how to assemble the balanced headphone amplifier kit · pdf file · 2013-01-01for...

Thank you very much for purchasing the Otomatsu amplifier kit. Please read this manual carefully prior to commencing assembling the amplifier kit. Ensure to pay attention in preventing any accidental electrical shock.

Table of Contents

1. Introduction and Circuit overview

2. Assembling Headphone amplifier module. 2 sets

3. Assembling the Balance drive module

4. Assembling the Power supply module

5. Case set

6. Assembling the case and cover modules

7. Assembling the back panel

8. Attaching together modules to the case

9. Wiring the power supply

10. Wiring signal path -1, -2

11. Checking all wiring

12. Checking the voltage level of key areas

13. Modification of Headphone cable

14. Improvement options

How to Assemble the Balanced Headphone Amplifier Kit BDR-HPA01E (Estimated assembly time: 10 hours)

otomatsu

If you have any technical question, please contact: [email protected]

Input Stereo RCA un-balance line signal Output Stereo XLR Balance x1. or Un-balance 1/4inch phone x2 Or capable to drive XLR input Power Amplifiers Frequency Response 5Hz -80kHz Total Harmonic Distortion + Noise 0.0046％ @40Ω load 1kHz Output power 1600mW x2 max. @40Ω load Headphone impedance matching 16Ω - 300Ω Power supply AC100V – 120V 50-60Hz Size W230mm x D180mm x H50mm

o t o m a t s u

Both of XLR and 1/4inch Phone jack are supported by the Combo jack. In the case of 1/4inch phone jack, the AMP drive has a single-end, and supports two headphones.

1

Rev.1.0 E All Copy Right Reserved by otomatsu

1. Introduction and Circuit Overview

AC100V – 120V

+ / 16V

Regulators Transformer

System Block Diagram

L-CH XLR output

R-CH XLR Output

RCA Input L R

Volume＋

Balance rive

circuit

1 ¼`` Jack

HOT

COLD

HOT

COLD

Left-CH

Right-CH

Total System configuration - Headphone Amplifier Module x2 - Volume + Balance conversion module x1 - Power Supply Module + Transformer x1 - XLR Combo jack, Screw, Knob, Petet, Wire, AC inlet…etc set x1 - Case set x1

Transformer Regulators module Case set

Headphone Amplifier Modules ｘ2

Volume + Balance drive Module

otomatsu Balanced Headphone Amplifier kit , BDR-HPA1E

2

Rev.1.0E All Copy Right Reserved by otomatsu

The assembling of 2 sets of headphone amplifier module and adding a volume + balance conversion circuit comprises a balance drive model headphone amplifier. For a power supply circuit, we use a stabilization power supply kit to compliment an exclusive compact, stylish case kit. The line level signal that goes to the RCA jack enters the volume control of the conductive plastic model which is made by TOKYO KO-ON DENPA Co. Ltd. Because this volume control has fewer ganging errors, it balances the right and left volume more efficiently. The signal then enters an unbalanced-balanced conversion circuit that makes 2 distinct high and low contradistinction signals of +HOT and -COLD. This part uses an OPAMP NE5532. It has 2 circuits and conducts precise, low noise and low distortion rate signal conversion. In addition it has a DC amplifier setup so that the frequency characteristic is flat from DC to 100 kHz The signal then enters the headphone drive amplifier which amplifies the electric power that drives the headphone. This part uses an OPAMP LME49710 with 1 circuit. We triple this amplification in order to be able to supply enough electrical current to the headphone impedance load between 16Ω and 300Ω in output buffer IC and LME49600. By using WIMA’s film capacitor for the input, we cut the DC component from the first part. Also for the output, it connects to the headphone jack through the audio grade bipolar electrolysis capacitor of the low direct current equivalent resistance and low leak current level not appearing on the DC component to the headphone. For the power supply circuit, we make the AC20V of 2 systems from 110V by using a toroidal transformer and making the DC stabilize with low noise Schottky Barrier diode and regulator IC LM317. It is a 2- system with a complete independent stabilized rectification that keeps the ground level stabilized. The headphone jack that is NEUTRIK brand supports both of XLR and standard stereo phone jack. For the balanced headphone wiring, insert L to the left, R to the right. It becomes perfectly balanced and is superior to LR channel separation. You can enjoy full drive SN too. In addition, you can insert it into a regular stereo phone jack. When you use a regular stereo phone jack, the same signals are made for both the right and left jacks so you can operate 2 headphones simultaneously. More over, by using a XLR balanced cable, you can operate a BLT power amplifier and use it as a balanced model preamplifier. In addition, it will be possible in the future to enhance the performance by replacing OPAMP.

