Tape Delay Circuitry

Using the web as a resource! This thread outlines exactly the obstacle Colton is faced with in building a tape delay:
http://www.electro-tech-online.com/electronic-projects-design-ideas-reviews/111155-cassette-recorder-circuit-guitar-effects.html


This would be a great IC to use, if we could find a place to sell us one...
UTC TA7668:
www.bucek.name/pdf/ta7668.pdf‎

Equivalent ICs and Spec Sheets!

Since a bunch of you are working on older pedal circuits that used the 4558 dual op amp IC, I poked around a bit to see if we could replace that harder to find chip with something we already have on hand, at least for breadboarding and prototyping.

I found this thread by doing a google search for "4558 equivalent".
http://music-electronics-forum.com/t19942/

I thought this would be a good chance for us to get better and understanding and using spec sheets, so check these two out and let's talk about them next week in class:

TL072:
www.ti.com/lit/ds/symlink/tl071a.pdf

MC4558:
www.st.com/web/en/resource/technical/.../datasheet/CD00000478.pdf‎

and another, just for fun, RC4558:
www.ti.com/lit/ds/symlink/rc4558.pdf

Keeping it Simple

Hey all,

I've decided to go simple and build the Lava-Rim 2 distortion pedal off of DIY Stompboxes.  I figured since I just entered the world of guitars a mere 10 days ago, keeping it simple would be the most logical way to go.

So, here is the link to the schematic if anyone else is interested.
http://www.diystompboxes.com/pedals/lava2.GIF 

I'll be doing research on the parts to figure out the type of transistor used and why it is built in this fashion.

Video on Transistors (Transform + Resistor = Transistor)

Hey all

Here's a short YouTube video clip on FETs, also known as Field Effect Transistors.  Short and has a bit of humor int it.  When It gets to the PN portion and the flow of electrons, I got a bit bored but the information/jargon helped me understand function when researching further. Enjoy!

http://www.youtube.com/watch?v=CLLcRRBph90

Useful Website for Schematics

I came across this website a few days ago.  It has schematics for all kinds of guitar pedals which could be useful for this class or future projects.

http://www.muzique.com/schem/index.html

Personally I'm interested in giving the Ibanez Tube Screamer a shot as it doesn't look as complex as I thought it would.

Acoustic Delay Pedal

Hey guys,

I'm finally linked in to this blog. So, I'm joining you all to build delay pedals being that I received an acoustic/electric guitar for my birthday just a week ago. 

With that said. I'm currently on this site...

http://www.mammothelectronics.com/EA-Tremolo-GuitarPCB-com-Pedal-Kit-p/kit-gpcb-eatrem.htm

Any thoughts?

Possible Project?

Howdy howdy.

I've always been a fan of the talkbox with my guitar. I used to have one but unfortunately I had to sell it awhile back. If you by any chance don't know what it is, it's a pedal basically with a built-in amplifier and EQ that's connected to a rubber tube that lets you control the sound with mouthing out words. That classic Peter Frampton sound.

Is anyone interested in possibly doing one of these? It sounds like it's something that could be simple.
I found the schematic for the model talkbox I used to own, take a looksie..

Hello All,
Here are two more analog delays from popular manufacturers that highlights the similarities in the design of a simple BBD analog delay pedal.  Good reference point and we could potentially all build a different circuit.  Thoughts welcomed.  I will also be posting more information later tomorrow for design thoughts, tips and some signal flow traces.

Edward

Boss DM-2
http://www.hobby-hour.com/electronics/s/dm2-delay.php


Ibanez AD-9
http://experimentalistsanonymous.com/diy/Schematics/Delay%20Echo%20and%20Samplers/Ibanez%20AD9.pdf

MXR Distortion+

Hello fellow classmates!

I have found a cool distortion pedal schematic online that I am going to build in class. It is an MXR distortion pedal from the 1970's. What's good about this pedal is first off, we have all the parts needed to build this at school in the locker. The second interesting thing about this pedal is it has a dual power source option, from either a battery or a plug in right from the wall. This is possible by the two power inputs being connected to different parts on the quarter inch jack. The AC power supply is connected to the battery being connected and activated through the ring of the jack, and the AC power supply being connected and activated through the tip of the jack. This way, you can have two options to powering up the pedal.

http://distortionpedals.org/wp-content/uploads/2012/10/mxr-distortion.gif
Joe

BBD Circuit Explanation

Hello All,

Here is a breakdown of the various stages of an analog BBD style delay circuit. This is overly simplified and is more concerned with the various stages and the components needed as explained in the “Delay” section of The Stompbox Cookbook. I have provided a visual reference with color coding to make the circuit a little more clear.

Input Buffer/A1-Salmon

This is the initial stage of the pedal and is run by a single op-amp. This section is very straightforward and can be used to increase gain, provide some filtering if desired and is the first section encountered by the input signal. It is biased by Bias Buffer/A3.

Pre-Filter/A2-Green

This is the pre-BBD filter section to remove clock noise. This section can get very extensive and complicated depending on how much filtering is desired and/or necessary. With with very long delays, such as those in excess of 400ms, the clock rate ends up in the audible spectrum and must be removed with a very steep filter or the resultant delays will be “noisy”. This section is also biased by the Bias Buffer/A3.

Bias Buffer/A3-Sepla

This section is used to provide a biasing voltage to the input and pre-filter op amp stages. This section also feeds the post filter with the same voltage at its non-inverting input.

