Second PF-500 Burnt-Out Last Night.......

[okcrum]

I was always taught that tripping the protection circuitry was cockpit error, in every other branch of electronics I've been in.

Smoke is one thing. A harsh limiter in an economy class D power amp design is quite another, and should surprise no one. Anyone here ever heard an iNuke clip?

That said, I've had no problems with my PF500s, both from early batches.

 

[arai]

Arai, we could just let this thing go, or we could continue with this circular firing squad, which ever you prefer. I vote for letting it go. What do you say?

Yes please, as long as you start reading my posts for what they are and stop making stuff up.

 

[jmattbassplaya]

Personally, I always found the PF heads to be on the more 'economic' side of bass amplifiers. I had one die on me (a 500) in GC when I was test driving it quietly in the bass room. That turned me off from them immediately, even though I was considering getting one at the time. I picked up an Aguilar TH500 instead and it has been as solid as a rock. Hell, the darn thing flipped 8 times in my truck with me and has been working perfectly since then (almost a year later ).

 

[Troph]

First point: No one in this thread has mentioned the 7 Pro, to my knowledge.

Well, I certainly don't see why it hurts to bring in some points from Ampeg Class D threads. FWIW, both the PF500 and SVT-7Pro use the same preamp circuit supposedly (and I would bet a few other shared design elements). In my experience, similar designs tend to behave (and fail) in similar ways.

But you are right, no one has done a scientific poll of the exact symptoms/issues encountered. And what people describe as "cutting out" differs greatly between players.

A high volume manufacturer can produce thousands of units in a single production run. The first company I worked for produced around 800 TV sets per day on each of at least five assembly lines. I personally performed overnight burn in and one-week life testing on samples of each of these assembly lines, as well as 500-hour burn in tests that were conducted at 40 degrees C and high humidity. I assure you very few sets left the factory with defects that we did not know about. No doubt, some defective units slipped through the cracks, but, even so, we consistently ran defect rates below 3%, and that was when solid-state TV technology was in its infancy.

With all due respect, your experiences at this unrelated TV manufacturer may bear little or no resemblance to the QA process at Ampeg.

Even if your assumptions are correct and they perform sufficient line sampling, what if the series of sample tests they perform don't happen to cover the conditions which led to the failures experienced by users? In the computer world, we refer to these as test holes, and every test system has them. What input signal ranges? What speaker loads? How many power cycles? If any of those miss realistic player conditions, then a design flaw for instance could easily remain latent/undetected across multiple HW revisions until finally addressed after user-escalated complaints.

TalkBass users are overall pretty gear-savvy and make good testers for the most part. We should try to be supportive of folks who report problems. It's fine to offer constructive suggestions. But lots of people around here seem more interested in defending the reputation of their favorite gear...

 

[jumblemind]

Yes please, as long as you start reading my posts for what they are and stop making stuff up.

+1

 

[jumblemind]

With G-K you get more than what you pay for

Not to pile on, but in response to people who say it's all due to the Class D tech and will never use Class D: When I had the PF experiences and found myself ampless for a gig while waiting on a new Aguilar to show up, I picked up a GK MB200. I did two club gigs with it, one in which I had it nearly dimed for four hours carrying a 4ohm load. It never hesitated and was barely warm to the touch at the end of the gigs.

Anecdotal? Admittedly. And I wouldn't make a habit of this at all, but it shows that a well-engineered, economical (nearly a C note cheaper than a MicroVR!) Class D micro can hang.

 

[KJung]

Not to pile on, but in response to people who say it's all due to the Class D tech and will never use Class D: When I had the PF experiences and found myself ampless for a gig while waiting on a new Aguilar to show up, I picked up a GK MB200. I did two club gigs with it, one in which I had it nearly dimed for four hours carrying a 4ohm load. It never hesitated and was barely warm to the touch at the end of the gigs.

Anecdotal? Admittedly. And I wouldn't make a habit of this at all, but it shows that a well-engineered, economical (nearly a C note cheaper than a MicroVR!) Class D micro can hang.

+1 Been gigging class D amps for over 20 years now, almost exclusively. Just like any other technology, some are good and some have issues. It has nothing to do with the 'type of power amp'. This particular Ampeg has had some issues, as have some of the GK models (they seem to have that sorted out finally). However, Aguilar, Glockenklang, Genz Benz, Markbass all seem very solid, and have had no significant, reoccurring and/or systematic issues.

To your point, one should not 'throw the baby out with the bathwater' just because a particular brand or particular product has some quality or design execution issues IMO!

 

[Back2Bass]

Got my PF-500 more than a year ago. I had one instance of it cutting out at a gig but got through it just after I got it. Had it checked put no problems found. Was it something unique to that venue? Been back 5 times never had it happen again. I have been using it ever since with no problems. I rehearse 2 times a week and do shows most every weekend the regular 9 to1 or 10-2 run it through 1x15 and 4X10 cabs(I know, but I like it) either stand alone or Di to board. Plenty of power and love the sound.

Guess I got a good one.

Ampeg Feel free to contact me. lol

 

[coreyfyfe]

It never hesitated and was barely warm to the touch at the end of the gigs.

For what it's worth, I've had this experience with my PF-500. I've run that amp through all kinds of different cabs and gigging and rehearsal situations. I've had the PF-500 carrying the room in 100+ person packed venues through a 2x10 and it's been loud enough.

Anecdotal evidence is just that.

I'll also add my cover band had problems with class D amps in our powered PA speakers/subs from a few different makers.