2.1. Assembling Headphone amplifier module. 2 sets

IN/OUT Jack x2

We don’t use those parts, so they are not included in this AMP KIT.

330uF x2

Power GND

Power –Vcc

Power +Vcc

Signal In HOT

Signal Ground

Signal In COLD

Signal Out HOT

Signal Ground Signal Out COLD

R11,R12 no t use

Top View

L-CH only LED Power supply

R3,R4 Gain Adjust

Part # Parts Value Qty

IC1 IC2 OPAMP LME49710 2

IC1 IC2 IC Socket 8pin 2

R1 R2 Metal Film Register 1k 1/4W 2



R7 R8 Oxide Metal Film Register 9.1Ω 1W 2

R9 R10 Metal Film Register 4.7k 1/4W 2

R11 R12 R13 not use

Gain adjust Metal Film Register

1k 1/4W 2

Gain adjust Metal Film Register 4.7k 1/4W 2

C1 C2 Film Capacitor No polarity Red

3.3uF 2

C3 C4 C5 C6 C7 C8 C9 C10

Ceramic Capacitor No polarity Blue

0.1uF 8

C11 C12 Bipolar Electrolytic

Capacitor No Polarity Green

470uF 16V 2

C13 C14 Electrolytic Capacitor 100uF 25V 2

PCB with LME49600 1

R1,R2 1k x2 BrBlBlBR Br

R3, R4 2kΩ x2 ReBlBlBr Br

R5, R6 100kΩ x2 BrBlBlOr Br

R7, R8 9Ω 1W x2 WhBrGoGo

R9,R10 4.7k x2 YePuBlBr Br

G. Adjust 4.7k x2 YePuBlBr Br

G.Adjust 1k x2 BrBlBlBR Br

Color code of Registers No Polarity +

-

nich

icon

MU

SE

Polarity 3

R13 no t use


Procedures for assembling the 2 sets are the same.

1. Take out each signal wire and power supply wire directly from the main circuit board.

2. Wire 2 jumper wires to the Volume.

3. Wire 2 jumper wires to the power supply SW.

4. When you make R3 and R4 into 2k, AMP gain (amplification rate) will triple. This is the default value. If it’s 1k, the AMP gain will only double. If it’s 4.7k, it will increase 5.7times. We added 1k, 2k and 4.7k, so you can choose the one that matches your headphone.

Please refer to [14. Improvement options] for details calculation formula.

Wire jumper wires here. Please use a lead wire of cut out resister.

Wire jumper wires here. Please use a lead wire of cut out resister.

No Polarity


C11 and C12 (Green) are in a condition of slightly above the circuit board because of the wide pin pitch. Please solder as close as possible to the circuit board.

Those C11,C12 are Bipolar type electrolytic Capacitor They have no polarity.

AMP module completed

PCB IC3,IC4 Output Buffer IC LME49600 x2 are pre-mounted. 1PIN is not connected Please keep open.

