Thermion wrote:In the SCA 35 chassis, I built an all octal (6SN7) linestage using a common cathode circuit with CCS on the cathode resistor. Shannon has been helping me troublshoot some issue with the CCS and ground loops. We are close, but still have some work to do. The point is that it is more difficult to do a linestage than one of the power amps. There are just more things to consider that can affect the sound. This is probably why Shannon hasn't introduced a product yet.
Hi Guys,
Just got back from the great Northwest!
There are many reasons I haven't done a preamp, but Thermion probably hit the biggest one. His preamp has been a tough nut to crack. But we'll figure it out and be better for it. That's one of my goals this summer.
Thermion wrote:In the near term, I think the PAS 3 and Foreplay are good choices for DIYers.
I think a 'new' PAS3 is a great idea. Since you could get the original manual from Gary Kaufman, get yourself some spools of teflon wire and rebuild one. If it is half as fun as the ST70, it would be worth it and a learning experience. Can I mod any standard PAS3 to a PAS3X or does it require a special control knob? I guess you could always add filter bypass switches on the back.
I see Bottlehead has introduced the
Foreplay III. While not as inexpensive as earlier Foreplays, this still seems like a value. For the budget minded, I think the previous Foreplay would be an easy one to 'clone'. Reverse engineering all the step-by-step sites dedicated to the Foreplay make this fun, too. It is also a good lesson on Paul Joppa's circuit grounding techniques. For example, his SNR for the Seduction is excellent.
What do people want in a preamp? Some want a phono stage and some don't. I would want one in mine, so it would have the functionality of the Foreplay and Seduction. If a diytube kit, folks could 'leave out' the phono side if they so chose. I think I would also want to incorporate a stepped attenuator on the PCB itself - though I'm not sure how to switch it. Yellow_Light_Colorz_PDT_01
Shannon