Phono Circuit Difference Between Spectral Preamps?

I have always contacted Spectral via fax and got same-day response. Yes, it's because all circuits, including the phono is class A and the volume is very limited in the unit with no ventilation. Same problem exists with SDR-2000s, where eventually all caps need to be replaced (in the PS and main unit).

Because I owned both the DAC and the DMC-20, I now run my 30SL with a slow speed fan on top of the top plate.

@Ack question, I currently own the DMC 20 and soon will be upgrading to the 30ss s.2. Want to use the dmc 20 as my phone preamp. How is that done? Specifically do I use the volume controls on the dmc 20? Thanks in advance.

It is the heavy bias and regulation that runs through most of Spectral preamps. A few ventilation slots in the main unit's top plate and things would've been almost solved. However, the factory feels that any chassis open field would be grounds for stray interference and therefore oscillation.
Old time Spectral and owner here.

Fan

I was a (20) yr Spectral owner. DMC 12 Never a problem,(outboard power supply) A pair of DMA 360s, Goodwins original demo pair. Again, never a problem! Waited 5 1/2 months for a Spectral 30SV! For (1) week it was "Magical" Then decided that it did not want to play well with others! First with Manley Steelhead; Then it decided that it did not like my Pass Xono either!
So I recently divorced from Spectral ( was not going to wait for the Mythical Spectral Phono Stage! ) Bought a pair of Pass 160.8s driven directly w/ Manley Steelhead (rolled NOS Telefukens) last night. Wife noticed as soon as she came in the front door ; that the sound was even better!! 
I would have to say: Vinyl, Manley Steelhead (w/ Telefukens) , Pass 160.8s, Avalons. I am one happy guy now! Everything that I have searched for in the last 20+\- yrs has all come together.
The Spectral DMC 12 and power supply both ran Cool. The Spectral 30SV runs warm; just as it states in the manual. Don't know if this will affect its performance/ longevity. Happy that I decided to not put up with its Wide bandwidth circuits! Old tubes and Class A SS is even better.