I listened to these in a Marantz 7. The Marantz takes a 6 pack of 12AX7s, 3 in the phono section and 3 in the line section so you are using 1 1/2 tube per channel in each section. I used the pass around tubes in the line section, along with a Sovtek LPS in the position that was split by channel. I left it there there, even though I have full complememnts of the other tubes that I compared the TJs with to try to get a fair comparison. The TJs also spent an evening being the driver tubes on another AKer's Magnavox 175. I primarily listen to records. My signature lists the equipment they were used with. They went up against well used Mullard 10M, current production Mullard and well used Teles. These tubes brought an all round life to my amp that others have been unable to. It was apparent immediately on the first song as I turned up the volume knob. Across the entire sound spectrum there was more body and more presence to the music. They bring it right out, everything opened right up. With other tube rolls it is often just a part of the sound is obvious or makes a real tangible change. Like the bass was this or the maids were that or the cymbals were.....with these tubes it was the whole thing. On the Maggie it was the same. It was obvious when we put these in. He had a pair of Maggie labeled 12AX7. We also used both of my Mullards and the Teles in his amp. We heard the same things with his amp as it was on mine. The Mullards brought something to lower end, the Teles brought some shine to the highs, after comparing them to the TJs, I would say a bit too much. The TJ tubes just open it up everywhere. I'm sold, I liked them so much I bought three for the line section of my amp. Now having enough tubes to populate the entire line section I have rolled the odd Sovtek LPS with the TJ. The difference is much less perceptable, nowhere near what the difference was when rolling the first two tubes. I'm even having a hard time quantifing it. The odd postiton is last on this amp, I assume it has less impact on the sound than on an amp where the shared tube comes first. The odd TJ also has only about 25 hours on it at this point. I suppose I could drive myself crazy rolling the odd tube, seeing if I can come up with an even more perfect combination, but for now I will be content to just sit back and listen to the full compliment of TJs.