Is It A Blog?
Thank you for visiting our blog or whatever this is. These posts are taken from emails to a “listening group” here in the St. Louis area. You really should read from the first onward since you might not understand some comments if you start randomly.
Listening Session 08-12-10
Dan came over for a session Friday night. I think we agreed on everything to a fair degree. Dan you can forward this with your comments to the group if you desire. Sturgus, Steve and Chris could not make it.
The Results Please:
* The D-75C, though making a valiant effort, was not too successful at driving the modified Advents. It seemed starved for bass power and a little dry/bright which is not something I've encountered too often. Switching to the modified DH-500 did the job, though this one only had a day or so of break in. It resides on our Demo/Used page right now. Still as it warmed up it started getting very good, started "pulling us in". Sunday night, using the intended highly modified DH-200 amp, which is here now also they sounded superb. Man I love those Exicon FETs. (explanation: We had been tasked by a customer to make the New Advent speaker circa 1970s more musical)
* The modified Advents were quite a surprise. I never would have guessed these could sound so nice with some damping, rebuilt/reconfigured x-over and new tweeter. Amazing really, but they want power - big power.
I think you all sort of know my front-end rig. The preamp was a Chameleon with two 6N6P tubes, Takman resistors, Jensens, etc that I am preparing from my pal Dick N. I hope to send it, finally, this week Dick.
This was a sort of email/note update and not a full report.
Made another x-over adjustment and it now sounds unbelievably sweet, natural and extended - vastly better than the previous version. I may still have a bit of adjustment to go as I might have moved the x-over frequency up a bit. Still if I had to live with it like it is I could handle that forever. Maybe it's just too seductive to screw with.
We finally finished up a Hafler XL-280 we had been working on. It is the first with a full complement of Takman resistors. It is totally amazing, period. It was breaking in as I listened last night. It's maxxed out. For the full description look at our Demo/Used page. I've never heard anything so open and transparent. I had some good listening last night.
Session on 08-19-10
As before this is my take on the proceedings, but Dan you may wish to add your thought and forward them too.
I guess the prime focus was progress on the Advent speaker redesign but a lot of other ground was covered too. The Advent(New Advent A3 version actually) was used for all listening but we'll get to that later. We can discuss whether this has been a sane use of my time later. It certainly has refocused my thoughts about drive requirements of speakers.
* We began listening on an XL-280 that I had just finished up, a real upscale item now on our Demo/Used page. It all sounded nice on average but as Dan pointed out it didn't have that freedom we crave. He was skeptical of the changes in the speaker at this point. Some of that might be marked up to break-in but not enough. I had recently added the double current MOSFETs to the already upscale DH-200 amp for the owner of the Advents so naturally we put that into the system. Yes, there seemed to be a greater ability to drive the speaker with the burly fets providing a more freely dynamic quality, but there still seemed to be a limit which was reached and then a sort of dryness set in. Also it didn't really seem to move dynamically in scale with the music giving a compressed sound. We returned to the DH-500 which we used last week and it took all of 3 seconds to hear that it was the only amp for these speakers. Now they were free, open and dynamic with images independent of any veiling and with a scaling of dynamics that was totally believable. Lord those Advents are inefficient. (The listening room is fairly large too probably not helping with the efficiency issue)
* I had added Cardas copper posts to the speakers and adjusted the crossover, adding a resistive L-Pad, not the rheostat thing. I thought the adjustments would allow for the sound, with grille cloth, to be balanced and coherent top to bottom. That required a slight cut in tweeter volume. This seemed to do the trick and remove the last vestiges of a feeling that the top though smooth was at a bit higher level than the bottom. Now it seemed that the x-over point was smooth too.
* During listening we had played around quite a bit with the Chameleon, using two different preamps and a few different boards. Dan had really not heard the changes that the Chameleon can express with different tube boards. I installed the single 5687 board which still has a BlackGate / polyprop bypass on the cathode resistor. While it was intriguing there was a definite chest cold quality to vocals. I simply removed the jumper to disable the cathode bypass and it was much smoother and more natural though we had lost some of the staging and freedom. Away to the bench I went with 5687 board in hand and I removed the BlackGate and it's bypass. I installed a Silmic II and just left out the bypass. Wow, what a brutal butt kicking the BlackGate sustained. I don't think I've ever heard the difference that starkly rendered. At that point the 5687 board was kicking rear assertively - sounding really great.
