To the page content
seventy years logo
Join Thomann's Anniversary! We award your loyalty with special offers! Get your deals

Adam Hall 5635 Humfrees M6


Rack Insulation Against Ground Loops

When rack mounting, additional conducting ground connections are created between 19" devices via the metal rails - the most frequent cause of hum noise.

Humfrees interrupts these ground loops. Devices are attached to the rack rails while electrically separated from each other. Additional plus: The front panels of the devices are protected against assembly damage.

  • 4 M6 screws
  • 4 Insulators
  • 4 Spacers
Available since November 1999
Item number 128225
Sales Unit 1 piece(s)
Type Set
Thread Size M6
Length 16
Amount 4
Note Rack Isolation
Show more
The shipping costs are calculated on the checkout page.
In stock
In stock

This product is in stock and can be shipped immediately.

Standard Delivery Times

309 Customer ratings

4.1 / 5

You have to be logged in to rate products.

Note: To prevent ratings from being based on hearsay, smattering or surreptitious advertising we only allow ratings from real users on our website, who have bought the equipment from us.

After logging in you will also find all items you can rate under rate products in the customer centre.


137 Reviews

bad product
ColmO 18.03.2014
its only true purpose is to prevent against rack rash, it does not isolate equipment from each other, rather it isolates the rack equipment from the rack rails, so if 1 unit is causing hum this will transfer along each unit as their faceplates arent isolated

the screws dont fit my adam hall rack or gator case, it comes with a soft adapter for smaller screws

you have to cut the pieces out of their molds which isnt too difficult, but takes some accuracy to get them looking smooth with no bits sticking out.

the rubber/plastic warps/goes out of shape and shift position before you have the screws tightened, its difficult to gauge when its tight enough, when it feels tight your left with a misshapen piece

I dont normally right reviews straight after using a product but was so let down by these that I felt the need to write a review. some old bicycle inner tube would work better, or 2 plastic washers per screw would achieve the same


Your rack deserves the best!
SpyX 14.06.2018
Your rack deserves the best.
If you are a pro you don't need my advice, you know what you'll do. But for the rest of us who build a rack I'll tell you that, this set is a must for your rack.
You have spend a lot of money to buy audio hardware devices, you want the best for your sound so the last thing you want is hum from ground loops created between 19" devices via the metal rails.
Here comes the "Adam Hall 5635 Humfrees M6".
Consists of (4) M6 screws, (4) Insulators and (4) Spacers this is a set for one device. In a very good quality it'll give insulation to your rack against ground loops and protection to the front panels of your devices against assembly damage. Also looks nice aesthetically.
Coming in a good price, don't even thinking to don't make this buying.


Quite good
svenoxtoby 11.05.2017
I have used these in many racks with both M5 and M6 screws. These ARE compatible with both M5 and M6 screws because adaptors are provided for M5 screws.

As noted by another reviewer the can get mis-shapen if you are not careful, but this has only been a cosmetic problem for me.

As for isolation, they have worked every time for me (tested). I have not had trouble keeping the faceplates isolated. Important: when testing for isolation/continuity, remember to unplug all of the power cables from power distribution unit to rack devices. Otherwise the meter will indicate continuity, since the devices are joined through the PE/ECC conductor of each piece of gear (and this is how it must be for safety - NEVER cut a ground/PE/ECC conductor.


Product is fine but a few quality issues
MrMesh 21.03.2019
I bought about a dozen of these to try and help deal with hum issues from my rack gear. For the most part they are effective, but at times the installation is troublesome and the the plastic that wraps around the rack ears is prone to breaking. In addition, the heat shrink around the screws can either come loose or isn't secured properly to the screw, so a heat gun is required in the event anyone has similar issues.