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Markbass Minimark 802 2x8

#21
Hi everyone,
So I finally decided to install an L-pad attenuator on that terrible piezo tweeter. Found a nice spot to put it, and after an hour or two of careful work (drilling, bolting, wiring, soldering) it was done.
The good : now I can turn down that tweeter all the way and go for aggressive diggin' on the strings, and slap without having that awful high freq farting thing going on.
The bad : just attenuating the tweeter is not eliminating the peak transients' harshness, you have to turn it down almost completely.
So, all of a sudden I remembered one thing I noticed in a GK 410 cab when slapping the hell out of dat bass : these was some flashy white light to be seen through the ports. As I looked inside, here is what I found : in the network circuitry, there is a flashlight bulb in series to the tweeter, that flashes as soon as a transient voltage peak goes accross it. The filament heats up almost instantaneously, absorbing the peak's energy - thus acting as a dynamic compressor - while the resistance of the filament rapidly raises up with temperature, thereby attenuating the tweeter.
So I am thinking now on adding a dedicated bulb (there are some on professional speakers catalogues, such as Eminence) in addition to the L-pad, so I can dial in a little bit of tweeter but without that horrible farty sound.

Any experience with this, anyone ?

Cheerz and may da groove be with ya :)
 
#22
paololoap said:
Hi everyone,
So I finally decided to install an L-pad attenuator on that terrible piezo tweeter. Found a nice spot to put it, and after an hour or two of careful work (drilling, bolting, wiring, soldering) it was done.
The good : now I can turn down that tweeter all the way and go for aggressive diggin' on the strings, and slap without having that awful high freq farting thing going on.
The bad : just attenuating the tweeter is not eliminating the peak transients' harshness, you have to turn it down almost completely.
So, all of a sudden I remembered one thing I noticed in a GK 410 cab when slapping the hell out of dat bass : these was some flashy white light to be seen through the ports. As I looked inside, here is what I found : in the network circuitry, there is a flashlight bulb in series to the tweeter, that flashes as soon as a transient voltage peak goes accross it. The filament heats up almost instantaneously, absorbing the peak's energy - thus acting as a dynamic compressor - while the resistance of the filament rapidly raises up with temperature, thereby attenuating the tweeter.
So I am thinking now on adding a dedicated bulb (there are some on professional speakers catalogues, such as Eminence) in addition to the L-pad, so I can dial in a little bit of tweeter but without that horrible farty sound.

Any experience with this, anyone ?

Cheerz and may da groove be with ya :)
Click to expand...
If the amp sounds best to you with the tweeter fully (or almost fully) attenuated you are better off just disconnecting the tweeter altogether. The L-Pad is not really intended to absorb all the power sent to it, so you could have problems with that in time (or sooner ;)). Forget the light bulb idea, that just acts as a kind of limiter, it won't make your tweeter sound better.
 
#23
Hello Jeff,
maybe you got me wrong, or I have probably not explained my point well enough. The problem with that piezo tweeter is :
1. Hissy treble at high volumes, especially with VLF turned up. Quite annoying but I could live with that...
2. Horrible transient peak in the attack of the plucked string, when plucked hard, attacked hard with a pick, or slapped / popped : with THIS ONE I CAN'T LIVE WITH ! It is utterly harsh and totally ruins the overall quite good sound of this little amp ! I can't believe Markbass hasn't done anything to tame this...
So I have installed a L-pad and it works, although - while it works fine for problem #1 - you have to turn the tweeter almost all the way down to get rid of problem #2.
So I tried the light bulbs the other day : I was hoping that they could absorb the initial string attack peak by dissipating it in a light flash. But unfortunately it did not work for me : first, it caused a sort of constant ringing overtone and secondly, it did not absorb that harsh peak, even with small 1,5V bulbs. I guess this is because of the high-pass filter / too little power to the bulb. So I gave it up, and just turn down the tweeter with the L-pad when I have to turn the amp up high.
Voilà, that's that.
I would really recommend developing a dedicated high freq compressor/limiter circuitry to Markbass, something that absorbs the initial string-pluck peak to the tweeter but not the woofers.
Hello Markbass - can you hear me ? Mi sentite ??
 
#25
Goose55 said:
Does anybody give me the answer....
Ik thought this amp was Class D. Also cos its only 15 kg for a combo, speakers and amp. But I can't find anything about this.
Is it Class D amp or transistor?
Click to expand...
It is both. Class D can be done with tubes but that is not very practical, in the real world. Transistors can be set up to run Class A, B, C, D, etc. So yes, the Minimark is a Class D transistor amp.
 

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