Table of Contents Table of Contents ........................ 2 Table of Figures ........................4 Section 1: About This Manual .................... 6 Who Should Attempt this Project? ................. 6 Tools you’ll need ......................6 Helpful Tools ........................6 Project Overview ......................6 Important Safety Notes ....................
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Install the Resistor Networks ..................31 Install the Ferrite Beads ....................32 Install the Control Cable Connectors and Controller Socket ........33 Components to be installed later ................... 34 Locations that remain unpopulated ................34 You’ve Finished this Side of the Controller PCB for Now ........34 Install the Push Buttons ....................
Install the Sockets, Integrated Circuits and Transistor ..........57 Install the Control Cable Connector ................58 Install the Motor Pots (Skip for NR version) ..............58 Section 8: Preliminary Final Assembly ................60 Wire and install the front panel input connector ............60 Install the headphone jack .....................
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Figure 24-showing socket orientation ................34 Figure 25-Switch and LED side of Controller Board ............35 Figure 26-Infra-red detector for remote control mounts 0.3” above plane of pcb .... 36 Figure 27-LED with white spacer added ................37 Figure 28-Completed controller, push-button and LED side and component side... 38 Figure 29-Silkscreen side of the Input Selector Board shows component locations ..
Section 1: About This Manual This manual gives the information needed to build and use Akitika LLC’s PR-101NR Stereo Preamplifier. The NR version costs less than the PR-101 as it omits: 1. The remote control 2. Motor pot for volume and associated components 3.
A lead-bending jig can make for quicker, neater assembly. It’s certainly not necessary. Is something in this manual confusing? Does something look wrong? Send your questions by email to dan@akitika.com. You’ll help yourself and everyone who builds the kit. Page 8 of 68...
Section 3: Building the Power Supply PCB This section details the process of building the power supply circuit board. Begin by carefully emptying the contents of the envelope marked “PR-101 PSU Module” into a broad soup bowl, as shown below. In general, you’ll start with the components that lay closest to the board, working your way towards the taller components.
You’ll notice that the component designations in the directions don’t go exactly in order. We have grouped them so that all components with the same value appear together. This makes assembly easier. You’ll find in the parts kit that similar parts, e.g. 3 1K resistors, are typically (though not always) taped together.
Figure 4-Assembling Heatsink to a Regulator Install the Regulators and Heat Sinks For each of the three regulators (U1, U2, and U3), the installation process is the same, with the result as shown in Figure 4. Note: U2 uses the tall heat sink! ...
Figure 5-Solder heat sink mounting rods to retain the heat sink Install the AGD-BGD jumper Prepare three 22 AWG red wires as shown in Figure 6. One will be used to connect AGD to BGD. The other two will be used for voltage select as described in the next section. Figure 6-Preparing power supply jumper wires Connect the AGD and BGD eyelets of the power supply PCB.
Figure 8-Jumper installation for 120 Volt Operation (left side) and 240 Volt (right side) Figure 9-Power Supply before transformer is installed, wired for 120 Volts These Components Are Not Loaded Three-pin headers TB1-TB6 and two-pin headers TB7-TB10 are not loaded in the standard kit assembly.
Power Supply Inspection Recheck your work to verify: 1. Correct diode polarity. 2. Correct polarity of polarized capacitors 3. Correct location of power supply voltage selection jumpers for the intended power source (either 120V or 240 V) 4. Verify that all installed components have been soldered. Section 4: Chassis Assembly and Power Wiring We’ll take a detour from PCB assembly to do some of the chassis assembly.
1. Remove the chassis from the packing material. Use a small Phillips head screw driver to remove the 11 screws that hold the cover in place (8 on the top, 3 along the back edge). Make sure to save the screws someplace safe, like your soup bowl.
7. When you look at the front of the chassis, the tape should not be visible. 8. Remove the “3M” paper backing from the double-sided tape. 9. Press the black plastic window against the newly exposed sticky side of the tape, being careful to center the window on the tape.
you get the orientation of the IEC power connector correct…it’s pretty well impossible to remove once installed! Figure 12-Installing power outlets and IEC connector...watch orientation! Installing the power switch…watch orientation! Push the front panel power switch into the front panel from the outside. Make sure you have the orientation correct with the O on the switch toward the chassis bottom before you push it in.
