Until recently, there were various disagreements regarding the calculation...
Nowadays, a huge number of interesting gadgets are easily available to the guitarist, so most likely you will come to the need to build a pedalboard. You will have to decide what board to buy or build, what pedals will be there and in what order, as well as the length of the cables, regardless of whether you buy ready-made ones or make them yourself. But perhaps the most important decision you'll have to make is how to power all the pedals on your new pedalboard. There are three main aspects to think about in this decision - voltage, current and insulation.
Fortunately for us, the popularity of Boss pedals made it possible to establish an unwritten standard for the power supply of gadgets, regulating the level of direct voltage (DC) and the connector (jack) used. Most gadgets are powered by a 9V battery. It was this simple fact that served as the starting point for the further appearance of inputs for 9V DC power adapters. These inputs were useful when musicians didn't want to deal with batteries, but instead preferred to be able to power their effects from regular alternating current (AC) wall outlets.
Boss chose to use a 2.1mm DC input jack with a negative in the center. And that's why most pedals on the market today use this "standard". If you look at the power input on your device, then there is a chance you will see something like this on the label next to it: 9 V DC, minus in the center (a pictogram depicting a jack, and with a minus in the center).
Naturally, not all pedals are powered by 9V, so if you have such pedals in your collection, then you should keep this in mind. Some devices even use 9V AC. Therefore, be careful not to connect an alternating current (AC) source to a device that requires direct current (DC). Also, there is a possibility that your gadget needs 18V or 24V DC; in any case, usually the manufacturer supplies such gadgets with a special adapter. And you need to be careful not to power your pedals with higher voltage than necessary - no one wants to end their pedalboard project in smoke!
Which power supply is suitable for guitar pedals?
Current is the next thing to think about. The current that the effect draws is not usually indicated on the pedal itself. To do this, most likely, you will have to look at the manual. For almost all analog devices, such as distortions, overdrives, fuzzes, wahs, compressors, the current requirements will almost always be low (less than 20 mA or so). This is because such devices use a small number of transistors and op-amps with low power requirements.
On the other hand, digital devices contain microprocessors or DSPs, possibly some kind of memory, logic chips, ADCs and DACs, plus analog elements. In this case, you'll literally be powering millions of microtransistors inside these digital chips, so these pedals have a much bigger appetite. Digital pedals typically draw more than 150 or 200 mA, and modern power supply manufacturers take this into account.
With regard to current, it is worth remembering that there is no crime in having more on hand than you need. But if your source can't supply the required current, your pedals may not turn on at all. Even worse, they may pass out in the middle of a performance. Think of current as the “horses” in a car. If you have 450 horses under the hood, you don't use them all when you leave the garage, but they are always waiting for you to step on the gas.
The correct voltages and currents are needed to make your effects work correctly, but another important consideration for a low-noise rig is isolated power. Generally speaking, strings and electronics in an effects chain can influence each other, for both good and bad.
The most common noise problem I see regularly when helping guitarists with their pedalboards is ground loops. Ground loops usually occur when the lotion circuit is powered by a daisy-chain wire, i.e. sequentially. In this case, a ground loop occurs between each effect in the chain!
Why should we avoid ground loops?
Well, firstly, because they allow harmful magnetic fields to introduce noise into the useful signal. And secondly, because these noise currents can leak into your audio path instead of just returning to the power supply. If you only use one type of effect - distortion - then you may not hear the painful effect of ground loops. But if your circuit has modulation and delay effects, then most likely their effect on the desired signal will be noticeable.
To solve this problem, power supply manufacturers have created supplies with multiple isolated outputs. The Voodoo Lab Iso-5 is an example of a low-cost, efficient source with multiple isolated outputs. Isolated power supplies use a transformer or multiple transformers to keep each output electrically isolated. This prevents the guitar signal ground from making contact with the pedals on the power supply side.
Ideally, you want to ensure that the ground path and the wanted signal path from the guitar to the amplifier are identical. Otherwise, the background and others like it will spoil the sound. Multi-output supplies, if properly designed, just like regulated power supplies, are cleaner than a regular outlet. That is, if there are several outlets nearby from which you power your pedals, then this is not bad at all. This also provides isolation if each outlet is used to power one pedal. [I believe this is relevant for those sockets where there is a third contact - ground, although I could be wrong. Note CraSS>
Overall, there is a lot to think about here, but if you think it through thoroughly before, it will save you from a lot of frustration in the future. Monitor the voltage, make sure there is enough current, and use decoupled (isolated) power supplies for each pedal. Happy Shredding!
