I have had a CD-77 since the summer of '07. Since that time I have tried every tube I could find in it (mostly because it is my nature to tinker and discover). In the end, the stock tube compliment that came with the player, Tungsram EZ80, Mullard M8162 (12AT7) and Philips 5687 turned out to be damn good and almost the best grouping, but I did settle on a slightly different set.
Before I start, I must make a serious recommendation that before you try rolling any tubes in the player, remove one of the tube damping rings one the 5687 and see what you think. I found that 1 ring on the top mica spacer actually tightened bass, one ring down low on the bottom mica spacer tightened the top end and one in the middle split the difference. Of course, using any rings at all has the effect of slightly constricting the sound, they are dampers and they do dampen. Rolling rings was truly amazing and added a whole additional element to this exercise. With the stock tubes, I actually found 2 rings on the EZ80 and one on the top mica of the 12AT7 and 5687 was my preference. The following tube rolling also includes the ring rolling too, while I will not go through each result of ring rolling, I will mention the final ring and tube configuration I now use.
Each tube position has a big impact on the character of the sound, but most critical turned out to be the 12AT7 spot and it is this tube that the stock player has perfect. The Mullard M8162 has a magical midrange and impact that no other 12AT7 could replicate. I tried the Tele ECC801s, Siemens E81CC, late 1950's Mullard CV491 square getter, Amperex ECC81, Philips 6201, GE 5-Star 12AT7, Raytheon 12AT7, Tungsol 12AT7 and Sylvania 12AT7. None of them had the soul, body and character of the stock M8162, so after all that work, the M8162 stayed, but I just use one ring on the top mica spacer.
The Tungsram EZ80 rolling was less challenging simply because there are fewer good EZ80's out there. The sound of the Tungsram is, like the Mullard M8162, the most powerful and weighted sound with a bass that was unrivaled. But I discovered that it is lacking in detail, microdynamics and air, even with no rings. So I tried the Tele Falcon EZ80 but that went too much in the other direction, too light with not enough weight and impact. The Amperex EZ80 was similar to the Tele but just to a lesser extent, of the two I preferred the Amperex, but neither was better, to my ears, than the Tungsram. Then I tried the Brimar EZ80 and found what I was looking for. While it does not have all the weight of the Tungsram, it is the closest to it in that category and what it does have is the detail, air and microdynamics that the Tungsram is lacking. So I have the Brimar EZ80 in that position with 2 rings on it.
Finally, the Philips 5687. The Philips has good energy and impact, great dynamics and if any downsides, can be a touch glassy or maybe it is grainy, just not as clean and free of any micro nasties on top. Of course I started with the Tungsol in that spot, I must have 10 pairs of these collected over the years and thought it would be the ticket, but it wasn't. It was just too soft and polite for my taste, it sucked the life out of the sound. I then went to the Amperex 7119 and found it to be ok but similar to the Tungsol overall and not better than the Philips. Then the Westinghouse gold pin 5687 which was diffuse and fuzzy sounding. Then I tried the Raytheon 5687 (propeller getter) and was very happy for a while. The Raytheon was the best of the group so far and did almost everything right except it was lighter in the bass than the Philips. But it was cleaner and so well made that I could go no rings and it performed flawlessly. I lived this way for 2 months, then I tried the GE 5-Star 5687 and had my tube. It was the closest to the Philips but was cleaner and more refined like the Raytheon. It was just a better version of the Raytheon in my book. It also did extremely well with no rings at all, so I was able to have the most open and undamped sound and still have things tight and under control.
Well that's it, this is how I have my AMR CD-77 configured. The AMR CD-77 is an amazing player. The TDA-1541A NOS DAC is so refined and natural sounding, the 70lb copper lined chassis is unrivaled and the flexibility of all the rolling you can do is a real treat. Yet the most impressive thing to me, is that the stock NOS tubes are just about the best configuration for the player and that is something that I have never experienced before. AMR really did a lot of homework before they designed this player, and to think that it is their first offering is just shocking. I'll be spinning this player for a long time to come and the nice thing is that I have been off the revolving door of new players for almost 2 years now! I am as happy with the player now as when I first heard it.
