to Techno.
Hi Njonker Glad you like the Anthem gear. I own the Amp 1 and did have the pre2L. If I'm not mistaken the tube should be a 6922 and it should be a sovtek. I replaced my 6922s with nos philips when I had the pre and valvos in my sonicfrontiers dac. I really like the valvos and the philips tubes don't sound bad.(replaced the pre2L with a ARC) You might try Anthems web site to see what tube upgrade they recommend for your player. Keep in mind you may pay a little more for their replacements. Good listening!
Sovtek 6922 are stock.I first went to a Valvo.Big improvment then went to a Siemens E188C Major Major improvment.
I also own the Anthem CD1. There is an upgrade from SF available....check the website......The piece I purchased via Audiogon has this upgrade...worth every penny!
I am using an RCA 7308 gold pin-made by Siemens. These are generally expensive tubes, but if you can find a few different types, you will be able to hear some improvement/differences.
Thanks all so much for the suggestions. Could you suggest a good place to buy new tubes at reasonable prices?

Kevin Deal of Upscale Audio recommends the
Ediswans for the CD1 - I have been very happy
with the tubes I bought from him. His website
is Give him a call,
he's a great guy to buy tubes from due to his
extensive knowledge.

Do not buy NOS tubes from the Sonic Frontiers
site that are recommended for the CD1 - absolute
garbage the two types they recommend. Wasted $100
or so dollars.
I agree the Brimar are not a good choice.It appears that Sonic Frontiers/Anthem have run out of the Valvo's they used to recommend.
Also stay away from the Ediswans.They are no better than a Brimar.