Hi all!
As promised, I continue reviews of music-related purchases.
Today's turn is the power supply for guitar pedals - another resident of my pedalboard.
Read further under the cut)
As you know, most guitar pedals have variable power supply - either (the most common option) 9V batteries ("Krona"), or a power source. Many musicians believe that battery power is optimal, because... This option a priori rids the audio path of distortion introduced by unstabilized power supplies, often downright cheap, from the nearest radio market. But it’s one thing when there are 1-2 such pedals, and concerts take place once every 3 months. What if you have to perform once a week, and the total supply of batteries in the board amounts to a dozen pieces? You can calculate for yourself how much this pleasure will cost. But in order not to risk being “silenced” in the middle of a performance, many put on a fresh set for each performance.
So, I’ve come to the conclusion that it’s time to buy a power supply for my pedals.
First, I turned to my, recently, favorite domestic manufacturer - AMT. But the price tag for their power supplies turned out to be very high, and given that my pedals are powered by both 9 and 18V, I would have to assemble a chain of different modules (AMT offers a unique modular power system, I recommend google), and this would generally be extremely inappropriate budget. Next, I looked at such a famous buyer as Yerasov. And I had almost ordered his power supply unit for myself, when I suddenly saw on Ali an absolute analogue of this power supply unit, but at a price 2 times lower. I started googling and saw that these clever guys were buying Chinese power supplies, changing the labeling on them, putting on an “OTK” sticker and selling them under their own brand. Moreover, according to numerous reviews, their power supplies are not isolated at all and are often loudly “noisy”. So I continued searching further. And among the reviews I came across the hero of my review - the CALINE CP-05 power supply. Of course, I knew that galvanic isolation in a block for 1900 rubles should not be expected, but who the hell is not joking?
In the end, I ordered this unit, especially since the options included delivery from the Russian Federation. In addition, I took a noise suppressor - the NoiseGate pedal (well, I’m sure that the power supply will make noise! And anyway, I want to muffle the “idling” of the compression pedal).
Payment screens
It's funny, but the seller got the track codes wrong.
It seems that it is indicated that the power supply will be sent by courier within the Russian Federation, and the noise reduction will be the usual aliexpress standard shipping, but the track code was given to me the other way around! I was confused, and until the last moment I could not understand what was coming to me!
So, on July 5, the order was paid for, and on July 10, it was delivered to my home. Delivery was carried out by IML.
Looks like a regular gray bag. Inside is a cardboard box, without any foam or other protective equipment. A small leaflet that I immediately threw aside.
Additional Information
Inside the common box with the manufacturer’s symbols, 3 more are neatly laid out. In one, the power supply itself, in the other, the network adapter, in the third, a “bundle” of connecting cables. By the way, the cables are very comfortable, with angled connectors, moderately soft, but not snotty as I was afraid.
Additional Information
The block itself is light, I was even a little scared. It feels like it weighs like an adapter, which is 10 times smaller.
Additional Information
At the top of the block there is a large logo with the number 5 (apparently a modification for the Nth number of channels), markings for input power and output channels. The manufacturer promises 7 9V outputs with current consumption up to 100mA for conventional analog pedals, 1 9V\500mA output for digital pedals, 12V\100mA and 18V\100mA.
On the side “front” there are holes for cables and a connection indicator. On the left in the corner is a switch that allows you to turn the backlight on/off. Looking ahead, it is better to turn it off because... even in the semi-darkness it burns out your eyes. Hellish Chinese blue diodes!
On the bottom side there are some strange silver hexagons recessed into the body plate. Strange. The case can be disassembled using 4 screws at the end.
Let's look at the power adapter. a regular power supply, like from many household appliances. Output 18V, 1A. I don’t know, it’s lazy to count, but I’m not sure that this power supply will pull the full load from all channels at the same time.
Additional Information
For some reason there are 9 cables for connection. Although there are 10 outputs. Strange. I'll write to the seller...
There are some short adapters, I don’t quite understand what they are for. most likely to change the polarity (usually “-” inside) Put it on the pedalboard faster!
Additional Information
The size fits perfectly! However, I calculated the board based on the BP from Yerasov, which is a little larger. So that's great. The fastening is standard - through Velcro to the bottom of the power supply.
