Plate amp EQ adjustments?

[mike.e]

Hi all,I have a plate amp like this - 350w RMS with remote control(from jaycar

Ive lost the site that showed which resistors to replace to remove or adjust the +6dB boost at ~35hz.
I know its there somewhere but the tags must be bad as I still cant find it.

Yahoo searches,and forum searches reveal nothing!!!

STOCK-CODE: AA0508

http://www1.jaycar.co.nz/productVie...&pageNumber=&priceMin=&priceMax=&SUBCATID=443

Thanks
Mike.e

 

[mike.e]

Update: Close but no cigar

http://www.pesupport.com/cgi-bin/archive.pl?read=199319

 

[DcibeL]

That amp looks very similar to the one I bought from Solen. If it is, it has the same input circut as this amp from Parts Express. Click "Detailed Specifications" of the PE link and in that PDF is a chart for the different resistor values that correspond to the different gain values.

 

[mike.e]

THANKS! Looks identical to mine.

Its probably the same pre amp design anyway.I can always try it and see what happens,we have oscilloscopes and signal generators here at tech

Im wanting to take the jbl2226 to peoples places for parties-the EQ isnt required and I need all the SPL I can get

Mike.e

 

[DcibeL]

Glad I could help.

 

[paulspencer]

There used to be instructions for that amp on this page:

http://www.customanalogue.com/sub_index.htm

Now it's a slightly different amp, however you could always email Joe [email protected] to get the info on the older version of the site.

 

[DcibeL]

The instructions there are for the version of the amp without the remote, or maybe the input module for the larger amp is just different. Either way, instead of changing R26 and R27, you change R23 and R24. You can still use the same resistor values to set the boost to 0, and add a little low frequency extension. In this case, R23=56K, and R24=180K. If you do not want any added low frequency extension, use R24=120K as stated in the Parts express PDF. The rest of the instructions should still apply, however I have not changed the crossover on my amp to a fixed crossover, but I imagine that it would work.

I don't know why the instructions tell you to place those 2 resistors on the back side of the PCB. It seems to me that if you put them on the side with everything else, it looks more professional and unmodified. Changing C1 to a high quality poly cap still applies to the larger 350W version of the amp. I didn't listen to my amp before I changed that cap to see what kind of difference it made, I just did it becaus it was easy and I had the proper cap lying around.

 

[DcibeL]

ApexJr has the schematic for the 350W amp without remote, so I would imagine the input module is a little different, but if anything goes wrong with the amp, these schematics are a great help.