by Blair » Fri Aug 31, 2012 8:08 am
I changed the title so I did not have to post another thread.
I should receive the MO-200A early next week.
Rather than doing this the way most people do it, and probably for good reason, I'm transplanting to a new chassis and modifying the PS.
A few design questions:
Regarding the power supply, the original design used a doubler. I see that the caps used were 450V. When you use a doubler, the initial caps used in the doubler do not have to handle the full voltage potential?
I'm adding a choke. Do you have to add a cap after the choke if the caps in the doubler are sufficient?
I'm adding a separate transformer for the screen Grids. I always hear that choke filters are best, but is there anything wrong with CRC filtering for this assuming that I only provide voltage for the Grids and the driver tubes plates?
Last:
I read somewhere that these are 5k primary output iron. I am only going off online information, so I will have to test these myself.
If that is the case, and I hook up a 4 ohm load to the 6.25 ohm tap, then the primary will look like a P-P loak of 3.2K, or if I hook an 8 ohm load to the 16 ohm tap, it would be a P-P load of 2.5K.
The EL34 looks to be a good choice for PPP into these loads. Is there any way to address the 700 ohm difference in loads between using the 16ohm tap and the 6.25 ohm tap?
Sorry if this does not make sense. I'm trying mostly to figure out whether to use a single tap, or put a tap to use with 8 ohms speakers and 4 ohm speakers even though the primary impedance will be different.
Thanks!
Blair