# Most failure prone amps



## nonreverb (Sep 19, 2006)

After reading and posting on a previous thread here regarding reliable amps, I'm going to ask the inverse question here. What amps are the most failure prone due to design and yes could include amps that for instance, run power tubes far too hot causing premature failure. I have 3 or 4 that come to mind but I'll let others chime in first.


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## GuitarsCanada (Dec 30, 2005)

There was a version of the Marshall DSL 401 that was notorious for running hot. Lot of people installed fans in them


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## hardasmum (Apr 23, 2008)

I always thought vintage AC30's were prone to failure because they ran so hot.


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## zdogma (Mar 21, 2006)

I have NEVER had to repair anything in my Carr or my Matchless amps. My Dr. Z was pretty solid too, its a 1998 model and other than a few microphonic ef86's/bad rectifier and a trip to nonreverb's house for a new power cord (cat chewed it).

I've had at least one breakdown with all my other amps.

My worst amp for reliability was a Soldano Astroverb, it sounded great when it was working, but it had tube socket issues, bad reverb circuit, loose wires, circuit board mounted tubes melting the circuit board, a whole bunch of problems. Odd cause my impression was that those amps are pretty bomb proof. I really think that the circuit board mounted EL84's were the problem with that amp. Close second was a Peavey classic 30.


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## WCGill (Mar 27, 2009)

I don't do repairs on a steady basis anymore which is a good thing as I hate working on the newer stuff. I find that circuit-board mounting of tube sockets (power mostly) and jacks leads to much grief. The tiny pots also are a source of trouble. As far as the older Fenders goes, the reverb 12AT7 was usually DOA. I've pretty much seen them all, not in large numbers though and these stand out.


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## TWRC (Apr 22, 2011)

Vintage AC30's are very prone to tube failure due to how hot they run. I had a tech install a 4"x4" fan at the bottom of my chassis to move the hot air through the vents and it seems to run less hot than your typical AC30. 



hardasmum said:


> I always thought vintage AC30's were prone to failure because they ran so hot.


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## zdogma (Mar 21, 2006)

TWRC said:


> Vintage AC30's are very prone to tube failure due to how hot they run. I had a tech install a 4"x4" fan at the bottom of my chassis to move the hot air through the vents and it seems to run less hot than your typical AC30.


You try these? http://www.thetubestore.com/Tubes/EL84-6BQ5-Tube-Types/Preferred-Series-7189-Premium-EL84

I put these in my old AC30 and my Matchless and not one tube failure in 2 years. They sound pretty much the same but seem to be a lot more durable.


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## keithb7 (Dec 28, 2006)

Most failure prone amps? Mint looking vintage closet queens , all stock with 50 or 60 year old parts. Darn it they always need repairs right from the day it is dropped off by the UPS guy. 

Seriously though in my experience, solid state Fenders that I once owned. Like the Princeton Chorus and Ultra Chorus. Pots on the front like the blackface design. However pots and jacks are hard wired on to the PCB. 
A few bumps? Broken.


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## Lincoln (Jun 2, 2008)

I used to know a guy that had a brand new Crate V something.......fairly recent. I believe about 18 watts, had tubes & 2 x 12's. I don't think he ever made it through a jam without it going "fizzle" or "sizzle" and then getting real quiet. He had it in for service so many times we lost track. It's gone now.


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## dtsaudio (Apr 15, 2009)

That would be the V33 or V18. 
Up until recently I was a service tech for Crate. That whole line had issues. If you blew a tube you blew the power supply.
The things have a switch mode supply that is just borderline.
The sad thing is they sound great when they work.
BTW if anybody owns one I have a fix for the power supply.


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## Intrepid (Oct 9, 2008)

GuitarsCanada said:


> There was a version of the Marshall DSL 401 that was notorious for running hot. Lot of people installed fans in them


I have one and installed a fan. No worries. Sounds great too.


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## LydianGuitars (Apr 18, 2013)

Intrepid said:


> I have one and installed a fan. No worries. Sounds great too.


and you should also install a properly spec'd bridge rectifier.


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## nonreverb (Sep 19, 2006)

dtsaudio said:


> That would be the V33 or V18.
> Up until recently I was a service tech for Crate. That whole line had issues. If you blew a tube you blew the power supply.
> The things have a switch mode supply that is just borderline.
> The sad thing is they sound great when they work.
> BTW if anybody owns one I have a fix for the power supply.


