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Digital & DSP / Re: SpinCAD Designer Experimental Release 1023
« Last post by potul on Today at 09:30:05 AM »
So far I have been able to open all my previous files with the new release. Great!

And for some reason your site seems to be removed from the black list. I can reach it from the office now.

Building your own stompbox / Re: Diy Flanger intermittent
« Last post by vinceg on Today at 09:27:57 AM »
The bias trimmer has a small useable range of settings, and you want to set the bias trimmer near the middle of that range.  Fully clockwise or fully counter-clockwise means nothing will come out of the BBD.  So...

7) While playing your guitar, gradually turn the BBC bias trimmer clockwise until you hear an acceptable flanger effect.  Take note of the position of the trimmer setting.  Then continue turning the trimmer until the flanger sound goes away.  Take note of that second trimmer setting.  You want to set the trimmer half-way between those two extremes.

About this point, the bias trimmer have a initial position where the sound there is, but after, if I continue to turn clockwise there is sound until it is fully. There is not a point where no sound.
I shouldn't entirely remove 2M2 resistor (or short it) 'cause I'd leave BJT un(mis)biased..

Try to remove 100nF cap or lower enough its value or place a big resistor in series with it..

Then you can "play" with 2M2 value..
12AX7's are going for stupid money these days, so some alternatives would be the 12AV6 / 12AT6 / 6AV6 / 6AT6 / 12SQ7 / 6SQ7.  The -AT6 has a of 70 and the rest of the tubes have a of 100 and the -AV6 triode is identical to the triode in a 12AX7.  The other part of the tube is a pair of diodes which have a common cathode with the triode but plates that can be used as shunt diodes for a distortion or rectifiers for an envelope-based function.
I tried the changes of wiring that you proposed, but there is practically no sound coming out...
Of course it doesn't..!!  :icon_wink:
(plz see my edited previous post..)

I have absolutely no clue how a 3PDT switch works. Do you have a schematic on how to wire it other way ?

There are many wiring ways/options according to desirable In/OUT grounding (or not..)

My best preferable is :


You better utilize the following complete enclosure wiring with indicator LED anti-pop for your next builds..!!  :icon_wink:
(much more solder/wire/item trouble compared to a SPST signal switch but you'll be rewarder with peace of mind and many nights long lasting blissful sleep..) :icon_wink:

What do you call BJT ?
Any Bipolar Junction Transistor to discriminate it from any Field Effect Transistor (FET) or any Unipolar Junction Transistor (UJT)..

But if you prefer to call them Myriam, Jenna and Natassa respectively, it should be fine with me..!!  :icon_lol:

Building your own stompbox / Re: Diy Flanger intermittent
« Last post by DrAlx on Today at 08:18:21 AM »
The VCO and LFO are circuit blocks, not single components.

LM311 and Q3 are part of the VCO.

Two of the LM324 op-amps are part fo the LFO.

The LFO is a triangle/square  osciallator.  Google "triangle square oscillator" and you will see images of some examples.

Building your own stompbox / Re: What Does the Foxx Phase?
« Last post by nickbungus on Today at 07:40:05 AM »
Brilliant - That is such a good spot.  Much appreciated.  I've amended the PDF

Thank you so much
Building your own stompbox / Re: No sound on a DIY Bazz Fuzz (1st project)
« Last post by FredG on Today at 07:36:46 AM »
Thank you for the answer Antonis !
I tried the changes of wiring that you proposed, but there is practically no sound coming out...
Just to be sure I understood you well for the changes, here is the actual wiring (not working) :

I have absolutely no clue how a 3PDT switch works. I was just following the instructions in the DIY link.
Do you have a schematic on how to wire it other way ? (or a link that explains how it works for noobs)

What do you call BJT ? (sorry : noob + french speaking makes it hard for me :icon_lol:)

And for your second post : yes the pedal works fine with the wiring on the second picture.  :icon_neutral:

And thank's to both of you, I  will change the resistor to the initial 10k value or lower.

For the volume question, now that this first experiment works, I will look for a 2 knobs pedal that blends the dry and wet signal.

Glad I found this awesome forum with quick and gentle feedback, you rock !!  :icon_biggrin:
Building your own stompbox / Re: Russian Diodes for dummies
« Last post by Fernando on Today at 07:34:12 AM »
Ivan, why the 3 D9V (Д9В) plots are so different? Specially one of them.
Older and newer units? Totally random?

Tested D9J and D9V again. Just to note - ge diodes have the same deviation as transistors' hFE  ;D
Please check the plot. A-K - A-K2 are D9V.  ;)
So the pics 0-12mA

But zoomed is about 0.3mA all the diodes (from 0.28 to 0.33mA).

So I think anyway we can use all of them and just listen. It's a question of sound color. 8)
Please correct me if I'm mistaken.


I'm trying to build a noise floor. According to this picture, all you have to do is remove 1 or 2 components.

I used this layout, and removed the 2.2M resistor and the second 100n cap.

When I take the components out, there is no sound. When I put them back, I get a functional Soda meiser. When I take out only the 2.2m resistor, I get lower gain and a lot of hiss. It doesn't sound like the demo.

Am I supposed to bridge the component locations or just take those components out?
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