[MarkM]

The bass is tighter; more defined; punchier. The top end is remarkably the same as before. The mids have more definition and texture.

To me, the biggest difference is in the sound stage. The height and width of the soundstage is greatly improved. The depth of the soundstage is what gets me the most. The depth is weird, as it is deeper than the speakers could possibly be from the wall.  It is remarkable now.

The change to the soundstage has made the bass more real; more taught.  It seems like I can reach through the center of the soundstage, almost into a triangle of space, and touch the drummer; or bassist; or into a grand piano to feel the strings.


Thanks, Frank. 

Have fun.
Jerry

I think Jerry nailed the review of these tubes perfectly and I have been very surprised that I have not seen more posts/impressions of them.  I'm blown away with how the sound has been transformed.   I used to use the low gain setting on my Ultra Preamp to get better control over things, not with the 6CG7 tubes!!

Strengths definitely are depth, imaging and a naturalness to voice/mids.   There is just a very well balanced tone to the music imo.  I initially thought the tubes might be a tad bass shy, but once I disengaged the low gain setting, the low end just filled in very nicely and well defined.   

As Jerry mentioned, the 3d depth to the music is amazing.    I plan on modifying the top of my cover with a couple flanges that will be anodized black.   Like the idea of seeing a hint of the tubes.

[trebejo]

Well, I think I'm ready to take the plunge. It would be less of a headache to use the tubes that are small enough to avoid changing the chassis of the ultradac.

Is this something to worry about? This fellow seems to think that the Mazdas might not be what they seem,

http://myweb.tiscali.co.uk/g8hqp/audio/valvedist.html

[oneinthepipe]

Well, I think I'm ready to take the plunge. It would be less of a headache to use the tubes that are small enough to avoid changing the chassis of the ultradac.

Is this something to worry about? This fellow seems to think that the Mazdas might not be what they seem,

http://myweb.tiscali.co.uk/g8hqp/audio/valvedist.html

I am using the Mazda 6CG7 in my T8 DAC and T8 preamp.  I haven't noticed any distortion.  The tubes fit fine.  Ogogilby ran the Mazda tubes briefly in his T8 DAC, and he preferred the Mazda to the RCA cleartops.

[trebejo]

I am using the Mazda 6CG7 in my T8 DAC and T8 preamp.  I haven't noticed any distortion.  The tubes fit fine.  Ogogilby ran the Mazda tubes briefly in his T8 DAC, and he preferred the Mazda to the RCA cleartops.

Thanks, I guess that does it! I'll ping Upscale Audio since (a) they are practically local to me and (b) they have five or six to choose from, each with a little story behind it.

[OgOgilby]

I enjoyed oneinthepipe's Mazda 6CG7 tubes enough that I ordered some from Upscale Audio yesterday. Thanks for letting me try them out oneinthepipe!

[kirch]

I was following this thread since I bought a preowned Ultra DAC to use with my Squeezebox to breathe some life into it.  I'm a tube head, but find out of convenience that I'm using the digital server more than my CD player the past few months. 

Initial impressions of the Ultra DAC were very nice.  Very tubey, but for my tastes took just a tad too much off the top end, but added dramatically to the separation and the 3 dimensionality of the soundstage.  Saw this tube rolling suggestion and immediately liked the idea of Electro Harminix tubes in the DAC.  Had great luck with them in a previous integrated a few years back.  Really liked their overally dynamic range and musicality. 

Just plugged them into the Ultra DAC and am really happy with their sound.  Very life-like.  Great inexpensive upgrade in my opinion.  If you haven't tried it yet, I highly recommend it, and give it two thumbs up!

 

[I.Greyhound Fan]

Has any one done the 6CG7 tube mod in the Ultra preamp?  I was wondering if it gives it more air and a wider sound stage.

I'm also considering the mod in my Ultra DAC to get a wider sound stage and more air.  I recently did the Burr Brown Op Amp mod and I have mixed feelings about it because it made the sound more forward, in your face and aggressive and took away some of the air and sound stage but with added clarity, resolution  and detail.  I'm hoping that by upgrading the tubes to the 6CG7's that I can gain some of that back and then some.  If not I'll give it a few more weeks and decide whether to put the old op amps back in.

Eventually, I would like to hear Franks new DAC and Preamp which is probably in my future.

Any thoughts would be much appreciated!

Larry

[oneinthepipe]

Replacing the rectifier tube made a huge difference in my U70.  I have a NOS Philips ECG tube.  I agree that a NOS rectifier tube isn't a cheap tweak, but I thought the results were great.

[Big Red Machine]

I ordered a few NOS Mazda tubes, which are shorter than the standard height 6CG7 tubes, and they might fit in the DAC and preamp without any modification.  They are purported to be good tubes, but I plan to compare them to the RCA clear tops when I get some.  I should receive the Mazda tubes by the end of the week.

NOS Mazda 6CG7 tubes are available from Upscale Audio for $40.00 each and from "Uncle Ned", formerly of Triode Electronics, for $29.95 each, including shipping within the U.S.

There is also a used pair of Mazda 6CG7 on sale here on AC for $50.00 (a good deal, IMO, and I am still tempted to buy them).

http://www.audiocircle.com/index.php?topic=72242.msg686767#msg686767

How do we find Uncle Ned?

[oneinthepipe]

How do we find Uncle Ned?

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=350256485694#ht_1777wt_941

[Big Red Machine]

Presently out but waiting for him to offer some more.

[I.Greyhound Fan]

Do you guys think its worth the money for these RCA Black Sable 6CG7 matched and balanced tubes  http://www.tubedepot.com/bsct-6cg7-rca-ct.html

or should I just stick with the standard RCA matched and balanced tubes?  The Black Sables sound like snake oil to me!

I've bought a pair of the Mazda Brimar tubes for my Ultra preamp and I am looking at a pair of tubes for my Ultra DAC.  I'm leaning away from the Mazda tubes because they are hard to come by.

Thanks,

Larry

[I.Greyhound Fan]

I just installed the Madza tubes in my Ultra preamp and all I can say is WOW!
The overall sound has tightened with increased resolution, more warmth, depth and tighter deeper bass.  Treble resolution is improved and cymbals sound more life like.  Mid range is slightly pushed back which is a good thing in my case as my Magnepans have a prominent midrange and the recent Burr Brown op amp upgrade to my Ultra DAC made the midrange to forward (I still may reinstall the old op amps as they have more transparency and wider sound stage but not as much resolution as the BB's).  The new tubes have given this hybrid preamp a more tubey sound.

I can't wait till I can install a pair in my DAC.



The only negative that I can hear so far is maybe there is a little more noise but I will re-evaluate that when the tubes have had some time to break in.

[Listens2tubes]

If your interested in vintage tubes here's my odyseey http://www.audiocircle.com/index.php?topic=76376.0

[I.Greyhound Fan]

In my on going adventure in tube rolling for my Ultra DAC and Ultra Pre amp I have come across of vintage NOS Tung Sol 6CG7's.

They are a very smooth and sweet sounding tube with a very liquid midrange, good bass and treble.  They are a little on the warmer side. In fact I prefer them to the Mazda's.  They are probably my second favorite tubes next to the RCA Clear tops which have more air and wider sound stage.  I hve tried them in my pre and dac paired with the RCA's and the Mazda's and they work well with both.  When paired it gives my hybrid system a completely analog sound.

tctubes.com has matched pairs for $69.

I have also found a pair of NOS Amperex 6CG7's and have them on order.  I'll post a review when they get here.  They will probably be my last pair of tubes for a long time. 

[turkey]

midrange and the recent Burr Brown op amp upgrade to my Ultra DAC made the midrange to forward (I still may reinstall the old op amps as they have more transparency and wider sound stage but not as much resolution as the BB's).  The new tubes have given this hybrid preamp a more tubey sound.

So you're saying that changing op amps also changed the FR of your DAC?

[martyo]

In my on going adventure in tube rolling for my Ultra DAC and Ultra Pre amp I have come across of vintage NOS Tung Sol 6CG7's.

They are a very smooth and sweet sounding tube with a very liquid midrange, good bass and treble.  They are a little on the warmer side. In fact I prefer them to the Mazda's.  They are probably my second favorite tubes next to the RCA Clear tops which have more air and wider sound stage.  I hve tried them in my pre and dac paired with the RCA's and the Mazda's and they work well with both.  When paired it gives my hybrid system a completely analog sound.

tctubes.com has matched pairs for $69.

I have also found a pair of NOS Amperex 6CG7's and have them on order.  I'll post a review when they get here.  They will probably be my last pair of tubes for a long time. 

Thanks for the feedback, keep it coming. I'm still running the Rca's in the T8 and the Mazdas in the DAC. The Tung Sol's sound interesting. I still need to get another set of the RCA's since I foolishly sold a set.  Glad they worked for you Larry. I have had to put any new tubes on hold for awhile, vacation at the end of the month in Stehekin Wa.

[ArthurDent]

I have had to put any new tubes on hold for awhile, vacation at the end of the month in Stehekin Wa.

       
Now that's off the beaten path marty. Don't forget your camera, the scenery is outstanding in that area.  Driving, flying ? If you get the chance the side trip to the Grand Coulee Dam is worth it. Really impressive structure.

Have a great trip, been warm that side of the mountains, but pretty much the best weather in the country this year. 

[martyo]

       
Now that's off the beaten path marty. Don't forget your camera, the scenery is outstanding in that area.  Driving, flying ? If you get the chance the side trip to the Grand Coolie Dam is worth it. Really impressive structure.

Have a great trip, been warm that side of the mountains, but pretty much the best weather in the country this year. 

Yes, I've been a little concerned about the heat. I'm usually pretty energy conscious but not with the AC.  But it's not the humid heat like here in the midwest and it cools off at night. We'll basically be off grid. Really unplugged.

In 1972 5 of us followed the fruit for a season. From the Sacramento Delta (pears), to Clear Lake Ca (pears). Then a very leisurely trip up the Oregon coast and finally to Lake Chelan and the apples. We lived 30 miles out of town in the last house on the state park road. It was a very cool experience, seeing new places and meeting new folks. Been trying to get back since then. I also met a guy that worked at the Rocky Reach Dam and he took me on a private tour through the bowels of the  structure. Not the Grand Coolie, but pretty interesting.

Flying into Seattle and spending a day, then driving to Chelan via 2, spend a night in Leavenworth (one of my mother-in-laws favorites stops), and on to Chelan and the ferry........

Funny, we'll be hiking and bicycling and horseback riding and rafting this time but back in '72 we tended to just work and party a tad.

Back to topic, sorry. 
 

[I.Greyhound Fan]

So you're saying that changing op amps also changed the FR of your DAC?

Changing the OP amps made a big diffence in sound.  The BB's moved the midrange forward, narrowed the sound stage and had less transparency.  Treble seemed rolled back a little as well. The sound was slightly smoother with a bit more bass though.  I went through a lot of different tubes trying to regain some sound stage and transparency but I eventually had the original OP amps put back in the DAC and I'm a happy camper because the 6CG7's really mate well with the stock op amps.  The 6CG7's give the music more depth and bass.

One thing to remember is that I'm not using all AVA gear.  My DAC and Pre are AVA but my amp is a SS Parasound Halo A21 and my speakers are Magnepan 1.6's. The Maggies already have a sweet and prominent midrange and they did not need a more forward MR that the BB's presented.  I ran into the same problem when I had my old Music Hall 25.2 CD player modded by Reference Audio Mods.  They did a number of mods including BB Op amps which dramatically transformed its sound from a nice open and transparent sound to a much more forward aggressive sound which I didn't care for.  So the MH is used as a transport.