Two new Vox amps both with major issues within two years

acd1687

Member
Messages
5
My wife bought be me an AC15C1 as a wedding gift two years ago. The following February I bought an AC4tv-mini as an at home practice amp. Now two years later both have what seem to be pretty major issues. The AC4 cuts out when at or over half volume and the AC15 doesn't make any sound as of a week and a half ago. From what I've read it sounds like the output transformer on the AC4 would need to be replaced (basically the same price as replacing the amp) and the AC15 needs to have a section of capacitors replaced that cause the fuses to blow due to not having the proper voltage rating.
When I reached out to Vox customer support the only response was to take both amps to an authorized repair shop at my cost. Basically they offered me a phone number.
I understand that warranties don't last forever but to have two different amps from the same company need repairs that are more than just maintenance is pretty bad.
I had wanted a Vox for a long time and am now regretting buying one. They sounded great when they worked but a two year life before requiring serious repairs is kind of a joke.
I apologize if this is the wrong place to post this but maybe someone can offer some advice.
 

sliberty

Member
Messages
4,111
It certainly would frustrate me too. Unfortunately, these days, many amps are made in far away countries using less than the highest quality parts. This allows them to be sold cheaply, but repairs don't figure well into that equation. If you spent $2000 on an amp and needed a $150 repair, it would seem like no big deal. But when you spend $150 on an amp, that $150 repair no lomger makes any sense. My advice is to fix the AC15 and replace the AC4. Not what you want to hear, but it's the best path forward I think.
 

manishthapa

Member
Messages
39
VOXAC10C1 gone bad...... any help would be useful.......
Belated but happy healthy successful new year to all.
Issue my 4 month old Vox AC10C1 is giving out a very very low scratchy (fatrty very low) sound ..........so I changed both power to JJ EL84 and pre amp to tung sol 12ax7 tubes. The sound remains the same. Could some one please suggest what other areas I have to look into. I believe it a very vague question, to be honest I have taken all precautions to stay safe to do what I did. This was a used amp I bought of online. Working perfectly fine......... i did maybe 3-4 gigs on it.........any suggestions would help before I take it to a authorized dealer who is quite far from where insaty.
 

lkft

Member
Messages
1,294
VOXAC10C1 gone bad...... any help would be useful.......
Belated but happy healthy successful new year to all.
Issue my 4 month old Vox AC10C1 is giving out a very very low scratchy (fatrty very low) sound ..........so I changed both power to JJ EL84 and pre amp to tung sol 12ax7 tubes. The sound remains the same. Could some one please suggest what other areas I have to look into. I believe it a very vague question, to be honest I have taken all precautions to stay safe to do what I did. This was a used amp I bought of online. Working perfectly fine......... i did maybe 3-4 gigs on it.........any suggestions would help before I take it to a authorized dealer who is quite far from where insaty.
Although you're issue is certainly related to the OP's issue it should be a whole new thread so as to not derail the OP's thread. :aok
 

sliberty

Member
Messages
4,111
VOXAC10C1 gone bad...... any help would be useful.......
Belated but happy healthy successful new year to all.
Issue my 4 month old Vox AC10C1 is giving out a very very low scratchy (fatrty very low) sound ..........so I changed both power to JJ EL84 and pre amp to tung sol 12ax7 tubes. The sound remains the same. Could some one please suggest what other areas I have to look into. I believe it a very vague question, to be honest I have taken all precautions to stay safe to do what I did. This was a used amp I bought of online. Working perfectly fine......... i did maybe 3-4 gigs on it.........any suggestions would help before I take it to a authorized dealer who is quite far from where insaty.

Just to clarify, are you saying that the sound is low volume and scratchy / farty all of the time? Try connecting to a different cabinet to rule in / out a bad speaker. if thats not it, although it seems really soon for this, it might be some bad filter caps. Maybe Vox simply used crappy ones, or they were defective. Changing filter caps is not a hard job in general, but you will have to remove the boards from the chassis since they are soldered on underneath. Also be aware that filter caps store energy by their nature. That means extra precautions need to be taken to avoid being shocked in the process. If you don't know how todo this, it might be better to take the amp to a tech.
 

