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By way of explanation for those who are waiting for us to finish their units:I have two technicians, in addition to myself that do the mods. One tech is pretty much exclusively doing the Sony 999ES mods, as well as P-3A DACs, Link DAC mods. My other technician is pretty new to us and is helping primarily with building power supplies and will be helping me build the preamps.That pretty much leaves me personally doing the Pioneer DV-59AVi mods as well as the Denon mods. Some of these are behind and ...
Well, I have been working with various tube circuits as part of the mods and I arrived at a circuit type that sounded particularly good to me. I worked with it further and consulted with Alan Kimmel on various aspects, arriving at a sound that I simply had to make into a preamp.I feel that our preamp bridges the gap between overly tubey tube designs and hard/clinical SS designs. I prefer a sound that is accurate, detailed and dynamic with good bass response and high-end sparkle, but WITHOUT a hard, co ...
I opted for SS rectification for sound. I like the fast and dynamic sound of SS rectification. Tube rectification softens the sound too much for my taste. There is some additional cost, but really cost was not the deciding factor.I really like the sound of HEXFREDs.I also chose SS voltage regulation for the same reason.Thanks,Dan
Regarding the 12-- series tubes, I too prefer the 12AU7. The 12AX7 and 12AT7 tubes are meant for high-gain applications, such as phono stages and mic preamps. In this application, they are excellent, but in a linestage application, where voltage gain is secondary to current buffering, these tubes are not ideal.The key is to look at the tube curves for the tubes in question. You will find much greater linearity in the 5687, 6SN7, 6CG7, 6H30, 12AU7 and ECC99. Compare this to the curves for the 12AX7 a ...
Regarding our choice of construction methods, I actually chose PCB over point-point. The reason here is actually two-fold.1) Cost. Construction cost goes up exponentially due to labor/time.2) Consistency. It is difficult to get the same consistency when building units point-point. Spatial alignment of wires/conductors, etc., actually is very important with respect to RFI/EMI, ground loops, etc. I have actually built prototypes with point-point wiring and found that in the end I preferred the PCB b ...