SHOD question

[Orson]

Hi,

I'm new here, but I've been building the vero layouts by |V| and others here for a long time. I laid off for a very long time (years) due to family stuff, and am now picking it back up.

I have assembled a SHOD (2nd layout). I'm stuck because the out put on the switch doesn't go to the vero board as is so often the case. The output apparently comes from volume 2 to the output jack. So is the output on the switch not used? Do I just leave that switch lug unwired and wire the vol 2 to the output jack?

Thanks!

[IvIark]

Hi Orson

It's wired exactly the same as the other effects, it's just the output goes from the Volume pot instead of a wire from the board.  

If you look at the first layout on the Offboard page, the blue Output wire is instead the Volume 3 wire which goes to the pot.  Volume 1 is connected to ground and then Volume 2 is the real output which goes to the top right hand lug of the stomp switch in the drawing

Good luck with your build

[Orson]

Hi |V|ark,

Thanks for the helpful reply.

I've been referring to the layout on the offboard page through this entire wiring job. I can't believe how much I've forgotten! So, to be clear, I just run the wire (blue top right hand in the diagram) from the switch to lug three on the volume pot then?

[IvIark]

Yes. It’s the same with most layouts that have a volume pot at the end of the circuit.

[Orson]

Okay, now I know! Thanks for the help.

[Orson]

One last thing - there are two grounds on the right hand side of the vero board. I have the ground from the DC jack going to the bottom ground. Can I tag the upper ground to the other jack, or inside the enclosure? Does it matter, I mean, it's all ground.

[Orson]

Sorry to keep bugging you with this stuff. You said volume 2 goes to the top right hand of the switch, and volume 3 is the blue output wire that goes to the pot. So volume pot lug 3 goes to the board, and volume 2 goes to the top right hand lug of the switch?

[IvIark]

Yes, all grounds need connecting up so do whichever way is best for your build. When I have a ground strip top and bottom of the layout like that I would usually have a link somewhere in the layout making the connection. But in that case there was nowhere to cleanly put the link without increasing the width to 22 columns which would make it difficult to fit in a 1590B box. So I just used two separate ground wires shown with the assumption that you would just daisy chain from one to the other.
So connect all grounds up to the same point. You could even use spare holes in the top or bottom ground rows and connect the off board grounds from jack sockets and DC socket to those holes. Or daisy chain between the lot of them, whatever works best for you

[IvIark]

Orson wrote

Sorry to keep bugging you with this stuff. You said volume 2 goes to the top right hand of the switch, and volume 3 is the blue output wire that goes to the pot. So volume pot lug 3 goes to the board, and volume 2 goes to the top right hand lug of the switch?

Yes that’s correct. Don’t forget pin 1 to ground or the volume pot won’t work correctly

[Orson]

Got it, thank you so much!

So it's up and running. Are you, or anyone else here aware of any way to increase the gain or drive? I used red LEDs thinking it would increase the compression and breakup, but I'm not sure it did. I assume increasing breakup via the clipping diodes would be to go to something with a lower vF. Maybe 1N914s or 1N200x? If memory serves, if I use green LEDs, that would decrease the breakup further.

Also, it seems a bit bass heavy. Is that something that can be shifted upwards?

[Silver Blues]

Quite a late reply on this, but no, going to LEDs will do the opposite of what you indicate, it will reduce breakup and compression because the forward voltage of an LED is higher (in some cases much higher) than a typical small-signal silicon diode like a 4148, and thus will not start clipping until it sees a much stronger signal. If you want to go far in the other direction what you want is a germanium or Schottky diode with very low (0.25 V or less) forward voltage.

[Orson]

Hi Silver Blues -

thank you for the reply. What I meant was that going to an LED with a lower vF might reduce breakup and compression. I thought green LEDs had a lower vF. I know not all LED vF are the same. So green LED are higher forward voltage?

Any ideas about the dark, bassy tonality? It seems like the tone control needs to be shifted upwards. I bought an actual MP Sweet Honey, and the one I built starts to sound like the actual SHOD when I crank focus all the way CW. Although it might be something else. Really frustrating. It sounds good, just too dark and bassy. Not sure how to address that.

Your reply raises an issue. It's a shame that TBE has gone almost entirely dormant. It's not that the internet lacks for resources so someone can ask questions about all the numerous layouts found here. But it's so much easier to ask those who are familiar with them, and especially those who designed them (|V|ark, Miro, and others). I hope that one day maybe this place could become more active, without requiring anyone to create anymore layouts, even if I think there are some important layouts that have been missed. Kyle Chase's Fuzz Fella (Red Velvet\BC183, blue BC108, and teal BC109) are Fuzz Face iterations that really deserve the TBE vero treatment.

Thanks again Silver Blues, and good to hear from you!

[Silver Blues]

Sorry for the late reply here.

LED forward voltage tends to track with photon energy - so the lower energy light has lower Vf, i.e. IR < red < orange < yellow < green <blue < UV. Red LEDs usually have Vf in the range of 1.2 V and blue in the range 3 V.

Going to diodes with lower Vf will cause your signal to clip <i>sooner, so will actually increase compression and breakup. Seems that layout 2 has red LEDs; if you want less compression and breakup, you want to go to a higher Vf LED, for example a green or blue. If you want more compression and breakup, go to an IR LED or regular 4148s or even Schottkies or germanium diodes if you want to take it to the extreme.

There are several filters you can tweak to play with the bass/treble content of the circuit. The Focus control just looks like a variable high-pass filter, which with the stock values cuts off at 145 Hz (which is actually cutting quite a lot of bass). You could try reducing or removing the 100pF cap between pins 1 and 2 of the op-amp and/or the 1nF cap between pins 6 and 7; this will decrease the amount of high-cut in these stages. You could also reduce the 220nF in the first stage.