WillLane

Member
Messages
2,670
My wife bought be me an AC15C1 as a wedding gift two years ago. The following February I bought an AC4tv-mini as an at home practice amp. Now two years later both have what seem to be pretty major issues. The AC4 cuts out when at or over half volume and the AC15 doesn't make any sound as of a week and a half ago. From what I've read it sounds like the output transformer on the AC4 would need to be replaced (basically the same price as replacing the amp) and the AC15 needs to have a section of capacitors replaced that cause the fuses to blow due to not having the proper voltage rating.
Long post ahead.

Tube Amps break down and have issues. SS amps do sometimes as well, but I think part of the responsibility of having the great tone of a tube amp is knowing the basics of how to work on the amp yourself, rather than having to take the amp to a tech every time it acts up. Neither of your issues are for sure properly diagnosed to be as severe as you are suggestion, I will get to that in a second. But with a company that moves as much product as VOX, there are bound to be issues. It does stink you have been burned twice. I do not think it is all attributed to shoddy build quality, although for sure some of it is the "cheaper" nature of the amps- but really, it is just sadly the luck of the draw. :(

You look at Fender as well- they move so much product that there are bound to be amps that have issues. JJ tubes are so popular because they are cheap- but there are a lot of failure rates compared to other companies. But they likely move more product than other companies. Bugera moves a lot of product as well- and although they really are a spotty brand IMO, their massive amount of failure reports, compared to other companies, are in part due to just the massive amount of product they sell compared to other companies. And really the high-cost of tube amp repair is not always because the fixes are that difficult, but that many techs cost by the hour and those hourly rates are high. Just a simple internal fuse replacement can take much longer than you would expect depending upon the amps' construction. And yes, filter caps can contain lethal voltages even with the amp off and unplugged. Knowing how to properly drain them and work around them is another reason why we pay techs so high.

About the AC15: Have you visually inspected the tubes? If the amp is ON (pilot lights on, which means the mains fuse is fine) but the tubes are not LIT, that may just mean the heater fuse (internal fuse) has blown and you could try replacing it with the exact same fuse. Check that fuse for continuity and if it does not have continuity, replace it and try the amp again. If it works, then good! If it does not work (fuse blows again) then professional tech time. If the heater fuse is intact but the tubes are not lighting, tech time. If the heaters are on but still no sound from the amp, check the HT fuse (internal) and check it for continuity. Then repeat the processes for the possible outcomes listed above. If the pilot lights themselves are not on, check the mains (external) fuse.

It may also be just that your tubes (either a preamp, all the preamps, or the power tubes) are very dead. AC's run their power tubes hot, what I have researched is that the general user should change them out every 6 months, with normal gigging use, to be safe. If you had a New-Sensor tube in V2 (Tungsol RI, Mullard RI and some others), the Cathode Follower role of that position could put too much stress on the tube and could have caused it to cease its function. Put a normal JJ 12AX7 in there and see if that helps.

About the AC4: I would just simply replace the power tube first and if that does not work try the preamp tube. If neither of those are the solution, tech time. Having a spare set of known-good tubes on hand is smart because many tube amp problems are just tube failure. Also be sure you are not moving your amps a lot while they are hot, which will damage the tubes.


VOXAC10C1 gone bad...... any help would be useful.......
Belated but happy healthy successful new year to all. Issue my 4 month old Vox AC10C1 is giving out a very very low scratchy (fatrty very low) sound ..........so I changed both power to JJ EL84 and pre amp to tung sol 12ax7 tubes. The sound remains the same. Could some one please suggest what other areas I have to look into. I believe it a very vague question, to be honest I have taken all precautions to stay safe to do what I did. This was a used amp I bought of online. Working perfectly fine......... i did maybe 3-4 gigs on it.........any suggestions would help before I take it to a authorized dealer who is quite far from where insaty.
+1 to check the speaker separately or to try a different speaker. Also check the solder connections on the tone pots (particularly the bass pot).
 

manishthapa

Member
Messages
39
Although you're issue is certainly related to the OP's issue it should be a whole new thread so as to not derail the OP's thread. :aok
ABsolutly agree, plead pardon my lack of knowledge. . I will in deed try to start a new thread.
 

manishthapa

Member
Messages
39
Long post ahead.

