It is currently Mon Mar 16, 2020 8:37 am

All times are UTC - 7 hours



Post new topic Reply to topic  [ 3 posts ] 
Author Message
Post subject: will my amp be okay?
Posted: Mon Aug 25, 2014 5:10 pm
Offline
Amateur
Amateur

Joined: Sun Nov 04, 2012 10:11 am
Posts: 195
Hey folks although ive been a gigging musician from quite some time i have been stuck on combo amps up until this year when i bought my self an Ampeg PF500 and an Hartke 410XL as a rig my question (being that i am a newb when it comes to power and watts) is at practice i normally have to crank the Ampeg volume to about 3 o'clock to cut through 2 half stack guitar amps to hear. i know the ampeg has 500 watts of power but i am runnning it through a 400 watt cab at 8 ohms. so my question is should i be concerned about my rig or should i have no issues also if anyone is familiar to the pf500 my thresh light flashes at every note but the peak does not thanks for your help


Top
Profile
Fender Play Winter Sale 2020
Post subject: Re: will my amp be okay?
Posted: Mon Aug 25, 2014 10:19 pm
Offline
Rock Star
Rock Star
User avatar

Joined: Thu Aug 07, 2008 3:12 pm
Posts: 6355
Location: Albemarle, NC
You should be OK Tamey75 in mating that head to that cab under reasonable use.

To me "reasonable" is where you don't crank the master volume past 12 o'clock. (My general rule is that if I have to turn a solid state bass head past 12 o'clock then I need a more powerful head or more efficient cab arrangement.)

The one problem I see here is having to crank the amp to 3 o'clock. That is too high and more than likely that setting is driving the amp into some clipping, even if it is inaudible. When the power amp clips it produces squared off wave forms that the speakers can not convert to sound energy so they get converted to heat instead. Long term that can cause speaker damage. (Speakers can be damaged by power amp clipping or by being pushed over their rated wattage. Either is bad.) This particular amp doesn't have any clipping protection or detection except in the preamp section. It also has thermal protection for the power amp module, but when clipping heavily the thermal amp protection (causing a power amp shut down) may engage too late to save your speakers. It also has a compression circuit and that can help even things out and prevent real serious clipping issues at 12 o'clock from aggressive play.

The PF500 connected to an 8 Ohm cab does not produce 500 watts. Instead it is specified to produce 300 watts into the 8 Ohm load. While your 400 watt speakers are safe power-wise when connected to this head and used responsibly, you have to realize that when you push this head much past 12 o'clock on the volume knob you are going into the clipping danger zone, especially if you have much bass EQ dialed in or the Ultra-Lo button engaged.

Five suggestions here.

1. This one is free! Rethink your EQ settings to get more cut-through until you can add another cab or replace the existing 8 Ohm one with a 4 Ohm one. I don't know what EQ settings you are using now, but typically bassists go for heavy lows, cut the mids some and boost the highs. Yes it sounds good, but it is a very power hungry EQ arrangement which is why I consider most solid state bass heads maxed out at 12 o'clock on the master volume. Instead I'd cut the bass to 10 or 11 o'clock, set the treble to 12 o'clock or less, disengage both ULTRA switches, set the FREQUENCY knob to the "2" setting (450 Hz) and boost the mids to get more punch or cut through instead of the master volume knob. I'd keep the master volume no higher than 12 o'clock and rely on boosting the mids to add cut through. You are much safer doing this than pushing the power amp into clipping which you are almost certainly doing at 3 o'clock if you have a lot of bass boost in the EQ. For some reason these amps like to hiss (a lot) when you crank the mids, if your cab has a horn control dial it down or switch the horn off if the hiss gets to be an issue.

2. Buy a second 8 Ohm cab and daisy chain the two cabs to get to a total 4 Ohm load which will use all 500 watts from the head. This will be louder and more efficiently use the amp's power potential. It will also move more air.

3. Replace the existing 8 Ohm cab with a single 4 Ohm cab if size and weight is a consideration. It won't move as much air as adding a second cab, but it will be louder than a lone 8 Ohm cab.

4. Also FREE! If you are gigging with a decent PA with subs, then patch out to the PA and let the PA boost the bass some. Use the rig more or less as a stage monitor and let the PA tech do the mix.

5. You possibly should have bought the PF800 instead of the PF500. The PF800 is 400 watts at 8 Ohms and would be a perfect match to your 400 watt 8 Ohm cab. This head also has the hiss issue when you crank the mids though.

OPINION: In my experience with Ampeg solid state heads they tend to be over-rated power wise when compared to other solid state heads from main line brands like Fender, Peavey, Carvin, Hartke, GK, etc of similar power rating. I'm not alone in that opinion of the solid state Ampeg heads in general being over-rated in power. You might want to try a Fender Rumble 500 head and compare it to the Ampeg. See which you think is louder. The Fender Rumble 500 head is rated 350 watts into 8 Ohms. I wager the Fender Rumble 500 sounds more than 50 watts louder than the Ampeg PF500 into an 8 Ohm cab. Also the PF series seems bass heavy to me compared to about any other major brand. The Ultra Lo switch makes the PF series almost too bass heavy for me, and I like a lot of bass. While all this is good for vintage tones, I have a great deal of trouble getting any sort of modern tone out of the PF series even into a cab with the horn on full. And hiss is a real problem so you have to dial down the horn to tame it. It is sort of a catch 22 making modern tone an elusive find for me in the PF series. I was not impressed performance wise with the PF series, but I do like the flip top convenience which you aren't using.


Top
Profile
Post subject: Re: will my amp be okay?
Posted: Tue Aug 26, 2014 5:33 am
Offline
Amateur
Amateur

Joined: Sun Nov 04, 2012 10:11 am
Posts: 195
Thanks Brother Dave that makes sense luckily your knowledge helps me understand the new world of heads and cabs I will rethink my eq and give it a shot thanks a lot!


Top
Profile
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 3 posts ] 

All times are UTC - 7 hours

Fender Play Winter Sale 2020

Who is online

Users browsing this forum: No registered users and 2 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum

Search for:
Jump to: