GK MB 200: Part Two

[Doug Parent]

If this gets a response from GK that would be even cooler. here's the deal:
On louder gigs I use my MB200 to power an additional cabinet which sits atop my other Berg. (Berg CN212 and Berg HD112)

I am going to assume that Jim Bergantino wires all of his products the same with correct polarity. Seems like a safe assumption.

Signal chain:

Bass plugged into MB200.
MB200 has HD112 connected.
Tuner out from MB200 into the input of:

GK MB800 which is powering a CN212.

The sound from the CN212 is out of phase with the HD112. Meaning the lows are cancelled with both amps on and both speaker cabs squawking.

Solution: I made a speaker cable with one end with reversed polarity. I used that on the MB200 and:

Problem solved.

I have tried various alternative means of ; splitting the signal, using the line out from thew MB200, and/or the effects send, same result.

Hypothesis: Somewhere in the internal signal flow of the MB200 the polarity is reversed.

Curious of RAG or anyone else has any comments or similar experience.

Just FYI, my MB200 is the model with the standard speak on output (black plastic) not the green "combo" speakon / 1/4" output jack.

Kinda stumped here as to why this would be.

 

[B-string]

First assume nothing. You spell assume "ass-u-me". You can check cab polarity with a 1/4" speaker cable and a 9 volt battery. Small battery terminal (+) to the tip and larger (-) to the barrel and both cab's speakers should move the same direction.
Each gain stage shifts 180 degrees, if the number of "stages" are not even between the bass's signal to the outputs of both heads the signal will be out of polarity.

 

[Doug Parent]

First assume nothing. You spell assume "ass-u-me". You can check cab polarity with a 1/4" speaker cable and a 9 volt battery. Small battery terminal (+) to the tip and larger (-) to the barrel and both cab's speakers should move the same direction.
Each gain stage shifts 180 degrees, if the number of "stages" are not even between the bass's signal to the outputs of both heads the signal will be out of polarity.

Ah so.

 

[Downunderwonder]

Headphone probably has its own little amp.

 

[RyanJD]

Used my MB200 for the first time in a live setting tonight.
I love the tight sound and response it gives compared the Carvin head I've been using.
The only thing that I'm a little unsure about is its low-end handling.
I played in drop D tonight and it felt like when I played anything on the E string, the response was just mehhh.

Fender J -> Boss Multi-effects (set pretty flat, with comp) -> MB200 -> 8 ohm Carvin 410 and line out to PA.

EQ on MB200: Gain: 12, treble: 12, mids: ~10, bass: 2-3.

The Carvin handles the lows better I think. (Though it does provide another 100+ watts at 8 ohms. Is that why?)
But all in all I really like this amp. I'm glad I got it.

 

[tbirdsp]

I'd be turning that gain up past noon into an 8 ohm cab.

Used my MB200 for the first time in a live setting tonight.
I love the tight sound and response it gives compared the Carvin head I've been using.
The only thing that I'm a little unsure about is its low-end handling.
I played in drop D tonight and it felt like when I played anything on the E string, the response was just mehhh.

Fender J -> Boss Multi-effects (set pretty flat, with comp) -> MB200 -> 8 ohm Carvin 410 and line out to PA.

EQ on MB200: Gain: 12, treble: 12, mids: ~10, bass: 2-3.

The Carvin handles the lows better I think. (Though it does provide another 100+ watts at 8 ohms. Is that why?)
But all in all I really like this amp. I'm glad I got it.

 

[Doug Parent]

The MB200 is "warm" to my ears at most settings until you get past the point when the dilithium crystals [Invalid or Expired Link Removed])

have exceeded their potential and you have no more go juice and Captain Kirk is pissed.

Used my MB200 for the first time in a live setting tonight.
I love the tight sound and response it gives compared the Carvin head I've been using.
The only thing that I'm a little unsure about is its low-end handling.
I played in drop D tonight and it felt like when I played anything on the E string, the response was just mehhh.

Fender J -> Boss Multi-effects (set pretty flat, with comp) -> MB200 -> 8 ohm Carvin 410 and line out to PA.

EQ on MB200: Gain: 12, treble: 12, mids: ~10, bass: 2-3.

The Carvin handles the lows better I think. (Though it does provide another 100+ watts at 8 ohms. Is that why?)
But all in all I really like this amp. I'm glad I got it.

 

[kleinenenten]

If this gets a response from GK that would be even cooler. here's the deal:
On louder gigs I use my MB200 to power an additional cabinet which sits atop my other Berg. (Berg CN212 and Berg HD112)

I am going to assume that Jim Bergantino wires all of his products the same with correct polarity. Seems like a safe assumption.

Signal chain:

Bass plugged into MB200.
MB200 has HD112 connected.
Tuner out from MB200 into the input of:

GK MB800 which is powering a CN212.

The sound from the CN212 is out of phase with the HD112. Meaning the lows are cancelled with both amps on and both speaker cabs squawking.

Solution: I made a speaker cable with one end with reversed polarity. I used that on the MB200 and:

Problem solved.

I have tried various alternative means of ; splitting the signal, using the line out from thew MB200, and/or the effects send, same result.

Hypothesis: Somewhere in the internal signal flow of the MB200 the polarity is reversed.

