Thursday, 1 December 2016

Hudson Electronics Broadcast

Original info:
The Broadcast is a transformer coupled, discrete Class-A germanium pre-amplifier based on the classic broadcast consoles of the 1960s. In the low-gain setting, the Broadcast can cover everything from sparkling clean boost through to transparent overdrive, all with a healthy dose of volume available to push your amp. The Broadcast features a specially selected Triad steel-core transformer and a NOS germanium transistor. Advancing the gain on the Broadcast starts to saturate the transformer and the pedal’s discrete circuitry, giving rise to a gentle and dynamic compression coupled with subtle thickening of the midrange. With the gain switch in the high setting and the trim control wound up, the Broadcast starts to deliver heavier distorted sounds with a warm and fuzzy edge to them. The Broadcast covers a wide range of driven and distorted tones whilst remaining dynamic, responding well to pick attack and the subtle nuances of every player.

Thanks to Tipunk777 for reverse-engineering his own pedal in the Forum section.
There are 2 layouts:
one with a 24V charge pump and one without.
02/11/2016 Layout updated! Gain 1 was connected to wrong spot. If you've built the previous layout, just connect it to row 7, right above Sw1.




18 comments:

  1. Great job with the vero, Alex - thx for sharing. The lower gain tones on the video really shine.

    ReplyDelete
  2. Built the second layout. Used the wrong transformer. It works and sounds like the video, but my gain and low cut pots aren't doing anything yet. Just finished so haven't looked it over yet.

    ReplyDelete
  3. Found a soldering mistake and now low cut works.

    ReplyDelete
    Replies
    1. Thanks NDF!
      Do Gain and Low Cut work?
      Is it verified than?

      Delete
  4. Gain still isn't working. It got late so I stopped playing with it. In the schematic in the thread I think the 10 uf attached to gain 1 was 100uf ? Would that change anything?

    ReplyDelete
    Replies
    1. The 10uF is correct but there may be a mistake somewhere else:
      can you try to disconnect Gain 1 and connect it to row 7, right above Sw1? If it works you should reverse Gain 1 & 2 after.
      Please, let me know if it fixes it.

      Delete
  5. It's all working now. Did the layout change recently? I had been working from a screen cap of it and didn't have the cut on the bottom row.

    ReplyDelete
    Replies
    1. Yes Alex changed the layout as there was an error.

      Delete
  6. It sounds pretty cool. Better into a clean amp than a dirty one for me. I used a tm009 for the transformer. Not sure what sort of difference that has made

    ReplyDelete
  7. Where can I find these transistors? Are there alternatives I can use? Ta ~~

    ReplyDelete
  8. Replies
    1. and should the bs549c be bc549c? a silicon npn?

      Delete
  9. Yes I think it is bc549c instead, I used a bc549 and an sft 352 pnp germanium transistor. I have a bunch sorted by hfe and I just grabbed one with 70 or 80 hfe.

    ReplyDelete
    Replies
    1. Thanks, I'll keep looking around for this pnp... This pedal sounds great!

      Delete
  10. I always socket the transistors and try whatever I have, I've found most pedals aren't too picky if you use the right type. I imagine many npn silicons and pnp gemaniums would be fine for this circuit

    ReplyDelete
    Replies
    1. Hi NDF!
      Did you make the changes to Gain 1?

      Delete