Ampeg PF350/500 Part V

[ryanfenderbass]

stiles72

ryanfenderbass mentioned in one of his posts that Ampeg told him that he should back off the bass control or if he needed more bottom, he should consider the new Portaflex HLF cabs to avoid cutting out issues.

http://www.talkbass.com/forum/f15/ampeg-pf500-350-part-4-a-849565/index41.html

After reading the post again, I can't say that Ampeg actually "admitted" running the bass full on would cause cutouts, but their response is sure pretty close to actually admitting it.

That being said, I still love the sound of my PF500 and so far still no issues but keeping my fingers crossed anyway.

Keep Low

This is all true (except the part about needing the HLF). They told me the PF500's power section doesn't have enough juice to drive a hefty amount of low end at higher volumes, especially at 4 ohms. You either need to cut the lows or squash the signal with compressor (to the point where the comp is audible) to drive the low notes at higher volumes. I put my SVT7PRO through the ringer the last 2 nights, no issues. I proved to myself that the extra horsepower really comes in handy when driving my low-mid heavy tone at higher volumes.

Still love my PF500 for practice and small gigs through!

 

[GregT]

This is all true (except the part about needing the HLF). They told me the PF500's power section doesn't have enough juice to drive a hefty amount of low end at higher volumes, especially at 4 ohms. You either need to cut the lows or squash the signal with compressor (to the point where the comp is audible) to drive the low notes at higher volumes. I put my SVT7PRO through the ringer the last 2 nights, no issues. I proved to myself that the extra horsepower really comes in handy when driving my low-mid heavy tone at higher volumes.

Still love my PF500 for practice and small gigs through!

That sounds like it makes perfect sense and I am glad to hear that you got that information straight from Loud. It actually might explain a lot for a lot of people. Neither of my PF500s have ever had a problem, but I run them at 8 ohms and not extremely loud. Loud enough for me though! I stand behind my earlier assessment of the PF500 as being perfect for small to medium sized gigs (without PA support) and if you want a more powerful Ampeg, they sure do build those as well. The PF500 is an easy carry backup head to carry to any gig also.

 

[60bass]

They told me the PF500's power section doesn't have enough juice to drive a hefty amount of low end at higher volumes, especially at 4 ohms. You either need to cut the lows or squash the signal with compressor (to the point where the comp is audible) to drive the low notes at higher volumes.

Imo you shouldn't have to do that. the amplifier should be able to deliver its rated power into a 4 ohm load at any of its tone settings without issues.

it sounds like ampeg is telling owners to make these adjustments to compensate for a weak design in the power section of these amps when using a 4 ohm load.

I really wish someone who has the proper test equipment and knowledge could bench one of these amps out while pushing it hard at 4 ohms just to see what happens when / if it cuts out.

 

[Musicman20]

Strange that it got through the design stage to be honest. But the price is very low! I saw a 500 in the flesh the other day and it looks like a nice compact bit of kit. Was the post above about these being made in the Behringer factory in China a joke?!

 

[fivestringgecko]

They told me the PF500's power section doesn't have enough juice to drive a hefty amount of low end at higher volumes, especially at 4 ohms.

Interesting... the tech I was in contact with told me it's how the gain knob and compressor interact. She mentioned that if you set the gain with the compressor dialed up, it's possible to overload the preamp without knowing it.

I love my PF500 rig, but I wonder if there's some little gremlin in the design that just interacts funny and it's a tradeoff for cost. Maybe redesigning the amp to fix the issue would result in a higher final price to the consumer? *shrug*

5sg.

 

[stiles72]

Imo you shouldn't have to do that. the amplifier should be able to deliver its rated power into a 4 ohm load at any of its tone settings without issues.

it sounds like ampeg is telling owners to make these adjustments to compensate for a weak design in the power section of these amps when using a 4 ohm load.

I really wish someone who has the proper test equipment and knowledge could bench one of these amps out while pushing it hard at 4 ohms just to see what happens when / if it cuts out.

This is what surprises me. Since I've got mine, I've ran it on a variety of cabs - but all at 4 ohms total - and I push a big low end on mine with never a cut out issue. Ultra low engaged, bass knob up - big and thumpy.

