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Messages - thomasha

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Open Discussion / Re: The zombie chorus - it's a trap!
« on: December 08, 2019, 06:00:40 AM »
You can roud the square wave up to avoid the ticks, boss uses it too.
Take a look at fig. 3 here>

Build Reports / Re: Auquaboy deluxe
« on: November 24, 2019, 03:31:46 AM »
Wow nicely done!

How does it compare to the sabrotone mode previously used with the aquapuss soundwise? Is it darker than the single chip version aquaboy?

Open Discussion / Re: Tayda still slipping...
« on: November 23, 2019, 06:57:12 AM »
IMHO it is a point of perspective.

In some contries two switchcraft jacks cost as much as a joyo pedal. Comparing to local products Tayda was really good for the price.
I had open jacks from other sources that were so thin, that they would bend when plugin in. After some time switched jacks would not switch anymore.

Since I moved and had access to quality hardware at a reasonable price my opinion changed. It's not as bad as some other stuff you can buy on aliexpress for the same price though.

I wish Mouser were more acessible outside the US. With the huge catalogue they have it would be much easier. Even in Europe taxes and shipping are prohibitory for DIYers.

Build Reports / Re: Economy memory man, a simple analog delay
« on: November 20, 2019, 04:26:31 PM »
The led blinking is the overload circuit. THe led only blinks whe the signal is strong enough to distort the signal. When the level is maxed it is always on.

Build Reports / Re: Economy memory man, a simple analog delay
« on: November 19, 2019, 02:52:45 PM »
So, after building the deluxe memory man I decided to add another BBD to get more time out of this circuit too.

That small yellow cap goes to another BBD between the potentiometer and the output jack. I twisted the clock wires, in white, so that there is no clock signal going direct to the input jack (in my first attempt that happened...). Interesting to see that stuff learned with tube amps also applies here even at much higher frequencies.

To compare the new version of the economy memory man with the DMM I made a short video.

I played the same lick to show the different sounds. Now the delay of the dirtbag sounds shorter, but still much brighter. Both are nice builds, but in the video the dirt bag sounds much fuller, while the economy memory man is kind os sterile. On the other hand, the economy version as much more low end.

Tech Help - Projects Page / Re: Aquaboy oscilattion bleeding in bypass
« on: November 10, 2019, 03:07:41 PM »
Just to clarify, you’re hearing the clock whine, not the crazy oscillations when feedback is maxed? 
Are you using a 3PDT? Which wiring? Grounding the input or output when bypassed?

Tech Help - Projects Page / Re: Aquaboy oscilattion bleeding in bypass
« on: November 09, 2019, 11:08:25 AM »
Was the delay at max. delay time (fully cw)? Or is the whine audible at every setting.

Try adjusting the cancel trimmer for min. whine. Another possibility is to adjust the clock trimmer, so that when this pot is maxed the longest time is still at a higher frequency.

Thanks guys, I will try some different configurations, but to me it is already a good analog delay. The modulation is really good!

Put a 1uF between pins 6 and 5 (in series with the 68k resistor) of the compressor side. I found this on the Memory Boy when I was tracing it out.
I added the 1uF and a 6.8k resistor, as in the PDF

You can also try lowering the rectifier cap (pin1) to 470n or 330n.
I tried to understand how the compander works, and one of the questions I had was how the control scales for lower voltage (the rectifier and variable gain). I can try this.

This was designed at the time of weak single coils, you're cutting the headroom already by lowering the voltage so the input not offering a huge range isn't too surprising. Plus it wasn't designed to be true bypass so unity gain would originally be wherever the level pot was set.
That makes a lot of sense. The first thing I noticed when I finished it is that it sholdn't be true bypass. The level drop to achieve the clean repeats would never be a problem, plus it can work as a booster. In the send and return section of the amp sometimes it is possible to adjust the volume too, in that case it is just a matter of adjusting the signal going to the pedal and the signal coming backl. Not that it matters when everything is already distorted...


this project took a long time to be finished, but was totally worth it!
I started from the Dirtbag schematic and made my first attempt with SMD parts.

