The 3000 has a slighly different frequency compensation circuit to make up for the lack of the second bass driver. The difference is just one resistor (I can't remember which one of them had it).

Thanks very much. Can one modify the Beolab 3000 amp to match the original Beolab 5000 amp? Stated differently: is it possible to swap a let's say defective Beolab 5000 amp section against a modified one of a pair of Beolab 3000s? The latter are much easier to obtain.

Where's the crossover located in these speakers by the way?

Greetings, Kai

Manbearpig wrote:

Thanks very much. Can one modify the Beolab 3000 amp to match the original Beolab 5000 amp? Stated differently: is it possible to swap a let's say defective Beolab 5000 amp section against a modified one of a pair of Beolab 3000s? 

Yes it is, and the difference is quite easy to find in the schematics (if you can't find it, you will need someone else to do the modification anyway, if you don't mind me saying - it's probably an SMD resistor so the job will need some skill).

Manbearpig wrote:

Where's the crossover located in these speakers by the way?

Inside the passive speaker part. The difference in the amps is not related to the actual speaker crossover, the amp doesn't know which speaker it is driving. I believe many people have swapped amps between 3000s and 5000s without actually knowing that they are different.

In my BL3000 amps the resistor is a regular axial resistor that is soldered in and then one leg is cut off.

Don't know if this is the case for all amps, though..

/  Johan

Johan wrote:

In my BL3000 amps the resistor is a regular axial resistor that is soldered in and then one leg is cut off.

Don't know if this is the case for all amps, though..

OK, in that case it would be rather easy to restore it to the 5000 incarnation as you don't even need to source a missing resistor. I suspect they all would be like that, as it easier in mass production to just assemble all the boards the same way and later snip a connection if you're actually putting a 3000 together.

I very much doubt that you would notice the difference - I would get it running and see what you think. If you think there is too much bass at low volumes (unlikely in my view) then attack the resistor.

Thanks very much for all the replies. Helps me a lot.

Cheers, Kai

tournedos wrote:

OK, in that case it would be rather easy to restore it to the 5000 incarnation as you don't even need to source a missing resistor. I suspect they all would be like that, as it easier in mass production to just assemble all the boards the same way and later snip a connection if you're actually putting a 3000 together.

Yes, I would suspect that's how they did.

So, making a it a BL 5000 amp would just mean bending that resistor (R231 if I remember correctly) into position and solder the leg back together.

/  Johan

Interesting and good to know..