Have the owners with cut out issues tried these heads on different cabs, or with different speaker cables? I happen to rember a while back - some of my newer light weight Carvin PA power amps didn't like the speaker cables I was running for our PA system. The amps would go into fault mode for no apparent reason, but through trial and error we discovered the culprit(s) were certain speaker cables. The cables worked perfectly fine on our older amps with the same speakers- but the new amps seemed to just be finicky. We eventually marked which cables the new amps "liked" and haven't had any issues since.

 

[Freddels]

Maybe someone that is having issues with theirs could contact Tom Bowlus and have it sent over to him so that it can be given to his testing crew. Maybe they could figure out what's going on with it.

 

[ryanfenderbass]

Interesting... the tech I was in contact with told me it's how the gain knob and compressor interact. She mentioned that if you set the gain with the compressor dialed up, it's possible to overload the preamp without knowing it.
5sg.

That's what Rebecca told me at first too, but I spent thirty minutes with another rep (protecting his name since he is an associate of Rebecca's) playing my rig over the phone and recreating the cut-out. He wrote down the various settings that made it cut out--It wasn't very hard to do. I swapped out various speaker cables (both the included 1/4" and heavy-guage Neutrik. Nothing changed the issue. It was at that point I was advised to get an SVT7PRO or scale back my tone settings/up the comp if I want to not worry about the cut-out. The general diagnosis was the power amp doesn't draw power fast enough to handle certain low-frequency transients, so the protection circuits kick it (aka the "cut-out") to avoid clipping the signal... which is apparently a very bad thing with class D technology. (Assuming I remember the explanation correctly).

If he was trying to sell me on upgrading to the SVT7PRO (joking), I'm okay with that... that amp is a beast. Love it!

edit: that was my 3rd unit. Ampeg requested that I send it back for testing. Hopefully my PF500 is on the bench as we speak and answers will being coming out shortly.

 

[tuckomf]

Well, despite some of the cut-out stories I've been reading over the past couple of months (because it took that long to get through all the posts! Holy cow!) I finally pulled the trigger on a PF-500 today. My local Guitar Center finally had one in stock for more than a week. I've been using an older Genz-Benz combo until now, and it has served me faithfully, and it's going to continue to do so for smaller gigs. I just needed a little more power recently, and I've been scouring everything to decide on an amp. I had a sweet deal on an SVT-CL, and there are some great prices on a lot of used gear, but when I though realistically about what's practical, the PF-500 made the short list. I played along with the in-store music at GC for about 2 hours, quietly on the songs I didn't know, and cranked when Space Truckin' and In-A-Gadda-Da-Vida came on, and I was able to dial in some pretty tasty tones. I love the Ampeg midrange control. Love it. It's pretty much the selling point of the amp for me. I was looking for something that was ~350-500 watts with a variable midrange, decent line-out options, and lightweight, and the new portaflex line seemed to fit the bill the best. I know there's plenty of love for them, and a fair share of fault stories, but I just wanted to share my little rave here about my new purchase.

 

[Bass 45]

Yesterday I got my PF500 back from Field Services in Phoenix Arizona.

Just to review, I took the amp there after having a discussion with an Ampeg tech a few weeks ago. When I told him it was cutting out on me - he suggested I may need a more powerful amp. After I explained that I had never had this problem before while using other lower powered amps, he explained that tube amps and hybrid amps handle being pushed differently than solid state/class D amps - then he suggested I bring it to the repair facility to make sure "it was running up to spec".

Anyway, after testing at Field Services, they found nothing wrong. I have mixed feelings about this - but the end result is I like the amps tone and portability - but I cannot use it for every gig.

Most of the time it works fine for electric bass - but most of my gigs are without P.A. support and many of them I am playing Rockabilly and Irish Bodran rhythmic slap styles on the upright bass. The amp cuts out fairly often under this circumstance. I will continue to bring the SVT's to those gigs.