Today I have 4 pedals, 3 of which are powered by 9V and one - the AMT Bass Crunch-1 preamp consumes as much as 18V. Great, there will be something to test. I turn on the board, turn on the backlight... and slena! Horror! I couldn't even take a good picture. The glow of these diodes is killer! I turned off the backlight and took a photo. That's better.
Additional Information
Next we join the combo. I have a small Kustom KG210FX at home. I have enough for home exercises. Well, what can I say... there is some noise at idle, but it’s hard for me to say whether it’s the power supply or the combo itself that’s making noise. I get stuck in the “gap”, because... I use an AMT preamplifier, but the amp itself has no digital amplification. While playing the guitar (I used both my regular Yamaha RBX 375 bass guitar and also dabbled with BC Rich Warlock), all the pedals worked properly and I didn’t notice any problems. You need to get to the studio and plug into a normal terminal. But for comparison, I powered the Robiton 18V preamp with a Robiton multi-adapter lying around and plugged it back into the amp. That’s when I realized what noise is! In general, CALINE is much cooler than Robiton) Who would doubt it...
I am sure that after properly installing the noise reduction, I will forget about these problems.
But there is no rest for the restless soul. I took the PSU to work, where I gave it to the electronics engineers.
I really wanted to check the seller’s promise about “10 isolated outputs.” What does it mean? This means that between the input and output there is a barrier, usually implemented in the form of a high-frequency transformer, so that there is no electrical contact between the input and output. I asked the specialists to check this.
They sent me photos with the comment “you’re on Apple,” there’s no insulation there. There is a diode cleverly plugged into the 8th output, which prevents continuity with a regular tester. But the land of all canals is common. In general, the seller’s deception is obvious.
I’m not an expert myself, the moped is not mine and all that. But I believe these people. I will definitely open a dispute.
Additional Information
As a summary - for undemanding musicians the power supply is very good, for 2000 rubles I think it has a right to exist. And for stage work, most likely, you can’t do without a well-tuned noise reduction. Or you can still splurge on a stabilized power supply with galvanic isolation for each channel. But it will already be from 8000 rubles. However, it is possible that over time I will switch to a more expensive option.
Therefore I bow, there was a group with you STRONTIUM and her crooked bass player! Thank you for your attention!
Planning to buy +1 Add to favorites I liked the review +5 +12The DIY topic raised by Sasha coincided with the fact that our workshop ordered a power supply for guitar effects. And I thought - why don’t I write an article about this?!
How to make a power supply unit (PSU) for yourself?
In principle, if you have average knowledge of radio electronics, accuracy, and most importantly - desire, it is not so difficult to do it.
In this article I will tell you - HOW TO MAKE A POWER SUPPLY - stabilized, for several pins and voltage ratings. Partly, using the example of the power supply unit that was ordered for us.
The first thing you need to successfully implement your plan is to draw up a good technical specification (hereinafter referred to as TZ). And then the element base is selected according to the technical specifications. A good technical specification is one in which everything is taken into account.
What to consider?
Dimensions, operating currents and voltages, number and configuration of outputs/inputs, ease of use.
This was T.Z. for our pedalboard:
- Desired dimensions: up to 55mm – height, up to 90mm – width. The goal was also to lighten the design as much as possible without compromising the following conditions.
- Operating currents and voltages: 9B,1A; 12V, 1A. Where 1A is the maximum current consumption for all effects with this voltage.
How to calculate what is your maximum current consumption? And what voltages? It's simple - usually the manufacturer indicates them either on the body of the guitar effect (voltage and polarity) or in the instruction manual (current consumption). Look and write them down.
In our case, there were 6 guitar effects with a voltage of 9V and current consumption of up to 100mA per effect. This means that to find out the minimum current consumption, we need to add up the effect currents: 100mA*6= 600mA=0.6A - this will be the maximum current consumption for 6 effects. If suddenly the power supply has more current, it’s not scary. But if it is less, it may fail.
A tube preamp will have to be connected to 12V. Its current consumption is 1A. To summarize: at 9V there will be a current reserve of 0.4A. At 12V there will be no reserve.
- Number and configuration of outputs.
Usually the number of outputs corresponds to the number of effects or a little more - if the power supply has a current reserve. In our case, the owner wanted 10 outputs for 9V and 3 outputs for 12V, in case instead of a preamp it was necessary to connect several effects with a maximum current consumption of up to 1A.
