2. amps-preamps
  3. 180574-2005

Harman Kardon HK990 Question

I pulled this amp out of storage the other day and hooked it up.  For the 1st time since I bought it, it occurred to me there is no way to bypass the high and low pass filter section when utilizing the subwoofer outputs. When the sub outputs are turned on, the setup process forces you to select a crossover frequency, even if you want to manage your bass via other options.  If any of you guys are still using this amp, how do you address this issue?  I guess I could just hook the subwoofers up to the preamp outputs.  My subs don't have high level inputs. 

danoroo
millercarbon's avatar
millercarbon
12,531 posts
 

Follow this guide to build a line out converter. The 2 resistors will cost like $2 if that. Or you can buy an LOC built. Quality doesn’t matter. I’ve done this for years, it works great. The parts are so small if you are careful it can be built into the bullet case at the end of the RCA you use to connect the sub.

https://www.epanorama.net/circuits/speaker_to_line.html

mofojo
2,303 posts
 

MC is back baby! 

secretguy
1,718 posts
 

yay

millercarbon's avatar
millercarbon
12,531 posts
 

Thanks guys. 
This one comes up a lot. When I bought a Melody tube amp with no pre or sub out I knew there had to be a simple solution. Not wanting to reinvent the wheel I decided to consult the brain trust here. Even put it in tech talk where it belongs. Stated very clearly that I was not going to change amps, just want to connect a sub. 
The only responses I got were buy another amp (!), don’t try (?), you’ll kill yourself(!!) and even if you unplug and turn off you will still kill your self because it’s lethal voltage. Even turned off. And unplugged. 
Somewhere on one of my system pages is a picture of the extremely simple and effective mod. Two resistors. 
Seriously, this is a truly cheap easy and simple mod. Search my system pages there should be pictures. I even made one with the resistors crammed inside the end of a RCA bulllet connection. That one is slick, bare wires at one end for speaker terminals, RCA at the other for the sub. 

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