The amp has also cut out while I was playing electric (I mostly play a '68 Ampeg AMUB-1 bass which does not have a very hot pickup). I am certain the cutting has nothing to do with my technique. My main instrument is Classical Guitar and I play the electric bass with the same delicate technique (never pop and slap). I do have an affinity for playing with the eq low. I would say I usually have the bass knob around 2:00 and the Ultra Low on. This, combined with a fairly loud volume setting which is unsupported by the P.A. brings the PF500 very close to it's limits.

The bottom line: for $369.00 on sale - I think it is a fine value - and I love the cabs so I will be keeping mine for the gigs that it is suited for.

 

[ryanfenderbass]

Yesterday I got my PF500 back from Field Services in Phoenix Arizona.

Just to review, I took the amp there after having a discussion with an Ampeg tech a few weeks ago. When I told him it was cutting out on me - he suggested I may need a more powerful amp. After I explained that I had never had this problem before while using other lower powered amps, he explained that tube amps and hybrid amps handle being pushed differently than solid state/class D amps - then he suggested I bring it to the repair facility to make sure "it was running up to spec".

Anyway, after testing at Field Services, they found nothing wrong. I have mixed feelings about this - but the end result is I like the amps tone and portability - but I cannot use it for every gig.

Most of the time it works fine for electric bass - but most of my gigs are without P.A. support and many of them I am playing Rockabilly and Irish Bodran rhythmic slap styles on the upright bass. The amp cuts out fairly often under this circumstance. I will continue to bring the SVT's to those gigs.

The amp has also cut out while I was playing electric (I mostly play a '68 Ampeg AMUB-1 bass which does not have a very hot pickup). I am certain the cutting has nothing to do with my technique. My main instrument is Classical Guitar and I play the electric bass with the same delicate technique (never pop and slap). I do have an affinity for playing with the eq low. I would say I usually have the bass knob around 2:00 and the Ultra Low on. This, combined with a fairly loud volume setting which is unsupported by the P.A. brings the PF500 very close to it's limits.

The bottom line: for $369.00 on sale - I think it is a fine value - and I love the cabs so I will be keeping mine for the gigs that it is suited for.

Yeah man, we're on the same page here. Same experience/end result I had with Ampeg through my phone diagnosis. My technique can get a little aggressive at times, but like you, my setup is simple and my p'ups aren't hot. When I need to bring the beef, my 7PRO brings it. When I need to lay back in a small room, my PF500 does just fine (and gotta love the stow-away portability!).

 

[John D]

As far as I know, I have read every post in this chain of Ampeg PF350/500 threads. Because of the complaints about cutting out, I opted for the PF350 instead of the 500. I wish now that I had picked the 500. The comments in this forum have finally convinced me that there is nothing wrong with most of these amps. IMO the defective amps are the few that died completely and didn't come back. With very few exceptions, the PF500 owners who have commented in this thread have either never had a problem with their PF500, or they have had repeated problems with multiple PF500s. The law of averages just doesn't work that way. Honestly, I don't know of anyone who is that unlucky.

Those of you who are having problems are complaining that you should be able to drive your amp to full power, without it cutting out. How do you know that you aren't able to do so? Have you measured the output at the point where the amp started cutting out? Do you know when you are putting out 500W? After all, there is very little noticeable difference in perceived volume between 250W and 500W. If you have bench tested your amp and you know for a fact that it is cutting out before it reaches full power, please share your findings; I may change my mind. Virtually any new out of the box amp can be overdriven with any normal passive bass, if you set high levels of gain and volume while boosting the bass or slapping/popping the strings. The amps are designed this way so that you can reach full output with a low output instrument.

It's unfortunate that some people are unsatisfied with their purchase, and I sincerely sympathize with you. However, IMHO the only problem with these amps is the owner's expectations. Sorry, for the long rant, but to me, this is the only logical explanation. At least Bass 45 and ryanfenderbass are "getting it". YMMV, IMHO, IME, etc.

 

[pfschim]

if this view point is coming directly from the manufacturer, this is a pretty poor reflection on this gear. Is the PF500 500w @ 4 ohms or not ? There should not be any qualifications relating to the power section not being able to handle too much low end without the use of the compressor to choke it.

