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Markbass mini CMD 121P problem

bass4u

bass4u

Supporting Member
Jul 7, 2007
802
458
maryland,usa
#1
I have a Mini CMD 121P combo amp that I just love. I was going to use it to record some tracks last night and noticed an extremely loud hiss coming from the tweeter. When monitoring through headphones with the amp miked there is no way I could record with the amount of hiss being picked up from the mic. I never noticed this before because I have only been using it in live performance situations. What is odd is the hiss is heard even with the gain and master volume turned completely down. Is this normal for this amp or is there something wrong with it? Sure wish there some way to lower the output of the tweeter or completely turn it off. TIA
 
#2
bass4u said:
I have a Mini CMD 121P combo amp that I just love. I was going to use it to record some tracks last night and noticed an extremely loud hiss coming from the tweeter. When monitoring through headphones with the amp miked there is no way I could record with the amount of hiss being picked up from the mic. I never noticed this before because I have only been using it in live performance situations. What is odd is the hiss is heard even with the gain and master volume turned completely down. Is this normal for this amp or is there something wrong with it? Sure wish there some way to lower the output of the tweeter or completely turn it off. TIA
Click to expand...

The VLE is your friend. Remember, this control is designed to work as a tweeter attenuator on the front of the amp. Dialing it in at about 9 o'clock will take the upper edge off your tone, and quiet a lot of the noise you have in your signal path.

Also, you should NEVER turn the VPF up past around 10 o'clock. Besides scooping the tone, it will add lots of upper treble to you tone if you turn it up to noon or past... not a good thing with a piezo tweeter with no attenuator.

Finally, the active treble control on the amp is set very high (10K shelving), and is also good for controlling upper level treble response without sucking upper mids out of your tone... a slight decrease in the is control will also help a lot with your situation.

That all being said, those Markbass cabs with the cheap piezo tweeters and no attenuators are not the best design I've seen. However, you have LOT's of control over the upper treble that can cause issues with a piezo type tweeter, especially when recording/mic'ing a cab.

Hope that helps. Of course, the best solution is to use the post EQ direct out!
 
#3
thanks for the tutorial. The issue I'm concerned about is why the tweeter has so much hiss with ALL the volume controls turned off and no instrument cable even plugged in. I would think the amp should be dead quiet if the gain and master volume are turned off with no input cable attached. Can someone verify this with their Mini CMD 121P to see if their amp is doing the same thing as mine.
 
#4
bass4u said:
thanks for the tutorial. The issue I'm concerned about is why the tweeter has so much hiss with ALL the volume controls turned off and no instrument cable even plugged in. I would think the amp should be dead quiet if the gain and master volume are turned off with no input cable attached. Can someone verify this with their Mini CMD 121P to see if their amp is doing the same thing as mine.
Click to expand...


ah, not sure about that. My LMII is very quiet through my cabs with the tweeters set at noon or so, even with the volume cranked a bit. Alexclaber or one of the other EE oriented guys mentioned that piezo tweeters extend much higher into the highest treble region than other tweeter designs, and hence can sound more 'hissy' given that very high upper treble, especially if they don't have an attenuator.
 
#5
I have one and the tweeter hisses a little. Never been a big deal to me. I roll off the treble with the VLE, and even when I didn't, you couldn't hear it in a playing situation.
 
#8
In a very quiet room, I can hear a slight hiss from the tweeter
with the master volume off. It gets louder as I turn up the
master volume. Its nothing you'd ever hear in a live context,
but from two feet away in a quiet room I can just hear it.

The lack of attenuation of the tweeter is the only thing I
don't like about this combo.
 
#9
B String said:
In a very quiet room, I can hear a slight hiss from the tweeter
with the master volume off. It gets louder as I turn up the
master volume. Its nothing you'd ever hear in a live context,
but from two feet away in a quiet room I can just hear it.
Click to expand...

thanks B string, I just wanted to know if the hiss was normal with the volume turned down. I was ready to take the amp back to Guitar Center for an exchange. I would like to know if there is any way to defeat the tweeter for recording. I can hear no hiss from the 12" speaker. In a live situation the hiss from the tweeter is not an issue.
 