3. For now, leave the remaining long end with the FASTON connector loose. Locate the white unswitched power harness. It has white wire with 3 FASTONs. 4. Connect the blue 0.25” wide FASTON to the IEC power contact farthest from the chassis wall.
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9. Connect Black wire of the twisted pair to the bottom row switch contact closest to the chassis wall. 10. Connect White wire of the twisted pair to the remaining bottom row switch contact. Locate the black switched power harness. It has black wire with 2 FASTONs. 1.
9. Connect the Black wire of the twisted pair to the top row switch contact closest to the chassis wall. 10. Connect the white wire of the twisted pair to the remaining top row switch contact. 11. Make sure that the wires are formed to avoid the nearby ground stud. Figure 14-Form switch wires to avoid the ground stud 12.
Figure 15-Adding Lug to Ground Harness Connecting the Chassis Ground Locate the #6 toothed lug. It’s packed in the “Screw Nut Lug” envelope. Locate the green ground harness. It has green wire with 3 FASTONs. 1. Cut the long green wire to 8” length as shown in Figure 15. 2.
Connect the Toroidal Transformer to the power supply Locate the following items associated with the toroidal transformer: 1. Toroidal Transformer 2. rubber mounting pads (qty 2) 3. #8-32 nut and split ring lock-washer For now, we’ll work only with the toroidal transformer itself. Save the moving pads, lock-washer and nut for the later step when the power supply is mounted to the chassis for testing.
d. Insert the brown wire into the power supply PCB hole labeled brown, and solder the wire on the solder side. Clip the extra on the solder side. e. Insert the blue wire into the power supply PCB hole labeled blue, and solder the wire on the solder side.
12V ground wire installation Done? () Twist and tin the bare end of the 10” ground wire. Insert the tinned 10” ground wire from the bottom of the power supply board into the center TB4 hole, marked AGD and solder it on the top side. Twist and tin the bare end of the 8”...
Insert the tinned 8” black wire from the bottom of the power supply board into the TB3 hole marked N12 and solder it on the top side. 5 Volt Power and Ground wires Locate the red/black 18 AWG bonded-paired wire (zip cord). Prepare a 14” length per the following diagram: 5V power and ground wire installation Done? ()
6. Wiggle the transformer to make sure it is centered on the dished washer. Rotate the transformer so the wires point towards the back of the chassis, as this makes the wires to the power supply PCB lay most naturally. 7.
Remove the power cord from the wall and from the IEC power connector. Warning: do not go any further until the power supply has passed its test. If you’re having trouble, please send email to dan@akitika.com for troubleshooting advice. Page 28 of 68...
Section 5: Assembling the Controller Carefully empty the contents of the envelope marked “PR-101 Controller” into a broad soup bowl. Locate the controller PCB, and read the next box very carefully! The controller board is a bit unusual in that components will be installed on both sides of the PCB.
Install the IC’s and Transistor Make sure to orient the IC’s correctly when you install them. After you install each IC, bend over two diagonally opposed leads to retain the IC. Then double check to make sure that: You have the correct IC in the correct location. ...
pins. 8 10K Install RN2 in the indicated place. Make sure that resistors pin 1 of RN2, marked by the dot, goes into the square pad in the RN2 hole pattern on the PCB. Solder the two end pins first to make sure that RN2 is sitting level on the board.
Install the Control Cable Connectors and Controller Socket Insert the 10 pin cable connector, P6. Make sure to match up the pin numbers on the silk screen with the pins on the connector as shown in Figure 22. Figure 22-10 pin cable connector pinout ...
Figure 24-showing socket orientation It’s best to hold the socket in place by bending over two corner pins in a direction that won’t encourage shorts to adjacent traces. If that makes you uncomfortable, you can: 1. tack-solder two corner pins 2.
Figure 25-Switch and LED side of Controller Board Important: Install all LEDs with the same orientation, anode left, cathode right! You’ll note an unusual order to the buttons below. If you follow that order, then you install the outside corner buttons first. That makes it easy to correctly install the rest of the buttons.
Use the same method to insert and solder in the rest of the switches. Designation Description Done Normally open push button switch Normally open push button switch Normally open push button switch Normally open push button switch Normally open push button switch Normally open push button switch SW10 Normally open push button switch...
