Modding HK4000 amplifiers - Visonik & MA Audio

[snoopdan 5,000+ posts]

Ive had numerous emails and questions over the years about this amplifier series on how to mod it. Ive also seen a couple of threads that had misinformation concerning the mods available so I hope that posting this will help people who actually use the search feature on here and find this.

History / Background -

The HK series board is made by the Anaba group, who primarily makes MA Audio and Visonik brand lines. The amplifier models were named the MA Audio HK4000 and the Visonik 4000xd. The HK 4000 series is the biggest amplifiers that they offer.

Mods :

Two main mods can be done to get the amplifier to perform "more" than what it was designed to do.

1. You can remove the protection circuit by removing resistors R256, R37, R41, and R262. Just make sure you clip them cleanly from the board. This allows the amplifier to run below 2 ohms. This DOES NOT MEAN THIS AMPLIFIER IS ONE OHM STABLE....it just allows you to give it that load without a protection circuit shutting the amplifier off. This amplifier should never be run daily modified and wired to below 2 ohms. This protection removal was originally employed by people who were doing burps for just a few seconds and even then the amps dont last forever in this manner. My advice : dont do the ****.

2. Replace the 1/4 watt resistors on all the FET's with 1/2 watt resistors. This will significanly lessen the possibility of you smoking them while running below 2 ohms. This still does not get around the fact that you shouldnt be doing #1 mod anyways, but this does increase the lifespan of your HK board. Below is me pointing to the area's of the board where the resistors are located right next to the FET's.

Visonik 4000xd

Good luck!

Click to read more...

 

[bdawson72 5,000+ posts]

Interesting

 

[BassAddictJ 5,000+ posts]

good thread

 

[snoopdan 5,000+ posts]

Thanks guys, I just keep getting hit with emails about how to do this properly so I figured a thread that people could search for would be more proactive.

 

[thegreatestpenn 5,000+ posts]

good job helping noobs. I have a feeling some brave souls will do this and be running back to you on why their amp blew up tho (even tho you gave plenty of warnings not to do it)

 

[22mountaineer 10+ year member]

I posted a thread awhile back, stating how everyone is saying that there amp is modded and that I highly doubt they even are. It is getting to the point to where EVERYONE is saying it, I finally started asking everyone who claimed theirs to be modded, how was it modded?

Nice write up, might start answering all of these questions, I think you are the only one who actually knew exactly what it was rather than others sayin oh its just a couple of resistors.

 

[audioatg 10+ year member]

Good thread snoop dan. Mabye this will help in getting ppl off of the HK's back. I said somthin in mister 22mountaineer's thread about these amps.

I also said that Im think some ppl who were are selling theses amps. Where telling them that it was modded when it really wasent modded at all. To mabye get it to sell higher or they just dont know about the amp at all anyways.

This is a good thread that it is educating ppl about them amp and to add to this education. Just like any other "higher" end amps. They do need a "beefy" eletrical system. Just like any other amp crapy power supply equals poor performance of the so said amp.

 

[brmcdonald68s]

i am using one of the hk 4000. do you have any suggestions for swapping out the blue L.E.D's with red ones do i just cut and re solder or is there anything i need to know? before i do it.

 

[snoopdan 5,000+ posts]

Im bumping this thread again due to the resurgance of people asking me how to mod these amplifiers, or for people whom have purchased these amps and not known if they were modded in the first place.

 

[audioarsonal 10+ year member]

Great thread.Like I have been telling people the mod is not really a mod to add anymore power it simply defeats the protection circut.If you are not experinanced I would just leave it as is.These amps will put out power at 2 ohms so no need to run below that!

As for the pics of the resistors.Dan can you get a litlle closer to the resistors with which one you are pointing at?I think its the 2 small round ones but its kinda hard to tell from the picture.

 

[snoopdan 5,000+ posts]

The resistors in the photo I posted are refereing to the "resistor mod" when you change out the 1/4 watt resistors out with 1/2 watt ones. This mod is for the truely hard core HK board owner, and should only be done by someone who's had soldering experience. Or are you talking about wanting a pic of the resistor clipping for the protection removal mod ?

 

[FAM4LIFE 10+ year member]

Slightly off topic but do the Visoniks perform well under 17volts? I recall a few folks saying they **** if you can't provide the current.

 

[avs20 10+ year member]

I ran mine@16v and they were absolute monsters. I know it's only 1v less, but you said under 17v

 

[snoopdan 5,000+ posts]

You can run them at less voltage just fine, just watch your transient voltage drops to make sure they dont dip long or too much below 11v. Also you gotta watch out for the voltage drop on the remote power lead as well - if you have lower than 11v on it (even though you could have 17 volts on the main power leads) the amp will appear as if its shutting down. Ive seen people get bit in the ass by this quite a few times, even people sold off their amps for cheap because they thought it was broken!

I seriously suggest a 1 farad cap on the remote power lead to stop this problem. I know that sounds a bit much, but if you're using this kind of amp in the first place then your setup is already getting beyond a normal daily bumpping setup.

Here is a good way to do this, with a relay and a cap -

 

[avs20 10+ year member]

That is actually a really good idea. I knew there was a use for caps! I might do that on my 802sx...