DC Blocker Trap Filter – Assembled in Case

Fully Assembled DC Filter/Trap/Blocker in a steel case with ability for mounting different AC Outlets types depending the customer’s choice.


  • USD: 92.59$


Nowadays the AC mains network is heavily polluted by various domestic appliances, industrial electrical consumers etc. This can lead to buzzy toroidal transformers (especially the power ones). Proposed DC trap (blocker, filter) will remove or at least lower the buzzing.
Schematic is similar to this one used in well known Vladimir Shushurin’s Lamm-1 amplifier. An article with in-dept explanation of how DC blockers work can be found on Rod Elliot’s site (

Here I’m offering you a fully assembled DC Blocker in metal case.

Dimensions of DC Blocker: 122x66x140 mm. (WxHxD).
Weight: ~ 0.85 kg.
For detailed description of PCB and schematic, please see my other items for sale: PCB for DC Trap Blocker Filter for toroids and DC Blocker Trap Filter – Populated PCB.

DC Blocker is built with following parts:
MASSIVE 33 000 uF EPCOS capacitors
– high-voltage diodes/bridge rectifier
– 10W power resistor
– WIMA MKS4 400VAC capacitor
– MOLEX 3-terminal connectors for AC input/output
– Schurter IEC power inlet with fuse
– Schneider AC Power outlet (Schuko, French, Euro-American, United Kingdom) or IEC C14 outlets
– steel case black powder coated
– 4 small rubber feet underneath the case.

As you can see from the pictures DC Blocker is offered in 5 different variants of AC outlet – Standard European (German Schuko type), Euro-American type, French type, United Kingdom type and with IEC C14 outlet.

Note for United Kingdom customers (mainly): Due to specific of the UK wall plug, attaching it to the Blocker can be uncomfortable sometimes when DC Blocker’s AC Outlet is in the standard position. Hopefully it can be easily rotated to 90 deg. clockwise or anti-clockwise (see attached pictures).

Of course such rotation can be done with all other AC Outlets too! Just let me know what do you want upon purchase.

A surge protection with 250V rated varistor and 8A fuse (Schurter Slow-blow type) is incorporated at the AC input (fuse can be replaced with 10A one upon request).

All parts used are freshly obtained from reliable sources (Mouser, Farnell, Digi-Key etc.).

Since some people need a more power, a DC Blocker version with C19 IN and OUT Mains connectors is offered too (see pictures in the gallery). This version does not have fuse and varistor on the input – just C19 input socket -> DC Blocker board -> C19 output socket. This allows the max. handled current to be raised to 15A.

And even if you think that all sockets (IN/OUT) just hamper the AC power, solution is offered: DC Blocker without Input/Output sockets but with cable glands for direct cable attachment to the board – see pictures in the gallery. Cables with outer diameter of 10 – 16 mm. can be attached to the Blocker via cable glands.

The terminal blocks used in the C19 and Cable glands versions are bigger than standard ones in order to accommodate cables up to AWG-11.

Note: Since some of AC outlet types are not widely used in Europe, please ask for availability before committing the order. Also, when completing purchase, note the type of AC Outlet you want to be used with the Blocker.

What the buyer will receive:
The package will contain 1 pcs. FULLY ASSEMBLED and tested DC trap/blocker/filter for toroidal transformers (toroids) in steel case.

Weight 0.9 kg

EU Schuko, UK Plug, US Plug, French Plug, Cable Glands, C14 Outlet, C19/C20 Outlets

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