B&W ASW-4000 Subamp

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ManUtd

ManUtd

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Joined 2003
#1
Has anybody of You got a schematic for this subwoofer?
I need to know the correct placement for all JRC2041DD op-amps and one 555 timer and a TLC072 opamp also.
What opamp can i replace with those JRC2041 op-amps?

Thanks,
ManUtd.😉
 
#2
IC503: TL072
IC404: NE555

The JRC 2041 is a plain 2xOpamp in standard design like 1458.
AKA: MC1458; MC1558; LM1458; LM1558
If you like to use a better type take a NE5532 instead, but as this whole amp is designd for low frequency only the Opamp is not critical at all.

I have the circuit as PAPER copies.
 
#3
Cybergent said:
IC503: TL072
IC404: NE555

The JRC 2041 is a plain 2xOpamp in standard design like 1458.
AKA: MC1458; MC1558; LM1458; LM1558
If you like to use a better type take a NE5532 instead, but as this whole amp is designd for low frequency only the Opamp is not critical at all.

I have the circuit as PAPER copies.
Click to expand...
s,


Thank You,this information was good help for me.
Regards,
ManUtd
 
#4
Cybergent said:
IC503: TL072
IC404: NE555

The JRC 2041 is a plain 2xOpamp in standard design like 1458.
AKA: MC1458; MC1558; LM1458; LM1558
If you like to use a better type take a NE5532 instead, but as this whole amp is designd for low frequency only the Opamp is not critical at all.

I have the circuit as PAPER copies.
Click to expand...

If you could make a PDF of that papercopy i would be thankful.
My amplifier have a faulty preamp but i can`t find the reason why.
Before i did anything with it i had signal trough Decoderinput and this option worked ok without any noise or "FM" modulation noise.
But on Line input i had small signal with noise.
After replacing opamp it doesnt work on either Line input nor decoderinput.It has very small signal coming trough amp and it is
Output stage is ok.
Do You have the values for zenerdiodes on Preamp also what type is IC 802?.What function is IC802?

regards,
ManUtd
 
#7
The original circuit of the power amp has a very poor protection circuit.

There is no real 4Q SOA protection for overload and short.
The supervisory circuit does not monitor any wrong dc levels at the output, but the used IC would be capable of that.
The output relay has way too weak contacts.

All that resulted in a complete damage of my sub.
The output stage failed due to a poor mounting of the power transistors to the heatsink, so that they got a break thru. The dc at the output then killed the speaker. The relay contacts just welded together....

After some discussions with B&W I got a replacement speaker and a new power amp (which was mounted wrong again... so I had to correct that first, otherwise...- you know...)

To avoid any more problems with the amp I changed the existing protection circuit to a real one and added dc-monitoring to the supervisory circuit.
I also exchanged the existing 2-parallel-contact-relay to a stronger one with a single contact.
The changes are not complicated, but very effective.
Since then the sub works fine.

If anyone needs a diagram of my changes feel free to email me. The pdfs are too big to put them here.
 
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