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Mods for the 205

  • Open Plan RecordingOpen Plan Recording
    Mark Chierego’s mod features a single layer headbasket, removal of waffle plates and various acoustic filters, point to point solid core wiring, Australian made ribbons (1.8 micron 99.9% pure aluminium), matched with either a Samar Audio Design toroidal transformers or the Lundahl 2912.
  • OktavaModOktavaMod
    Michael Joly’s “standard” mod for long-geometry Chinese ribbon mics removes mechanical filters and adds acoustical damping, resulting in improved LF and HF extension, better HF detail, and reduced mechanical resonance. The “premium” mod includes retensioning of the ribbon and a Lundahl transformer.

BidirectionalApex Electronics 205

Bidirectional Ribbon Microphone

The Apex 205 is the best-known retail version of Alctron’s HRM-8B, a large-format ribbon design that has, according to Oktavamod’s Michael Joly, “obvious internal resemblance to the AEA R84.” The same ribbon motor design can be found in the Nady RSM-2 and the Shinybox 46 (the latter being remarkable in that it has all the mods you’d want to do built in from the vendor).

Common mods for these mics include:

  • Re-tensioning sagging ribbons
  • Removing blast filters from behind grille
  • Swapping the stock transformer for a Cinemag (e.g. CM-9888) or Lundahl (e.g. LL2911) or Edcor (e.g. RMX1)

For sound samples of a shootout between the AEA R92, Coles 4038, and a pair of OktavaMod-modded Apex 205s, see drBill’s ribbon mic shootout on solo piano.

The Apex Electronics 205 is also known as: Apex205.


Frequency Response - BidirectionalClick Graph to Compare!
205 Bidirectional Frequency Response Chart
Pickup Patterns Pads & Filters
Bidirectional (2 mV/Pa; 30 - 18,000 Hz)
Ribbon Construction Impedance SPL/Noise
50x5mm, 2-micron aluminum ribbon 600 Ohms (Low) Max SPL: 165 dB
Weight Length Max Diameter Interface(s)
524g (18.48oz) 170mm (6.69'') 55mm (2.17'')
  • 3-pin XLR male (1)
Power Specifications

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