Any experience with EZ-80s, 5687s or Bendix 6900s?

After this last weekend, the tube configuration on my AMR CD77 is Philips 5687 in the rear, Mullard CV4024 (12AT7) in the middle, and RFT EZ80 in the front. I have heard good things about the Bendix 5687, but haven’t had a chance to audition them. This past weekend I had some extra time compared four different sets of EZ80’s (front position).

Tesla – rolled off highs & lows; very warm; sounded like a screen was placed in front of the speakers. I was not impressed at all.
Brimar – similar to the Tesla, but not quite as warm and not as rolled off at either end. The mid-range is where these tubes excel.
Tungsram – great extension both top & bottom, but poor density. Music had a hallow sound, like listening through a pipe. Also has a bit of boost in the upper mid-range. I had used these previously, but was never happy with them.
RFT- Magic time! This is by far the best tube I have tried in this position. Voices are real; in the room with you real! Thunderous bass, excellent midrange and a delicate high end. If one can find fault with them, it would also be a bit of push in the upper midrange, but far less than the Tungsram. Mind you, I’m knit-picking (but isn’t that what we all do with this “hobby”?). I plan on adding a third set of damping rings to the tubes – my guess is that it will help control it a bit.

Remember, no tube is perfect. All have their strengths and weaknesses. What works in my system my not work in yours. You really have to experiment to find out what’s best for you. In my opinion, this is one of the great strengths of the AMR; you can customize it to your liking. Also, you can easily move the damping rings to different points on the tubes to make even finer adjustments to the sound. Additionally, if your machine is not a 77.1 (the current version), you can have Darren Censullo of Avatar Acoustics modify it to the new standard – a substantial improvement!

Hi Frank:
I purchased the RFT's on ebay just a few weeks ago. The seller was/is "LCI_ELECTRONICS" (which looks to be the same seller as "ORPHEUS_2005", both located in Bulgaria. I purchased the RFT's & Tesla's from the same seller, and received both sets in just over a week from the payment clearance date! Go to ebay, and type in EZ80; he is still listing more of them for sale.

Please let me know how the Bendix 6900's sound in the AMR. I am very tempted to purchase a set, but at $600 a set...
Ken G.

Frank, here's an update for you:

I was fortunate to find a lightly used pair of Bendix 6900’s within 5 miles of my front door. The seller agreed to let me try them on the condition that I could return them to him if I was not happy with the sound. Upon replacing the JAN Philips 5687’s with the Bendix, any thought of returning them quickly vanished. From an already very quiet background, it is now even quieter. Voices (now) have a much more detailed, textured and richer quality – a “3-dimentionality” if you will. Lower mid-range is much fuller and layered than before. Bass response is also significantly improved. As with the mid/low-mids, bass has a fuller and richer presentation. As mentioned in my earlier post, changing the position of the damping rings on the tubes also allowed me to “tune” the tubes to my liking. The Bendix easily surpassed my expectations!