I guess I can sum it up in that:
The Advents, with Dan's blessing too, are pretty much ready to ship.
After seeing only a bit of the versatility of the Chameleon I think Dan said something about wanting one.
A little more planning on his Threshold Stasis 3 mod was discussed.
If the economy ever improves the 300 Watt mono is on my to do list.
Some 'new to me', excellent beers were tested and approved.
Somehow a last minute listening session took place last evening(08-26-10). I thought it was too late to call Chris and Sturgus. Again it was Dan J. in attendance.
1.) The Stasis 3 has a bias issue that was quite common to the amp as I understand. It was decided to fix the issue before going off and buying cool capacitors and so on.
2.)The x-over change to the Advents was a big focus. I can still barely believe I'm working on speakers. We started out the evening with exactly the same Chameleon preamp/mod DH-500 amp/5687 Active Board as last Friday, but they had a week more burn-in on them just like the speakers. Dan was attributing most of what we were hearing to the burn-in and to some degree he was clearly correct. I assured him though that the slight update to the tweeter x-over had made a lot of difference. How much? Enough to change human behavior I say. Thursday night after I made the change I sat down to some listening. I'm guilty, like a lot of listeners, to want that buzz of our favorite cuts from a disc. Maybe you just play a disc for one cut, maybe two or three and then you move on to the next disc for delectable cuts there. Things were different that night. I would play that favorite cut, the next one would start and I'd think I wanted to listen to that next cut too. I found myself listening to full CDs , moving to the next CD and doing the same. I heard and appreciated some music I had barely known about before. That's why I say this speaker changes human behavior - in positive direction too. I know it is hard to believe that this speaker can be that good. I would say that if you think a modern speaker is really going to sound more like real music regardless, then you might be in for a surprise.
3.)It's hardly a surprise that an all-out Chameleon preamp would outperform the base model. More surprising is how well the base model acquits itself, but more on that some other time. This preamp has a custom outboard power supply with dual toroid power transformers, Jensen four-pole caps, a DC heater supply, Schottky rectifiers and our favorite Ixys HyperFred bridge rectifiers. There is a totally separate phono and line stage section in this outboard power supply. The actual line stage is a Chameleon Elite with Jensen four-pole caps, Aura-T Teflon coupling caps, Takman, Platinum and Mill's NI resistors. The phono stage has (2) 12AX7 and (2) 12AT7 tubes in SRPP mode with passive RIAA compensation. We did not get around to listening to phono Friday. As you would imagine this preamp was immediately superior with a very smooth character and vanishing background noise. The line board had some break-in but the power supply was brand new. It was very impressive in it's listenability, highly resolved micro-detail and utter naturalness.
4.)Active Boards are the heart of the Chameleon and several transplants were done. These were all pretty much done in the Elite model. The 5687 tube PC-2T Active Board was sounding very natural with lots of subtle texture. We tried it with and without cathode degenerative feedback. Silmic II caps are the real treat for a cathode bypass easily outshining the BlackGate in this function. We both liked it better with a cathode bypass. It seems like this is the case all across the single tube active boards. At this point I recommend, for my tastes, using cathode bypassing without reservation. I hope I don't miss a board here but I think the PC-1T 6H30Pi Active Board single tube board was next. I think we tested two different plate currents too. It was good and in some ways beat the 5687 but something was missing. We next tested our PC-4T Active Board with moderate current and the 6N6P tube. This was really good with a notable quietness and low distortion sound. It played big dynamics with authority. Very impressive. Finally as the night was growing lengthy we tested a higher current version of the dual 6N6P board. Now that got our attention. It was even more authoritative and natural than the medium current version. So far it's the board of choice. Wow!
Bye for now!
Comments from Dan J.
I've a few comments to ad to John's assessment of the evenings progressions with the preamp. The Silmics yielded improvements in sound-stage with a glorious black background. I'm so impressed how this cap presents micro dynamics within space without smear or the slightly forward presentation I think common to the BlackGates in the preamp.
Now that Advent speaker is truly impressive at this stage of development. Perhaps John might consider adding the Classic Dyna A25 as a candidate for modification in the future. Mine are modified otherwise I'd volunteer them.