Resurrecting my old phase shifter

I have embarked on the challenge of reviving a 20-plus-year-old DIY device of mine. This blog post is the first of a series of posts describing the process of bringing back to life my prized Electronic Projects for Musicians phase shifter.

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But first, some background:

During my first heavy binge on DIY musical electronics, I built around 25 devices or so. Very few of them survive today.

The ones that did survive were among my favorites, of course. They included a two-channel tube pre-amp, a noise-reduction device, a two-channel limiter, the EFPM dual tone filter, and my favorite – the phase shifter from EPFM.

My copy of EPFM contained sound samples from the devices in the book. Back in the dark ages, the sounds were provided via a piece of flexible plastic that was bound into the book. You tore it out along the perforated line, then fired up your turntable. You dug out one of your vinyl LPs, put the piece of plastic on it, and gingerly placed the needle on it.

Somehow, this set-up allowed the book purchaser to listen to the sound of the effects.

I fell in love with the sound of the phase shifter. It was amazing to me. I made it my goal to build one.

I wisely started out with simple effects. I did make plans for the phase shifter, though. I still have my copy of EPFM. The page containing the phase shifter parts list shows where I jotted down notes about price and quantity of parts.

Wisely, I bought a circuit board from Paia Electronics. I managed to score four of the hard-to-find Clairex CLM-6000 opto-isolators. (Nowadays, the readily-available NSL-32 would work in place of the CLM-6000.)

When Anderson needed a dual op-amp for one of his EFPM designs, he chose the Raytheon RC4739.  It was a fine op amp, but had an inconvenience: it was contained in a 14-pin DIP case. Most dual op-amps are built in eight-pin cases. Back then, you still could buy 4739s, but they are extinct today. I used two 4739s in the phase shifter.

I built mine with the specified parts. An aluminum Radio Shack (RIP) enclosure served to contain the device. The power would come from an external 9-volt AC-powered power supply, another project from EFPM. I still have the power supply. The phase shifter and power supply were connected by a plug, which could be separated. The power setup is cumbersome. I hope to change that some day, possibly as part of this project.

Anyway, I decided in earnest the other day to try to get the thing to work. When I put it in the true bypass position, it howled through the amp. In the un-bypassed position, there was no sound.

Initially, I tried to fix a few obvious things in the hope the problem was something simple. But I didn’t get anywhere. So, I decided to rebuild the device. The plan is to keep the enclosure, circuit board, the potentiometers and most of the switches. It will have a 3PDT true bypass stomp switch with an LED indicator light.

 

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Anyway, I took a good look at it. I felt strange looking at work that I had done more than 20 years ago. The solder joints looked good. Hey, the thing had worked at some point!

Nonetheless, I would’ve liked to have had some conversations with my 20-year-younger self about this project

Current me: Was green the only color of wire you had?

Younger me: Do you think I was made of money? It worked!

Current me: Why did you leave that rat’s nest of wires? Have you ever heard of organization?

Younger me: I don’t care how it looked. It worked!

Current me: Why didn’t you use mylar or film capacitors? Those ceramic caps look downright nasty.

Younger me: Do you think I was made of money? It worked, didn’t it?

Current me: Thank you for using the Vector T-42 clips to make connections to the circuit board much easier!

Younger me: You’re welcome.

 

vector T42 clip

I proceeded to disassemble it after I failed in my feeble attempts to get it to work. The circuit board came off of the standoffs. All of the connections to the board were de-soldered and removed. The T-42 clips made this work easy. The clips fit into a standard circuit board hole. They should be soldered, but they’ll hold pretty well on a friction fit. Because of the clips, I didn’t have to de-solder one side of the board and then try to quickly pull the wire out of the other. The clips also will make it easier to solder the new wires. A pack of T-42 clips is on my want list. They can make connections much easier.

After de-soldering the wires from the pots and switches, I went to work on removing certain items from the circuit board. I theorized that the integrated circuits (4739 and 4136) had been fried or otherwise had gone bad. So, I planned to replace them.

 

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It was a battle to remove the sockets of the 4739. They had to come out because I planned to replace them with eight-pin op amps such as the NE5532. However, the footprint is a 14-pin design. I have a plan to solve that problem, which I will discuss later. There also is a 4136 quad op amp on the board. It’s not a common chip, but is still available.