Many thanks for the Total recall and Dirtbag PDFs, they have a lot of info, and are really helpfull! The mods for the v3205 worked like a charm.

Got some tweezers and started this one. Well, the tweezers were too big for the 603 resistors,
but luckily my wife has some really sharp tweezers for eyebrows, and they were really good for the job.

I added all the v3205 mods to the layout, because for a first try I would not use expensive MN parts...
Let's see some pictures!
I used a double sided PCB, so the thermal transfer was interesting, but etching was OK. Here I already added the connections from one side to the other.

Then some components:

I wish it looked better. My early mistakes are highlighted with green wire. Maybe in my next layout I do a better job designing both layers, so that 2 layers are enough.
The small board is for the SA570 and the first TL072. It fits over the pots, between the enclosure wall and the input jack.

A view from inside the box:

The input jack moves over the pots when the cable is connected. The gap is really small.

Then a crappy pic of the build:

I soldered everything like a lid, where most of the wires to the pots work like a hinge, with the overload circuit holding the other side of the board down.

Another bottom view:

And the final result:

and a sample:

Now, some questions...
1- I did the calibration with a 250 Hz 0.5v p-p sine wave, and noticed that the signal distorts at the compander when the LEVEL pot is above 9 o'clock (1.8v p-p at pin 7 of the first BBD). In other words, the compander distorts the signal, visible with an oscilloscope, before the BBD does. The compander gives a fairly high gain (0.2v p-p clean to 1.3v p-p clean). Is that right? Vref of the compander is 1.77V, what is well within spec, I guess.

2- I wanted to reduce the gain of the second stage, before the compander, so that both compander and BBD would distort at the same time.
Unity with true bypass is achieved with the LEVEL pot at 12 o'clock, what means distortion when using humbuckers. Would it make sence to reduce the gain pre-compander to avoid this kind of distortion?


Build Reports / Re: 1590LB Headphone Amp
« on: August 21, 2019, 10:54:07 AM »
Nice sandwich!
Using the pins to connect both boards makes it much more professional that any other sanwiched boards i've seen in DIY.

General Questions / Re: Small Good Distortion in 1590A box
« on: July 22, 2019, 12:52:51 PM »
Ok... I probably made a mistake there, the layout was 10x18...

In the first stage shouldn't it be 100k and 330k? You can reduce this 100k resistor to see how much gain you can get from it.

General Questions / Re: Small Good Distortion in 1590A box
« on: July 21, 2019, 03:04:08 PM »
There is a Rat layout with 10x12 using vero. How small do you want the layout to be?
The size of the components is IMHO more important than the size of the board. Large caps are a no go.

Since all these schematics are based on opamps it would be easy to make some changes and achieve over the top gain from them. Not sure if it would sound good without some filtering...

General Questions / Re: Sometime circuits squeal, sometime not
« on: July 21, 2019, 04:47:30 AM »
Squeal is normally a symptom of some undesired feedback. The component and wiring positioning is very important in this case.
When you made the changes, did you move the wiring around?
Interesting that with battery there was no squeal... in my experience with amplifiers the feedback normally comes from another stage, not from the supply, unless you are using a switched power supply. But then, it should be more like a whine...

Shielded cable for the potentiometers helps to avoid some kind of feedback, but fuzz and high gain circuits can be very sensitive. Try moving things around.

Sometimes when boxed the squeal goes away (effect of the enclosure) or when you put the board close to a ground plane (or enclosure wall) it creates a shielding effect against emitted signals.

General Questions / Re: Small Good Distortion in 1590A box
« on: July 21, 2019, 04:44:23 AM »
I have to agree with the RAT, it is awesome for high gain...

The crunch box was also one of my favorites when I started.

Build Reports / Re: Economy memory man, a simple analog delay
« on: July 11, 2019, 01:46:52 PM »
So when I finally had some time to make a video,
I realized I have no idea what to play.

So, just as an update, the clock was set to max delay at 155k, so 55k more than the original.

And the final schematic:

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