Post-Filter/A4-Light Blue

This section, much like A2, is for post filtering of the clock signal from the audio signal. This section is very crucial and be quite extensive, as in the case of the Electro Harmonix Memory Man, with multiple filtering segments running through this section of the output stage. This section also provides the output buffer for feeding the next pedal or amp in your signal chain.

BBD IC Voltage Feeds-Olive-Sepla

The Bucket Brigade Delay is used to provide the delay in milliseconds for the operation of the chip. Here the chip can consist of up to 4096 capaciators that are alternately triggered to release voltage in an on/off fashion. The rate of this action is determined by the BBD Driver which is a separate clock source IC that feeds Clock 1 and Clock 2 inputs on the BBD IC. The BBD IC has many input and output paths that are similar in function on all BBD ICs and it is biased by its own trimpot.

BBD Driver-Light Orange

The BBD Driver is used to supply the clock 1 and 2 voltages to the BBD IC and to control the rate of delay. A trim pot is often used here to alter the delay time and this circuit is fairly straightforward in its design.

There is definitely more to any actual pedal design such as the addition of a compander that compresses the input signal to the BBD IC and then expands it upon output to provide consistency in the delay repeats and to provide optimal input/output signal. This section is not necessary to design a functioning pedal but in pedals that provide longer delay times, it may be desirable if signal fidelity is desired.

Ecthing circuit boards

Here are a few different ways to etch your own circuit boards:

This is probably the cheapest, the laser printer toner transfer. All you need is the etchant chemical and a copper clad board (I've also done this using a sharpie to draw the resist onto the copper clad board):
http://www.instructables.com/id/PCB-etching-using-laser-printer/

Jameco sells a kit for $46 to do photo resist etching, which is by far the best way to make really professional boards. Check out the video on their site explaining the process:
http://www.jameco.com/Jameco/PressRoom/makeoneetch.html

Making a Tape Delay while waiting for parts

For those of you interested in making a tape delay while we're waiting for our parts to arrive here's a nice explanation of tape delay from the Stompbox Cookbook:




Here's a picture of the one I built in high school with a hacked boombox and two extra tape heads:

Below are some other examples of homemade tape delays. You can find lots more with a quick google search.

We'll make a much better one with our fantastic knowledge of electronics and mixing circuits...

Makezine two walkman tape delay:
http://makezine.com/2008/04/30/diy-analog-tape-delay-mac/

Hacked tape deck delay:
http://hackaday.com/2010/12/20/tape-delay-made-from-recycled-cassette-decks/

BBD Component Substitution List

Hello All,
Here is a list of substitute parts for the impossible to obtain parts for the Delay pedals.  These are all available from Small Bear Electronics and would require minimal reconfiguration of the circuits.  Let me know what you all think and then I can order the amount of parts that we would need.  Should be about $20 a person to purchase the components that we can't raid from the school supply (resistors, capacitors, op-amps, etc). 

BL3208 (direct substitute for the MN3208 which is a 2048 stage BBD driver)
http://pdf1.alldatasheet.com/datasheet-pdf/view/164433/BELLING/BL3208.html

BL3102 (direct substitute for the MN3102 which is a BBD Clock source)
http://pdf1.alldatasheet.com/datasheet-pdf/view/164431/BELLING/BL3102.html

We will need to use two of the 3208s to simulate an MN3205 or MN3005 which is a 4096 stage BBD.  There is a diagram for this type of configuration on the small bear electronics website.
https://www.smallbearelec.com/HowTos/MN3005/3005_to_2x3008_SCH.pdf


Edward

Component Datasheets

Hello All,
Here are the datasheets for the most popular BBD, Clock source, Operational Amplifier and Compander IC's that I have seen in the delay schematics.  I will post more to this as I find them as a resource and if anyone finds any others, feel free to post them here.

BBD-MN3005
http://pdf1.alldatasheet.com/datasheet-pdf/view/87983/PANASONIC/MN3005.html

Clock Generator-MN3101
http://www.alldatasheet.com/datasheet-pdf/pdf/14238/PANASONIC/MN3101.html

Clock Generator-MN3102
http://pdf1.alldatasheet.com/datasheet-pdf/view/158293/PANASONIC/MN3102.html

Compander-NE570
http://pdf1.alldatasheet.com/datasheet-pdf/view/82893/PHILIPS/NE570.html

Compander-NE571
http://pdf1.alldatasheet.com/datasheet-pdf/view/18878/PHILIPS/NE571.html

Op Amp-4558
http://pdf1.alldatasheet.com/datasheet-pdf/view/115033/ETC1/4558.html

Edward

Various Analog Delay Schematics

Hello All,
Here are a couple of schematics for various analog delays from popular manufacturers.  I am posting these for comparison and analysis purposes. 

Boss DM-2
http://www.hobby-hour.com/electronics/s/dm2-delay.php


Ibanez AD-9
http://www.dirk-hendrik.com/Ibanez_ad9_analog_delay.pdf

We're going to use this blog as a place to share info (and progress) on building a bucket brigade delay.

Colt suggested starting with the Echo-o-matic in the Stompbox Cookbook (posted on my dropbox)
There's a great explanation of delay effects on page 144. Vigen is going to post his interpretation of the circuit (with colors) this week. Understanding the various stages will be helpful in interpreting any other bucket brigade delays we might try to build.

Vigen is in favor of building the Deluxe Memory Man from a schematic we found here:

And some great info on bucket brigades here:
http://www.gearslutz.com/board/geekslutz-forum/615501-bucket-brigade-delay-chip.html

Echoplex Tape Delay

http://www.loopers-delight.com/tools/oldechoplex/tape_echoplex_schem.html