Tube Output stage - Please share your opinions..

polkatese

Tubees,
wondering if someone can share a quick impressions of his/her (naa, no female 'round here) experience on CDP tube output stage as it's compared to either an op-amp or analog stage. I am hoping we have tube-fanatic(s) here that can educate me on this subject. I took a blind plunge of having this done on my player, haven't got it back yet, but curious as hell on what its going to sound like....thanks

organ

dangerboy owns a tube DAC. Let's wait for him to give some info.

If the tubes are 12AX7, exchange them with 5751 tubes. www.thetubestore.com has NOS JAN GE 5751 for $20 each. The 5751 is better than any 12AX7 I own. Check out Joe's Tube Lore on www.audioasylum.com under FAQ.

Never heard a tube output stage on a CD player before, but I'm sure you should get some of that tube sound through the amp and to the speakers. You should get a warmer/more organic sound with better soundstage, more air, dynamics and micro dynamics. You can change the sound by trying out different brands of tubes.

Maurice

polkatese

thanks, Maurice...I will save the url and see what do I get. Sounds like it's gonna be a fun ride.

organ

You're welcome. Another great online shop for tubes is www.triodeelectronics.com

It will definitely be a fun ride:). I buy tubes almost weekly. It's so fun to try out different brands. The best sounding tubes I've heard are NOS (New Old Stock). If you really like the result from the CD player, you might want to check out a tube pre. There are good ones under $300.

Maurice

danger boy

I'm very new to tubes myself.. but with that being said.. here is what i have found out so far from using the tube DAC that i have had for the last 6 months.

I find the tube DAC gave my CD's a bit more open and airy sound to them. Certainly the clarity of the music improved quite a bit too. and that's mainly what I was hoping to get. I'm a stickler for clean audio. (I even now am starting to buy those Mobile Fidelity Sound Labs gold CD's that used to be around.. cleanest sounding CD's you can buy). It's kind of tough to explain.. but the music now seems more pleasing to listen to. Instruments have better seperation it appers to me.. more lively and natural sounding

I try and listen to CD's without a external DAC now and it just sounds muddy and flat to me.

I am running two 12AX7 Mullards right now. I haven't expiremented with other tubes yet. I've read that the Mullards are some of the better tubes out there.. just behind the Telefunkens and Bugle Boys. Both of the latter costing more than the Mullards.

Before I bought the tube DAC. (Cal Audio Alpha) I was exploring and doing some research on tube CD players. The ones I kept coming back to were the Carver SDA 390t and SDA 490t. I never was able to find either player at an online auction where I could afford it. So i went with an external tube DAC instead.. the guys in here highly recommended a tube DAC. I haven't regretted that decision one iota. It's been great.

Here is a link to a few (3) reviews about that Carver 390t CD player. I'd still be interested in hearing it some time.
Carver 390t

Like Maurice said.. it will definitely be a fun ride.

organ

danger boy,
I'm still saving up hoping to find the exact same DAC as yours, used.

Have you decided which tubes you're going to purchase next? Try to get a pair of 5751 along with your new 12AX7. To my ears, the 5751 is cleaner sounding with less grain on the highest frequencies but the biggest difference is the soundstage. The depth increased at least a few feet.

Haven't heard any Mullard 12AX7 but I did purchase a pair of Mullard 12AU7(ECC82) for the pre amp. They are very good but I'm still switching back and forth with the RFT(E Germany). The RFT has more slam, clarity and air. Not as warm as the Mullard though and a little leaner on deep bass. For some music, I find the Mullard much too warm and can make my system sound "slower" than the RFT.

Maurice

organ

Here's some links you might find interesting:

Joe's Tube Lore
http://www.audioasylum.com/scripts/d.pl?audio/faq/joes-tubes.html

The Cool Sound of Tubes
http://www.spectrum.ieee.org/select/0898/tube.html

A good tube forum:
http://www.audiokarma.org

Maurice

madmax

My luxman cdp has a tube output. Pretty much you are taking out a cheap last stage and running through the tubes instead. How much this helps is proportional to how cheap the last stage was and the quality of the stages before it. If all was good to the final output of the cdp then just feeding into a tube preamp would be equal to your mods. If the tube in the cdp replaces something of lesser quality and the stages before it are adequate then you may come out way ahead. It all depends on how good that last stage was. Further, just running the signal through the tube will add whatever characteristics the tube has.
madmax

danger boy

Maurice,

thanks for the advice on tubes.. I am wanting to try out other tubes. I think i read in the instruction manual for this DAC that it can only use 12AX7 tubes. I'll have to recheck that to be sure though.

I see tube DAC's like mine on audiogon every now and then... and once in a while on ebay. They run between $300 and $450 US. It would be interesting in your case.. if you did have a tube DAC to go along with your tube pre. What pre are you using?

Al

organ

I think i read in the instruction manual for this DAC that it can only use 12AX7 tubes.

The 5751 is a direct replacement for the 12AX7 for less microphonics. It also has a lower gain so you might have to turn the volume on your pre just a tad higher.

What pre are you using?

Antique Sound Lab AQ-2004DT.


madmax,
That's very interesting. It's nice to be able to get the sound you want from every output in the audio chain. Getting the best combo between DAC, pre and amplifier is going to be fun.

Maurice

polkatese

thanks all for the input and useful links...I am saving this one for reference and look forward to play with it when the time comes.