Upgrade Your Dyna-70 Upgrade Circuit Card for Improved Sound Quality For All Automatic & Manual Bias Dyna-70 Systems A new product for 2024, yet one that is hard to explain why you need it… we will try to keep it simple. Most audio designs that use an LM-334 Regulator, implement it in an “uncompensated” manner. Meaning that as your amplifier operates and slowly heats up, the audio signal can be distorted by this heating, which is a result of using a silicon-based solid-state component.

Since silicon devices are known to have this property, one must cool the silicon to counter the effects of this phenomenon or, compensate for it as it warms. A good example is the application of heat sinks, cooling fans, and even water cooling for high-performance gaming computer processors. The original LM-334 was top mounted in the Dyna-70 PCB where the vacuum tubes heated the -334. We moved the -334 to an underside (bottom side of the Dyna-70 circuit board) location to shield the part from heat, which worked “OK” as a temporary fix (ref. ECN001 in “Documents”), but for us it was not good enough. We knew the best solution was a thermally compensated -334.

If you have a Dyna-70 Ultimate Upgrade system that was built in the past 5-6 years, odds are you need the thermally compensated SMT-334, since we just introduced these in late fall of 2023 this pretty much means everyone who has built a Dyna-70 Ultimate Upgrade kit. What if you do not upgrade? You will miss the ideal stereo image and channel separation caused by the warming, and the stereo image will “wander” and not be distinct or focused after operating for a few hours. We have in-stock and set of two is only $30.00