Reckhorn A-402 subwoofer amplifier - Warning!!!

Jump to Latest
#21
and where is over 70% of LCD PANELS produced?
and where is over 80% of COMPUTERS produced?

the list can go on to at least another 50 major products.

its just too overwhelming that they have LIFE CHANGING economy conditions in the last 25years.

cheers
henry
 
#27
BASH amps have a habit of blowing up, often catastrophically. I saw this recently with a friends Cambridge Soundworks speaker set. It sounded fantastic when it worked, but one day there was a bang, some burning, and when we opened it up to look most of the control IC's were fried, and one psu capacitor had exploded.
 
#29
sharpi31 said:
The replacement caps arrived last week and I decided to measure them both to select the best one to use. One of the caps measures 6640uF and the other measures only 4340uF. Both are NCC KMH 10000uF 100V caps!!!!!!!!!
Click to expand...

With long lead times perhaps the amp manufacturer bought the NCC caps from the grey market instead of buying directly from the factory.
Recently I have seen many fakes that look identical to the original. Beware!
 
#30
Dayton also has crappy caps, but they seem else robustly built and have long warranty.

I have a used Rekhorn A-401 here and it is fine, but hums pretty bad if the other units in the system are ungrounded. The A-401 is ungrounded so it needs to be grounded via the RCA cable. Or possibly by some other means 🙂
 
#33
Hello everyone. In my opinion this amplifier is something common, nothing from another world as they speak here. The six 10,000uf capacitors are pirated, not original Rubycon. Mine are already swollen and I have to change them.
 
#34
The printed circuit is of poor quality and some components are poorly calculated. For example, you have to change the two 680 ohm resistors, from the power supply part for the ICs, for ones of 1k and 2-3W. (R50 and R73). Also the 1k2 resistor R44 must be changed for one of 1k5-1k8 and 3W so that the relay voltage is around 12V. There are models that use 24V relays.
 
#35
Transistors Q13,Q14, Q24, Q25 and bridge BD1 could use a small heatsink. You also have to redo all the welds because I found many cold welds.

On the plate the filter capacitors say that they are 4700uf/80V. In this case, 6800uf/100V or 8200/100V can be mounted. I don't know if at 10,000uf/100V there are 35x50mm ones to fit into the casing.

IMG20221022101326.jpg


IMG20221022101316.jpg


IMG20221022101308.jpg


IMG20221022101301.jpg


Photos made after cleaning and re-soldering the printed circuit. Mount some terminals on the board to be able to test with various resistors without having to disassemble the printed circuit each time.

IMG20221022102237.jpg


As I said capacitors are pirates. None measure more than 5200uf and surely they are not for 80V. You can see in the photos how they are swollen.
 

Attachments

  • IMG20221022102345.jpg
    IMG20221022102345.jpg
    258.7 KB · Views: 83
#37
rickmcinnis said:
Will send to you tomorrow

The schematic is on my work computer.

I have no idea if I have blown the output transistors since I know next to nothing about solid state stuff. I certainly hope I have not.

If you could advise me how to check I would be GRATEFUL!

I am afraid I will not be able to add much to the discussion of how to improve the amps but I would be glad to try changes and let you know what I think fo them.

There does not seem to be much different between the two amps. The 402 did have some kind of filter at the output jacls, a disk ceramic cap from the negative terminal of the output that connects to the chassis. Since it is not on the 403 I plan on leaving it out.

Look for the note tomorrow. I will title it RECKHORN SCHEMATIC.

Thanks,
Click to expand...
Hi Rick. You can send me the schematic please of the A403? Thank you. livoto1970@yahoo.es
 
You must log in or register to reply here.
Top Bottom