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Ampeg PF500/PF350

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#1,162
I haven't bumped into that problem with my 500 and I only use it with a 4 ohm cab. Odd that it's happened with two different heads/models and your cabs. Have you ruled out issues with basses, cables etc? I have noticed on mine if I'm using the input/headphone jack (always run without a load when practicing like this) it's much louder (at a basal level) than the micro-VR that I used to use and will sometimes give me a similar effect to what you describe when I first turn on a track from my computer/ipod, never with the head through the cab though.
 
#1,164
Jeff_K said:
So, this is the 3rd time I'm talking about this now. I had a 350 and now have a 500 and they both did the same thing when I put a 4 ohm load on them. If I turn it up a bit, give a hard slap with my thumb or even just dig in a bit, I get a short pop, the sound dissapears for 2 seconds or so, then comes back. I've done this with a single 4 ohm cab (my Avatar), and two 8 ohm cabs just to make sure it wasn't my Avatar cab only. The amp's cool as a cucumber, it can happen as soon as I fire it up. I've also made sure I'm using a speak-on speaker cable, just to rule out the possibility of all that power going through a 1/4 jack being a possible issue.

I've watched the LEDs when this happens. No blink or flash. I've had the compressor up high, down low. I can avoid the problem by two ways - with a 4 ohm load I have to dial the bass knob way back, to the point where it sounds thin and doesn't sound like a bass any more, or use an 8 ohm cab (and the only one I have right now is a single 18). When on an 8 ohm load the problem never happens. Never.

It breaks my heart - the reason I bought this thing was to be able to use one of my two Avatar B210 4 ohm cabs... for practice, smaller gigs, etc. It would really have been the ultimate portable rig.

I suppose I can contact Ampeg and see what they have to say. Anyone have any opinion on their customer service?

Thanks for listening.
Click to expand...

Very strange. Since it happened with two different heads, there must be something going on with your setup that the PF heads don't like. Or possibly you just got two heads that have a bug in them. It's rare for that but it does happen. Over in the GB Streamliner thread somebody ended up getting two units that had issues, so it does happen. Other than here in this thread I haven't seen anyone else complaining of this on other boards so I still think you're just having a run of bad luck.

You didn't mention if you tried a different bass or not. Is your axe active or passive? Shouldn't make a difference but you never know.

One thing I'd try if you haven't already is to have a look at the preamp out and poweramp in jacks. The main signal for the amp passes through those jacks. If they have even a small bit of gunk or residue on the contacts, or just aren't making good contact when in the closed (no plugs in them) position it can cause cutouts. Those cutouts can happen anytime at low or high volume, or with low input or high input settings. Get some deoxit (Radio Shack has it) spray a 1/4" plug with it and run them in and out of the jacks a bunch of times and see if it works. If it helps a little bit but not 100%, and you feel comfortable doing it, you'll have to pop the lid and spray them down. Might not hurt to pop the top and do a visual just to see if there's any loose connectors or anything else going on in there.

If you're still within your 30 days, just return it to GC. If not Ampeg should get you taken care of pretty quick.

Good luck and keep us posted.

Keep Low :bassist:
 
#1,165
Jeff_K said:
So, this is the 3rd time I'm talking about this now. I had a 350 and now have a 500 and they both did the same thing when I put a 4 ohm load on them. If I turn it up a bit, give a hard slap with my thumb or even just dig in a bit, I get a short pop, the sound dissapears for 2 seconds or so, then comes back. I've done this with a single 4 ohm cab (my Avatar), and two 8 ohm cabs just to make sure it wasn't my Avatar cab only. The amp's cool as a cucumber, it can happen as soon as I fire it up. I've also made sure I'm using a speak-on speaker cable, just to rule out the possibility of all that power going through a 1/4 jack being a possible issue.

I've watched the LEDs when this happens. No blink or flash. I've had the compressor up high, down low. I can avoid the problem by two ways - with a 4 ohm load I have to dial the bass knob way back, to the point where it sounds thin and doesn't sound like a bass any more, or use an 8 ohm cab (and the only one I have right now is a single 18). When on an 8 ohm load the problem never happens. Never.

It breaks my heart - the reason I bought this thing was to be able to use one of my two Avatar B210 4 ohm cabs... for practice, smaller gigs, etc. It would really have been the ultimate portable rig.

I suppose I can contact Ampeg and see what they have to say. Anyone have any opinion on their customer service?

Thanks for listening.
Click to expand...


i have had that happen to me twice as well. each time with a different cab combination hooked up. not to big of a prob for me cause i have been running this amp very hard for the past almost 2 months. i will have to keep an eye on it. its also only happened when i use my 18v bass with it. i wonder if that has something to do with it? other than that i love this amp. i have been using my pf115 with my g-k 1x15 and love it. i am soon going to get another pf115. and then another pf500 and then two more pf115. so i'll will have 2 heads and 4 1x15's. whahaha, good bye guitar players!!!
 
#1,168
Fletz said:
I always say this: if you can swing it, go 500. You can always turn down.
Click to expand...

Fletz Have you had any issues with the 500 cutting out when driving it hard through your 4 ohm 410HLF? I've had no issues on my 500 but I'm just running mine at 8 ohms with a single Hartke HX115 HyDrive. I'm thinking the cutting out has something to do with the input gain structure when using active basses.
 
#1,172
Is the cutting out something that you can reproduce consistently? If so, I'd suspect it's a design flaw or it's intentionally designed that way. Although I can't believe any company would intentionally design a circuit that cuts out. Unless it's a sign that the amp is being pushed too hard and needs to be dialed back a bit to keep it from blowing up. Or is it random? If so I'd suspect a bad amp.

