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JHS wrote:The toggle switch (on/off/on) is attached to the FB-loop on IC1a and replacing the 1,2nF cap.
cap values are 1n / - / 2,7 or 3,3n.

Sorry JHS, I think I didn't understand: do you mean in the central (bright) position no caps are connected on the feedback loop and the 'normal' position is 1nF cap, right?

thank you

One might also like to add some filtering of the V+ and the Vr. Just a thought.

Jake

jakehop wrote:One might also like to add some filtering of the V+ and the Vr. Just a thought.
Jake

actually the unit I built "as-is" seems a bit noisy, I think some filtering would be useful... a 100R series from V+ followed by a 100 uF cap to ground could help getting rid of hum and RF, a 47-100uF form Vr to ground would too.

nooneknows wrote:actually the unit I built "as-is" seems a bit noisy, I think some filtering would be useful... a 100R series from V+ followed by a 100 uF cap to ground could help getting rid of hum and RF, a 47-100uF form Vr to ground would too.

That's what I thought. It's really good practice, and I do it in all my effects, as you almost never can have too much filtering, unless it's an amp we are talking about.

My clone was a bit noisy too, but after boxing it's dead quite.
BTW: An input hum-filter will alter the sound to much and IMHO it sounds best stock powered by battery.

JHS

My pcb layout (verified)

I have not included the 3 way toggle switch. To do this, replace the 1,2nF cap with two wires going to the DPDT on-off on and put caps of the preferred value (I used 1,2 / 0 / 4,7 nF)

The absence of power supply filtering, reverse protection diodes et. al. looks like it was a conscious choice by the pedal designer. The folks at Hao come up with some neat tricks to fine tune their pedals. My favorite is the Rust Booster - use one opamp of a dual opamp, and 'incorrectly' leave the other opamp unconnected.

JHS wrote:BTW: An input hum-filter will alter the sound to much and IMHO it sounds best stock powered by battery

in which way does it affect the sound? the only possible trouble I could think of is a slight voltage drop across the blocking resitor in series to the Vcc (usually it's circa a 100R) or across a diode if it's put in series too (0.6V), it could compress a bit the signal swing capability of the device, but we're talking about a distorsion unit...

The loose power filtering is part of the "sound-generation". With better filtering the RD will sound stiff and trebly.
I tried it already (with an NS LF353N) and there was an audible difference in tone.

IMHO there's no need for a better or additional filtering in FX devices, 'cos any common AC/DC adapter is well filtered and stabelized on the DC-side. Same for the absolute nonsens polarity protection. Any idiot is able to connect a FX with a 9V DC adapter w/o making mistakes (there's a socket in the FX and a corresponding plug from the adapter, so what can go wrong?).

JHS

JHS wrote:Same for the absolute nonsens polarity protection. Any idiot is able to connect a FX with a 9V DC adapter w/o making mistakes (there's a socket in the FX and a corresponding plug from the adapter, so what can go wrong?)

There's a sentence here that says "the mother of idiots is always pregnant". Sometime ago, not long ago, I lent a tube screamer clone to a person I know. He said that at his home the fx didn't work. Guess what? I found out he used one of those adapter where you can invert the polarity. My tube screamer has a diode...
thank you

I have a couple of questions for Mr. JHS;

1. When you talk about the drawbacks of extra filtering, are you talking about putting decoupling arrangements (series resistor, filter to ground)?, or just filter capacitors?

2. The evil diode protection is the series one?, because I can't see where the diode from ground to V+ can influence the sound.

Thanks in advance.

Help me!! Please upload HAO Rust Driver scheme with 3 way swith mode!

here you go:

https://i14.photobucket.com/albums/a303 ... IVER-1.jpg

nokaster wrote:here you go:

https://i14.photobucket.com/albums/a303 ... IVER-1.jpg

and where switch?

lkey,
look at the previous posts.
For example,

sadrew wrote:I have not included the 3 way toggle switch. To do this, replace the 1,2nF cap with two wires going to the DPDT on-off on and put caps of the preferred value (I used 1,2 / 0 / 4,7 nF)

You can always experiment with the values of caps. Have fun и удачи.

@fuzzer
I think there is more going on than only a voltage drop caused by the diode.

At least to my ears a circuit sound different if powered by 9V and a diode in series (8,4V on the IC) compared to 8,4V on the IC generated by a laboratory supply w/o the diode. When I dropped 0,6V voltage via R connected in series it sounds different too compared to a 0,6V drop generated with a diode in series. Without the diode and 8,4V (with R or laboratory supply) it sounded more musical to my ears.


For another comparison I've connected the diode in parallel to the power supply. Same voltage but some circuits produced a more muddy (similar to a heavy worn out battery) and others a more harsh and thinner sound. The difference in sound was not that much w or w/o the diode but clearly audible with any vintage circuit I've tested, but less audible if the circuit has a well-filtered bias-divider with 2x10k and 2 100uF electrolytic caps.

IMHO the effect of the diode could be minimized if the bias supply is generated via IC and the diode is connected in parallel with the power supply.

JHS

Thanks for the response. How do you explain the differences you hear with the diode in parallel? It is virtually out of the circuit?, ¿no?

Thanks in advance.

On vintage FX with loose or none filtering the effect of the diode ic clearly audible, sometimes more muddy, sometimes a stiffer tone. Very few 'til zero difference in tone if the bias-divider is well filtered or the bias is generated via IC.
If the FX is powered by battery the effect is more audible, if it's powers by a good filters net adapter less audible.

You can do the tests again with different bias dividers, different types of diodes and a single trannie boost (470k/470k - 100k 100k - 47k/47k - 10k/10k + different filtering) to hear if there's an audible effect of the diode.

IMHO if the effect is audible or not depends on the circuit design.

JHS

to be fair, JHS has ears that not all of us agree with, though they are good ears!

In most circuits I've built that had no protection, I've gone back and added it and retained all the same tone and clarity of befor the mod. That may or may not be due to the fact that my power supplies for my pedals are all the incredibly regulated kind, so I'm probably not making a lot of change by filtering, but it is good practice.

I just built the Rust Driver, and I must say... I'm pretty impressed. It sounds really good through my Fender Blues Jr. I had to use a TL072, because that's the closest thing that I have to the specified IC. Anybody tried both? Is there much difference?

I also had to use a 47n instead of the specified 56n for the C1(in the schematic below). Would this make much difference?

I first tried a pair of 1N4148 diodes, and then tried a pair of 3mm red LEDs, and I think I prefer the LEDs. What other diodes are worth trying in this circuit? What about a pair of 1N34a germaniums or a pair of 1N5818s?

I'm not able to turn my amp up very loud at the moment, so I'm not able to get the full affect of the tone, but so far, I really like it. I wish the highs weren't rolled off when the volume knob is turned down. That's my only complaint, but it can always be fixed with an EQ pedal.

Here's the schematic I made following the Matsumin schematic, along with the perf/pcb layout. The layout fits nicely into a 1590A enclosure.

>HAO Rust Driver schematic and layout<