BackFrom Beosound to High-Fidelity.
Optimize your Beolab 8000 with high Quality components.
Last updated 3105.99.
Knowledge about SMD components is needed to carry modifications out.
This section illustrates, how to upgrade your Beolab 8000 for optimum sound performance. The reason for developing this sound uprade, was that i was dissatisfied with the response in the treble range, the treble being over boosted which irritates the ears after a while (maybe do to transient distortion).
If your speakers has the above mentioned symptom, i believe you will get bennefits with this modification.
This upgrade is based on my experience with the speakers in my home.
My room is about 35 square meters, and consists of wooden flors with single loose carpets, walls made of stone and soft funiture.
Under the above mentiond conditions the speakers performed unacceptable when transients in the treble range, has to be reproduced.
The modified speakers is of the type with ABL (adaptive bass linearisation).
Early produced speakers without ABL will not fit directly to this upgrade.
The modifications relate to the changing of opamps and capacitors in the bass and treble cross over network, and pre-amp, and changing of the input caps in the treble output amplifier.
No optimization is done for the acoustic response of my room. I have just fitted other components in the audio circuits, where better alternatives was available.
The bennefits is a more crisp bass response, and an improved treble transient responce. The sound is in general more pure and comfortable.
Disassembly of the Beolab 8000.
Removal of the front cover from BL 8000.
Press, with a finger, in the corner of the front cover, pull the inner edge out at the same time ejecting the lock clip. Use this procedure to loosen all 18 lock clips from top to bottom, 9 on both sides.
Carefully pull the inner edge of the cover at the top of the BL8000 outwards, pulling the cover upwards at the same time, just until the heatsink in bottom of the BL 8000 is fully visible.
Use a scalpel to cut the rubber gasket at the point between the heatsink and chassis.
Unscrew the 6 torx 20 screws which secure the amplifier module.
Carefully remove the amplifier module, by inserting a screwdriver between the chassis and heatsink.
Remove the connector in the top, pull the amplifier module backwards, remove the 3 connectors at the bottom, and remove the amplifier module.
Please note the position of insulating foam at the top and bottom of the speaker, it will make the reassembly easier.
Click here to view disassembly
Start Beolab 8000 modifications.
Before any work is carried out on the amplier module, it is recommeded to discharge the power supply capacitors e.g. across a 500 ohms 5W resistor.
At the factory the components are glued to PCB before soldering, so a hot air solder station is recommended to remove the components, the temperature should not exceed 375°C to avoid damage to the PCB tracks and components.
Components which have to be changed, are all marked with a X on the photos.
Parts list for modification Beolab 8000
10 Pcs. Burr-Brown. OPA 2134UA. Or Analog Devices. OP275GS. (IC2,IC201,IC202,IC203,IC204)
4 Pcs. Polyester caps 470nF 10% (63V) 5.08mm pin spacing.
(C5 and C7) Thomson: BF074D0474K or Siemens B32529-C474K
Farnell partnumber:146-082 (Thomson) or 218-522 (Siemens).
8 Pcs. 2n7 2,5% 63V or 100V. 5.08mm pin spacing.
(C 211, C212, C213, C214) Polypropylene or PPS film capacitors.
e.g. Wima FKP 2 series (polypropylene) or Evox-Rifa SMR type (PPS film)
Click here to visit Farnell.com
| BL 8000 Main board Changes(All models). Replace IC2 with OPA 2134UA or OP 275GS. Replace C5, C7 with 470nF polyester film |
Loosen the 6 torx 10 screws, and remove the sub pcb with the cross over network.
| BL 8000 Cross Over network changes.(ABL) Replace IC 201, IC202, IC 203, and IC 204 with OPA 2134UA or OP275GS. Replace C211, C212, C213, C214 with 2n7 2,5 % Polypropylene or PPS film capacitors Care should be taken when components are soldered, use a temperature controlled solder iron with a temperature of max 280°C for max 5 seconds. |
Reassembly of the Beolab 8000.
Remount the cross over network PCB, tighten the 6 torx screws.
Before the amplifier module is remounted in the chassis, ensure that the rubber housing around the on/off indicator in the bottom of BL 8000 is in the right position.
Mount the 3 connectors in the bottom, and ensure that the insulation foam at the top and bottom is properly fitted. Insert the amplifier module, remount the connector in the top. Tighten the 6 torx 20 screws carefully.
It is recommended to test the speakers at this stage, before the front cover is remounted.
Carefully push the front cover downwards. Hint- pull the edge outwards at the same time.
Fasten the lock clips, by pushing the corners on to the front cover with your thumb.
No responsibility is taken for damage to the speakers.
Comments or questions to this page e-mail to jnj@adr.dk
Components are available on request.
END.