#12
bass4u said:
thanks B string, I just wanted to know if the hiss was normal with the volume turned down. I was ready to take the amp back to Guitar Center for an exchange. I would like to know if there is any way to defeat the tweeter for recording. I can hear no hiss from the 12" speaker. In a live situation the hiss from the tweeter is not an issue.
Click to expand...
The problem with totally defeating the tweeter is that the high end in the speaker itself cuts off highs at 3.5K and sounds even lower. So if you want any highs, you pretty much have to have the tweeter on a little. But I've tried micing it for recording, and I don't hear the hiss, even when the tweeter is up all the way. But if it bothers you, the best I can tell you is to gate it.
 
#13
machinehead_1 said:
With the volumes off I hear no hiss at all. Off course, I'm not recording, just listening.
Hope this helps
Click to expand...


I guess I need to go to Guitar Center and listen to another Mini Cmd and hear for myself if there is any hiss with the volume off. I would think there shouldn't be any sound from the tweeter at all with the volume off. It seems from reading this thread there are conflicting results from different user's of this amp.
 
#14
Today I visited my local Guitar Center and listened to the Markbass combo line up. The Mini CMD 121P, Mini CMD 151P, CMD 102p and Minimark all had a noticeable hiss coming from the piezo with the volume control all the way turned down. The CMD 151 Jeff Berlin model was dead quiet since it doesn't have any type of tweeter or piezo. I guess thats the nature of the beast. I'm going to try to figure out how to defeat the piezo for recording purposes only. When I record my bass, I record one track using the DI and another track with a mic about three feet away, then blend the two tracks in the final mix. Thanks to everyone for all their comments and info.

Oh by the way I made an impulse buy on a Fender Jazz Squier bass with a beautiful green metallic finish for $99. It actually played comfortably and sounded surprising good through a Markbass CMD 102p. The CMD 102p was on sale for $799....good price.
 
#15
You can pull the tweeter off the crossover, but it voids the warranty. You can put a sponge over the tweeter (this works very well, BTW). Or you can use the VLE. I use the VLE because the tonal effect of using it works out to the same as the other two solutions.
 
#16
There should be NO sound with the volume and gains down. I have to turn the master up all the way to hear hiss.

Do you have anything plugged into the effects loop? I don't know if this is before or after the master volume control. If it is post, then something else could be causing the noise.

Otherwise, If you are within the 30 days, take it back to GC and get another one. First problem I have heard of.
 
#17
JimmyM said:
You can pull the tweeter off the crossover, but it voids the warranty. You can put a sponge over the tweeter (this works very well, BTW). Or you can use the VLE. I use the VLE because the tonal effect of using it works out to the same as the other two solutions.
Click to expand...

Ditto--the VLE essentially IS your tweeter attenuator on these.
 
#18
Gio S said:
There should be NO sound with the volume and gains down. I have to turn the master up all the way to hear hiss.

Do you have anything plugged into the effects loop? I don't know if this is before or after the master volume control. If it is post, then something else could be causing the noise.

Otherwise, If you are within the 30 days, take it back to GC and get another one. First problem I have heard of.
Click to expand...

Well I would think that there shouldn't be any sound at all from the piezo with all the volumes down and nothing plugged into the amp but there is an audible hiss coming from the piezo on my amp and ALL the combos I tried at Guitar Center today. Is it possible all of these amps are faulty? Also people keep mentioning the VLE to adjust the piezo but this has no affect when all the volumes are down so the VLE is not the answer. So I'm back in the same predicament I was in before, some people say the hiss is normal, some say it isn't. Maybe someone from Markbass could enlighten us all. (hint)
 

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