Bridge on LM1875

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knight1112

Member
Joined 2019
#1
Hi everyone,

Currently I'm using this PCB for LM1875 with AC 17-0-17 to drive 4ohm 4inch speaker.
Amplifier PCB for TDA2030/LM1875 - oddWires

And now I want to change new speaker from Peerless with 8ohm 6.5 inch, 60W RMS and peak 100W as manufacturer.

Peerless by Tymphany 830657 6-1/2" Paper Cone SDS Woofer

Because I really like sound tone from LM1875, so I have planed make this PCB run as Bridge Mode,

The question is this config is good option for Peerless ?
Also can I remove C10 in PCB ?

Thanks & Best Regards
 
#2
knight1112 said:
Hi everyone,

Currently I'm using this PCB for LM1875 with AC 17-0-17 to drive 4ohm 4inch speaker.
Amplifier PCB for TDA2030/LM1875 - oddWires

And now I want to change new speaker from Peerless with 8ohm 6.5 inch, 60W RMS and peak 100W as manufacturer.

Peerless by Tymphany 830657 6-1/2" Paper Cone SDS Woofer

Because I really like sound tone from LM1875, so I have planed make this PCB run as Bridge Mode,

The question is this config is good option for Peerless ?
Also can I remove C10 in PCB ?

Thanks & Best Regards
Click to expand...

It is not a good idea to bridge single LM1875s because the LM1875 is already short of current capability to run 4 Ohm speakers. The current limiter kicks in at around 32W in 4 Ohm and around +/-21V of supply. Your supply voltage is higher.
 
#3
knight1112 said:
LM1875 with AC 17-0-17

new speaker from Peerless with 8ohm 6.5 inch

planed make this PCB run as Bridge Mode,

The question is this config is good option for Peerless ?
Click to expand...
No.
24V rail and 4 ohm equivalent speaker or 48V and 8 ohm (same thing, because of bridging) needs 6A peak capability from chipamp.

LM1875 is limited to 4A typical and guaranteed minimum 3A.

C10 question becomes irrelevant.
 
#4
FauxFrench said:
It is not a good idea to bridge single LM1875s because the LM1875 is already short of current capability to run 4 Ohm speakers. The current limiter kicks in at around 32W in 4 Ohm and around +/-21V of supply. Your supply voltage is higher.
Click to expand...

For the transformer there is no problem, I can change to 15-0-15.
But the problem is how can I drive this speaker 8ohm 6.5 inch, 60W RMS as bridge config
 
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