Curious of RAG or anyone else has any comments or similar experience.

Just FYI, my MB200 is the model with the standard speak on output (black plastic) not the green "combo" speakon / 1/4" output jack.

Kinda stumped here as to why this would be.

Can you chain from the 112 straight to the 212? Or vice versa? Don't know if those cabs have the in/outputs for it. Would get rid of carrying around an extra amp, too, if you don't have to bring the 800 anymore.

 

[Doug Parent]

Can you chain from the 112 straight to the 212? Or vice versa? Don't know if those cabs have the in/outputs for it. Would get rid of carrying around an extra amp, too, if you don't have to bring the 800 anymore.

The CN212 is 4 ohms. The HD112 is 8 ohms. Together in parallel = too low impedance.

 

[Munjibunga]

Can you chain from the 112 straight to the 212? Or vice versa? Don't know if those cabs have the in/outputs for it. Would get rid of carrying around an extra amp, too, if you don't have to bring the 800 anymore.

They do have two input/output jacks (actually two Speakons and two quarter-inch), but what Doug said.

 

[kleinenenten]

The CN212 is 4 ohms. The HD112 is 8 ohms. Together in parallel = too low impedance.

Ah gotcha. I wondering why you wern't attempting something "that" simple. You seemed like a bright fellow in your post. Makes sense now.

 

[Munjibunga]

Ah gotcha. I wondering why you wern't attempting something "that" simple. You seemed like a bright fellow in your post. Makes sense now.

He seems like that, doesn't he.

 

[Doug Parent]

He seems like that, doesn't he.

 

[NWB]

Used my MB200 for the first time in a live setting tonight.
I love the tight sound and response it gives compared the Carvin head I've been using.
The only thing that I'm a little unsure about is its low-end handling.
I played in drop D tonight and it felt like when I played anything on the E string, the response was just mehhh.

Fender J -> Boss Multi-effects (set pretty flat, with comp) -> MB200 -> 8 ohm Carvin 410 and line out to PA.

EQ on MB200: Gain: 12, treble: 12, mids: ~10, bass: 2-3.

The Carvin handles the lows better I think. (Though it does provide another 100+ watts at 8 ohms. Is that why?)
But all in all I really like this amp. I'm glad I got it.

That's a pretty scooped EQ (12 isn't flat) and the little head probably isn't going to handle that much low-end with its limited power.

B-String has posted what the flat settings are for the MB200 and I'd try that first. Definitely cut some that bass back. Also, make sure that contour switch is off.

 

[RyanJD]

That's a pretty scooped EQ (12 isn't flat) and the little head probably isn't going to handle that much low-end with its limited power.

B-String has posted what the flat settings are for the MB200 and I'd try that first. Definitely cut some that bass back. Also, make sure that contour switch is off.

I see, I wasn't aware of that.
Yeah the countour option doesn't do much for me. I had it off.

I'll look for that post. Thanks!

 

[Downunderwonder]

Flat is 10 o'clock treble, 2 hi, 1 low, 10 bass.

Left to right 10,2,1,10 easy to remember.

 

[kleinenenten]

Flat is 10 o'clock treble, 2 hi, 1 low, 10 bass.

Left to right 10,2,1,10 easy to remember.

Wow! My settings are almost identical to that! I boost bass to noon, and low mids to 2. Didn't realize I was so close to flat, but a little EQ goes a long way I guess!

 

[kleinenenten]

I see, I wasn't aware of that.
Yeah the countour option doesn't do much for me. I had it off.

I'll look for that post. Thanks!

Contour sounds great for slap, but I have no practical application for slap. I can only do the one slap piece anyway.

 

[RyanJD]

Flat is 10 o'clock treble, 2 hi, 1 low, 10 bass.

Left to right 10,2,1,10 easy to remember.

Thanks. I'm gonna have to write that down!

Contour sounds great for slap, but I have no practical application for slap. I can only do the one slap piece anyway.

I'm pretty much in the same boat. No use for it, really.

 

[Zapp]

by 12 do you mean "due north", i.e. half gain, no damping/cut?
I ask because I play every week, always in drop d [the whole thing, i.e. D, G, C, F] and no issues - the bottom 'blossoms' with good punch, and the bass control is very touchy. I only go to about 1pm, rarely 2 on the low bass.
this using a stock squire vmj with compression wounds.
the diff may be the speaker: I use a single older GK 115 MBX, horn off [needs replacing... the only thing about the cab I don't like].
if I run the gain or the bass up past noon, the group starts talking about me in an impolite way

Used my MB200 for the first time in a live setting tonight.
I love the tight sound and response it gives compared the Carvin head I've been using.
The only thing that I'm a little unsure about is its low-end handling.
I played in drop D tonight and it felt like when I played anything on the E string, the response was just mehhh.

Fender J -> Boss Multi-effects (set pretty flat, with comp) -> MB200 -> 8 ohm Carvin 410 and line out to PA.

EQ on MB200: Gain: 12, treble: 12, mids: ~10, bass: 2-3.

The Carvin handles the lows better I think. (Though it does provide another 100+ watts at 8 ohms. Is that why?)
But all in all I really like this amp. I'm glad I got it.