Diamond Bass Compressor

I have read a lot of great things about this compressor.

This is the schematic traced by WhiteKeyHole on FSB.

The bass version has a switch to select the pivot frequency of the tilt EQ between 900Hz and 250Hz. There are no gut shots of it and I couldn't find the schematic or the component changes needed to build the bass version. The only reference I could find was from John Kallas at the Sabrotone post: (link)

I just raised the values of the 100n’s C7, C8,& C18 to 470n’s and slightly changed the frequency cap on the tilt eq.

From what I know, the only differences between the guitar and bass versions could be the changes sugested by John Kallas to eliminate the low end loss and the switch for the tilt center frequency, so I just needed to find how to configure the EQ.

The Tilt EQ

I found and article by Chu Moy on headwize.com (Designing A Pocket Equalizer For Headphone Listening) that explains the history of the Tilt EQ topology.

The guitar version of the Diamond Compressor use this exact configuration and component values (after C2) to get a pivot frequency of 900Hz with a 6db boost or cut on both sides of the tilt.

The only thing left was to find the component values to change the center frequency. I found a great article by Francesco Balena: Implement an audio-frequency tilt-equalizer filter; where he derives the transfer function for this eq design.

Using the next formula we can calculate the pivot frequency F_P:

Replacing the component values of the Diamond we get what is expexted:

This is the center pivot frequency for the guitar version:

Deriving M_L and M_H from the next formulas we can obtain the maximum low-boost asymptote as M_L (bass boost) and the maximum high-boost asymptote as M_H (treble boost).

We get this:

You take 20 times the log of M_L and M_H to get the response in decibels:

Wich yields a 6db boost and cut as advertised by Diamond.

I have simulated this filter in LTSPice

And we get the expected result

Note: I have used 47K for R_F in my calcs as it is the prefered value.

Changing the pivot frequency

We can change the pivot frequency by changing the value of C. Using 20nF capacitors we get an F_P of 251.37Hz, as you can see in the sim plot

To implement the switch as in the comercial version we can use a DPDT to select between two pairs of capacitors:

I have yet to build it, but I learned a lot studing this.

Configure your tilt EQ

I have implemented an on-line Tilt EQ Calulator to help you configure your own filter. Or you can use the next table if you want 6db bass and treble boost and cut.

P₁=50k, R=15k, R_F=47k

C	Pivot Frequency
20 nF	251,37 Hz
18 nF	279,30 Hz
15 nF	335,16 Hz
12 nF	418,94 Hz
10 nF	502,73 Hz
8 nF	628,42 Hz
6,8 nF	739,31 Hz
5,6 nF	897,74 Hz

You can even achieve an asymetric bass and treble boost. The next sim plot is what you get with: P₁=50k, R=33k, R_F=47k, C=6.8nF

Special thanks to:
Francesco Balena
WhiteKeyHole

Seamoon Funk Machine V2

I used the layout by IVIark with a buffered blend to mix some clean signal. This effect has some character, its only usable on a narrow spot of the Freq an Depth pots but when you find it this thing screams FUNK to your ears. I really like it because the envelope works as a reverse sweep, it sounds Awww instead of Waaa.

How do you get the DIY fever? (MusicMan Stingray 2-band Preamp)

I wanted a Stingray for cheap, so I bought an SBMM Ray4. I knew before buying that the preamp wasn't any good.

I needed a real Stingray preamp and I found the way to get one, building it myself. Bajaman at freestompboxes.org traced the schematic of the original MusicMan design.

UncleFluffy at talkbass.com started a thread where he offers the PCB's for anyone interested. He even uploaded his Eagle Cad files, and this is how I got my boards. I sent the files to Oshpark.com and received this.

After populating the components it looks like this.

I also shielded the control cavity.

Installed new knobs.

And my bass became alive, it now sounds really musical and has the sound I wanted. I still want to replace the pickup but that will come later.

And this is how I got the DIY fever. Once I have bought all the tools to mount my preamp the only thing I needed to build a pedal was to buy the components.

Green Russian Big Muff V7

My second fuzz, this one is famous among bass players and after building it I can see why, it has tons of low end.

I added a 47pF cap at the input to ground to kill the RF interference I get at home. You can see it at the bottom of the board, I actually socketed it just in case I want to take it out.

It was really tricky to squeeze the board in this enclosure, this is what you get when you buy pre-drilled enclosures. I had to order a dc jack that fits from the inside to be able to put everything in.

You can see the layout at tagboardeffects.blogspot.com.

Ecstasy Overdrive

I really dig this one. A great overdrive that works really good with my bass without any modification. If you want to build one use the layout by IVIark at tagboardeffects.blogspot.com.

Fuzz Attack - Mastotron

This is my first complete pedal. I built it almost two months ago and I wanted to record a demo before posting it but I will post demo on a different post.

Its a simple board but has a lot of knobs so its a great choice if you want to practice your enclosure wiring abilities. 

I used the layout by IVIark from Guitar FX Layouts. Follow the link for a description.

Corgi Amp

This is one of the first things I built. I really wanted a little amp to practice at home as I don't have a proper amp at the moment. I usually play through an audio interface with an amp sim but its not the same as a real speaker, so I decided to build a Ruby Amp.

The Ruby Amp it's a 9v battery amp using an LM386 power amp, designed  by runoffgroove.com. The layout was made by the user rizibiz from freestompboxes.org. The layout is for the bassman mod version of the Ruby.

I included a gain knob and a grit switch just like in the Noisy Cricket by beavisaudio.com.
I used a generic 8ohm speaker I found in a local electronic shop here in Madrid, in Barquillos street, and the shop owner is from Canary Islands, just like me :).

I must say I'm very happy with the result, this little thing has a lot of sounds and can be really noisy. You can see what it can do in the video. I recorded it with my phone so don't expect too much quality.