Earthquaker Devices Talons

[Alex]

Verified!

[Travis]

What a beauty! This could have been a real pig, but the way you've done the pin spacing for the caps and grouped the wires to the EQ pots couldn't be more perfect!

Thanks albru, excellent work

[Frank_NH]

Very nice!  And verified too.  Oh man...another build in the queue.  Thanks Alex80

(Edit:  unfortunately, there go all my remaining 10K resistors... )

[Synsound]

Wow! That looks awesome. I've been itching for new stuff to build. Thank you.

[negativefx]

Nice job man, the layout looks great

[motterpaul]

A really outstanding layout. Thank you so much and I really hope you do more.

There is nothing wrong with the layouts done by the regulars here - they work fantastically, but the symmetry you managed to achieve, I imagine that wasn't just an accident. I'm guessing you worked quite awhile to get it that way.

[Synsound]

Just finished it up and she works like a charm. I had to use 3mm clear LEDs as I didn't have 5mm. Do you think it would be worth ordering 5mm or are they just the same thing with a bigger housing? This is getting boxed up for sure. Tons of control and low noise even at full gain. Thanks again.

[IvIark]

Nice job buddy

[rocket88]

They might have a different forward voltage, but I'm not sure. I think I have some 5mm reds that I can measure for you if you want.

Edit: I tested both when i got home

3mm Water Clear LED - 1.90V
5mm Water Clear LED -  1.82V

to me, it's close enough that it shouldn't matter if you use 3mm or 5mm.

[Synsound]

Thanks for taking the time to check on that.

[rocket88]

Any time buddy. Always happy to help out, and it took 2 seconds. Oh, tested them with my DCA55.

Btw, I found something rather interesting. I tested my green, blue, and white water clears and you know what I found? All three have relatively the same forward voltage. Each of them measured a forward voltage between 2.80V & 2.95V. I didn't test the diffused LEDs, but I'm actually genuinely surprised that blue, green, and white water clears have basically the same forward voltage.

[motterpaul]

I built this and it works well. But I noticed in the demo and here that the "presence" doesn't seem to do much at all.  Now - this was the only perfect fit part I didn't have so I used a 10k pot.

Also - I don't seem to get much out of the treble and I would like to make the circuit brighter. I built this pretty quickly and it did work on the first try - so I guess I'm getting better, but I don't think I would box this up unless I could make it a little brighter - and when both "presence and treble" don't seem to have much - that indicates maybe there is room for mods.

Any ideas?

[Frank_NH]

I would eliminate the presence control altogether.  Just remove the 3.3 nF cap and jumper the pot inputs on the left.  

The Talons' tone stack is in fact similar to the active 3 band Baxandall shown here:



(This comes straight from the TL082 data sheet  ).

The Talons uses different pot values.   I don't know for sure, but if you wanted to increase treble, my guess would be to try increasing the treble pot from 100K to 250K and see what that does.

[Travis]

Thanks for the info Frank

It seems that rather than adding a jumper, one could also move the bottom leg of the far left 1K down two rows. I was also thinking of omitting the presence pot

[motterpaul]

I agree, thanks.

FYI: watch this from about 5:55  https://www.youtube.com/watch?v=e6_4zHC7Kl8

Just not that much on presence or treble. Still a very nice layout, though.

[Frank_NH]

Those guys a PrymaxeVintage make every pedal sound good!

Seriously, the reason the Presence doesn't work is because the 3.3 cap and 5K pot with the 1K in series form a low pass filter that starts rolling off highs at 8 kHZ!!  Maybe your dog will notice that...

In any case, why have an extra tone-related control when you already have a 3 band active tone stack.  Doesn't make any sense.

I also noticed that the Mid control had a wide range.  When he turned it all the way off, the overall sound really dropped.  That's probably because the mid scoop is way too wide.

The Baxadall active tone stack is supposed to be flat with the controls at noon and boost/cut the frequencies when turned right/left.  Try experimenting with the control pots.  I bet increasing the treble pot will boost the treble.  You may also find some resources online which go over how to design such a tone stack (outside of simulating it in Spice).

Let us know if you do any experiments.  I may try building this one tonight or Sunday, if I can get some quality building time.   

[motterpaul]

8 khz is not that high if you have steep slope (12 dB per octave) but it also depends on the scale of the slope the pot provides (how many octaves down from 8kHz does it affect the tone?) - an audio taper would seem to make more sense since it has a "thicker" response (more dB per octave)

But I agree, Obviously there is something wrong with the presence. Isn't "presence" usually a control over the amount of negative feedback? If it is just another LPF that is redundant and useless.

And like you said, the mid has tons of range. These are things beyond my understanding. They are the same types of pots - why would one be so effective and the other dead. I guess is all in the cumulative parts of the RC filter for each control.

I will take out the Presence and change the treble pot later on today. If you have more ideas lemme know.

[motterpaul]

Okay - I changed the treble pot to 250k. That seems to be a little high. In fact, I think the whole tone stack needs to be reworked because that somehow reduced the effect of the bass.

I am also curious - this has a very heavy fuzz. I am thinking the 3.2M resistor on the input may be way too high.

Unfortunately my soldering gun burned out. So, I went to Fry's to buy a new (a BIG electronics store in the West) and they were nearly sold out of all soldering guns. they had a few Weller and Hakko 20-watts, and some mega-expensive solder stations I just don't think I need.

There were also completely sold out of 10k resistors (any wattage except 1/2-watt), even in individual packs.

This is ironic, because with radio Shack gone we now have no other place to buy this stuff.

[Frank_NH]

Hi Paul,

Thanks for the feedback.  So the treble went up but the bass went down?  That doesn't surprise me as I've read about the shortcomings of the Baxandall tone stack and this is one of them ( i.e. the frequency bands interact such that modifying one setting affects the others).  There are some better three band tone stacks out there, so perhaps some additional research is needed.   It's also very likely that someone else has done this already...

[motterpaul]

There wasn't a lot of bass control to start with - and now there seems to be none. The mids are less also and when you boost it, its isn't a "good" freq - it's more of a low mid hairy sound.

I guess this pedal would be a good project for someone - but it just doesn't seem well-tuned to me. I mean it could also be the diodes and other things. Maybe if those were re-worked the tone stack would be better. Anyway - this just reminds me of why I tend to prefer other circuits.

I also thought "maybe single coil pups would work with it a lot better" because they are brighter, but they don't sound better, they lose their clarity.