Happy New Year, Everyone!
I, too, have concern about the nature of noise in the system. I have been running the "new" Clarinet constantly during my awake hours for the last 6 days. The Clarinet and the new interconnects are undergoing a burn-in period. The system sound is changing enough to confirm that burn-in is real IMO.
The Clarinet is an excellent addition to the system that I am VERY happy with. Right now I have the Cornet2 and an Oppo DV-983H DVD player connected to the input with the third channel with no connection. When I switch between these inputs, the DVD player and the channel with no connection are dead silent until the volume control on the Clarinet is turned up to about the 3 o'clock position (nearly all the way). When the Cornet2 is selected, tube rush noise is evident and, as the volume is increased, a slight hum reveals itself. As I have reported earlier in this thread, I have been working on, and continue to work on reducing the hum. Whether it is a hum or a buzz may be an important distinction that I am not sure I can entirely distinguish. But this quest of noise reduction has been fruitful in moving down the noise floor.
A large reduction in noise occurred when I replaced my "economic" used tubes with NOS Telefunkens. The 12AU7 Telefunkens in the Clarinet were very quiet except for an intermittent ring. The ring was not volume dependent or input dependent. So it was evident that the ring came from the Clarinet. Tubesforever wrote that he experienced similar ringing that was solved by tube selection. So I tried swapping the tube positions and the ringing went away.
The Cornet2 is now the major focus of noise reduction. I have noticed that when I place my hand on the transformer, the Cornet TX is hotter then the Clarinet's. There is one more tube in the Cornet than the Clarinet so this may be the reason. But, I have a notion that heat is equated with noise (entropy). The first stage tube in the Cornet may be the most critical position for a low noise tube. Isn't this a reoccurring theme throughout the archives of this chat site? I've tried a GE, Mullard, Amperex Bugle Boy, and Telefunken 12AX7 tube in this critical spot and the the Telefunken is clearly the lowest noise winner in my system. Unfortunately, the Telefunken is also the most expensive. However, apart from the noise, each tube has interesting sound characteristics that could appeal to different tastes. The GE was used, noisy and used for component burn-in so its sound was not expected, nor performed to the standard of the others. The Bugle Boy added a liveliness to the music that is fun and beyond the laid back sound of the Mullard and Telefunken. I would likely be happy with the Bugle Boy if I could find one (they seem to be harder to find) with lower noise. The Mullard has a full, well behaved, maybe even lush sound that is pleasant that I would also be happy with if the Telefunken was not so quiet. But because the Telefunken is so quiet with a reputation of having a long life with little drift, this is my choice (today).
The laying of hands was an interesting experience. When I placed one hand on the Clarinet transformer, I could move my other hand over various components and places around my system to induce noise. I took this as a way to identify what items may benefit from further modification. I did a similar test with the non-shielded interconnects as written previously. When the noise increased when my hand or the cable was in close proximity to any item, that item was suspect. The shielding of the interconnects was very important in my system. These shields are connected only to the source ground lug. When I lift these connections a definite rise in hum occurs, so I am encouraged that something good is accomplished. In terms of the most critical interconnect, it seems to be the IC between the SUT and the Cornet2. The SUT can be quite noisy if not properly grounded. I have tried to examine my grounding system to determine where the center of the star grounding is. It appears to be the shield of the Cardas tone arm cable from the turntable at the SUT input. This arrangement provides my system the lowest noise floor so far (but is subject to further testing) and creates the largest hum when disconnected.
I have become very happy with the metal-based Mullard GZ34 rectifier tube. It was worth punching out the chassis to a 1.50 in DIA hole to accommodate it. It takes about 10 seconds for the red LED to turn green, so I feel much better about running expensive tubes. I have not done extensive measurements of the heater voltages so I am not sure how different the heater potential is. The GZ34 is reported to provide slightly more current then some of the other rectifier tubes. Am I correct to assume this?
The Clarinet sound may not exist. Just a clean amplification of what I imagine to be true to the source. A funny thing about the vinyl reproduction; the surface noise is not as noticeable as before. Either the music is more dynamic or the signal-to-noise has increased or the quality of the music has improved to the point of making surface noise superficial. Thrashed vinyl even sounds better. I bought the Beatles White Album for a buck at a garage sale that was trash but it almost sounds passable now that the Clarinet is in the system (sorry, but no lead to gold type of miracles). This is great for those old original jazz albums that have great sound but have been played (and played). It is difficult to explain the wonderful sound that comes from the Clarinet together with the Cornet2 without lapsing into overused verbage. It has become exceedingly difficult to lay a vinyl record on the turntable and become preoccupied by something other than the music. The first thing I do when waking up in the morning is to turn the Clarinet and the Cornet2 on to get them "warmed up."
The Clarinet and the rest of the system is still burning in. So more later...
May you all have a prosperous new year.
Ron
