I am in the process of building a F5 Turbo. I am going to use 2 kits to make on high powered Class A Amp at 100 W/ch approximately. I see on the front end there are spots for two sets of transistors (2SK170/2SJ74). I am assuming that these two sets are there ao one can drive multiple output stages. Is this correct. Each output will have 2 N boards and 2 P channel boards. Can I get away using one set of the 170/74 combination or should I use 2? The board shows q1 and q1.1 as well as Q2 and Q2.1.
2 N/P output boards is 4 pairs. You should re-read the manual, it explains in more detail. Qx.1 & Qx.2 is for using a second pair of JFETs in parallel to drive the increased capacitance/high end roll off of 4 or more pairs. Also good for when lower IDS JFETs is all that you have available. You probably can get away with a single >= 10ma JFET pair for 4 OP pairs with a slight reduction in top end. Since F5 has top end in the MHz you probably won't notice. lol It's there as an option anyways. I personally used the 2 pairs with 8ma Toshiba JFETs & 4 OP pairs. Watch for oscillations! Good idea to use the 1nf comp. cap. as default plus other details in the manual.
TJ
TJ
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C3 & C4 are the 1nf (1000pf) comp caps.. If you're using 2N & 2P boards per channel, you only need one per.
TJ
Yes I used the compensation caps. That wasnt really the question. The answer I got that was what I thought is that there are two locations for front end pairs in case you want to parallel transistors when driving a large number of output transistors due to the buildup of capacitance and needed drive current. Just thought it would be a good idea to check.
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