Before I start, I must make a serious recommendation that before you try rolling any tubes in the player, remove one of the tube damping rings one the 5687 and see what you think. I found that 1 ring on the top mica spacer actually tightened bass, one ring down low on the bottom mica spacer tightened the top end and one in the middle split the difference. Of course, using any rings at all has the effect of slightly constricting the sound, they are dampers and they do dampen. Rolling rings was truly amazing and added a whole additional element to this exercise. With the stock tubes, I actually found 2 rings on the EZ80 and one on the top mica of the 12AT7 and 5687 was my preference. The following tube rolling also includes the ring rolling too, while I will not go through each result of ring rolling, I will mention the final ring and tube configuration I now use.
Each tube position has a big impact on the character of the sound, but most critical turned out to be the 12AT7 spot and it is this tube that the stock player has perfect. The Mullard M8162 has a magical midrange and impact that no other 12AT7 could replicate. I tried the Tele ECC801s, Siemens E81CC, late 1950's Mullard CV491 square getter, Amperex ECC81, Philips 6201, GE 5-Star 12AT7, Raytheon 12AT7, Tungsol 12AT7 and Sylvania 12AT7. None of them had the soul, body and character of the stock M8162, so after all that work, the M8162 stayed, but I just use one ring on the top mica spacer.
The Tungsram EZ80 rolling was less challenging simply because there are fewer good EZ80's out there. The sound of the Tungsram is, like the Mullard M8162, the most powerful and weighted sound with a bass that was unrivaled. But I discovered that it is lacking in detail, microdynamics and air, even with no rings. So I tried the Tele Falcon EZ80 but that went too much in the other direction, too light with not enough weight and impact. The Amperex EZ80 was similar to the Tele but just to a lesser extent, of the two I preferred the Amperex, but neither was better, to my ears, than the Tungsram. Then I tried the Brimar EZ80 and found what I was looking for. While it does not have all the weight of the Tungsram, it is the closest to it in that category and what it does have is the detail, air and microdynamics that the Tungsram is lacking. So I have the Brimar EZ80 in that position with 2 rings on it.
Finally, the Philips 5687. The Philips has good energy and impact, great dynamics and if any downsides, can be a touch glassy or maybe it is grainy, just not as clean and free of any micro nasties on top. Of course I started with the Tungsol in that spot, I must have 10 pairs of these collected over the years and thought it would be the ticket, but it wasn't. It was just too soft and polite for my taste, it sucked the life out of the sound. I then went to the Amperex 7119 and found it to be ok but similar to the Tungsol overall and not better than the Philips. Then the Westinghouse gold pin 5687 which was diffuse and fuzzy sounding. Then I tried the Raytheon 5687 (propeller getter) and was very happy for a while. The Raytheon was the best of the group so far and did almost everything right except it was lighter in the bass than the Philips. But it was cleaner and so well made that I could go no rings and it performed flawlessly. I lived this way for 2 months, then I tried the GE 5-Star 5687 and had my tube. It was the closest to the Philips but was cleaner and more refined like the Raytheon. It was just a better version of the Raytheon in my book. It also did extremely well with no rings at all, so I was able to have the most open and undamped sound and still have things tight and under control.
Well that's it, this is how I have my AMR CD-77 configured. The AMR CD-77 is an amazing player. The TDA-1541A NOS DAC is so refined and natural sounding, the 70lb copper lined chassis is unrivaled and the flexibility of all the rolling you can do is a real treat. Yet the most impressive thing to me, is that the stock NOS tubes are just about the best configuration for the player and that is something that I have never experienced before. AMR really did a lot of homework before they designed this player, and to think that it is their first offering is just shocking. I'll be spinning this player for a long time to come and the nice thing is that I have been off the revolving door of new players for almost 2 years now! I am as happy with the player now as when I first heard it.