R3, R4 are gain adjust registers Please refer to “ 14. Future Development”

Left CH only

C3 0.1u

C11 470uF 16V BP

C14 100u 25V

-

+

IC1 LME49710

3

2 6

7

4

R5 100k

C6 0.1u

C2 3.3uF

R2 1k

R8 9.1 1W

C10 0.1u

R9 4.7k

R7 9.1 1W

R10 4.7k

C8 0.1u

-

+

IC2 LME49710

3

2 6

7

4

R1 1k

C7 0.1u

R3 2k

IC4 LME49600

2

1 4

5

3

C12 470uF 16V BP

R6 100k

C9 0.1u

C13 100u 25V

R4 2k

IC3 LME49600

2

1 4

5

3

C1 3.3u

C5 0.1u

C4 0.1u

Vcc+ GND Vcc-

IN + GND IN -

OUT HOT GND OUT COLD

4


2.2. Assembling Headphone amplifier module. 2 sets

The Portable headphone amplifier kit has a virtual +/- 2 way power supply, but in this kit, we changed to a real +/- power supply. There is no basic circuit change except this. By supplying +16V,-16V with this change, it can give the full performance that OPAM has that are THD, SNR, Slew Rate, Frequency Response, ….all of specification. Moreover, capability of output buffer IC LME49600 also increases as you can reserve sufficient drive force for the load fluctuation of the headphones.


3.1 Assembling the Balance Drive Module

Please check and confirm that all parts are included before commencing soldering each of the parts onto the PCB. Volume control (VR1) is the last part to be soldered onto the board. The volume control is made of a plastic conductive material, so be careful not to overheat the part and the surrounding area when soldering.

1k x8 BrBlBlBr Br

120Ω x4 BrReBlBl Br

47Ω x4 YePuBlGo Br

100kΩ x2 BrBlBlOr Br

All parts

Completed

Registers color code

NE5532P x2 IC socket x2

Metal Film Registers

PCB Terminal Volume

Film Capacitors 0.1uF x4 electrolytic capacitors 100uF 50V

+ -

Electrolytic Capacitor C5,C6 100uF 50V has pin polarity +/- Long lead is plus + Short lead is minus - Other components have no polarity

OPAMP pin orientation

Top View

Parts List

Parts number parts parameter peaces

VR1 Volume Control 50k A 1

R1 R2 Metal film register 100k 1/4W 2

R3 R4 R5 R6 R9 R10 R17 R18 Metal film register 1k 1/4W 8

R7 R8 R11 R12 Metal film register 120 1/4W 4

R13 R14 R15 R16 Metal film register 47 1/4W 4

C1 C2 C3 C4 Film Capacitor 0.1uF 63V 4

C5 C6 Electrolytic Capacitor

100uF 50V 2

CON1 CON2 CON3 CON4 Terminal 3P 4

IC socket IC socket 8pin 2

IC1 IC2 OPAMP NE5532 2

PCB Print circuit board 1

Caution: The Conductive Plastic Type material Volume control is very sensitive to overheating when soldering with a soldering iron.

5



3.2 Balance drive module schematics

Volume + Balance drive

R4 1k C4 0.1u

R14 47

GND

L+

C1 0.1u

C3 0.1u

R-

R8 120

R10 1k R+

+

C6 100uF 50V

Vcc-

-

+

IC1 NE5532P

2

3

4

8

1

R11 120

R15 47 L

Vcc+

+

-

5

6 7

R7 120

GND

GND

R9 1k CON2

R

CON4

R12 120

R1 100k

R2

100k

+

-

5

6 7

Vcc-

R3 1k

CON1

L-

Vol1 50k A

R16 47

-

+

IC2 NE5532P

2

3

4

8

1

+ C5 100uF 50V

C2 0.1u

CON3

R13 47

Vcc+

R5 1k

R6 1k

R18

1k

R17 1k

GND

6



Top View

4.1 Assembling the Power supply module

This is the jumper wire for making +/- two voltage. Please make use by cutting out the lead of the registers.

Please refer to the manual of Regulator kit as there is no change.

1. Soldering the jumper wire on the regulator PCB for making +/-2 two voltage supply.

2. Soldering four jumper wires between Transformer and Regulator PCB.

3. Mounting four terminals onto the regulator PCB. (Two are in the regulator set and the additional two are in the case set)

4. Set the output voltage +16 and -16V by adjusting trimmer pot screw. Trimmer pot, Blue small cube Set the output voltage by adjusting the screw.

