Super Metal Pedal, I need more volume.

[gainrider]

Hello everybody
A month ago I built a typical MI audio crunch box pedal.

I noticed that something was missing and I added in series eliminating the volume potentiometer of the Crunch box the output circuit of a DIEFET.
Now it sounds thunderous, very forcefully. but it could have more volume.

But ... it lacked gain, grain.
I have added diode rectification in the second stage of the crunch box, it improves the sound a lot but loses a lot of volume. What I can do?

[Vivek]

instead of Si diodes in soft clip across IC 2

Try RED LEDs with 2k7 resistor in series with one and 4k7 in series with the other

[antonis]

Try LEDs of higher forward voltage drop on hard clipping configuration (LED pair to GND), or even delete particular clipping stage..

[Elijah-Baley]

I'm not sure if it will work, but what's if you encrease that R21 56k? Eventually decrease R27? Probably that voltage divider designed for the difet schematic works fine, but here cut too much volume.

What did you mean with this?

[...]
But ... it lacked gain, grain.
[...]

If you find it a bit muddy and you need more presence or high end, maybe R28 and C28 cut too much treble, you could decrease C28 and/or R28, or jumper R28 and take off C28.

[antonis]

Volume issue is output signal amplitude issue..!!
(it has nothing to do with particular or overal gain so long as signal amplitude is already hitting supply rails..)

2^nd stage gain (upper circuit) is X100 (multiplied by 1^st stage variable gain of a unity minimum..) so for an about 40mV_peak input signal there is 4V_peak IC1b output, which is the maximun obtainable amplitude..

That amplitude is further mainly dominated by hard clipping diode pair forward voltage drop..

So, don't try to raise volume by altering stage(s) gain 'cause you'll result into altering distorted waveform shape but not amplitude (volume)..

[gainrider]

Well, without any diode cliping, ( in the second gain stage, and hard cliping) it's sound loud. But if I connect hard cliping ( red led) the volume downs to 50%. And if I connect the second gain stage clipping diodes it's down to 15%.

It's a shit because with the second gain stage clipping diodes sounds amazing, but I need more volume.
😩😩

[antonis]

You have two options..

1. Use higher voltage power supply together with higher diodes forward voltage drop..
(same distorted waveform but of higher amplitude..)

2. Utilize an output booster..
(of a gain about V_BIAS / V_LEDFVD..)

[bushidov]

I had to do something similar to one of my "metal" pedal designs for similar reasons (tone stack volume suck). Like Antonis mentioned as option 2, add a boost stage at the end. Here is the one I ended up using on mine, as an example. Mine was okay having an inverting boost (common drain), but your miles may vary.

[duck_arse]

I had to do something similar to one of my "metal" pedal designs for similar reasons (tone stack volume suck). Like Antonis mentioned as option 2, add a boost stage at the end. Here is the one I ended up using on mine, as an example. Mine was okay having an inverting boost (common drain), but your miles may vary.

you need some gate bias on that circuit - a 1M resistor to ground, maybe.

[antonis]

you need some gate bias on that circuit - a 1M resistor to ground, maybe.

Ultra-meticulous attention to detail..

[gainrider]

Where I need to put a 1M?

I tryed the booster anda its run well!
But now I need to add Moré presece and tone on the half Of the pot. What Do you think I can Do?

[antonis]

Where I need to put a 1M?

Between Gate and Ground..

[Elijah-Baley]

In case you want to try again without that boost add you can increase R21 56k in the DieFet schematic. Indeed, now I found a recommendation about it on the original thread of the DieFet (in another forum). You cout try to replace that 56k with a 470k to increase volume.

For more presence you could jumper R8, and leave off R9 and C8 on the Crunch Box schematic.
Or maybe you can play around it replacing R9 with a pot, and see if you like more this Presence control or the Presence of the DieFet.
If you don't like none of them, just remove both without thinking about it too much, you already have the Tone control of the Crunch box.

[gainrider]

Well. I tryed all!
Puting 470k in r21 sounds better but I need the boostee too!
I try all preseces changes but I can find the sound I like.

Probably can I change something in the tone control?
I think that tone in 40% should be the 0% and the 100% the 100%? What can I do for that?

[Elijah-Baley]

To get more overall presence, more high end, you could change some parts that cut treble.
In the Crunch Box schematic you can decrease: C2, C4, C6.

I'd leave off R8, R9, C9, seeing you have the Presence control of the DieFet. This will give you more treble.
Change the 10k Tone pot with a 5k rev log (are you using a rev log, right?), and decrese C8 from 39nF to 10nF. This rise up the minimum setting, the range will be probably less wide, but more balanced.

If you want even a bit extra volume and still more treble jumper R27 120k (after changed the 56k with a 470k as I suggested before) in the DieFet schematic. And you can decrease C28, too. Ore leave it off.

The Crunch Box seems to be pretty "middie", so If all these changes don't make the sound bright enough, you should change in the Crunch Box the C5 220nF with a 100nf. This probably will give you a bit of less body, but even a more open sound.

You can keep the output booster, of course, if you need.

A lot of experiments, but I hope you can get the sound you like.