I de-soldered the solder-side connections of the sockets as best as I could. I managed to pull the socket out, but many of the metal legs didn’t come out of the circuit board. What was left were small pieces of metal, sticking out of the board.

Further removal of solder on the solder side of the circuit board was fruitless. Then, the light bulb came on! I applied the solder iron tip to the bottom of the socket legs. That sent heat to the solder side. The pieces of metal then came out easily.

 

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While doing battle with the sockets, I accidentally tore the top of a ceramic capacitor. I looked at the schematic and discovered that mylar or film capacitors would be better than the ceramic ones. So, out came all of the ceramic capacitors.

The resistors and electrolytic capacitors remained on the board, as did the Clairex CLM-6000 opto-isolators and the 4136.

Replacing the capacitors won’t be too risky. I don’t want to change too many parts, though, because of the risk of introducing new problems into the circuit. I’ve sourced some NSL-32 opto-isolators in case the venerable CLM-6000s have stopped working.

I bought some parts from Jameco to get the project rolling. Among the parts are upgraded capacitors, a few NE5532 op amps and 14-pin wire wrap sockets. The wire wrap sockets have long legs.

The plan to replace the 4739s with 5532s is based on a product sold by Paia Electronics some time ago. I will insert the 5532 into the bottom of the socket, or on the side without the notch.

I will cut off a small piece of stripboard. I’ll mount the 14-pin wire-wrap socket in the 14 holes in the circuit board. I will then use jumper wires to connect the circuit board signals to the appropriate NE5532 pins.

Anderton nicely included in EPFM a guide for substituting 8-pin dual op amps for the 4739. It should prove very helpful. The NE5532, in addition to being available, is a good value for a low-noise dual op amp. There are better (and more expensive) dual op amps, but the NE5532 is a good compromise of price and performance.

I also plan to order some NSL-32 opto-isolators in case the CLM-6000s don’t work. Digi-Key, sells both the NSL-32 and the 4136 op amp.

However, I’m not going to replace everything at once. The first step will be to insert the 5532 setup. Re-wiring of the leads to power and potentiometers will follow. This time, I’ll use different colors of wire to avoid confusion! I also hope to keep the leads shorter and better organized. I also will replace the ceramic capacitors with an upgraded capacitor.

At that point, I’ll test it. If it doesn’t work, I’ll double-check all of the connections, be sure that power is getting ot the chips, and give it a good “eyeballing.” If it doesn’t work, I’ll assume the 4136 and/or the CLM-6000s are not working. I’ll order the parts and then install them. If that doesn’t work, I’ll start pulling my hair out!

Stay tuned!

The DIY time warp

As mentioned in previous articles, I recently returned to a serious pursuit of the DIY musical electronics hobby after being away from it for a long time – I’d say about 20 years.

Strangely enough, I got out of the hobby at about the same time the Internet was coming into its own. Now I know what I’ve missed!

Lately, I’ve spent hours surfing the Internet and finding great circuit ideas. There are several forums that give advice. Small parts and pedal businesses have sprung up – something they probably could not have done before the Internet.

So, how did one get information on musical electronics back in the stone age? First, there were books. The classic is Craig Anderton’s Electronic Projects for Musicians. I have both the first edition and the revised edition.

I also stumbled across a book by the British writer R.A. Penfold. The use of veroboard (stripboard) in the book’s projects was a discovery. A friend of mine who went to Great Britain actually brought back a piece of it for me!

I wish I had not torn up the book through overuse. It’s going for $70 on Amazon now!

I scoured the magazine racks for electronics magazines in the hopes that there might be a musical DIY project in them. Guitar Player was running Craig Anderton’s column, which would feature some DIY projects. Electronic Musician and EQ magazine ran good projects fairly often. Jules Ryckebusch, a Naval officer whose specialty was nuclear reactors, created and wrote about some nice projects, particularly for the home studio.

I drove the local librarians crazy. I would track down DIY articles by finding references in books, articles, and in directories of periodical literature. After identifying an interesting article, I’d submit an inter-library loan request for it. Usually, a photo-copy of the article was in my hands within a couple of weeks after putting in the request.