+16V +16V GND GND GND GND -16V -16V Additional terminal x2 are

bundled in the case kit parts. Please mount the four terminals as shown in the below picture.

Actual parts are little bit different from this picture 7



4.2. Power Supply Module schematics

JUMPER LINE x4

D11 1N4007

F1 FUSE holder 0.5A

J1

C4

0.15u P1 5k

3

1

2

D7 11EQS06

C2

0.15u

R4

240

C10

100u 25v

D3

D12 1N4007

10VA

115Vx 22V

x2

D5 1N4007

D8

D9

C6

4700u 50V

DC OUT 2.5-22V

D6 1N4007 D1 11EQS06

H1

J2

1 2

HS2 U2 LM317

3

1

2 VIN

ADJ

VOUT

P2 5k

3

1

2

H2

D2

H3

C8 10u 50V

C5

100u 25v

H4

C3 10u 50V

R1

240

J3

1 2

+

T1

Troidal Trans

6

3

4

5

11

12

13

14

3

R3 240

-

D10

R2

240

DC OUT

2.5-22V

C7

0.15u

C1

4700u 50V

D4

JUMPER

for

+/-

J4 2 HEADER

AC100V

50-60Hz

C9

0.15u

HS1 U1 LM317

3

1

2 VIN

ADJ

VOUT

8



5. CASE set

Case 1

Volume Knob 1

AC inlet 1

Power SW 1

Spark Killer 1

LED register 7.5k 1

Terminal for Power supply 2

Bipolar Capacitors 470uF 16V BP

4

RCA jack 2

XLR Combo jack 2

Wire Red, Blue 1.5m

Wire Black 3m

Petet 16

3mm screw short 20

3mm Screw long 4

3mmナット 4

Black Tapping screw for XLR Combo

4

Washer small 1

Washer large 1

Y-lag for Ground 1

Band 4

Thermal shrink tube 5cm

Isolation sleeve 4

Panel Sticker 1

Petet x16 LED register Washer large 3mm nutx4 3mm screw x4 3mm screw x20 Black tapping screw x4

GND Y-lag Washer small x1

RCA jack x2 XLR Combo jack x2

Band x4 Thermal shrink tube

470uF 16V BP x4 Volume Knob Power SW

Spark Killer

AC inlet

Isolation sleeve

Terminal x2

Wire Red, Blue, Black

CASE Top x1 Bottom with GND screw hole x1 Side x2 Back panel x1 Front Panel x1 Hex socket screw x8 Hex wrench x1 Rubber foot x4

There are spare screws in the box. Color of each parts might differ.

This capacitor is in the AMP Module box



6. Assembling the case and putting each circuit board in it

Use hex wrench to assemble the case

Place Power module like this.

No Pettet for Volume +Balance PC

GND screw hole

10


Temporarily assemble the chassis and glue on the power supply circuit board. Place the power supply circuit board on the back edge left; otherwise it will touch the other circuit board or RCA jack.

Put the adhesive spacer on the each circuit board with the screws.

Caution: The adhesive spacer’s double sided-tape is very strong. Once you applied, it won’t come off. Before you glue the circuit board, carefully make sure its positioned without peeling the white paper, then carefully peel the paper and install it.

Make a cut into the power SW’s hole at the front panel using a file or another appropriate tool. Match this cut and SW’s projection.

Decide a position where the INPUT RCA jack and the terminal of the power supply circuit board will not touch.


7. Assembling the back panel

Pre-soldering

11


Put the AC inlet and RCA jack on the back panel. Put the vinyl sleeve cover on the soldered part to prevent electrical shock and shorting.

The ability of soldering neatly to RCA jack is by putting the spare solder on both terminal of the lead and RCA jack beforehand. By doing this, it will melt together neatly providing good soldering coverage. For the HOT terminal, covering the thermal contraction tube will protect the electric short with other signals.

