Thursday, 3 January 2013

Dan Armstrong Yellow Humper

Adding to Dan Armstrong library, The Yellow Humper bass booster. This layout is using two SPDT switches instead of the original setup. You could get closer to the original with using 2PDT, taking the ground to pins 2 & 5, Lo wire to pins 1 & 3, and finally Hi to pin 5 - leaving pin 4 unconnected. Personally i would still go with two individual switches...

It is rather similar to the Purple Peaker, but was designed specifically with bass guitarists in mind. With the Humper, the musician can select a single 7 db peak or hump in the frequency response centered at 100 Hz to give his instrument a very solid bottom range in the" 1 " switch position. If he selects "2" 'he will get the same low end peak plus a 10 db peak at 2000 Hz to enhance his overtones and presence. Like the Purple Peaker, the Yellow Humper improves the signal even in the "Off' switch position due to its low 200 Output Impedance. The Yellow Humper was designed to let any bass. and many keyboards sound more powerful without be­coming rumblv or thumpy. Like the Peaker. it is excel1ent for use in recording. The Humper's input impedance is 100 k Ohms, and its Signal-to-Noise ratio is a very quiet 92 db.

According to discussion, the board works fine, but it is recommended to use a pot for volume at the output. 100K log will probably be ok. (board out to lug 3, new output from lug 2, lug 1 to ground)


10 comments:

  1. I accidentally removed Andre's comment... Thankfully it was in the local cache so i could restore it:

    André Góis5 January 2013 01:26
    Great!
    Any change of doing a Maestro Parametric Filter MPF-1?
    I know it's a complex one, but it would be awesome!
    Thanks again!

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    1. That's four pages of schematic and it's not just complex - it's massive.. That's something i wouldn't even try to do.
      +m

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  2. Hi guys, had a crack at the this one and seem to get a pretty large volume increase just with effect engaged. The lo switch seems to work by adding an obvious bass boost (pretty loud at this point). Engaging the hi switch either with or without the low makes a constant high whining sound and distort the signal.

    Ps. thanks for a great site, your work rate is phenomenal!

    ReplyDelete
    Replies
    1. With the volume backed off it is a bit more manageable, then you just get the whine when the high is engaged by itself (rather than with the low).

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    2. Hmm.. You could solder one 100K trimmer to a 3x4 piece of vero, take that as volume pot (1 to ground, 2 to output and 3 to board's output). Do you think i should add volume pot to the layout?

      But it seems to be working nearly as intended! Should i tag it?
      +m

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    3. Thanks, I'll try that out, I was backing off the guitar volume so might that suit a trimmer on the input to the circuit?

      I'm not sure if it is working correctly though, here's quick sample. With the effect bypassed it is very quiet. (bypassed, on, low sitch, low + high, high).

      http://soundcloud.com/cliffmustard/yellowhumper

      I've probably made a mistake somewhere but can't see it yet.

      Delete
    4. Yep, 100k trimmer on the output did the trick, thanks Mirosol!

      Delete
    5. Thanks to you. I added a note about volume pot and tagged it.
      +m

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  3. can i use 1nf instead of the 1.5 nf indicated?

    ReplyDelete
    Replies
    1. You could also use a 1nf and 500/470pf cap in parallel?

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