- Ease of use.
The following requests were put forward: that the power cord for the power supply be removable, that the power supply be retracted under the pedalboard.
Now you can select the parts needed for manufacturing.
What will be needed for production?
- Housing of required dimensions. We chose a plastic case 55mm x 85mm x 140mm. Since the power supply will be retracted under the pedalboard, the likelihood of it being trampled is reduced – i.e. what parameter, such as “vandal-proof strength”, is missing. But such a case is significantly lighter than a metal one. Such a case will cost 150-300 rubles.
- Transformer. The task of choosing a transformer of the required ratings (9V x 1A; 12V x 1A) and at the same time of such dimensions that it fits into the case would not be an easy one. At the same time, it would weigh quite a bit. (We implemented the power supply circuit somewhat differently, but I will describe how most people do it - the simplest and most reliable way - i.e. with a transformer). Find a transformer. You can have one - the highest value, but you need to remember that in this case the current must be added. Those. you can take a transformer with two windings of 12V and 1A each, or one winding of 12V, but 2A.
In general, the upper voltage value should be selected according to the maximum, and the current should be the total value. Still, you should choose the transformer first - according to its financial and power/dimensional characteristics, and the housing - at the very end, so that the transformer and everything else fits. The photo shows a transformer that is slightly larger than the body in height. With two secondary windings - 9V and 12V. Such a transformer with 1A windings can cost from 1000r to 2000r.
- Parts for rectifier and stabilizer:
Diode bridges of the required parameters – i.e. with a reserve of current and voltage. The rule here is simple - the larger the margin, the more reliable the design. However, the price is higher. It makes sense to choose elements with a margin of 3-5 times (you can make them from 4 diodes, or you can buy ready-made ones). Capacitors, stabilizer microcircuits. What capacitors are needed is usually written in the manual for the microcircuits, but the same rule applies here - the larger the capacitance, the less ripple, the more stable the power supply.
If we take our technical specifications, then we would need: 2 diode bridges (in the photo - up to 200V in voltage and up to 1.5A in current), 2 stabilizers - 9V and 12V, 4 capacitors. Typically, such power supplies use microcircuits of non-regulated stabilizers designed for one rating. Stabilizers of the L78XX or LM78XX family.
Capacitors. We took 10 µF capacitors. The minimum or standard capacitor values are specified in the instruction manual for the microcircuit.
You will spend about 500 rubles for everything.
- Printed circuit board. If you do DIY, then you need single-layer fiberglass, ferric chloride, choose a method for applying the pattern of tracks on a printed circuit board, and properly tuned hands with a head that will implement all this. The results of skillful hand etching are shown in the photo:
Probably if you are making a printed circuit board for the first time, maybe. It won't be as attractive, but it will be quite functional. This will also cost about 500 rubles - if you etch the board manually.
We order the production of printed circuit boards in Zelenograd. In specialized production.
Yes! Also be sure to consider how the PCBs are attached. And the fact that microcircuits require cooling!
In our case, an aluminum plate acts as a radiator (look at the photo with details). You also need to unsolder the wires to connect the power supply to the guitar effects. The total cost of consumables for home production with these parameters will be about 2000-3000 rubles. Not counting the time costs.
This is the power supply we made for guitar effects:
Everything is in the best accordance with the specifications - lightweight, installed under the pedalboard, removable power cord, 12V - 1A - 3 outputs, 9V - 1A - 10 outputs, a set of cords for connecting with guitar effects + 1 spare (14 pcs of different lengths - to suit the sizes pedalboard).
The order of further work:
1. We find, select, buy the necessary parts and consumables.
2. We manufacture printed circuit boards (apply wiring, drill, etch).
3. We mount printed circuit boards (we solder transformer leads, diode bridges, capacitors, microcircuits).
4. Prepare the case: drill mounting holes, install fasteners, mount: inputs/outputs, transformer, printed circuit boards.
5. Testing, finishing work. At this stage, we check voltage ratings, ripple levels, and the quality of the design as a whole. Let's complete the finishing touches.
6. Congratulations! You have your own stabilized POWER SUPPLY for guitar effects! :)
Have questions?
Write in the comments. I will answer either by myself or through joint efforts.
Kirill Trufanov
Guitar workshop.
