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Poweramp 5, our top-of-the-line power amplifier for music enthusiasts, audiophiles and recording studios. And, of course anyone who simply want the best possible music reproduction from the deepest bass to the smallest detail.
How to (easily!) build your own Poweramp 5 power amplifier using the PA5L component kit with ready-cut cabinet parts.
(For info about the kit itself and how to get it, click here.)

This is a long webpage because these are step-by-step instructions. The amplifier is very simple to assemble.
Just follow the step-by-step instructions, and the amplifier will be ready for use in just an hour or two, even if you have never built an amplifier before.
No special tools are needed, only pliers an screwdrivers. No soldering at all.
Among our customers are carpenters, professional musicians, garbage men, café owners and other persons with little or no experience in electronics, but they have all succeeded to build their own amplifier, usuallly in 1 - 2 hours.
Warning. Donīt use electric screwdrivers or other powertools. Use ordinary hand tools and donīt use more power than what is needed to get the parts together. The screws heads for the box are pozidrive, PZ1.
There are three different lengths, approximately 9.5, 13 and 19 mm, called short, mid-length and long screws in the texts below.

Start by attaching two of the four mounting blocks to the front using the mid-length screws.
The wide long slot is turned upwards with she square hole of the front to the left, like this:

Do the same thing with the back, also here noticing the way the blocks are turned:

After this, take the bottom part and fix the rubber feet using the short screws:

The distance between the upper rubber feet and their border (where the back panel will be placed) is slightly shorter than between the lower rubber feet and their border (where the front will be placed).
Before joining the wooden panels you should mount some of the electronic parts on their respective panels, that would be more difficult with the panels in place.

Start with the rear panel where the inputs and outputs are to be mounted, first fastening the RCA terminals.
First, separate the parts. (Both the black/white and the black/red RCA terminals and their cables):

Place the black (= left) terminal in the hole closest to the edge like this. (When the back panel is in place, and you look at the amplifier from the front, the black terminal will be to the left.)

On the inside, first put the black cable with its ring contact in place, the hole closest to the edge.

Then the spring washer...

...and then the bolt. First use your fingers, not any tool, until it takes threads properly.

Then use pliers to tighten, but not too hard! When the spring washer becomes flat it is enough. Too hard and you might damage the thread.


Then do the same with the red RCA terminal.
After this, twist the wires together like this:

There are also four thin wires like these in the kit:
One white short wire, one long red wire and two black wires, one short, one long.

Twist the short wires (black and white) together like you did with the wires from the RCA terminals. Then do the same with the long wires (black and red). These will be used later, when connecting the volume control potentiometers to the amplifier modules.

Now, mount the speaker terminals onto the back panel.
To make it easier to get the holes for cables vertical, use something with 4 mm diameter to hold the terminals...
(We happened to have a 4 mm drill which we screwed in place like this.)

...and hold it so that the hole becomes vertical when fastening the terminals:

The normal placing is black terminals in the middle and red terminals outside, like this:

Mount the speaker terminals from the outside, and fit the rest in this order:

First the cables with ring contacts. Black wires to black terminals and red to red, of course.
Remember to hold the 4 mm (drill or whatever) so the holes of the terminals become vertical as in the picture above the previous picture.

Then the flat washer, then the spring washer and finally the bolt:

Tighten the bolt until the spring washer becomes almost flat:

Now you attach the power input socket, contacts up, fuse holder down like this, using two of the short screws.

(Fuse: 5 x 20 mm, 1.6 A slow burn fuse for 220-240VAC, 3.2 A for 110-127 VAC.)
The fuse is only included in the kit with the 230V transformer.

After this, the rear panel is ready, put it aside for now.

Wiring of the Power Supply Unit PCB:
This is the output screw terminal of the PSU board. Both H are minus, both A are plus and the rest are ground points. The reason for using letters is to make it more simple to connect to the amplifier modules.
In the kit you find cut and stipped wires with two thicknesses plus a green/yellow grond wire with cable shoe. The thinner wires are NOT used for the PSU board, so put them aside for now.
There are two lenghts of wires, approx. 15 and 30 cm.
Fasten the wires with a normal screwdriver, insert the wires and tighten the screws (by hand, not using any power tool!)
From left to right the wires are connected like this.
Left H: Black short wire. Right H: Black long wire.
Left D and G: White short wires.
X (any of them is OK): Green/yellow ground wire.
Right G and D: White long wires.
Left A: Red short wire. Right A: Red long wire.
Then screw the PSU board onto the bottom panel using four of the short screws. Look from beside, and donīt screw tighter than this, the screws should hold the PSU board in place, but not bend the board. Screewing too hard can cause cracks in the PCB.
When fastened to the bottom panel it should look like this. We have placed the short wires to the left and the long wires to the right, as that is where they will go later on, and to make it easier to fasten the front panel.

So this is the bottom panel, seen from above. Left = left, right = right, up = back, down = front.

We recommend that you donīt fasten the mains transformer until later even if you could do it now. The transformer is relatively heavy and makes handling more difficult at this stage.