I'm leaning towards the thought that it's something in the design of the input gain that's causing the front end to get too hot a signal and overloading the input and possibly causing issues with the limiter or protect circuit.

Have either of you tried using the preamp out / poweramp in jacks to try and isolate which section of the amp is acting up? Run the preamp out to another amp. You'll find out right away if it's the preamp that's acting up. Run a signal into the poweramp in jack from the preamp of another head and crank it to see of the power section acts up.

This might be a dumb question but have you contacted LOUD support and asked about the issue? Considering the low price point on the new PF series, you could call it an "entry" level amp for Ampeg. Maybe it's just not that robust of a design? Considering the QC issues Ampeg has had over the last few years, I would find it hard to believe that LOUD would cut corners on any new design from Ampeg.

Sure would to know Ampeg's take on this.

FWIW So far no issues running my PF500 with a passive P through a Hartke HX115 @ 8 ohms. I've really pushed it hard too. Haven't taken it out on a gig yet but I'm able to crank it to gigging levels here at home because my neighbors are cool :)

Keep Low :bassist:
 
#1,173
"I'm leaning towards the thought that it's something in the design of the input gain that's causing the front end to get too hot a signal and overloading the input and possibly causing issues with the limiter or protect circuit".

I believe that. My old inexpensive combo did the same thing when pushed too hard, even with the limiter off it would still kick in to protect the amp.
 
#1,177
Jeff_K said:
So, this is the 3rd time I'm talking about this now. I had a 350 and now have a 500 and they both did the same thing when I put a 4 ohm load on them. If I turn it up a bit, give a hard slap with my thumb or even just dig in a bit, I get a short pop, the sound dissapears for 2 seconds or so, then comes back. I've done this with a single 4 ohm cab (my Avatar), and two 8 ohm cabs just to make sure it wasn't my Avatar cab only. The amp's cool as a cucumber, it can happen as soon as I fire it up. I've also made sure I'm using a speak-on speaker cable, just to rule out the possibility of all that power going through a 1/4 jack being a possible issue.

I've watched the LEDs when this happens. No blink or flash. I've had the compressor up high, down low. I can avoid the problem by two ways - with a 4 ohm load I have to dial the bass knob way back, to the point where it sounds thin and doesn't sound like a bass any more, or use an 8 ohm cab (and the only one I have right now is a single 18). When on an 8 ohm load the problem never happens. Never.

It breaks my heart - the reason I bought this thing was to be able to use one of my two Avatar B210 4 ohm cabs... for practice, smaller gigs, etc. It would really have been the ultimate portable rig.

I suppose I can contact Ampeg and see what they have to say. Anyone have any opinion on their customer service?

Thanks for listening.
Click to expand...

I just tried out a PF500 yesterday and am considering getting one soon. I really dig the tone and it seems somewhat thicker sounding than my Shuttle 6.0. Darn good price too.

This problem has me a bit concerned though.

However, my house is a stone's (or micro head;)) throw away from LOUD and I could just walk over to their HQ with any problems. I suppose I could show up on their doorstep with amp and bass in hand if any issues were to arise.
 
#1,178
NWB said:
I just tried out a PF500 yesterday and am considering getting one soon. I really dig the tone and it seems somewhat thicker sounding than my Shuttle 6.0. Darn good price too.

This problem has me a bit concerned though.

However, my house is a stone's (or micro head;)) throw away from LOUD and I could just walk over to their HQ with any problems. I suppose I could show up on their doorstep with amp and bass in hand if any issues were to arise.
Click to expand...

Genz Benz's offices are about 23 miles from my place. I've walked in there a couple of times to get my GB amps serviced so I can relate to your post. GB has always taken care of me without any issues. Their CS is one of the best out there. I would assume LOUD would do the same.
 
#1,179
60bass said:
Is the cutting out something that you can reproduce consistently? If so, I'd suspect it's a design flaw or it's intentionally designed that way. Although I can't believe any company would intentionally design a circuit that cuts out. Unless it's a sign that the amp is being pushed too hard and needs to be dialed back a bit to keep it from blowing up. Or is it random? If so I'd suspect a bad amp.

I'm leaning towards the thought that it's something in the design of the input gain that's causing the front end to get too hot a signal and overloading the input and possibly causing issues with the limiter or protect circuit.

Have either of you tried using the preamp out / poweramp in jacks to try and isolate which section of the amp is acting up? Run the preamp out to another amp. You'll find out right away if it's the preamp that's acting up. Run a signal into the poweramp in jack from the preamp of another head and crank it to see of the power section acts up.

This might be a dumb question but have you contacted LOUD support and asked about the issue? Considering the low price point on the new PF series, you could call it an "entry" level amp for Ampeg. Maybe it's just not that robust of a design? Considering the QC issues Ampeg has had over the last few years, I would find it hard to believe that LOUD would cut corners on any new design from Ampeg.

Sure would to know Ampeg's take on this.

FWIW So far no issues running my PF500 with a passive P through a Hartke HX115 @ 8 ohms. I've really pushed it hard too. Haven't taken it out on a gig yet but I'm able to crank it to gigging levels here at home because my neighbors are cool :)

Keep Low :bassist:
Click to expand...

thanks for the helpful advice. i will try it. to answer a question, it only has happened twice on me with my active bass. it has never happened on a passive bass. now i have been using that amp a lot and i always push it hard. i play in a very loud band so this amp and all my others gets pushed to the max. it has never happened on a gig, just at home, and after it happened it was good to go. still ran it at the same volume. it seems like it happened when i tried to start out that loud instead of bringing the volume up.
 
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