I don't think I've had the misfortune of working on one of those......yet.
There was one called the Crate Blue Voodoo series. It was possibly the worst tube amp I've had the displeasure of working on. One giant board littered with halo solder cracks and soldering them risked detaching the solder pad from the board...a nightmare.


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## dcole (Oct 8, 2008)

nonreverb said:


> I don't think I've had the misfortune of working on one of those......yet.
> There was one called the Crate Blue Voodoo series. It was possibly the worst tube amp I've had the displeasure of working on. One giant board littered with halo solder cracks and soldering them risked detaching the solder pad from the board...a nightmare.


Some PCB's are terrible for detaching solder pads. Fender's Blues Junior and their ilk are terrible for this. Thin PCB's mixed with thin traces leave a terrible setup for lifting traces and it doesn't help that lots of people want these amps modded. I had a friend bring one in that he wanted reverted to stock. The guy that modded it was supposedly a professional and there was lifted traces all over the place. I have honed my skills at repairing PCB amps mostly because of these little guys. You can get components off without lifting traces if you go at it correctly. So in my opinion Fender's PCB amps are terrible as a reliability stance as they can be a bugger to repair and use small PCB mounted pots and jacks. There is no flexibility in the system so stuff can crack and break.

On the flip side, I have worked on a Blackheart 100 watt head that used a super thick PCB with wide traces and each hole was platted through so there is a very solid connection point at each hole. Its hard to lift a trace on this amp which makes it easier for repair and being more robust in general due to its larger size. So good reliable PCB amps can be had but its hard to tell if time isn't in the equation.


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## nonreverb (Sep 19, 2006)

I hear ya . I've modded/repaired more Blues Jr's than I care to admit. The concept of mounting power tube sockets on a pc board and then inverting the tube so all the heat goes directly up into the solder joints is IMO a reckless design. Halo cracks on the tube sockets are an all too common problem. Pair that with the EL84's running way too hot and the danger that the first contact to desolder being the bias and you see the problem. I've had these things come in with the power board burnt to the point where the board is useless.
They finally partially got the drift when they beefed up the solder joints on the power board although they still refuse to put a bias adjust in them....sigh....oh well, keeps me busy I guess.



dcole said:


> Some PCB's are terrible for detaching solder pads. Fender's Blues Junior and their ilk are terrible for this. Thin PCB's mixed with thin traces leave a terrible setup for lifting traces and it doesn't help that lots of people want these amps modded. I had a friend bring one in that he wanted reverted to stock. The guy that modded it was supposedly a professional and there was lifted traces all over the place. I have honed my skills at repairing PCB amps mostly because of these little guys. You can get components off without lifting traces if you go at it correctly. So in my opinion Fender's PCB amps are terrible as a reliability stance as they can be a bugger to repair and use small PCB mounted pots and jacks. There is no flexibility in the system so stuff can crack and break.
> 
> On the flip side, I have worked on a Blackheart 100 watt head that used a super thick PCB with wide traces and each hole was platted through so there is a very solid connection point at each hole. Its hard to lift a trace on this amp which makes it easier for repair and being more robust in general due to its larger size. So good reliable PCB amps can be had but its hard to tell if time isn't in the equation.


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## TB72 (Apr 19, 2010)

Having played a lot of festivals with provided backline, my vote goes to the Fender Hot Rod series (Devilles and Deluxes).

I know since these amps are so plentiful, you're bound to see more broken ones, but still... I've seen enough of these amps fail (be it on myself, band mates, or other bands), that I now look upon them with great prejudice.


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## zdogma (Mar 21, 2006)

TB72 said:


> Having played a lot of festivals with provided backline, my vote goes to the Fender Hot Rod series (Devilles and Deluxes).
> 
> I know since these amps are so plentiful, you're bound to see more broken ones, but still... I've seen enough of these amps fail (be it on myself, band mates, or other bands), that I now look upon them with great prejudice.


Too bad really, the Deville is quite a decent sounding amp.


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## Jim DaddyO (Mar 20, 2009)

I had an original Peavey Classic 30 and I have heard they run hot also. But mine hung in there like a trooper and always sounded good. Who ever I sold it to got a great amp with not many hours on it.