I started a notebook of DIY audio articles and schematics. It survived several moves over the years. I almost threw it out once; I’m glad that I didn’t.

So, some old-fashioned research and digging kept me well supplied with DIY information. Back then, one had to work hard to get any information; now, the hard work is in determining what information is worth keeping and what should be disregarded.  There’s just soooo much good stuff!

It’s nice, though, to see some good old standbys hanging around. Anderton’s EPFM is still out there. He also did another nice DIY book: Do-it-Yourself Projects for Guitarists.

EPFM still soldiers on. Many of the parts used in the projects, some of which were hard to find back in the 1990s, are even more difficult to find now.  Thanks to folks such as Small Bear Electronics, the hard-to-find parts are accessible.

Parts hunting was a major part of the hobby. The thrill of the hunt and the excitement of finding that rare part was a nice rush! I accumulated several electronics suppliers catalogs, some of which were two inches thick. I identified the suppliers who were more suited to what I wanted and stayed with them.

Paia Electronics was great – they offered circuit boards and kits for the EFPM projects as well as a host of other great analog devices. Paia founder and DIY legend John Simonton died a few years ago, but Paia carries on. They’re carrying the flame for DIY electronics, especially analog synthesizers.

Two of my favorites were Mouser Electronics and All Electronics. Mouser was/is a huge electronics parts distributor catering both to hobbyists and huge manufacturers. They did not have a minimum dollar amount for an order and charged only actual postage.

All Electronics, on the other hand, was somewhat of a surplus electronics parts store. Even though they were a fraction of the size of Mouser, they stocked a surprising amount of the stuff I wanted.  I looked forward to their monthly catalog just to see what new exotic goodies they had unearthed!

I also found an electronics store in a nearby big city that had counter sales. Through special order, I managed to snag some SSM2120 chips for some of the Paia studio devices.

Interestingly enough, I now live in a town of about 35,000 people and it has a full-service electronics store. They don’t stock many analog components, but I’m often surprised when I need a rare part and they have it.

I’m friends with one of the owners. We always have a pleasant chat when I come in, even though I rarely spend a large amount of money there.

What I would’ve given to have had a resource such as Small Bear Electronics back then! Small Bear mastered the art of sourcing  exotic music electronics components so we hobbyists wouldn’t have to.

As stated earlier, my main musical gear is in the digital realm. Recently, though, I dug up some old analog signal processors that I built in my first run at the hobby. Analog is cool and I might find a way to integrate those old projects into my digital setup. Regardless of what I can do with them, those old projects were worth it just for the fun of building them and that incredible feeling of plugging one in and using something that I had built!

 

Getting bi-polar power the easy way

When I started out making DIY electronic projects, I did projects from Craig Anderton’s classic book Electronic Projects for Musicians. Most of the projects in the book required bi-polar power.

The typical stomp box uses one battery to provide what I would call “single-sided power.” This works well for most stompboxes because of good design. The power provided to the effect is positive and negative. Simple enough.

Bi-polar power is positive, negative, and ground. In a circuit that uses operational amps, or op-amps, bi-polar power provides more headroom and better performance. However, providing bi-polar power is more complicated than using single-sided power.

The most basic way is to use two nine-volt batteries. When connected correctly, you can get +/-9 volts (nine volts bi-polar power). For a project that doesn’t consume much power and has plenty of room in the enclosure, this works well.

The next option is to build a power supply. EPFM has a project to build a nine-volt, AC-powered bi-polar power supply. A WORD OF CAUTION: this project involves connecting an AC power cord (the kind that plugs into the wall) to a transformer. You’ve got to be very confident in your skills to build this. I built one on a perfboard for a multi-effects project  and lived to tell the story. Later, I built one in a plastic box using a printed circuit board. That was  much easier and less harrowing to do. Still, it required caution and great care.

One of my favorite EFPM projects was the Phase Shifter. It had several operational amps and other power-using circuitry. It was not practical to run it on two batteries. I ran it using a power connection from the aforementioned EPFM power supply. It was inconvenient to lug that big plastic box around and connect it to the phase shifter box, which was not too small itself.

