My entry is nothing special with regard to the circuit. Even though it is remarkably similar to the design found on the
Boozhound Laboratories , I came up with the circuit myself after reading many books and websites throughout the year. I understand the purpose of each resistor and capacitor in the circuit and why I chose the value. Even though I have built several Bottlehead kits and other projects, I never understood anything about what I was putting together. Now I can look at another circuit and actually decipher what is there. This is a big step for me!
I was beginning to think that I would not have an entry either, but have managed to pull it together at the last minute. Then there was a horrible hum that would not have prevented my participating, but certainly would not have allowed me any chance of scoring well. Once I got that worked out, I was disappointed with the sound. Of course, I was playing it with my bench system - an old NEC external CD drive meant for a computer, into a Adcom solid state preamp from the early 90's with Spica TC-50 speakers. I turned the Adcom all the way up (literally) to get a decent level to listen. Problem was, there was huge amounts of audible distortion. In addition, the sound was dull and lifeless.
So, I swapped out the NEC with my ARCAM CD73 (which we will be using for the competition). Big difference! The level put out by the ARCAM was higher than the NEC, so I had to turn down the Adcom but there was still a lot of distortion.
Finally, I decided to bring the system into the home theater room where I have my ART Arrays and my Foreplay III. HUGE DIFFERENCE! I'm sure the Foreplay has more gain than the Adcom, but its only on the third click. The ART arrays are around 92dB while the Spica's are 84dB efficient (just looked that up didn't realize they were that inefficient). Now, the room is filled with sound (as arrays will do) without any distortion. No buzz, no distortion! I'm VERY surprised by the bass. I have yet to run it through some torture tests to see how much there really is, but on regular music tracks it is very pleasing.
Finally, after reading about Steve's linestage not working and our needing a continuously variable volume control I tried something I never tried before. I read somewhere that Lightspeeds should not be used to drive tube amps (not sure why, something about impedance mismatching or something). So, I'm using the Foreplay simply as sort of a tube buffer. I ran from the CD player to my Lightspeed Attenuator to the Foreplay III then to my amp. WOW! I'm really amazed how good this system sounds. I have the parts for another Lightspeed on the way for a different project - now I'm thinking I might want to follow it with a tube buffer.
I will be at Steve's early tomorrow to get things set up. This should be fun!
P.S. The chassis is a
cutlery tray and the transformer covers are
cutlery caddies from Ikea