I have been reading through the PF350/500 thread because I am genuinely interested in giving this amp a try. But one of the reasons I am interested is that my current amp (Mesa Walkabout) is showing it's clean volume limits at the top of its power rating (300w @ 4 ohms/500w @ 2 ohms). So, if the PF series amps do not really deliver on their advertised specs, then I will probably look elsewhere.

 

[pfschim]

As far as I know, I have read every post in this chain of Ampeg PF350/500 threads. Because of the complaints about cutting out, I opted for the PF350 instead of the 500. I wish now that I had picked the 500. The comments in this forum have finally convinced me that there is nothing wrong with most of these amps. IMO the defective amps are the few that died completely and didn't come back. With very few exceptions, the PF500 owners who have commented in this thread have either never had a problem with their PF500, or they have had repeated problems with multiple PF500s. The law of averages just doesn't work that way. Honestly, I don't know of anyone who is that unlucky.

Those of you who are having problems are complaining that you should be able to drive your amp to full power, without it cutting out. How do you know that you aren't able to do so? Have you measured the output at the point where the amp started cutting out? Do you know when you are putting out 500W? After all, there is very little noticeable difference in perceived volume between 250W and 500W. If you have bench tested your amp and you know for a fact that it is cutting out before it reaches full power, please share your findings; I may change my mind. Virtually any new out of the box amp can be overdriven with any normal passive bass, if you set high levels of gain and volume while boosting the bass or slapping/popping the strings. The amps are designed this way so that you can reach full output with a low output instrument.

It's unfortunate that some people are unsatisfied with their purchase, and I sincerely sympathize with you. However, IMHO the only problem with these amps is the owner's expectations. Sorry, for the long rant, but to me, this is the only logical explanation. At least Bass 45 and ryanfenderbass are "getting it". YMMV, IMHO, IME, etc.

this is a very interesting POV.

so, if I understand you right, your saying it's the user expectations that are wrong. If they expected to be able to use their equipment at the upper end of its openly advertised power specs without it dropping out/cutting out, then its their expectations that are at fault, not the manufacturer or the gear itself ? Interesting.

As to your comment "there is very little noticeable difference in perceived volume between 250W and 500W" - while being factually true, there were multi page tirades here on TB when the TC RH450 amp was shown to only produce 238w (?) vs the expected 450 (per TC's advertised specs). So, people do rightly expect to get the full advertised capability of an amp without breaking up/cutting out.

I am not intending to enter into a flame war here. Per my prior post, my original interest in the PF series was driven by my growing need for more avail power (clean power at that). I also see that there are plenty of users who have had good experiences with the PF too. But it does seem to be reported that Loud is actually telling owners of the PF500 (in particular) that they can't use the amp at the outer end of its specs without issue and that seems wrong to me.

 

[John D]

this is a very interesting POV.

so, if I understand you right, your saying it's the user expectations that are wrong. If they expected to be able to use their equipment at the upper end of its openly advertised power specs without it dropping out/cutting out, then its their expectations that are at fault, not the manufacturer or the gear itself ? Interesting.

As to your comment "there is very little noticeable difference in perceived volume between 250W and 500W" - while being factually true, there were multi page tirades here on TB when the TC RH450 amp was shown to only produce 238w (?) vs the expected 450 (per TC's advertised specs). So, people do rightly expect to get the full advertised capability of an amp without breaking up/cutting out.

I am not intending to enter into a flame war here. Per my prior post, my original interest in the PF series was driven by my growing need for more avail power (clean power at that). I also see that there are plenty of users who have had good experiences with the PF too. But it does seem to be reported that Loud is actually telling owners of the PF500 (in particular) that they can't use the amp at the outer end of its specs without issue and that seems wrong to me.

Your first paragraph completely misses my point, and I never said anything that you suggested. I am merely saying that you were expecting more from the amp than you are getting. Further, it is your opinion that you should be getting more, yet you don't have any measured proof of what the amp is actually doing.

I will change my opinion when even one of you proves that you are not exceeding the published power specs of this amp, before it cuts out. I am not trying to start a flame war either. I am merely reviewing the reports in a logical manner and giving an unbiased opinion.