Fasten the back panel. Use the long screws and hold the back panel and bottom panel together like this when screwing them together.

Afterwards it should look like in the picture to the right.

After this, do the same thing with the front panel. Round holes for the volume controls to the left, rectangular hole for the power switch to the right. On all four mounting blocks, the 7 mm wide slots will now be facing upwards.

NB. If you bought the PA5L kit (without the transformer) the transformer you buy from someone else will not be marked the same way. See the very last part of this page.

Slide the amplifer modules in place.
The mounting blocks may be a bit tight, but avoid bending the back or front outwards when doing this.
Both amplifier modules are equal, so which one is placed to the right or left is not important.
Be careful when handling the amplifier modules. Avoid touching the components with any tool, and donīt drop them on a hard surface, which could cause permanent damage.

Now, connect the wires to the power input socket on the back panel.
It is extremely important not to make any mistakes here, follow the instructions carefully.

Begin with the ground wire from the PSU board.
It connects to the most upper contact of the AC terminal, the one placed in the middle of the terminal seen from above.
Hold on to the terminal on the outside while doing this, not the panel. Some force is needed and that could otherwise damage the threads for the screws holding the socket.

Then connect the two yellow cables with female contacts on both ends to the power input socket, the terminals to the left in the picture, the ones above each other. Donīt forget to hold the terminal, not the panel, with the other hand.

On the front, attach the red power switch.
Notice the small spike the red arrow points to.
It must be turned downwards to make the ON-light work only when the amplifier is turned on.
Notice: The indicator light only works with 200 to 250 VAC mains voltage, but you can always see if the amplifier is on or off by looking at the position of the button.

Now attach the other end of the two yellow cables (from the AC terminal) to the switch, the two terminals closest to the mounting block, as seen on this picture.

Important: When pushing the cables onto the switch, hold on to the switch from the outside, not the wood, or the switch will be pushed out of the front panel.
Mounting the transformer
Here we use the 230V transformer, but you should be able to mount any suitable toroid transformer the same way.

Start by mounting the screw (fixing it with one of the bolts) in the hole to the right of the PSU board.
 Put one of the rubber mats on top
Then the transformer. Try to place is as well centered as possible. Make certain the four low voltage wires can reach the PSU boardīs 4-way screw terminal with some marginal.
Then put the other rubber mat on top.
Finally the metal washer, and screw on the second bolt.

VERY important:
If you have a strong grip, use your fingers only, otherwise pliers. But be careful:
The transformer should be fastened just so you cannot turn it by hand without some force. If you can turn it by hand without any real force, fasten the bolt another 90 degrees (1/4 rotation). If that is not enough, another 90 degrees...
It is very important that you donīt go too far. Too much preassure can cause damage to the transformer windings.
Picture: Trying to turn the transformer. If this cannot be done without some force, it is enough.

When the transformer is in place, attach the soft red wires with terminals to the power switch.
Remember to hold the switch on the other side, so it is not pushed out of the box.

Now, connect the four stiffer wires (secondary voltage) from the transformer to the 4-way screw terminal of the PSU board.
If the transformer was included in the kit, they are marked with 1 - 4 lines or dots.
Connect the wire with one dot to no 1, the wire with two dots to no 2, the wire with three dots to no 3 and the wire with four dots to no 4. (If you have bouth the transformer locally, one secondary winding goes to 1 and 2, phase marking to no 2, the other secondary winding to 3 and 4, phase marking to no 4. See special instructions about the transformer at the end of this page.

Now it is time to connect the volume controls.
From the input RCA terminals, connect their wires to the volume controls  (potentiometers with 1-2-3 screw terminals) this way.
Right channel: Red to 1, black to 3 (see picture).
Left channel white to 1, black to 3
Just screw teminal 1, wait with terminal 3 until next step

Then connect the thin wire pairs to the volume controls, black to 3, red or white to 2:
Here you see the right channel wiring (red and black).
The left channel is exactly the same, but the wires are black and white (and the pair to 2 and 3 is also shorter).

Now, you attach the volume controls to the front, with the numbers pointing upwards.
The one with white/black wires to the left, the one with red/black wires to the right.
Use pliers with moderate force to tighten the bolts.
Now it is time to connect the amplifier modules. Carefully follow these instructions, as placing wires in the wrong places can cause permanent damage to the modules.

As you can see, both modules have a screw terminal marked A-B-C-D-E-F-G-H
A, D, G and H are connected to the same letters on the PSU board.

Here we show you right module, but the left module is connected the same way. The only difference is the colour of the wire going to the B terminal. It is red on the right module, but white on the left module

First the red wire from A on the PSU board to A on the module. (Shorter to the left module, longer to the right, of course).

From the right volume control you have a red+black wire pair (right channel).
Connect the red wire to B and the black wire to C.

Then the white wires from the PSU board. D to D and G to G.
Then the black wire from the PSU board (H) to H.

Finally, the wires from the loudspeaker terminals. Red to E, black to F:

The left amplifier module is connected exactly the same way, except for the colour of the wire running from volume control (terminal 2) to the B terminal of the amplifier module. On the left channel it is white instead of red.