Install the LEDs Figure 27-LED with white spacer added This section is a little tricky, so please follow the instructions carefully for best results. Getting the LED’s straight and true will allow you to insert the front panel PCB into the chassis (in a later step) with a minimal amount of swearing.
2mm x 5mm green 2mm x 5mm green 2mm x 5mm green 2mm x 5mm green Use the procedure outlined above to install D11-D15. 2mm x 5mm green 2mm x 5mm green 2mm x 5mm green 2mm x 5mm green 2mm x 5mm green Once all the LED leads are soldered, cut the length a bit more.
Notice the pattern of push-buttons on the controller, and the pattern of holes in the front panel. Match the patterns, and insert the controller push-buttons through the holes in the front panel. Wiggle the controller a bit as you gently attempt to insert it into the front panel.
Re-check the front panel to see that it’s seated correctly. If it is, snug up the 4 4-40 screws that hold it in place. Install the Microcontroller 1. Locate the microcontroller IC. It is packed in its own bag in anti-static foam. Do not remove it from the foam yet.
Section 6: Assembling the Input Selector Board Carefully empty the contents of the envelope marked “PR-101 Input Selector” into a broad soup bowl. Figure 29-Silkscreen side of the Input Selector Board shows component locations Install the Resistors Install the resistors using the same procedures outlined in the previous section. If you’re using a lead bending jig, all the resistors should be bent at a width of 0.45”.
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100K Brown, black, black, orange, brown 100K Brown, black, black, orange, brown 100K Brown, black, black, orange, brown 100K Brown, black, black, orange, brown 100K Brown, black, black, orange, brown 100K Brown, black, black, orange, brown 100K Brown, black, black, orange, brown 100K Brown, black, black, orange, brown 100K...
4K02 Yellow, black, red, brown, brown 4K02 Yellow, black, red, brown, brown 4K02 Yellow, black, red, brown, brown 4K02 Yellow, black, red, brown, brown NL means not loaded NL means not loaded Install the Small Capacitors Now we’ll install the following small capacitors. If you have a lead-bending jig, use the 0.4”...
1N4148 75 V switching diode 1N4148 75 V switching diode Install the Bypass Capacitors The bypass capacitors are pre-formed to the correct span. Drop each one in, and bend the leads to around a 45 degree angle to hold the capacitors. Solder, then clip the leads in the normal fashion.
Install the Control Cable Connector Look at this drawing CAREFULLY to be sure that you’re putting P1 in correctly! Match the indicated features that shown pin 1, 2, 15, and 16 to the silk screen pin numbers marked on the PCB. Designation Value Description...
If you’re using this trick and like to be extra careful, just solder two diagonal leads for each relay. That let’s you flip the PCB to inspect that all the relays are flat to the board. After that, you can finish soldering all the relay pins. Be careful to get all the relay pins! Install the Transistors Insert each transistor into the board, making sure that the shape of the transistor follows the silk-screen outline on the PCB.
Install J1 and J2 Align each connector carefully with the holes in the board. Squeeze the connector onto the board. Keep your fingers outside of the hole pattern so you don’t jab yourself when the pins pop through the board. It will take a little squeezing and wiggling, but it fits very nicely and securely.
These Connectors Are Not Populated The connectors listed here are not populated. In a later step, you will wire directly to the PC board. 1. TB5 and TB6 are inputs that can be used if you buy the phono preamp option card.
Install Input Selector Signal Wiring If you’re not experienced with the preparation of shielded cable, please read Appendix 1 before you go on. Locate the more slender gray-jacketed cable. It is shielded cable. Beneath the gray jacket you’ll find: Red 22 AWG stranded wire ...
Select one of the 7” pieces with a remaining red wire (and no black wire). Solder it into TB12’s RT terminal. Insert it from the component side and solder it on the solder side. Cover the accompanying drain wire with ½” of the outside gray jacket material.
Insert the tinned green wire into the GND hole of the input selector’s TB13. Insert the wire into the solder side of the PCB, and solder it on the component side. Insert the tinned red wire into the POS12 hole of the input selector’s TB13. Insert the wire into the solder side of the PCB, and solder it on the component side.
ICs in the input selector board. Do not go farther until the voltages are correct. If you reach a road-block, send email to dan@akitika.com for troubleshooting advice. Install 16 pin ribbon cable...
