OK, I think I have all the relevant threads merged here.
Essentially, we have been working with a supplier for quite some time now who offered the ON Semiconductor MJE-350 at a reasonable price when bought in bulk. We had been purchasing bulk lots for quite some time, with great results, but the last batch we received were from a different manufacturer that we are not familiar with. Unfortunately, the supplier did not notify us that they made this substitution.
To that effect, some MJE-350's in recent Speedball kits may produce this defect where hum is encountered at 0 volume level. To remedy this situation, we can offer a replacement pair of MJE-350's. If your Speedball does not exhibit these symptoms, you would not want or need to replace these transistors.
If you are in a hurry to patch this up, you can purchase MJE-350's from your favorite local seller. A Motorola, ON Semiconductor, ST Microelectronics, Fairchild, Texas Instruments, or even an NTE-39 are going to work great! For those who have Speedballs or other kits using MJE-350's on order, we will not be putting these parts in your kits.
We do appreciate all of you letting us know that this was an issue, giving us some time to determine the nature of the problem, and we look forward to providing assistance to remedy this issue.
-PB