Now all electric and electronic components are in place and connected. It is time to put the volume control knobs in place. If both both volume control potentiometers have their terminals straight upwards, this is the way to get both volume control knobs right:
Turn the slot of both potentiometer shafts as horizontal as possible. Here we have put a metal ruler in he slots, so they get almost perfectly horizontal. Then we remove the ruler, being careful not to turn the shafts while doing so. (If you donīt have a ruler this thin, you can use a knife or similar, of course.)
Then, just push on the knobs with the index pointing straight up. (Both, of course, this is just to show the slot of the left potentiometer shaft.)

Now you are ready!!! Everything is in place, all wires connected. So, just plug in the AC cable, connect your sound source and you are ready to go -- or maybe not?

PLEASE check all wiring again. Here is a checklist:

PSU board terminal A Amplifier modules terminal A Red wire
PSU board terminal D Amplifier modules terminal D White wire
PSU board terminal G Amplifier modules terminal G White wire
PSU board terminal H Amplifier modules terminal H Black wire
PSU board terminal E or F Ground terminal of power input socket* Yellow/green wire
Red speaker terminal Amplifier modules terminal E Red wire
Black speaker terminal Amplifier modules terminal F Black wire
White wire from left volume control terminal 2 Left amplifier module terminal B White thin wire
Black wire from left volume control terminal 3 Left amplifier module terminal C Black thin wire
Red wire from right volume control terminal 2 Right amplifier module terminal B Red thin wire
Black wire from right volume control terminal 3 Right amplifier module terminal C Black thin wire
Yellow wires from power input socket Right terminals of the power switch*

*) Power input socket:

As high voltage is dangerous, look at this picture once more, and make certain you have put the yellow+green wire in the right place.
The yellow-only wires to the left, the yellow+green wire in the upper-middle terminal.

Everything was OK? Then screw on the top panel, connect the sound source (preamplifier, CD- or DVD player, computer earphone output (green socket), DAC or whatever with 0.9 V (or more) output signal. Then the loudspeakers (8 - 16 Ohm)  and finally the AC cable.
First set the volume controls low (about 9 oīclock position) and switch on the amplifier. With an active sound source, the sound should come within a fraction of a second. If both loudspeakers play music, it is OK to increase the volume.
The modules are of course carefully tested before delivery, so if the wiring is correct, the amplifier will work perfectly.

If there is no sound or only on one channel works, turn off the amplifier directly and re-check the wiring.
If something is wrong, it has to be a wiring problem. Or, maybe, the loudspeakers. If you can measure resistance, loosen the loudspeaker cables and check so the resistance of the loudspeakers with cables attached is c:a 6 - 8 Ohm.
If it is close to zero, the loudspeaker or cable has a short circuit and must not be connected to the amplifier.

If there is something wrong and you cannot find what is wrong, just take a few photos of the inside of the amplifier and send them to us by email, and we will help you out. However, when this was written we have sold quite a few kits, and so far not one has failed, and if you follow the instructions above (especially the wiring list) nothing should go wrong.

If you bought the PA5L kit, without the mains transformer it is important you identify the windings. You should have a label on the transformer or a data sheet, showing the markings of the primary and secondary windings
First of all, the primary windings. They are usually thinner than the secondary windings because they carry less current. Clamp the two red female contacts onto the wires, so they can be attached to the power switch. Polarity is not important.
Then identify the secondary windings, and this is important. Here are a two samples:
The polarity can be shown in different ways: On the left picture it is 0 and Vsec (which can be for example 22 or 24 V), on the right a black dot is indicating polarity.
Primary voltage (in these cases 230 V) polarity is not essential, but the secondary polarity is very important.
Here we have the same transformers, connected to the input screw terminal on the PSU board.

Letīs call the two secondary voltage windings "winding 1" and "winding 2".
And the polarity marked wire from each one "polarity wire", and the other wire "non polarity wire".
Then the 1 - 4 screw terminal is connected like this:
1 Winding 1, polarity wire (red on the left transformer, red on the right transformer).
2 Winding 1, non polarity wire (black on the left, yellow on the right)
3 Winding 2, polarity wire (yellow on the left, blue on the right)
4 Winding 2, non polarity wire (orange on the left, grey on the right.
(As you see, colours are not the same, there is no standard.)

On the INDEL transformers we use both wires from the same winding has the same colour, and both ones from the other winding another colour. And the polarity is indicated by a short plastic tube close the the transformer body:

In this case this is one way to connect:
green with polarity tube to 1, green without polarity tube to 2, blue with polarity tube to 3, blue without polarity tube to 4.
However, forget the exact colours, Indel changes them every production cycle. The only thing that seems constant it that the primary voltage wires are red. (So far...)

If you have bought the PA5C kit, you donīt have to worry about this, as we mark the secondary wires with one, two, three and four lines. And you just connect the wire with one line to 1, the wire with two lines to 2, three lines to 3 and four lines to 4. It couldnīt be more simple.

© Valulutronic, Sweden 2019