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## TB72 (Apr 19, 2010)

zdogma said:


> Too bad really, the Deville is quite a decent sounding amp.


Yeah, they can be. I even owned one for a time...had several issues with that one as well.

But the mistrust has gotten into my head, and I can't shake it.


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## Wild Bill (May 3, 2006)

All amps can develop problems, although it is also true that some develop a lot more than others. I agree with all the reports about Crates, Blues Deluxe/Deville/whatevers and older Peaveys with their cheap printed circuit boards.

However, there is another question that goes hand in hand with the topic of this thread - which amps cost more to repair?

This is the sort of thing the salesman at the store NEVER tells a buyer, even if he knows! While the amp is new you have a warranty but what happens when the warranty is over?

As Fender now has got the Chinese building most of their models this caused a problem for warranty repairs. Standard parts like resistors and capacitors are not a problem but what about custom things like a slider pot? These are always custom to the amp. Fender buys production volumes and in the old days if a tech needed one he could phone up the lady in Michigan and she would just "steal" one from the production inventory. Now that all the inventory is in China she can't do that anymore. Worse yet, the Chinese refuse to send her just one! They insist on sending complete boards, which of course are very expensive compared to the cost of just the one part.

Fender's solution was to make a "Do not fix - replace only!" list for warranty on Chinese models. Here's how it works. You buy a Fender amp made in China. If it has problems you take it back to the store and the salesguy checks it out and then tells you "Gee, the factory are such nice guys that they say just give you a whole new amp!"

Wow! You go home impressed. Then one day, the warranty has expired. You go back to the store and the salesguy comes out from the back and politely tells you "Sorry! It's out of warranty! We can't fix it! Buy another amp!"

So you take it to a private tech and he gives you the sorry truth - he can't source a custom part so he can't fix it either.

This of course won't happen with amps not made in China but they are getting rare from the big traditional amp names. This is part of the reason for so many new boutique amps on the market, built on this side of the ocean with parts that are easy to get. You might pay a bit more in the beginning but you save it over the life of the amp.

Pretty well any modern amp with a printed circuit board takes a bit longer to repair than the old vintage handwired BlackFace amps, Traynors, HiWatts and the earlier Marshalls. Marshall JCM800's aren't too bad. The board is simpler and mods aren't usually all that hard to do. Anything newer can be a bitch and slow a tech down, which means more labour hours on your bill.

Those old vintage amps are a breeze to make deep mods compared to modern circuit board amps. There is no reason why they may last another 50 years, or more! They will always be repairable.

One of the most expensive for repairs are Boogers. The old ones aren't bad but once they went to the Rectifier series their circuit boards became a densely packed jungle! They do things like stack a half dozen little relays like coins with epoxy and then bring their wires out and down to the board like a spider web. Of course, if one blows its always the one on the bottom.

I have American tech friends that tell me they double their shop labour rate for Boogers, because their blood pressure goes up so high while they are cursing trying to work on a Booger circuit board that they need more money for meds!

Others just say fuk it and post a sign. Right under where it says "No Stairway to Heaven" it says "No Boogers!". They figure the business is not worth it.

I find most if not all of the boutique amps are very well build and very easy to work on. Dr. Z makes a beautiful amp from a tech's viewpoint, for one.

So if you are going to buy an amp, it is probably just if not more important to know what it might cost you for service AFTER the warranty as it is to know which amps are failure prone in the first place.

With those BluesDeluxe series, I've found that the circuit boards are so thin and cheap that not only do you have to be extremely careful not to burn or lift the traces but also when the amp gets to be a few years past warranty some of those solder points can go bad, causing aggravating crackling noises. Finding the culprits is a big PITA and besides, fix a few and in a few months you have a few more new ones. I had one so bad that when placed on my rug you would hear crackling as my cat walked in front of it! It was just that sensitive. A proper fix involves taking out the boards (always time consuming) and reheating every solder point you can see! This shotgun method usually fixes things up but in another 8 or 10 years it will likely come back again.

Most players only think about how that new amp sounds and then how much will it cost to take it home. After warranty repair costs are always an unpleasant surprise. A bit of research up front, even if it means paying a few dollars more will likely save you a LOT more money as the years go by! I tell my customers to give me a call if they are looking at an amp, new or used. Often I can give them some useful info. Any tech who values his customers would cheerfully do the same.

Wild Bill/Busen Amps


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