Before I took a hiatus from DIY electronics many years ago, I decided to find a way to run that phase shifter on something more convenient. A few years ago, I briefly resurrected the hobby to try to find a solution. As it turned out, either my EPFM power supply or my phase shifter died, because I couldn’t get the phase shifter to work. That left me dead in the water.

I dug out a few old studio DIY projects from the attic a few days ago. They included a PaIa dual compressor and “HissWhacker” (a noise reduction device). Both had power connections to a 15-volt bi-polar power supply which I also had built. It apparently didn’t survive one of my residential moves, because I can’t find it.

So, if I want to play with those devices, I’ll need to find a good source of bi-polar power.

 

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I have set my sights on a wall-wart based power supply. Wall-wart is a slang term for a wall transformer, one of those black boxes into which the plugs are built in. They’re used in all sorts of electronic devices. You probably have several. You might even run your stomp boxes  off of one.

There are a couple of options: a wall-wart with AC output or one with DC output. The typical wall-wart has DC output. That’s probably what your stomp box uses. (However, some musical devices use AC output wall warts. I have an ART tube pre-amp that uses one.)

Many Paia electronics projects use an AC-output wall wart. Circuitry to turn the AC signal  into a bi-polar supply was designed into the circuitry. I suppose one could analyze those schematics and build the circuitry to use an AC-output wall wart for a project that requires bi-polar power.

However, my plan is to use a DC-output wall wart. They are easier to obtain than a VAC-output wall wart. However, the key to doing this is building the circuitry to turn a single-sided DC current into bi-polar value.

Fortunately, there are magic chips that make that possible, and in a simple circuit to boot! Meet the MAX1044 and the ICL7660. Both can take a 9VDC current and output bi-polar +/- 9 volts.

How do these chips do it? I don’t know. I tried to figure it out from the data sheet, but it’s beyond my knowledge.

Still, the circuit is simple:

bi-polar from 9V

All you need is a chip, two 10uf electrolytic capacitors and a  power source.

I breadboarded the circuit to see if I could get it to work. Over the years, I have mangled many a good circuit beyond recognition. I used a  ICL7660 chip. It and the MAX1044 basically do the same thing, but the ICL7660 is less expensive.

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Above is the breadboarded circuit with a 9-volt battery connected. After I carefully laid out the circuit, I connected the battery and tested it with a digital multi-meter. It worked as advertised! It put out bi-polar nine-volt power! Yes!

However, working with a battery wouldn’t solve the problem of the phase shifter and the other devices. So, I set it up to test the current from a wall wart.

My breadboarding setup has a power jack and breadboard power connections.  So, I plugged in my trusty Boss nine-volt wall transformer. Nothing blew up, so I figured I was OK to that point.

Out came the multi-meter. I checked and double-checked. Yes again! It worked! Whoopee!

Now, my excitement may be premature. I don’t know if the setup will power the phase shifter or any of the other bi-polar-power-gobbling devices in my arsenal. I’ll dig out that phase shifter, solder up a little power board with the ICL7660, and see what happens!

 

 

“Bread-boarding” your projects

If you want to try out a circuit without going to the trouble of soldering the components together, a solderless breadboard may be just the ticket for you.

A solderless breadboard allows you to make all of the connections in a circuit, test the circuit, then make corrections and changes very quickly. The breadboard connections are not permanent.

Breadboards may be used to create new electronic circuits or verify a circuit. This is called prototyping.  If you’re planning to build a project, you may want to breadboard it first to ensure that you know how to connect all of the parts correctly.

 

breadboard diagram

If you find a circuit in which you’re interested, you can breadboard it and quickly determine if it’s worth committing to a permanent project.

In my previous DIY life, I planned to put together a breadboard. However, I lost interest in the hobby for awhile, thanks to the typical demands of life and my tendency to rotate hobbies.

 

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However, I had purchased a small breadboard and a set of jumpers. Those items managed to survive a couple of residential moves. As I returned to the hobby, I renewed the plan to make a breadboard.

The breadboard is just part of the total bread-boarding operation. Ideally, the breadboard is part of a setup that includes a power supply, input and output jacks, a provision for potentiometers, and anything else that might be part of the project.

 

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Just how does a breadboard work? It consists of a pattern of “holes,” for want of a better term. The holes are arranged in horizontal rows in a grid pattern. Stiff wires, such as the leads of electronic components, can be placed in the holes.