As for the TC issue, I did not read any of that thread, and I only know about it from mentions it received in the SVT 7 Pro thread. Regardless, my understanding is that no one complained about the TC amp until BGM reported their test findings. Anyway, TC has nothing to do with the PF500 issue.

I think we all want and deserve to, "...to get the full advertised capability of an amp without breaking up/cutting out. No one has denied that fact. The issue is that you have not given any indication that the amp does not produce its full/specified power output, other than your opinion. Truthfully, I would like to be proven wrong on this one. I would rather learn that Ampeg had identified a problem, recalled all the potentially defective amps, and modified them to meet their full specs. I hope you can get your issue resolved so that you can enjoy your amp.

Cheers,
JD

 

[pfschim]

I hope you can get your issue resolved so that you can enjoy your amp.

to be clear John D, I am not a PF series owner at the moment and so, have not had any issues with the amp myself. I was just checking into them to consider if I want to add a PF amp to my current available equipment.

I have also read most of the PF350/500 thread and keep coming across these cut-out/drop out issues being reported.

Seems to me that most of the folks reporting the issues are not ranting against the PF amps, and have contacted Ampeg for support. In some cases, as reported above, they have been given some interesting responses from Ampeg about their issues with the amps dropping out.

I am not sure where you are coming from when you say that "you [sic] have not given any indication that the amp does not produce its full/specified power output, other than your opinion." These issues are being reported by fellow TB members. Its not an opinion, it's a report of a real world, on the gig issue with the amp cutting out/dropping out when pushed.

I also realize that in any given set of manufactured items, there will be a percentage of bad/failed units. This is to be expected in mass manufacturing. OTOH, if Ampeg techs are telling people that they can't push both the volume and low end controls on this amp without using a certain level of compression to choke the levels, than that is a problem with the unit, and not with the user or their expectations.

I feel as if you ought to be able to dime every control on your equipment and have it work - not necessarily sound good, but not stop working either.

In any event, I may try one of these amps just to hear it in action, but I am not encouraged by some of the reports I am reading.

 

[GregT]

In all my playing years as a guitarist and bassist, I can't recall ever turning an amp up all the way other than just to see what it did. The last area on the volume knob has always seemed off limits to me. On most amps it has never delivered the tone I was looking for anyway turned all the way up. Even on my Fender Deluxe Reverbs, I rarely get past 4 or 4 1/2. If I needed a really loud Fender guitar tube amp, I'd have the Twin Reverb. I feel the same way about my PF500s. It isn't based on any facts or numbers though. I just like to get an amp up to its sweet spot. I know mine can go louder than I use them and I am certain that the time will come when I need to turn it up some. If I were playing a lot louder on a regular basis, I wouldn't use my PF500. I would still use the PF115HE cabinets though.

I did sell my Markbass Jeff Berlin after I got the Ampegs. I believe it was 350 watts also with one 15 inch speaker. As far as raw volume, there is no comparison. The Markbass could and did bury the PF500/115 for volume. I had them side by side so I feel it was a valid test. But, and this was the reason I sold the Markbass, the PF500/PF115HE left no doubt (to us) as to which had the better tone!! Plenty loud enough for what I use it for and it sounds great.

 

[pfschim]

In all my playing years as a guitarist and bassist, I can't recall ever turning an amp up all the way other than just to see what it did.

I do not do this either (usually sounds really bad). But I think you should be able to do it and have the amp actually work. Otherwise it should be considered something of a design flaw.

 

[GregT]

I do not do this either (usually sounds really bad). But I think you should be able to do it and have the amp actually work. Otherwise it should be considered something of a design flaw.

I agree wholeheartedly!

 

[PluckyThump]

The PF-500 is equipped with a limiter which should prevent the amp from exceeding its maximum output, regardless of what the user does with the knobs. The amp should not be cutting out except when it overheats, and the fault LED is supposed to light up when that happens. If the user asks more of the amp than what it can deliver that should show up as a lack of desired volume and/or very poor sound. Not as no sound at all!