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Diaphragm for Foster Fostex Speaker D-420

Part Number:D-420
Diaphragm for Foster Fostex Speaker D-420
SS Audio Speaker Diaphragm D-420
Diaphragm for Foster Fostex Speaker D-420
Your Price:$16.95
List Price:$24.00
You Save:$7.05


In Stock 350

Quantity Pricing

  • 2 - 3
  • $16.00
  • 4+
  • $15.00
Foster & Fostex Speaker Diaphragm Part # D-420

  • Voice coil: 1" (25mm)
  • Diameter: 1.75" (45mm)
  • Length: 2.875" (72mm)
  • Impedance: 8 ohm, DCR: 7 ohm
  • Phenolic dome with copper voice coil on Nomex former.
  • Fits Foster & Fostex N30, 025H30, H025N30, H025N27, H025N28, FT300H drivers and many others
  • See the "Fits Models" tab for all applicable cabinet and driver numbers. 
  • We also sell the long shaft Cerwin Vega version of this diaphragm. Part # D-420L
  • See our Cerwin Vega diaphragms page for details.

  • Our most popular replacement diaphragm!
5 Stars
fast turnaround,easy to replace.sounds like new again.thank you!
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Reviewed by:  from kansas city. on 11/10/2018
5 Stars
All Around Great
Very, very Good! Works great and good shipping
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Reviewed by:  from Seekonk. on 8/26/2018
5 Stars
I got the D-420 really fast ,thanks for that fast turn around, I installed it myself and Monitor is back working , but i should have ordered Two,,,,,,,,thanks again
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Reviewed by:  from Indianapolis , In. on 8/16/2018
3 Stars
Was told this diaphragm would fit a particular Electrovoice tweeter used in a stage monitor. The screw holes lined up correctly, but the outer diameter of the phenolic base board was a few thousandths larger than the original, meaning that it would not drop in between the 5 locator pins on the magnet assembly. Forcing it into place would have warped the base board and likely caused issues. I filed the phenolic down in 5 places using a fine tooth flat file, and after a while was able to get it to fit. Whether or not my work was accurate enough to keep the voice coil properly centered in the gap I do not know. The speaker works, and nobody complained about it sounding funky. I am not the first buyer to experience this dimension issue. Simply Speakers may want to review the list of speakers for which this aftermarket diaphragm is claimed to fit. 3 out of 5 stars for that reason...............................Response from Simply Speakers: Thanks for the review. We have not run into an issue on this model in regards to the EV branded drivers and fitment, but will take a close look on the next EV driver we encounter to verify.
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Reviewed by:  from Yorkville. on 9/6/2017
5 Stars
End User
I bought some used speakers and found the mid range was blown, looking for a replacement and found that I could just replace the diaphragm was was easy and was a no brainer. No need to replace the whole speaker when you can replace just the diaphragm!
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Reviewed by:  from Houston. on 4/17/2017
5 Stars
plant manager
excellent product. good quality. quick shipping, under a week for regular ground shipment. much cheaper than replacing the whole tweeter. the sound is like new. highly recommended.
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Reviewed by:  from ontario, canada. on 3/24/2017
5 Stars
they work grate
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Reviewed by:  from Reidsville. on 2/27/2017
5 Stars
Residential Basement Bar Sound Guy
Customer support was excellent! Explained what I needed and cross referenced my part number. Very helpful! Fast shipping, fair prices will bring me back when the need arises! Many Thanks!
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Reviewed by:  from Blue Ridge GA. on 12/4/2016
5 Stars
The speakers arrived very well packaged and sound extremely good in my Speaker system. Thanks for carrying these replacements at a reasonable price
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Reviewed by:  from British Columbia . Canada. on 9/9/2016
5 Stars
This is an high end product and worked very well with my old type Yamaha speakers
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Reviewed by:  from Canada. on 8/31/2016


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