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debugging time

Posted by vinnie2 on June 21, 2017 at 07:30:49:
Got a breadboard put together (see link) but I am having trouble getting it to work properly. I am getting sound out the other end, and it sounds ok with low B+, but as I increase the b+ toward what it should be it starts breaking up and distorting.
I had to make a few changes due to not having the parts I needed as follows;
1.I used a 6dj8 driver as I do not have a 6n1p and it appeared from the text that either would work. It sounds better than the 12at7 I first used.
2. For my b+ for the driver I just used a clip lead from the b+ connection to the opt to the 4.3k (I used 3.9k) resistor.
3. I looked in the tube manual and it said for 6bq5 in pp the cathode resistor should be 130 ohms, so I used that instead of 400 ohms.
4 . I used 0.1uf for the two capacitors between the two stages instead of 0.46uf, as per the recommendation in the text of the schematic.