Attach 2 lock washers as shown in the picture on the left. One is with lead of GND. This prevents making too much space between the knob and front panel because the 2 lock washers for the volume control sticks out from the front panel. The lock washers make the electric connection secure between the Volume control body and chassis ground. The chassis is made out of a black anodized plated aluminum. Since the volume is made of a conductive plastic material it will cause a humming noise to occur when you touch the knob, so certain connection between Volume control body and chassis ground is required. This is one technique for good SNR.

Attach the RCA jack to the back panels by sandwiching the plastic washer on the back and front. This is to prevent the jack from coming into contact with the electrical panel. Wiring of the GND will be dropped from a power supply substrate on the chassis later. This is one technique for good SNR.


8. Attaching together modules to the case

Do not touch the

Headphone AMP PCB and

Combo jack together here.

12


We would like to caution again that because the double sided-tape has a strong adhesive bond, once you install the petetto on the circuit board it will not come off. After you attach the adhesive spacer to the circuit board with the screws, do not peel the white paper and please ensure its positioned as you line up the circuit boards. Once you are confident that the positions are correct, peel the paper and attach them carefully. Even though it may only touch slightly, it will hardly come off so do it slowly and carefully. Please pay special attention to this procedure.


上面図

9. Wiring the Power supply

GN

D

DC

- D

C+

GN

D

DC

- D

C+

- + Vcc

+

Vcc

-

GN

D

Jumper wire

Spark Killer No Polarity

LED register 7.5k Power SW

AC inlet Center ground pin is open, no connection.

DC+（16V） Red DC- (-16V) Blue GND Black AC wiring Red

Please use isolation sleeves to prevent from accidental electric shock.

Use sleeve

For easy wiring access, take out the side panel of the case. 13



10.Wiring signal path-1

Signal HOT Red Signal COLD Blue Signal GND Black

L/ G

ND

/ R

R+ R- GND GND L- L+

Chassis Ground Use small Washer to Screw bottom

Input RCA jack LEFT RIGHT

XLR Combo jack

XLR Combo jack pin assignment is as the following pictures. All pins are independent and isolated, so is a very flexible configuration.

1 2

3

G

Front view of XLR plug (male).

XLR Combo pin assignment

S Sleeve R Ring T Tip 1 GND 2 HOT 3 COLD G Case GND

Compare to ¼`` male plug

上面図

14



10.Wiring Signal Path -2

Protect case by vinyl tape underneath

Good soldering hint: Wire should be pre-soldered to the plating before soldering , as shown as the below picture.

15


Chassis ground is fasten by 3mm screw and small washer, like this picture. High light XLR Combo wiring. Good soldering hint : All wires should be pre-soldered by plating before wiring to the XLR socket.


11. Checking all wiring

All wiring is finished.

16


Use thermal shrink tube for LED register


12. Check the voltage level of key areas

上面図

Connect the Black lead of multi tester to Chassis ground

+16V

+16V

-16V -16V

0V 0V

1. Use DC voltage setting of multi meter 2. All OPAMPs should remove from the socket. 3. If, all voltage are working OK, then insert OPAMPs and check the same points again. 4. All voltage should be the same before/after OPAMs insertion.

0V 0V

4pin 0V

4pin 0V

7PIN +16V

4PIN -16V

7PIN +16V

4PIN -16V

0V

0V

0V

8PIN +16V

4PIN -16V

4PIN -16V

8PIN +16V

Volume should be turned off.

0V

4pin 0V

4pin 0V

7PIN +16V

4PIN -16V

7PIN +16V

4PIN -16V

It is OK around 5-10mV at all “ 0V” points

17



13. Modification of Headphone cable

otomatsu

2 1

3

LEFT RIGHT

Gray

Yellow Blue Red Red Blue Yellow Gray

Yellow L HOT Gray L COLD Red R HOT Blue R COLD

SENNHEISER HD-25-1 II

SENNHEISER HD-598

Before After 18

2 1

3


Modifying the regular headphones to the balanced drive model. You can modify the headphones if the L and R cable are separated. In the case of a headphone which has one cable, until we cut the jack we won’t know if LR wiring is separated. If you cut and there are only 3 wires, you can’t remodel to the balanced drive model. In this case, you can only use regular headphones. Please back to new regular jack.