 

[Stealth Fighter]

Well, I certainly don't see why it hurts to bring in some points from Ampeg Class D threads. FWIW, both the PF500 and SVT-7Pro use the same preamp circuit supposedly (and I would bet a few other shared design elements). In my experience, similar designs tend to behave (and fail) in similar ways.

But you are right, no one has done a scientific poll of the exact symptoms/issues encountered. And what people describe as "cutting out" differs greatly between players.


With all due respect, your experiences at this unrelated TV manufacturer may bear little or no resemblance to the QA process at Ampeg.

Even if your assumptions are correct and they perform sufficient line sampling, what if the series of sample tests they perform don't happen to cover the conditions which led to the failures experienced by users? In the computer world, we refer to these as test holes, and every test system has them. What input signal ranges? What speaker loads? How many power cycles? If any of those miss realistic player conditions, then a design flaw for instance could easily remain latent/undetected across multiple HW revisions until finally addressed after user-escalated complaints.

TalkBass users are overall pretty gear-savvy and make good testers for the most part. We should try to be supportive of folks who report problems. It's fine to offer constructive suggestions. But lots of people around here seem more interested in defending the reputation of their favorite gear...

Since you are so knowledgeable about Ampeg's QA process, is it possible that you work for Ampeg? If so, please enlighten us. I doubt that you have any more insight to the inner workings at Ampeg than most TB members. I, too, have worked in the quality/reliability department for a computer manufacturer, which, by the way, is no more similar to building audio amps than TV manufacturing is. Further, I am well aware of potential shortcomings in normal QA testing methods and the so-called "test holes" you mention. Additionally, I have experience in Amp repair for a Peavey dealer, FWIW. All of that coupled with your experiences and opinions just makes us too guys on the Internet who happen to share opposing views, nothing more and nothing less. I do agree, "TalkBass users are overall pretty gear-savvy and make good testers for the most part." However, some of the comments I read on TB lead me to believe that the posters have very little if any knowledge or understanding of how amps work. YMMV.

I still stand by my original premise that it goes against logic to assign all of the reported PF series amp failures to poor design or manufacturing practices, without examining the possibility of operator error, at the very least. If you chose to defy logic, that is your prerogative. For your information, I am not some fan boy of Ampeg, and have only recently become an Ampeg user. Even so, as I mentioned earlier, I have paid fewer that $0.41/day to own and enjoy my PF-350. It does what it does well and it pleases me. That makes me a happy camper.

John

 

[lomo]

it goes against logic to assign all of the reported PF series amp failures to poor design or manufacturing practices, without examining the possibility of operator error, at the very least.

John

I don't see user error accounting for unusually high failure rates in any other bass amplifiers???

Some amps have more than their fair share of issues (early GK MB series and Mesa M9s come to mind), regardless of "type".

 

[aborgman]

I think they said the failure rate was only around 3-5%.

On a consumer product of this type, an "out the door to the customer" failure rate of 3-5% is astronomical.

I mean REALLY, REALLY high.

 

[Russell L]

By now I am convinced that I will never own one.

 

[bassguppy]

I just feel sad for all the PF owners who've had issues with the amp. It's great sounding if Ampeg is your thing. I purchased mine soon after they were released brand spankin' new and its been a solid performer running at both 8 and 4 ohms. Never an issue.

 

[Jheake]

I never had any "cutting out" issues with mine either. That said I did sell it only a few months after I bought it, but only because it lacked headroom. I now own a PF-800.

I sympathize with the gents on TB that have had problems for sure. That can be so frustrating. I had a Rev A Svt7pro that did that to me. I moved on from it, and came back to it around Rev C and the problem was gone. I still like my PF800 better than the 7Pro.

I can see why guys hate on Ampeg though. They are (to me) the Fender of Bass Amplification (in terms of being the biggest company, not their business practices) So its easy to defend the little guys and pick on the bigger company's.

I mean I watched a vid from NAMM where one of the Ampeg Reps said they sold like 12k PF-500s in the first 2 years. Thats astounding to say the least.

Dont get me wrong I am not defending anyone in this situation, I find it interesting and unfortunate that all these folks are having problems, no matter the cause. It just plain stinks.

Just in case anyone thinks I pulling numbers out of the air here is a link to the video. He starts talking about the PF-500 at 6:20 or so.

 

[bassguppy]

I mean I watched a vid from NAMM where one of the Ampeg Reps said they sold like 12k PF-500s in the first 2 years. Thats astounding to say the least.

12K is insane. I would have thought maybe 1/4 of that.

 

[B-string]

You think that's insane you should see JimmyM's house and garage Just Kidding

 

[Stealth Fighter]

You think that's insane you should JimmyM's house and garage Just Kidding

That's funny, but it's getting closer to the truth every day. Next up is the b-15 heritage.

 

[JimmyM]

I wish! Nah, I think the HSVT and the black Precision is about it for me and major purchases for a very long time. I know this because my wife said, "The HSVT and the black Precision is about it for you and major purchases for a very long time." But to her credit, she did say to keep the old SVT. Of course, her motivation was to let it appreciate in value for the next 20 years, but whatever...works for me.

But if my PF350 ever breaks down out of warranty (coming up soon), I'll get another the next day. For me it's been a total champ and gets louder than I'll ever need.

 

[johnpbass]

I wish! Nah, I think the HSVT and the black Precision is about it for me and major purchases for a very long time.

Until the V4B comes out...