Dave
This is an ancient post. I know I have spoken with you privately. I have a DMC-10 that I have modified as you are aware. You can adjust the bias current in the output stages to deal with "heat". More importantly, you have to be careful you do not use too high a bias current in the output stages or you will create secondary breakdown issues in the output stage. The user's manual (and a few posts in forums) have recommended current levels that are safe and still sound good.
As to the mystic "wide bandwidth" stability issues, these are dealt with by using modern, upgraded power supply coupling caps. The best 105C electrolytics you can buy bypassed with a large number of high frequency NPO ceramics. These must be used both before and after the solid state voltage regulators. It also helps to put in some series output resistors and these will prevent oscillation with longer capacitive cables. Since I modified my DMC-10 I have never had an oscillation problem, and I had the unit connected to a 500 MHz digital OsCope for over a week trying to capture the nasties. Before the mods, I did see some low level oscillation at 10 MHz. Much over that will not be passed by the series coupling polypropylene caps in any event.
This is an ancient post. I know I have spoken with you privately. I have a DMC-10 that I have modified as you are aware. You can adjust the bias current in the output stages to deal with "heat". More importantly, you have to be careful you do not use too high a bias current in the output stages or you will create secondary breakdown issues in the output stage. The user's manual (and a few posts in forums) have recommended current levels that are safe and still sound good.
As to the mystic "wide bandwidth" stability issues, these are dealt with by using modern, upgraded power supply coupling caps. The best 105C electrolytics you can buy bypassed with a large number of high frequency NPO ceramics. These must be used both before and after the solid state voltage regulators. It also helps to put in some series output resistors and these will prevent oscillation with longer capacitive cables. Since I modified my DMC-10 I have never had an oscillation problem, and I had the unit connected to a 500 MHz digital OsCope for over a week trying to capture the nasties. Before the mods, I did see some low level oscillation at 10 MHz. Much over that will not be passed by the series coupling polypropylene caps in any event.