I had a similar problem with my dbx286s channel strip, and fitted a toroid to solve the problem.
This is the one I used:
https://cpc.farnell.com/multicomp/mcta015-18/15va-toroidal-2x18v/dp/FF01539
One thing to note -- ( and apologies if this is already obvious! ) --
If you do fit a bolt to mount the toroid, you
must make sure it cannot come into contact with the metal top cover of the unit.
If the metal top cover and the bolt make electrical contact, the bolt and the case will create a single shorted turn through the toroid core ... Not a good idea!!
How close to the top of the case the new transformer comes will depend on the vertical dimension of that transformer -- which may vary between types.
In my case I did not fit the bolt - nor the top mounting washer - but used double sided tape to attach the transformer to the bottom of the case, and a suitably sized pieces of neoprene on top, to ensure that the case top held the transformer firmly, via the neoprene. No chance of a shorted turn.
Couple of other points -- that may not apply to the 160?.
While my 286s performs well, the 'bean counters' at dbx seem to be in control, when it comes to actual construction.....
There is no on/off switch or primary fuse in the AC connection socket. Fusing relies totally on a single thermal fuse fitted directly to the cheap (and noisy!) original mains transformer.... ( Which actually also runs quite hot as well).
When replacing my transformer, I added an internal inline fuse in series with the live connection to the input socket, for my own peace of mind
(Not actually shown in the attached photo - I added it later) .
The replacement transformer also runs quite a lot cooler, and is now virtually silent..
When it came to recommending a channel strip to a friend, I was hesitant to suggest the dbx 286s because of the shortcomings listed above, so I suggested he might like to try the SubZero RS100 instead.... A lot more features, and quite a lot cheaper than the 286s. (About £100 + tax)
Not a well known item it would appear, from a quick internet search? ...
Some details here:
https://d1aeri3ty3izns.cloudfront.net/media/60/600722/download_600722.pdf
I suggested he buy from a well known dealer with a return policy - which he did.
He bought it here:
SubZero RS100 Recording Channel Strip at Gear4music
I think it could be that this is an exclusive item to that company here in the UK, so I'm not sure how easy it is to find outside the UK?
It performs really quite well - and has a primary fuse also fitted to the AC input IEC socket ... and an on/off switch, (which is perhaps a bit less important? )