Tube Amps break down and have issues. SS amps do sometimes as well, but I think part of the responsibility of having the great tone of a tube amp is knowing the basics of how to work on the amp yourself, rather than having to take the amp to a tech every time it acts up. Neither of your issues are for sure properly diagnosed to be as severe as you are suggestion, I will get to that in a second. But with a company that moves as much product as VOX, there are bound to be issues. It does stink you have been burned twice. I do not think it is all attributed to shoddy build quality, although for sure some of it is the "cheaper" nature of the amps- but really, it is just sadly the luck of the draw. :(

You look at Fender as well- they move so much product that there are bound to be amps that have issues. JJ tubes are so popular because they are cheap- but there are a lot of failure rates compared to other companies. But they likely move more product than other companies. Bugera moves a lot of product as well- and although they really are a spotty brand IMO, their massive amount of failure reports, compared to other companies, are in part due to just the massive amount of product they sell compared to other companies. And really the high-cost of tube amp repair is not always because the fixes are that difficult, but that many techs cost by the hour and those hourly rates are high. Just a simple internal fuse replacement can take much longer than you would expect depending upon the amps' construction. And yes, filter caps can contain lethal voltages even with the amp off and unplugged. Knowing how to properly drain them and work around them is another reason why we pay techs so high.

About the AC15: Have you visually inspected the tubes? If the amp is ON (pilot lights on, which means the mains fuse is fine) but the tubes are not LIT, that may just mean the heater fuse (internal fuse) has blown and you could try replacing it with the exact same fuse. Check that fuse for continuity and if it does not have continuity, replace it and try the amp again. If it works, then good! If it does not work (fuse blows again) then professional tech time. If the heater fuse is intact but the tubes are not lighting, tech time. If the heaters are on but still no sound from the amp, check the HT fuse (internal) and check it for continuity. Then repeat the processes for the possible outcomes listed above. If the pilot lights themselves are not on, check the mains (external) fuse.

It may also be just that your tubes (either a preamp, all the preamps, or the power tubes) are very dead. AC's run their power tubes hot, what I have researched is that the general user should change them out every 6 months, with normal gigging use, to be safe. If you had a New-Sensor tube in V2 (Tungsol RI, Mullard RI and some others), the Cathode Follower role of that position could put too much stress on the tube and could have caused it to cease its function. Put a normal JJ 12AX7 in there and see if that helps.

About the AC4: I would just simply replace the power tube first and if that does not work try the preamp tube. If neither of those are the solution, tech time. Having a spare set of known-good tubes on hand is smart because many tube amp problems are just tube failure. Also be sure you are not moving your amps a lot while they are hot, which will damage the tubes.


+1 to check the speaker separately or to try a different speaker. Also check the solder connections on the tone pots (particularly the bass pot).
Yes of all the knobs bass and gain were the most effected( they turned out to be the most disturbing ones) if that makes any sense
 

WillLane

Member
Messages
2,670
Yes of all the knobs bass and gain were the most effected( they turned out to be the most disturbing ones) if that makes any sense


Oh, that poor AC10. :cry:

What I am saying is to check the actual solder connections of the internal potentiometer. The connections may be loose or otherwise just bad causing a bad connection. What you would be hearing is the current just barely making it through the bad connection. Also be sure your input cable is fine and the input jack of the amp is clean. Get some electrical contact cleaner and give it a spray to be sure.

However just changing tubes is a pretty safe procedure as you are not really having to contact the amp internals, but checking pot connections would require you to drain the filter caps to be safe. If you are not comfortable doing that and working around high voltages, please just take the amp to a tech and save your heart.
 
Last edited:

Axe-Man

Member
Messages
7,982
It's a bummer but remember this is a very cheap, made in Asia to the lowest price point amp with a single sided PCB and tube sockets on the PCB.

It should last for a while (longer than just 2 years) but let's be honest, it's just not made to last.

A dual sided PCB with decent traces is a long term amp but they cost a lot more.

Take them to a reputable tech and go from there. It might be simply better to buy another amp second hand but it might just be tubes and/or a resister etc...it'll still cost for the tech time though.

For the cost of those two amps you could buy a hand wired AC15 and get a reverb pedal. That is a proper long term prospect if you love the Vox sound.
 




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