Need advice on Unico 12AU7 tube rolling

Don't have one brand for you to try, but these tubes are not expensive in the world of high end audio. Check a place like Triode Electronics in Chicago (great source for tubes & related parts.) For about $200 you could buy a pair of every 12AU7 they offer (8 pair).

To replace tubes, just turn the equipment off and give it 10 or 15 minutes for the tubes to cool completely. Pull the old tubes out of their sockets (gently with not too much rocking) and then insert the replacement. The tubes can only be inserted in one orientation, so look carefully at the alignment. Replace the cover, fire things up and listen!

When I owned a Unico the tubes I liked the best were Telefunken. Radiotechnique might work for you. The addition of Herbie's HAL-O tube dampers made them more refined and focused and is recommended.

Check out this Search link on AudioAsylum.com for posts regarding the Unico and tubes: http://db.audioasylum.com/cgi/search.mpl?forum=tubes&searchtext=unico

Good luck.

Sorry, but I overlooked an important detail of your question. I thought you were referring to the Unico integrated amp, not the CD player of which I unfortunately have no experience. The information I posted may or may not apply to the CD player. In an Audio Note CD2 CD player my favorite tube is the Amperex 7316 although both the Telefunkens and Radiotechniques are also good choices. Perhaps a Unico CD player owner will weigh in with a more informed recommendation.

Thank you very much. I checked the website of Triode Electronics and their prices seem to be very reasonable.

Also what is the difference between NOS and New tubes ? Apparently NOS seem to be more expensive - hence the quality is much better with NOS tubes ?

In NOS which brands/makes are normally popular ? I hear lot of names Philips, Siemens, Mullard, Sylvania, RCA, etc from Britain, USA, Russia, etc.

I like the sound of Brimar 13D5 tubes in my Unico. They are a 12AU7 type tube and are NOS, which stands for New Old Stock. You can find them on ebay, but a more reliable source might be Tubemonger.

I also own this cd player. If you want detail and clarity I highly recommend Radiotechnique and RFT tubes. In terms of transparency and detail I haven't found a better tube than the Radiotechnique in my system. It may sound a little lean in your system though depending on your other components. If you want a little more body to the sound with most of the transparency of the RT & RFT then try a pair of Amperex Bugle Boys. Have fun, this player is very responsive to tube rolling.

As noted by another poster, "NOS" stands for "New Old Stock." These are tubes manufactured years ago by well regarded companies, many who are no longer in the tube business. Some people regard these old tubes as superior. In fact, there is a dirty little secret in that some dishonest people are actually relabeling modern tubes with old labels such as GE, Mullard, Telefunken and so on. Buy NOS tubes only from a reliable source.

(Tubes have zero deterioration in storage as long as they are not physically damaged. A 50 year old tube that has never been used is as good as the day it was made.)

Many well known manufacturers of tube got out of the business years ago and almost all modern tubes are now made in Russia, China, Slovakia and the Czech Republic. There are a very few American made tubes but they tend to be specialty, broadcast or military items.

Thanks a lot for all your nice inputs. This motivates me to do some tube rolling. Will try Radiotechnique, RFT, Amperex Bugle Boys, Brimar or Telefunken after doing some more reading. Good to know that the player responds to tube changes.

Also are there any recommendations for more authentic and popular tube sources which are reliable ?

Thanks in advance

2 Tube retailers that come to mind are Tube World.com and Upscale audio.Both are well established and reliable.Welcome to tubes.You are gonna have a lotta fun!!