PF500 + 115HE situation. 12 o clock gain, 12 o clock volumen, passive bass, farts

I thought maybe you'd mistaken the distortion you can get from these for a fault, but it's hard to see why it's malfuntioning with the gain so low. I use the exact same rig and have the gain usually between 2 and 3 O'clock (with the volume not getting above halfway).
If it's squawking in protest with your settings it might be a fault. What do you do on the actual Bass? Are you of the school that just turns everything all the way up? I tried that on my StingRay and it was terrible. No amount of amp EQing could fix it.
This video may help -

 

yeah, I have the same PF500/115HE set-up in a rehearsal studio and there is no way these amp settings should produce over excursion/distortion/farting
I notice you have the FX mix level control dimed .. is there a reason for that ? do you have a pedal inserted into the FX loop ?
Not saying that it should cause the rig to fart out, but still .. you never know.

Another thing to check is whether the cab top seal is good. I have known these cabs to make odd noises when the seal was bad/leaking.
Is it possible there is something touching the speaker cone paper ? . either inside or outside ? I seem to recall another TB member had the speaker lead wires actually touching/rubbing on the speaker surround and it caused a farting/distortion/buzzing type sound.
I have had issues with the screws on the cab rattling/vibrating which causes me tighten them all up every now and then.

On the bass side of things, do you know for certain that the bass signal is clean ? is it an active Squire, and are the preamp batteries fresh, is the cable good ?
Sounds like you know to check the bass, so let us know what you find.

good luck

 

A Stingray has active EQ - if you have the knobs all the way up, you're putting some pretty serious EQ gain in at the source and might very well clip the input of the amp. Yeah, you aren't going to be able to EQ that out easily. The OP specified passive bass - which will only have treble roll off. Everything dimed there will yield flat response...or as close as it will get.

 

The bit you need is at ~5:35, If you've actually attached it already, you should be fine.

 

when I was talking about the screws and bolts on the cab, I was talking about tightening them ... all of them. You have to be patient and look for all of them.
Top, handles, corners (each of these has a couple) tweeter/speaker jack control cavity, clasps that hold the top to the cab, nuts that hold the the speaker to the baffle. lots of them and most get loose on my rig over a period of a few months of regular use.

On my PF500/115HE rig they were all pretty loose and were definitely rattling at certain freqs, which besides being annoying, can sound like distortion/farting.

of course, it is entirely possible that your amp has a distortion problem too, so after you try all of these suggestions, you may need to find a qualified tech to check it out.

good luck/buena suerte

 

It's not an issue of power, it's an issue of your cabinets. The 115HE is a single driver, sealed cabinet. You're trying to get all that sound out of a single driver, so strike one. And since its a sealed cabinet, it won't be as loud as a ported cabinet so you're probably trying to get more out of it than it's designed to do. Strike two. Plus a sealed cabinet can tend to 'fart' more just due to the design. Strike three!

The solution would be to add another matching 15, as one obviously cannot deliver what you need.

 

Fart, clip or briefly cut out, whatever you want to call it.
FWIW, My PF500 w/ matching cabs 2x10 and 115 cut out regularly(at least once a gig or rehearsal).
It's a little disconcerting to have finally got the gear I wanted and have this anomaly with it.
I'm running my G&L ASAT in passive mode with gain & volume at 12 or 1 o'clock.
Doesn't happen with any other amp I use.

 

Howdy OP. My PF 800 and PF115HE will do the same farting with the settings you're using.

It's all in the gain structure with the PF heads. I quickly learned to set Gain 9-10 O'clock, Bass at 11:00, Mids at 1:00, Mid selector at #5...or whatever your flavour, High at 9:00, and, get this...Master at 4:00. Master at 5:00 produces too much noise. Loud/large venues require me to turn up the gain, but anything over 12:00 is unbearably loud for the audience.
These settings have allowed me to play loud without those protesting noises emanating from my speakers.

Other heads through the same cabinet do not produce flapping noises, even cranked up. Others tried are GK1001RBII, Ampeg SVT 3PRO, and my VT Bass DI through a Peavey PV2600 power amp. All of these have been into the PF115HE and/or PF115LF.
My conclusion from this is that the PF solid state heads (PF 500 and PF800) produce bigger lows at lower gain structure settings than the other amps. Or, the PF heads just can't match the other amps for honest to goodness thump.

 

Thanks,
I'll give these setting a try.

 

I've had 2 PF115HE cabs. Both farted at levels my current 115s handle without a problem.
I wasn't using an Ampeg PF amp. But I found the PF115s just couldn't take the amount of power of other 15s that I was used to. When I used two together. ..obviously I was only gig each 115 half the power and they sounded good. ..but I wanted to be able to use 1 x 115.
I sold em and bought a couple of Fender Bassman Pro Neo 115 cabs. No such problems. .even with a Super Bassman amp powering one. ..very loudly. Two of the Bassman Pro Neo 115 cabs. .. YOOOOOOOOJ sound. ... too much mostly.
Bottom line. .. I usually use just one 115 Bassman cab with one of a few different amps. .. V4B, Super Bassman, Aguilar TH500 and no farting.

 

That's hard to say other than the head is limited to 400 watts when using an 8 ohm cab such as the PF115HE and LF. The actual wattage isn't really measurable in a gigging environment with the tools at hand. That all would rely on how hard you play, gain structure and volume selected. I play at varying volumes from low to high using the Gain knob. So...anywhere from one watt, to ear splitting. Who knows how "ear splitting" converts to watts.
I'm now using the PF115HE for tame circumstances, and the PF115LF for more vigorous gigs. There's a Berg HD212 for sale in the local area. It's got me interested. Steering away from Ampeg now.