I suspect that the energiser units needs some caps replacing.
dylanthecat:
After speaking to One Thing Audio, they suggested that it is normally the diodes in the energiser units that go.
They will, of course, do this work for you if you need.
The capacitors are NOT electrolytic in the DM70’s, so they are usually OK and One Thing said that the resistors are normally OK.
Apparently the diodes available at the time were not of a high enough rating, so tend to fail over time.
The bass drivers have green felt DIY surrounds that are not helping
It seems that the brother of the person who did mine had been active with your bass units!
I managed to get hold of a pair of 13 inch Leak Sandwich bass units in 8 ohm versions (most are 15 ohm).
These seem a good match in the DM70 cabinets, but will require four new mounting holes.
Wembley Speakers tell me that they should be able to redo my surrounds on my original speakers.
If you have the Continentals where the bass units have the curved front this may be your only option. (Some Continentals have a curved adaptor plate for the bass unit)
I currently have them hooked up to a pair of Williamson KT88 mono blocks. They are rated at 20wpc. I have been using these on my Maggies and Apogees to good affect. Do I need more power? I have a pair of NAD 214 that are 500+ when bridged.
Regarding power, that I think is personal.
I have an Art Audio Quintet which when in triode mode only gives me 15 watts, but seem to control the bass units well. Of course I can not get thrash volumes, but it still seems to go to realistic volumes with classical and most progressive.
When I tried my 70 watt Unico mosfet amp, I found that it offered very little extra headroom and no better bass damping, so I have stuck with my Art Audio.
