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)
I accidentally removed Andre's comment... Thankfully it was in the local cache so i could restore it:
ReplyDeleteAndré 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!
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.
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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.
ReplyDeletePs. thanks for a great site, your work rate is phenomenal!
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).
DeleteHmm.. 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?
DeleteBut it seems to be working nearly as intended! Should i tag it?
+m
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?
DeleteI'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.
Yep, 100k trimmer on the output did the trick, thanks Mirosol!
DeleteThanks to you. I added a note about volume pot and tagged it.
Delete+m
can i use 1nf instead of the 1.5 nf indicated?
ReplyDeleteYou could also use a 1nf and 500/470pf cap in parallel?
DeleteYour 2PDT switch wiring example is nonsense.
ReplyDeleteAlmost. Just forgot to mention it should be 2-pole on-off-on switch. Then it makes sense. The original has one position or "lo", middle position for "off" and one position for "hi+lo". With on-off-on switch it suddenly makes sense. I'll append this to the description. Thanks for noticing.
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I just built this, probably a bit late to the party, but I want to share what I found. The good news: the layout is basically OK, it "works". But there must be some problems with the original schematic.
ReplyDeleteFirstly, the input impedance is only 68k. This loads down the pickups and results in massive tone suck. But if you look at the Purple Peaker layout, it adds a 150k resistor in series with the input and a 680pF cap bypassing this resistor. These components raise the input impedance and restore the full frequency response when the switches are disengaged. They also bring the gain down to unity and make a volume control on the output unnecessary. All you need to do is install the 4u7 cap as the 100n is installed on the Purple Peaker, and add the 150k, 680p, and jumper as on the Purple Peaker. The result is reasonably flat but with a very gentle boost in the low frequencies, up about 5 dB at 20Hz.
The second problem is the gain of the "humps". The description claims 7 dB at 100Hz and 10 dB at 2kHz. In reality, these frequencies are boosted by about 25 dB, almost to the point of self-resonance. I found that adding a 15k resistor in series with each of the toggle switches brought the boost down to a reasonable level. An alternative would be to replace the toggle switches with pots so you could adjust the boost. Connecting to pins 2 and 3 of 50k log taper pots should give a good range. I suspect the Purple Peaker may have the problem of too much boost in its peaks.
Hello Eddie, nice to know you... I made schematic for the Yellow Humper based on your comments, I just wanna ask about adding 15k resistor in series to each of the toggle switches... Where exactly is the 15k resistor placed? before or after the toggle switch?
Deletethanks,
cheers from Indonesia.
I built this using EddieB's comments kinda. I put the 4.7 input cap on rows 1 and 2, then put the 150k/680p in parallel from row 2 to 4 and put a cut on row 2 under the first cut on row 1. I did not have 39K resistors so I used 33k, that caused a squeal when I had the treble maxed out,so had to add a 3.9k resistor in series with lug 3 of the 'high' going to ground to keep the squeal down.
ReplyDeleteUsing pots rather than the switches makes this more useable.
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