Very nice RCruz.
Initial impressions. I came home with a RIAA. It wasnt the Simplistic
HAving been around the block with the Salas Shunt, I was not surprised by the black as night background, but he was. We had some hum, but I believe it was layout and trafo related. The 50Va hammonds I bought hummed from the very beginning. The shunt reg was set for 38V and 175mA. They should not be working that hard. Dissapointed to say the least. Hum was not bad, but noticeable playing classical and with volume cranked, naturally. You could tell the caps had not been broken in, having that compressed new cap sound. Not worried at all, as I am sure that will go away. As for the sound, It was wonderful. Punchy and dynamic. Clean with good overall presentation of the soundstage. Brother could not get over the fact that he was enjoying a SS RIAA so much. He said it was the only other SS RIAA he had heard the he liked, with one exception being the XOno. Not bad company. I look forward t more listening, as I know the caps will continue ti develop and losen up. IF this thing decompresses like I expect, I will have a big hats off to Salas. I do trust his ears. Brother told me to get the best componenets I could. I will be looking at Auricap or Multicap, leaning toward Auricap. I am considering going with Rush's DCB1 output, As we want to use Vcap in the output and 2uF Vcap is borderline crazy. I have not put it on test bench officially, but It is very quiet. It is my hope that we are reaping the rewards of the SMD parts and excellent design of Salas in both the Shunt and Riaa stages. I want to try to find the 369, as I want the lowest noise option. Any help here is appreciated.
What can I say, Salas. Another winner. I may pick your brain about layout to make sure it is not an issue in terms of noise. Thid thing deserves a concentrated layout attempt. It will only get better.
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See to sort out the hum issues first, box it up in metal and use coax for signal. Tx & rectification in separate box. Even with new lytics its the hum that adds low freq harmonics and sounded kinda squat. Good start nonetheless. 60dB totally quiet phono ain't easy in the open, so far so good. Congrats.
Salas,
Any way to use 12 mA idss 369? I have a pair at 12 I would like Buzzforb to use, if you could make the circuit work for that high idss. Is it a whole new design?
Rush
Not in our test, it was the same like the telescopic with open lid in same box, psu and grounding arrangement. Had no hum or buzz. It will pick up from a contaminated ground as much as a telescopic from a contaminated rail. There is no high gain phono we can afford to roughly test unpackaged and expect no hum nonetheless.
The 369 will beat them below 300Hz only. Gate capacitance is roughly the same for one 369 and two K170. You will lose 1.5dB gain with the single 369 in this circuit.
P.S. Having two positions already its easy to check one or the other config.
Salas,
redesigining everything and working on the PSU. I am going to have the Toroid in a seperate case, with shielded umbilical bringing the secondary voltage into the main case. I am unsure of how to ground the main case to earth. I will bring earth in the umbilical so the case can be grounded. Just wandering if I just run a wire from the prereg ground to earth ground, sperated by dual diodes. Any suggestions on wire up for quiet ground?
redesigining everything and working on the PSU. I am going to have the Toroid in a seperate case, with shielded umbilical bringing the secondary voltage into the main case. I am unsure of how to ground the main case to earth. I will bring earth in the umbilical so the case can be grounded. Just wandering if I just run a wire from the prereg ground to earth ground, sperated by dual diodes. Any suggestions on wire up for quiet ground?