7. Disconnect the IEC power cord and switch off the AC power. If the relays activate as described above, proceed to the next section. If you reach a road- block, send email to dan@akitika.com for troubleshooting advice. Note about H1 and H2 Holes on the board for H1 and H2 do not receive components.
Section 7: Assembling the Tone-Volume-Balance Board {Note: The Tone volume balance board for the PR-101NR is loaded differently than the same board when built for the PR-101. Those differences are noted here in these instructions} This section details the process of building the Tone-Volume-Balance circuit board.
You can identify the resistors by color code. I always like to cross-check the identification by using a Digital Ohm Meter. All of the resistors can be bent at 0.45” width for easy installation. Designation Value Color Code Done 24R9 Red, yellow, white, gold, brown 24R9...
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The following diodes are not installed in the NR version of the preamp 1N4004 Not installed 1N4004 Not installed 1N4004 Not installed 1N4004 Not installed 1N4004 Not installed 1N4004 Not installed 1N4004 Not installed 1N4004 Not installed Now we’ll install the following small capacitors: Bend leads to 0.4”...
Install the Relay and the Manual Pots Designat Value Description e Relay DPDT, 5 volt coil POT1 10K Pot Linear taper, balance control, large metal body POT2 10K Pot Linear taper, volume control, large metal body POT3 10K Pot Linear taper, treble control, small plastic body POT4 10K Pot...
Note that in the NR version, the follow steps are NOT DONE (in this shaded box) Install U7, the motor driver for the balance and volume pots. As in previous IC installation steps: Get the IC in the right way by matching silk screen and IC orientation marks ...
Designation Length D Done POT1 Long Wire 5/8” Solder one end in the upper motor terminal. POT1 Short Wire ½” Solder one end in the lower motor terminal. Figure 39-Motor POT wiring detail Repeat the process for POT2. Designation Length D Done ...
Figure 40-Showing Location and type of POTS for NR Section 8: Preliminary Final Assembly Wire and install the front panel input connector Identify the shielded cable that originates at TB7 and TB8 of the input selector PCB. Solder the free end to one of the 1/8” phono jacks, connecting the wires as shown in Figure 41.
Figure 42-Inserting 1/8" jacks in the front panel Install the headphone jack Install the second 1/8” phono jack into the hole marked with the headphone pictogram, fastening it per the detail in Figure 42. The headphone jack will have no wires at this time.
SELECTOR OUT, LT TB1, LEFT IN Black wire SELECTOR OUT, TB1, LEFT GND Drain wire with gray insulation SELECTOR OUT, RT TB2, RIGHT IN Red wire SELECTOR OUT, TB2, RIGHT GND Drain wire with gray insulation IN TO OUTPUT TB3, RIGHT OUT Red wire AMPS, RT IN TO OUTPUT...
4. Remove the IEC power cord. Warning: do not go any further until this test is passed. If you’re having trouble, please send email to dan@akitika.com for troubleshooting advice. Test the Tone Volume PCB Step 2 Figure 43-Showing 10 pin Ribbon Cable Installation and Orientation 1.
Section 9: Final Mechanical Assembly In this section you’ll complete final assembly of the PR-101. This consists of: Final mechanical Assembly Final Mechanical Assembly Figure 44-Install plastite screws (6) in the holes between the left and right channel input jacks 1.
Section 10: About the Preamp Architecture Features The PR-101 preamp has a very flexible design. It features: Selection amongst six inputs Support for two tape decks Buffers for the “to tape” outputs minimizes loading and distortion from connections to non-powered tape decks ...
Appendix 1 – Shielded Cable Preparation This section tells how to prepare the end of a shielded cable. 1. Cut the shielded cable to the overall required length. 2. Use a utility knife with a new, sharp blade to cut the plastic jacket of the shielded cable 1”...
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5. Separate and twist the drain wire. 6. Peel back and remove the foil. Remove the plastic wrap from the red and black wires. The drain (bare wire), red, and black wires are exposed now that gray insulating jacket, foil shield, and plastic over-wrap have been removed. 7.
Block Diagram The input selector selects amongst six inputs. The signal selected on the input selector is buffered and output to tape1 and tape2 for recording. The signal delivered to the balance control input can be either the one specified on the input selector, or the output from tape1 or from tape 2.
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