All of the holes in a row are electronically connected to each other. Depending on the breadboard’s design, there may be channels that separate the sections of a row and break the circuit connection.

 

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Jumpers are wires that can be used to connect one row to another.  They also can be used to jump a signal across a channel.  They are an essential part of breadboarding. They are the equivalent of wire in a permanent circuit.

In a breadboarded project, you will use electronic components as you would in a permanently-soldered project. A breadboard allows you to try different values of components and different semi-conductors in the circuit to find the best combination.

A much more thorough description of a breadboard may be found here:

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My personal breadboard is in its preliminary stages of construction. It’s far enough along so that I can do some basic circuits with power provided.

 

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My breadboard consists  of a small solderless breadboard attached to a piece of lumber that came out of my junk pile. There is an electrical junction box screwed to the board to serve as the mounting point for jacks, potentiometers, power connections and who knows what else.

The box cost me all of $1.25 plus tax at a home improvement store. It was in the electrical section.

When planning this setup, I wondered how I would mount the solderless breadboard to keep it from moving. Much to my pleasant surprise, I discovered the solderless breadboard had an adhesive backing. So, I just peeled off the paper and stuck it on the lumber in what I hope is a good location.

 

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I drilled several three-eighth-inch holes in the metal box. The box was difficult to drill, even though I used my drill press. I had to ream some of the holes later. I didn’t have any grand plan for the holes; I just drilled a bunch of holes that were not too close to each other. I also opened up one of the punch-out holes in the side to have an opening through which to run wires.

I screwed the box vertically onto the piece of lumber. The only thing I’ve installed in the metal box so far is a power connector. I soldered two wires to it, one red (for positive) and one green (for negative/ground). I also soldered a separate green wire to part of the metal box.

This was enough to handle my first breadboard project. As I try more projects, no doubt this setup will expand!

Back to the world of DIY stomp boxes

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About 25 years ago, the DIY-electronics bug bit me. For several years, I fired up the soldering iron, tried to understand schematics, pulled out my hair when the darned things didn’t work, but generally had a blast.

Other hobbies came along, though, and the advancements in commercial stomp boxes took some of the financial benefits out of DIY electronics. However, you shouldn’t do DIY stuff unless it’s for fun. Unless you are really, really good, you likely aren’t going to save any significant amount of money by building your own stompboxes.

However, the bug bit me again recently. It may have started when those old electronic skills helped me resurrect my Cry-Baby wah-wah pedal. I then salvaged an abandoned project and got it to work.

Then, I discovered Tayda Electronics. This company  offers a nice selection of PCB boards and instructions for guitar-based stompboxes. They also sell a huge variety of parts at very nice prices.

The Tayda parts are less expensive than the parts I bought 20 years ago – and the value of the dollar is quite a bit less now. Ten metal film resistors for 12.5 cents? I couldn’t get one metal film resistor for 12 cent back in the 1990s.

I’m not going to tell you that Tayda is the only company that sells parts at these kind of prices. I haven’t done comprehensive research on parts prices. I stumbled across Tayda’s site, liked what I saw, and off I went.

Tayda doesn’t sell guitar stomp box kits per se; for a given project, they offer a circuit board, on-line instructions, and sell the individual parts that you will need.

Each project’s web page lists the parts needed to build the project.. In some cases, there are links to order each part at Tayda’s store.

I decided to further wade back into the DIY stomp box world. My DIY skills once were pretty good. (Hey, I built the Craig Anderton Quadrafuzz!) But those skills needed refreshing. A simple, fun kit would be the ticket.

Back in the DIY day, I built the treble booster from the book Electronic Projects for Musicians by DIY guru and general musical electronics genius Craig Anderton. I liked what it did to the sound of my guitar. Or, perhaps the high end of my hearing was starting to go.

Anyway, I thought I would revisit the treble booster idea. I went for the Brian May treble booster. I have May’s book about how he and his father built the “Red Special,” which to this day is Brian May’s no. 1 guitar.

There were numerous references in the book about how May used a treble booster to create his signature sound. The Tayda project sounded like a good bet, so off I went.

