Sound shut down when raising gain on a Markbass

[agedhorse]

The input impedance of most amps is 1M (typical), but even 100k won't cause instability unless there is something wrong with the input stage (or the design of it).

 

[Pings Bass]

The

The Gage site says you shouldnt need a preamp.
I was given a dead Realist pickup and found it had a couple of resistors built into the output jack. I assumed they were for impedance matching. There was an open at that point. I just wired it direct to the jack and got it working.
I always use an FDeck HPF with upright bass anyway.

The fdeck is the buffering pre I use as well. More for the buffer and hpf than the preamp.

 

[Engle]

The fdeck is the buffering pre I use as well. More for the buffer and hpf than the preamp.

I don't think the one I have actually has any gain, but I put it on the quiver and it's nice to have a volume control and hpf at the bass.

 

[Pings Bass]

I don't think the one I have actually has any gain, but I put it on the quiver and it's nice to have a volume control and hpf at the bass.

I believe the series 1 and 2 can give a modest gain boost, but not series 3. All models offer 10M input impedance.

 

[Marley's Ghost]

I have a LMII Marco which shuts down when I push the lows at 4 ohms. It works fine within certain limits.

 

[Lorenzo Ponce]

Hey there

So, I tried to use an MXR bass compressor as a buffer. So far, so good, no issue when cranking up the gain - except with the neighbors, who seems to have a very low impedance level...

For the record - although I'm not sure if that matters - the MXR specs states : Input Impedance 1 MΩ Output Impedance 600 Ω. And also - what does it means, I have no clue, maybe totally irrelevant to my problme but I share it to fuel the experts discussion - max Input Level +14 dBV Max Output Level +8.5 dBV

I'll give it further test in real life gigs conditions and let you know if it is solved. Thanks for your help guys

 

[agedhorse]

This reinforces the instability theory. We have many players using the Realist pickup with the Subway and Rosette amps which are all ~1M.

 

[jimmydean]

I never cared for MarkBass amps and one day I found one I liked only to have it shut down multi times during a gig . Their amps have a protection mode that shuts itself off..........returned and never darken my door again!

 

[Jeff Scott]

...digital equipment sometimes senses anomalies and will go into a protection mode.

There is nothing digital about the OP's amp.

 

[Minimalist]

Interesting thread. I experienced the same issue with this amp but 2 different P basses. Never had an issue with any other amp. From what I understand, this seems to be a design issue? Maybe I misunderstood previous comments. Needless to say, I will be returning this amp.

 

[SJan3]

likely, look up it's input impedance and if it's 1M or greater, you're good. if the pedal is 'true bypass', you need to have it on to actually buffer your signal. at least try this to conclude if your problem can be solved by a buffer.

another buffering option is using a HPF (the Thumpinator has 2M input, I believe) or using a buffer in your pedal tuner (Peterson Strobostomp HD has a 4.7M input impedance per specs).

This amp happens to have a 2M input. I don't play upright but does that help your problem?

• INPUT: impedance 2 Mohm, max. voltage 15 Vpp
• EFFECT RETURN: impedance 33 Kohm, max. voltage 10 Vp