Audio Research CD7's 6H30 tube rolling

Hello Flkin , after 2 years of use , I decided to rollout the current 6H30P-EB tubes by the DR version , I swapped all the 7 tubes . Result is that the NOS tubes sound better
in every aspect the AR is famous for . But I also have changed the clock with its own powersupply ) Tentlabs , a Dutch brand ).This makes the CD7 even a more better player ,bigger soundstage and more air .I think that in my situation the clock is responsible for 60 % and the tubes for 40 % for the better sound.
Greetings from the Netherlands Hans

I have also bought a quartet of -DR tubes, but still waiting for the Halo Tube dampers to install them (I should get them next week).

The brightness you expirienced is typical for an early stage of burn-in. It will go away after some 300+ hours. After that, the player needs some 100h additonal hours of break in to sound its best (400h+ total).

I have left the player for 3 weeks straight in repeat mode to speed up the burn in process. Befor the burn in process is completed, the player sound medicore IMO. At some point (after 200h) I even wanted to return it to the dealer ! But after 400h it really starts to sing. For me it is a keeper. I went through some 10+ players in the $9-22k range before I decided to get CD-7.

Hi all!

Thanks for detailing your experiences. The comments that I should wait longer before commenting on the sound is very valid. It's just that 400 hours takes such a long time to pass when you are burning new equipment!

And when the new NOS tubes come, it will probably take ANOTHER 400 hours before I compare the sound again!

Hansk46 - Greetings from Thailand! Interesting that you can update the clock - didn't know that. I'll have a look at that too.

Elberoth2 - you ordered the Ultrasonic 9s also? So did I and they too are on the way. I wonder if the metal construction will be problematic inside a high-voltage machine such as the CD7. The older versions were made of some form of plastic.

Having used the CD3 mk1 and mk2 for a long time, I didn't really have any choice but to get the CD7! I haven't heard any other CD player as engaging and real as the ARCs. Right now (170 hrs perhaps?), it's already very good but the soundstage is still smaller than the CD3mk2 and the sound is not quite out of speaker box yet. I can tell distinctly that my Watt Puppies are there whilst I couldn't with the CD3mk2.

After you get the NOS tubes and have burnt them in, please let us know your opinion. I plan to do the same.

Cheers!

I do not think that you have to burn in the new tubes as much. 24-48h should do. The parts that are most sensitive for break in are coupling capacitors - but you do not change them.

And do not worry about the long break in period. Try not to listen, as I did. 3 weeks of continous play is all it needs. Since you already did 170h, leave it for additional 10 days in reapeat and you will be done.

Elberoth2, have you had a change to try the CD7 with different feet? ARC states that the feet they use are balanced to the weight of the machine indicating that they have put some thought to using good feet.

However I notice that the rubber feet are the same as the CD3 mk1 and mk2. And in both of these machines, changing the feet produced an improvement in the sound.

I used aluminum pucks to support the CD3 on a Symposium Isis rack. If you are aware of how the Isis works, the top shelf is compound isolated with 2 sets of rollerblocks in the supports and the theory of the rack allows for the pucks to transfer vibrations within the cd player into the shelves.

In a blind A/B test using none vs 3 vs 4 pucks, I concluded that 4 pucks sounded the truest to the music.

Haven't tried changing anything on the CD7 yet but I'd bet the same will hold true as the construction of the machines look pretty similar.