I dutifully ordered the PCB board, a bunch of parts, and an enclosure. I eagerly awaited the arrival of the goodies.

I placed the order on a Sunday night. Arrival time was advertised at 7-16 days. The package arrived one week and a day later – Monday. Everything arrived in good order.

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The parts all were enclosed in a bag. When I opened up the bag, I discovered the parts were in their own little bags! And labeled, no less!

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This will make it much easier to identify the correct parts as well as store the leftovers for future use. I was very impressed with how the order was packaged.

OK, so now it was time to plunge into it.  I holed up in my infamous mini-barn/workshop/man cave, turned on the heater and fired up the soldering iron.

Whoops, not so fast! One must survey the project and plan its construction before plunging into it. But that’s no fun! Well, anyway, I decided to drill out the enclosure and place the outboard parts before doing any soldering.

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The enclosure was an aluminum Hammond 1590B, which appears to be a standard among stomp box enclosures.  I printed out the parts placement guide from the on-line instructions and proceeded to plan the drilling.

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Carpenters say measure twice, cut once. So, I attempted to do that.

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I had an idea of where the input and output jacks should be located, based on the diagram. However, I did get into a bit of a rush and didn’t carefully plan the location of the other holes.

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I used this handy drill gauge to determine the size of bit to use for the potentiometer. A one-quarter-inch bit was the ticket for this one.

However, I couldn’t find my 3/8-inch bit to use for the jack holes. I re-organized my barn recently, and, as you might guess, I can’t find anything!

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So, how would I create a 3/8-inch hole for the jacks, much less a half-inch hole for the 3PDT switch? The tapered reamer, pictured above with the enclosure, would be the ticket.

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However, the reamer is uncomfortable to use. I had to take several breaks during the process of expanding holes from one-fourth inch to three-eights inch and to one-half inch. I have since bought a 3/8-inch drill bit!

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Backing up a bit, here’s how the drilling part worked. I am fortunate to have a small drill press. I used a clamp to hold the enclosure in position and drilled the initial holes with the one-fourth-inch bit. As mentioned previously, a tapered reamer finished the job.

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In the picture above, the holes are drilled and I have begun test-fitting the parts. I drilled the potentiometer hole in the wrong place, so I drilled another one. I figure that the knob will cover up the mistake! (Hey, this is do-it-yourself stuff!)

OLYMPUS DIGITAL CAMERA

So, now we’re ready for some soldering! The small size of the board amazed me. The current practice seems to be to directly solder the pots to the board so that the pot(s) serve as the mounting for the board. That requires a small board.

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Here’s one look at the circuit board after I’ve soldered in a few resistors. Periodic inspections of your soldering work will save you much grief later.

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Here’s the project not long before completion. I didn’t do a very good job of following the layout, so thing are kind of crammed. I may or may not be able to get a battery in there. However, I probably will run it off of a power adapter most of the time anyway.

Problem spots included the LED . With the 3PDT switch, it should’ve been possible to active the LED when the circuit was engaged. With a 3PDT switch, you can set it to either run your guitar’s signal through a wire and to the output, which leaves the sound unaffected; or click the 3PDT switch again, and sends the signal through the circuit. Those functions take four of the six switches in the 3PDT switch.

A 3PDT switch consists of  six open/close switches. When you push the button, one set of switches are closed. Push it again and the other set of switches close.

One of the remaining switches was for the LED.  However, after much frustration, I discovered that the individual switch for the LED didn’t work.  I pushed the 3PDT button to the point I was certain the switches were set to send the effect through LED.

However, some detective work with a multimeter disclosed that the particular switch used for the LED didn’t work. It didn’t close, which means that the power signal could not connect to the LED.

I tried some experiments with the LED. With a resistor wired in series with the LED, I touched the appropriate end to a lug of the power supply and the other end to ground.  It didn’t work immediately. I suspect I didn’t use the right resistor.

If the wiring of the 3PDT switch sounds complicated, Tayda has produced a PC board to which the  switch is soldered. After solder ing it to the switch, you may then attach your wires to the appropriate pad, such as input, output, or positive and negative power,  The LED also is connected to this board.

So, no LED “on” light for now. After some final testing came the big moment for a DIY’er. I plugged the guitar into the effect and then plugged the effect to a Mustang I amplifier. I plugged in the power chord.