SENNHEISER HD-25-1 II is full independence of L and R wiring, and you can exchange the cable. If you cut the mini jack and peel the wire, 4 lead wires appear as the bottom left picture.

The body of the SENNHEISER HD-598 has 4 polarities. You can change the cable. There is one LR cable, but there are 4 independent wires inside, so as you can see from the picture you can remodel it to the balanced drive model.


14. Improvement Options

1. Amplification Gain adjustment

You can change the gain as you change R3 and R4. Please try a gain appropriate to the optimization of your other headphones. Formula (R1 +R3) / R1 = GAIN Default value 2k (1k + 2k) / 1k = 3x gain In the case of 1k ( 1k + 1k ) / 1k = 2x gain In the case of 4.7k (1k + 4.7k ) / 1k = 5.7x gain Note: Make R3 and R4 the same value. When you change OPAMP, confirm that the minimum gain magnification is shown on the data sheet. There is an OPAM that oscillate when it becomes less than double-quadruple such as NE5534A,LT1028,OPA637 etc.

C3 0.1u

C11 470uF 16V BP

C14 100u 25V

-

+

IC1 LME49710

3

2 6

7

4

R5 100k

C6 0.1u

C2 3.3uF

R2 1k

R8 9.1 1W

C10 0.1u

R9 4.7k

R7 9.1 1W

R10 4.7k

C8 0.1u

-

+

IC2 LME49710

3

2 6

7

4

R1 1k

C7 0.1u

R3 2k

IC4 LME49600

2

1 4

5

3

C12 470uF 16V BP

R6 100k

C9 0.1u

C13 100u 25V

R4 2k

IC3 LME49600

2

1 4

5

3

C1 3.3u

C5 0.1u

C4 0.1u

Vcc+ GND Vcc-

IN + GND IN -

OUT HOT GND OUT COLD

3. Change the OPAMPs

By changing the OPAMP, you can improve further performance. You can enjoy the change of the sound quality. Balance drive module (Dual in one package type) Original NE5532P Candidate OPA2134, OPA2604, LME49860 NJM2114, TL072, RC4558 JRC MUSE series OPA627 x2, LME49990 x2 Need conversion socket Headphone AMP module (Single in one package) Original LME49710 Candidate OPA627A, LT1115, LME49990, OPA604 AD797, OPA827, NE5534A In the case of OPA627A, need Dip mica capacitor 10pF between pin2 and pin6 in order to compensate the phase. 20p capacitor is placed under the PCB

4. Change operation mode of LME49600 for much higher speed response 1pin of f LME49600 is open, but when you connect to the land of the board with the parings of the lead of the resistance, you can change into broadband mode. 100Mhz of LME49600’s high level property extends up to 180Mhz. However in this case, depending on the equivalent OPAMP and set up of gain, there is a possibility of oscillation, so please add some 10pF to the phase compensation condenser of DIP MICA between 2PIN and 6PIN of OPAMP. You can amplify the output electric current as you pile up and stack LME49600 and connect with each pin of 2 LME49600. In this case, the amount of heat generated increases, so attach some adhesive to the top and bottom of LME49600.. 19


2. Improvement of super low sound level characteristics Eliminating the output coupling condenser by removing the BP electrolysis condenser of C11, C12 470u and by short-circuiting, you can improve the super low sound level frequency property. But in this case, the DC offset voltage will emit some mV. There is a risk of damaging the voice coil if the large number of the DC leaks a stream of electric current to the head phone by any accident, wrong wiring, and or a solder bridge. Try this challenge only if you are confident.


how to assemble the balanced headphone amplifier kit · pdf file · 2013-01-01for...

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