Hi Midi,
The layout is important to me as I am designing a replica copy of the original 03458-66509 board but without actually owning one, so it all has to be done from photos like yours.
From the tests carried out on the vintage LTZ1000 parts, is there a conclusion that the vintage parts produce more noise than the modern parts?
Also, could it be these vintage parts were part of a larger set that were all tested / sorted and these were the parts that were not as good.
I wonder if the heater power is linked to this low frequency noise, so the harder the heater is driven (for the higher die temperatures) the more the die temperature fluctuates and creates a greater swing in the noise level. If the radiated and conducted heat loss is kept low, then perhaps the noise swing will reduce.
I know that it has been said running the LTZ1000 at a reduce temperature will dramatically improve the long term stability.
Running at a higher temp. accelerates the aging process towards long term stability, but at the same time reduces its life span.
Rob