I hit a chord. Success! It worked. So, now it was time to play with it. I compared the bypassed and effected sounds. The potentiometer increased the volume as the treble increased. It indeed was a biting sound.

Back in the day, I liked using a treble booster before a distortion. I didn’t get that chance at the moment, but I will try it later.

So, here are the overall impressions of the Brian May treble booster: the instructions assume some basic knowledge of electronics. The instructions, which are online, are not detailed step-by-step instructions. However, the project is basic, so such instructions may not be necessary.

The board is priced reasonably at $6. As mentioned before, the parts prices are very good. The enclosure cost $4.99, also not a bad deal.

So, if you’re looking for a basic DIY stomp box on which to learn skills; or, if you just want another stomp box for the board, then this is for you.

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The Tea Philter do-it-yourself project

A couple of years ago, I got the urge to build a stompbox. DIY audio devices were a major hobby of mine about 25 years ago. I built about 25 audio electronic devices over a stretch of several years.

However, life changes and other interests put the DIY work on the back-burner. Few examples of my efforts remain with me.

However, a stompbox kit called the Tea Philter by modkitsdiy.com caught my eye. It was a very simple pedal but with a lot of tonal potential. It makes it easier to get the “cocked-wah” sound. This is produced by rocking a wah-wah pedal to a specific point and leaving it there. The wah pedal changes the tone of the signal in such a way to make it sound better once it comes out of the amp.

teaphilter1

(Pictured: the Tea Philter – simplicity is beautiful!)

The legendary German guitarist Michael Schenker made great use of this method.

The Tea Philter has one knob that goes through the tonal range of a wah-wah pedal. But, instead of having to rock a wah-wah pedal and hope it stays put, you can just turn a knob on the pedal to the preferred point and leave it alone.

The pedal includes a true bypass footswitch and the ability to run on a nine-volt battery or external power. The housing is a sturdy metal box that is pre-drilled.

The Tea Philter is described as a simple project and it is. I figured that with all of my experience, it would be a piece of cake for me. But it wasn’t.

Now, none of my issues were the fault of modkitsdiy.com. The kit has the best instructions of any DIY kit I’ve ever attempted. The construction was simple point-to-point wiring. The instructions featured very well-done illustrations to help you build and troubleshoot the pedal.

But two years ago, I just couldn’t get the darned thing to work! I got so frustrated that I gave up on it.

teaphilter2

(Pictured – the innards of the Tea Philter.)

Recently, I’ve had a resurgence in my interest in DIY stomp boxes. Coincidentally – or perhaps not coincidentally – I was rummaging through some stuff in my garage and came across the Tea Philter that I had attempted to build. I decided that, by darn, now  I would get it to work!

To prepare for the attempt, I bought a couple of electrolytic capacitors of the same value as the one used in the circuit. I also got a couple of the same type of transistor that was used. I theorized that I may have burned out those components while soldering them.

With those items in hand, I got to try out my new soldering station on this project!

Now, troubleshooting any DIY project can be a frustrating experience. I tried to proceed methodically on this project. My favorite troubleshooting tool is a digital multi-meter with an audible continuity check. That means that you can touch each probe to points on the circuit that should be connected. If there indeed is a connection, the multi-meter will beep.

So, I started the process. I did find one wire that was not properly connecting two points of the point-to-point wiring. So, I fixed that. I also decided to swap out the transistor. However, I later discovered that I installed it the wrong way, so I went ahead and swapped it out again, I made sure I had the emitter, base and collector wires soldered to the appropriate places.

I checked out a bunch of other stuff, then plugged it in and powered it up. No joy. There was a bad hum and no signal was getting through. Back to the drawing board.

workbench

(Pictured – my humble work area for electronics, at least for the time being!)

More troubleshooting was done. I checked as many connections as I could. I measured the resistance of the resistors to confirm that they were working correctly. I replaced the electrolytic capacitor. I re-did any solder joint that looked even remotely suspicious.

Finally, I discovered another connection that didn’t give me the desired beep on the multi-meter. Out came the soldering iron and some more solder.

I again hooked it up and applied power. Success! I could turn the tone knob and hear the frequency sweep of the circuit. The next step was to run the signal through my digital modeling amp on some distortion settings.

