Cab power handling (farting...)

[1958Bassman]

I'm confused by this.

What have is (both bought used):

-Older GK 400RB II head

Rated 125w @ 8ohm / 200w @ 4ohm


-Bag End s15d cab

Rated @ 8ohm continuous 200w / peak 400w

Sensitivity 103

My question is this:

With master at noon, and all EQ set flat, it will start to "fart out" at 10 o'clock volume when I dig in on the E.

I understand this is a pretty efficient cab, and it does get loud pretty quick, but I thought it would have more head room in handling what really isn't a high powered amp played with a passive P bass (full volume) with flats.

I'd appreciate any advice from the more technically adroit.

Thanks

Do you have pickups that are really hot or an active bass? If so, you should be using the -10dB switch.

Do you use any effects? Specify everything in the signal chain.

 

[1958Bassman]

School me!

Read the manual- it's on the GK site.

 

[Fretless55]

So B-string, getting back to boost level; mine is always on, I never did get a foot switch with the amp. Should I just dial it down? Seems like I just loose "oomph" when I do.

My dilemma certainly seems to have alot of variables...

Thanks

 

[Fretless55]

Just for a bit closure (although I'm still open to any advice...)

It did help to roll the boost all the way off. Seems incompatible with such an efficient cab.

I guess...

 

[B-string]

I have never run the boost fully off myself, I really like the harmonic content it adds.
I really believe you either have an amp that needs attention or a cab that is faulty. The only way to know without seeing a tech is to start sub'ing, amp with different cab, cab with different amp and finally different bass. Your bass isn't active is it? Bass boost on an active or a weak battery can cause lots of trouble.

 

[Shardik]

Get a sound pressure level (SPL) meter. Measure SPL about 1m/3ft when it starts to "fart out". My guess is that it starts at around 117dB outside or in a large concert hall and about 120 dB in a smallish room (because of the added room response).

If that is the case, this indicates that you have not reached the amp peak value or that the cab is beyond its linear response capabilities.

And by the way: Remember ear protection.