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21/02/2014

Simple CabSim

Schematic

This is a nice and simple cabinet simulator designed by Lart. You can find more information about it on diysompboxes.com. What I really like about this cirtcuit is that it only does one thing and it does it well, without external controls this is a perfect solution to drop in a preamp stompbox or a D.I. box.


Alternative transistors

I have simulated it in LTSpice with pairs of PNP / NPN from different series. In the next plot you can see the frequency response using the specified BC560C/BC550C pair, 2N5087/2N5088 and 2N3906/2N3904.



As you can see, 2N508X come pretty close to BC5X0C, with 2N390X having a smoother curve.

Veroboard layout

I have drawn a vero layout to build it, its a bit croweded but smaller than I was expecting. I recommend using a multilayer ceramic for the 1uF capacitor.


My build

This is my build, I used 470pF and 220pF in parallel beacuse I didn't have any 680pF, and 2N390X pair being the only pair I have at hand.


This sounds really well with a 1W PUNCH amp, I'll post a video when I have it boxed up.


11/09/2014 Update: I have uploaded my LTSpice file for anyone who want to try it. Right click on the link and choose "Save as": SimpleCabSim_yeraym_vulcanofx.asc

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10 comments:

  1. pulse06/09/2014, 20:11

    Thanks yeraym, very interesting to me. I wonder could you share your ltspice files for this?

    ReplyDelete
  2. yeraym11/09/2014, 13:34

    Sorry for the delay, I needed to upload the file. I have included a link at the end of the post.

    ReplyDelete
  3. pulse16/09/2014, 22:10

    Thank you, works perfectly!

    ReplyDelete
  4. Boba726/09/2015, 19:39

    Thank you, really nice cab sim that I put in an enclosure with a headphone amp and a switchable jack out (for recording).
    Works perfectly (though it took me some time to get it working, it's quite a dense veroboard… :) )

    ReplyDelete
  5. cacopanda10/04/2018, 12:04

    This comment has been removed by the author.

    ReplyDelete
  6. Unknown18/05/2020, 03:07

    A mod suggestion: Use 330R for R25 instead of 100R, and use a 68k in series with a 100k variable for R23 instead of 82k. Can tweak R23 to taste or install a pot.

    ReplyDelete
  7. Kinski20/11/2020, 21:12

    Could I run this at 18v?

    ReplyDelete
  8. rere13/12/2022, 08:08

    is it possible to add xlr out? and how to wiring for xlr out?

    ReplyDelete