I found the most interesting sounds at the 3 to 5 p.m. settings. A fully counter-clockwise position produced a treble boost that added bite to the sound of the Telecaster-style guitar I was playing.

I’m not quite sure why this project gave me so much trouble – maybe I’ve been spoiled by printed circuit boards and was just careless with the point-to-point wiring technique.

I should also note that the kit does not come with an LED to indicate that the unit is engaged. However, modkitsdiy.com has a schematic that will help you make the mod, providing you get the necessary 3PDT stomp switch, the appropriate resistor and an LED.

This would be a great first project. You can download the instructions at www.modkitsdiy.com and look at them before committing to the kit. The instructions are written in a way that would be appropriate for a novice DIY electronic kit builder.

Anyway, I now will be getting my Michael Schenker groove on in a big way, thanks to the Tea Philter!

 

Switching the control plate on a Tele

I have a Telecaster-style guitar. It has a Douglas body and a Guitarfetish neck. The pickups are both from Guitarfetish. The bridge is a Wilkinson with brass saddles. Tuners are Wilkinson E-Z lock.

So, as you can tell, this guitar has been modded a LOT! Still, I had one other modification that I needed to make. I wanted to do some volume swells on a particular song that I was recording. However, in the stock configuration, the volume knob on the Tele is almost too far away to easily do volume swells. I know that didn’t stop Roy Buchanan, but I’m not Roy Buchanan.

So, I decided to re-arrange the controls so that the volume knob would be at the front of the control plate, or closer to the picking hand. I first saw this modification on the Telecaster of Terry Kath, founding guitarist of Chicago. Many others also have done it.

So, here’s what the control plate looked like before I dug into it:

2-control plate

You may notice that the screw at the end of the plate is missing. I’ll fix that, too.

4-open controls

When removing the nuts on the potentiometers, it’s nice to use a wrench such as this. I used to use pliers. Aaaagh! The size is 7/16.

5-removing nuts

Here’s the control plate removed from the cavity. The wiring looks messy. Maybe I can fix that, too. Notice the toothpicks glued into each screw hole. That should help with the screw problem.

6-disconnected controls

 

The pots have been removed.

7-disconnected

I discovered that the wire from the input jack would not be long enough to reach the re-located volume pot. So, I had to replace that wire. An electric screwdriver makes quick work of removing the screws of the backplate.

9-electric screwdriver

Here’s what the control plate looked like after I finished the wiring. It’s much neater than it was. The big gray wire is the new input jack wire. I probably made it too long, but it will work.

10-finished

I used a wiring diagram that I got from the RioGrande pickups web site. Their wiring diagrams are very clear and easy to follow. Go to their web site and click on the support tab. That should show you the link to the wiring diagrams.

I had to replace several wires because of them not being long enough. I also re-checked some connections. I did have a treble-bypass circuit added to the volume knob, but I decided to leave it out. It cluttered up the control compartment and I’m not sure it did much good anyway. The purpose of the circuit is to prevent your signal from losing high frequencies when you turn down the volume knob. I usually play with the volume knob full up, so I didn’t use that feature much.

The switch should be reversed so you can choose the pickups in the same order as before.

Here’s a shot of my messy work area while the work was in progress. If you do this project, be sure to be better about protecting the guitar than I was. I should’ve put some kind of protective paper or something on the guitar. In this picture, I’ve even put a tool on the finish – a definite no-no, but I got away with it.

8-work area

I’m using a razor blade to cut off one of the toothpicks that filled up the screw hole. If you use a razor blade, be careful!

11-toothpick

I put everything back together and plugged it in. It worked! The first time! That’s not always the case with my mod jobs.

If you are fairly new to guitar electronics and want to do this project, remember to take your time. I find that a multi-meter with an audible continuity check helps a lot. In this project, it helped  me discover that a stray wire was causing the input wire to send its signal to ground. That would’ve caused there to be no output.

With a multi-meter set to continuity check, you can put the probes at two points of a connection to see if the signal is going from one place to the other. You also can check to see if the ground connections are where they should be – and shouldn’t be.

When all was said and done, I was able to play those volume swells much easier. Oh, I’m glad I know how to solder!

 

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