I indicated that I would provide you after the RMAF with a full break out of all the upgrades we now make to the 2.0 to bring it to the level of the 2.1.
Subsequent to my first post about the upgrade we made further improvements to the 2.1. These were in response to a slight high frequency edge we noticed in crescendoes, whether those of a female vocalist or of a symphony orchestra. After listening carefully, we concluded that this edge was really high output breakup. To solve this problem, we went back to the drawing board to figure out how to beef up the power supply so we could increase the output voltage and thus better handle sudden peak surges.
As a result, we increased the number of power capacitors and changed the number of rectifier diodes to permit us to increase the output voltage from 100 volts to 140 volts. To our ears this change alone resulted in softer highs, especially on loud crescendoes, and much more pronounced dramatic contrasts, as if the dynamic headroom had sudenly increased dramatically. In works like Scherazade, where sudden dynamic contrasts abound, we found the sense of raw power unleashed by the crescendo had vastly more energy than before, so that what formerly seemed fine and responsive, now in retrospect seemed compressed. We found this voltage change abounded in other pluses and resulted in no minuses.
Some of you, Sherod, for example, noticed an increase in gain, while Grannyring did not. Whether you do or don't experience increased gain will be a function of the tubes you are using and whether they translate the increased voltage into gain--Sherod's do and Grannyring's don't.
The other changes have already been described. The most important being that we upgraded the old multipath wiring harness from the RCA jacks to the volume pot and to the main preamplifier PC board and replaced it with a new upgraded Transparency wiring harness, which like the Transparency now comes wrapped in an extra isolating layer of Teflon for better noise suppression. The layout was also changed. Because of the better noise suppression of the harness, we were able to dispense with the line filter. For your interest the line filter was never a part of the n upgrade: it was always part of the original design and exists in the TP 2.0 as well. It will be returned to you for use elsewhere in your system if you wish. Because the internal harness is essentially an internal Transparency harness, like that cable, it needs almost 100 hours to burn in. The improvements that come from upgrading cabling are those that we experienced with this upgrade--better microdetail retrieval, improved harmonic texture, etc.
The next big change was to replace the Hovland caps, which also will be returned to you, with the larger, more expensive shielded capacitors we now use in the TP 2.1n version. In addition, we take a small 0.22 uf Solen cap and parallel it with the large cap. In our experience, this softened the highs and removed a slight high end burr without rolling off the top. The improved caps to our ears dramatically improved the soundstage, both side to side and front to rear and improved the imaging. We also found them to provide a less veiled sonic signature. The Hovlands are very smooth, but in comparison they are quite compressed and appear to mask the harmonic texture of the instruments. While there was a slight loss of smoothness with the new caps, we found the gains substantially outweighed the losses, and we abandoned the Hovlands without regret.
Some listeners, Sherod, for example, and another of our 2.1 customers, are hearing things as a result of the capacitor change, that frankly we are not, which is disconcerting, since we are finding it difficult to be of help because we can not reproduce what they are hearing. Joseph has actually gone so far as to replace the caps again with Hovlands in order to conduct an A-B to see if he can reproduce what the others describe, but without success. He wonder whether the increased soundstage of the new caps requires a slightly different speaker placement because of the wider and deeper soundstage. Frankly, this is just a guess, since we really can not reproduce what is being heard, and other owners and revieweres of the 2.1 do not report it.
The other changes in parts, e.g., by virtue of adding capacitors, contributed less to the sonic improvement.
If any of you are having problems with ground loop issues or tube microphonics, Joseph will look into them at this time.
Finally Joseph will inspect the preamplifier to be certain it is operating properly.
Some owners have tended to over-value the significance of the cap change. They are not the whole story, though in terms of cost, they are the biggest cost item--$85 with the Solens at our cost. Some have asked if they can install them. Sometimes, one sees very wide traces on the PCB. For example, we saw them at the RMAF. But wide traces increase inductance and thus impair the sound so Joseph's traces are very fine. Sonically this is a benefit but it means they are easily damaged, so we do not encourage replacing parts. Doing so without our authorization will void the warranty.
Finally, Joseph is finding that the entire upgrade takes him about 5 hours, longer than he had expected, so we are compelled to increase thee price of the 2.0 to 2.1 upgradeto $375, and the cost of the 3.0 to 3.1 from $400 to $475.
On an entirely different note, Joseph feels he has gone as far as he can with the 2 series preamp design. He wants to put his energies to designing an amp and to designing a dual mono design preamp with upgraded hardward and parts, just to see what he can do when he is not preoccupied with meeting a price point.
The amp is a source of concern since there are so many ways to go.
Soon I will place a post asking for some direction from you. I will also in the next couple of weeks post a report on the show.
Thanks for all your ongoing support.
Victor
