When I built my SSE a few months ago, I added switches for cathode feedback and UL. They not wired and I am thinking of using them to switch cathode resistors into parallel with the board cathode resistor.
In plain SE mode with 89db speakers (Polk rt600i), volume is not lacking even with the 5 or so watts. For this reason, I cannot imagine using UL just to gain extra power. What about cathode feedback. Given my Edcor opt's, I get great bass, but can only use the single 8 ohm output for feedback.
When I get my Pensils built with Markaudio 10p driver, they will be around 91db efficient.
What would I get with cathode feedback? What are the benefits? What should I listen for, if I were to implement it?
Thanks,
Charlie
In plain SE mode with 89db speakers (Polk rt600i), volume is not lacking even with the 5 or so watts. For this reason, I cannot imagine using UL just to gain extra power. What about cathode feedback. Given my Edcor opt's, I get great bass, but can only use the single 8 ohm output for feedback.
When I get my Pensils built with Markaudio 10p driver, they will be around 91db efficient.
What would I get with cathode feedback? What are the benefits? What should I listen for, if I were to implement it?
Thanks,
Charlie
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You may find it better use of your time to play with the stuffing in those Pencils as I found this has interesting affect on the bass, but let the drivers break in first. By adjusting the stuffing I found it affected the depth of bass and the imaging performance of the speakers when used with stereo.
Great replies and advice. I'll use the already installed switches for switching in resistors to adjust cathode current for EL34 and 6L6 tubes.
I am thinking of running 820 ohms on the board with two different values to switch in parallel to give 680, 520 and 500 ohms approx.
I suppose I could run tubes a little with lower cathode currents given that loaded B+ is 425 volts.
Thanks,
Charlie
I am thinking of running 820 ohms on the board with two different values to switch in parallel to give 680, 520 and 500 ohms approx.
I suppose I could run tubes a little with lower cathode currents given that loaded B+ is 425 volts.
Thanks,
Charlie
My SSE with cathode feedback
I built an SSE several years ago. I have a switch to select triode/UL and a switch to select cathode feedback on/off. I never use the cathode feedback. I have tried it several times with different speakers and different sources, and all I hear is a significant loss of volume without any change in quality. I have heard that cathode feedback can improve sound when using small or cheap OPTs. I have some decent sized Transcendar OPTs. I run old stock 6L6GC's. My B+ is just a wee bit over 400vdc. I do occasionally switch from UL to triode and back, but the difference is slight. I suspect you will be very happy with your SSE in permanent non-cathode feedback and permanent triode or UL mode. Enjoy.
I built an SSE several years ago. I have a switch to select triode/UL and a switch to select cathode feedback on/off. I never use the cathode feedback. I have tried it several times with different speakers and different sources, and all I hear is a significant loss of volume without any change in quality. I have heard that cathode feedback can improve sound when using small or cheap OPTs. I have some decent sized Transcendar OPTs. I run old stock 6L6GC's. My B+ is just a wee bit over 400vdc. I do occasionally switch from UL to triode and back, but the difference is slight. I suspect you will be very happy with your SSE in permanent non-cathode feedback and permanent triode or UL mode. Enjoy.
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