Hello , Ive recently had a noise out of this amp. Without a guitar plugged in it makes a noise. I will descibe the sound which may have some humor.It sounds like a ticking or farting sound and then like a zooooooot sound. then it will quit and repeat the process.It does it on any channel or manual switch, pre-set,etc!!!Can anyone help a struggling muscian out on this probelm. Any help will be a great help. Thanks adv
:o
How often? Any chance of a sound sample? All gains/volumes at zero, all tone/EQ at 12o'clock.
If the amp has an FX Send and Return try plugging a jumper lead across these two and see if it makes a difference.
Hello, Thanks for the response.I went ahead and did what you said to do. Heres what happen when I jumped the return and send.The sound got louder and I can put my hand on top of the left side of the amp and a pronouce flange sound comes out of the vent on top of the amp.When i first plugged in and powered up it took about 3 mins. for it to make the noise.I have already reset the amp to factory settings.(No change).Im just wondering if a tube could be at fault or a IC going bad.Once it starts making the noise after warm up, The noise is constant( Like a loop).Even though I set the gains , master at zero or on ten and the eqs on 5 it still does the same thing.I have to go to work now so I will read my post tonight. Thanks again for your help.I really appreciate your response. ADV
Well I read a review, and oh dear, its got a silicon Fx wunderbox. So I went for a look with no real hope in my heart - and got lucky straight away (find service manual attached).
If you can bring this one together with another amp that also has an Fx loop you can try cross-patching them, i.e. Fx Send on one to Fx Return on the other, and this way you can determine if the problem in yours is in the output stage or, more likely, in the preamp (and it sounds most likely in the internal effects unit).
You can check that the supply voltages are correct and getting to the Fx unit, that all internal connectors are properly seated, and the IC themselves too if they/any are socketed.
PS - it looks like all signals go through the A/D-D/A conversion. :-\ The manual shows how to enter test mode but gives no details of what to expect. ???
Look in the owner manual for reinitialize or restore factory settings. Try it.
Hello Roly, I thank you for the service manual.Our computor has been down, Im just now getting a chance to reply.Do you know if that was for the 2 channel or the 4 channel. Mine is the 2. I will figure that out looking at the schematic. Im a newbie to the solid state amp scene so I may have to ask more question.LOL! I have tried re-setting to factory settings.( no change) I put another ax-7 in it, took awhile for it to start acting up again. Maybe that original tube has some issues as well. I think that 1981 super champ i have has a send and return on it. I will try out what you said.Well Im going to start lookig at the scematic so once again thanks, adv
Even as a tech I'd find your amp a bit daunting since it basically converts the input signal into a digital stream which is then operated on by its computer before being converted back to analogue. This makes it a bloody nightmare to service, HOWEVER since removing and replacing the 12AX7 made some change to the fault it is possible that it could simply be the valve/tube making poor contact with its socket, something very common in valve/tube amps. I therefore suggest that you try scrubbing the connector contacts by working the 12AX7 in and out a few times. If its not something simple like this, as a newbie I don't think you have much chance of servicing this amp - sorry. :(
ANother couple years, and I will have been soldering for 60 years. I got into guitar amps and such about 45 years ago. I have run a pro audio repair facility for over 25 years now. I am an experienced professional. And I absolutely HATE working on Vox Valvetronix stuff. My best wishes to the novice who wants to wade into one.
Thanks Enzo and Roly,,, that tells me I'm not going nuts when (as a novice)
I bork at working in that kind of equipment.
I get lucky with some stuff, often just bad connections but when it's terminal digital most of it is way beyond the novice.
Which is why I stick to analog simple Systems.
@ ADV,,, I was almost sucked into the Valtronics stuff but one simple A/b test and I dropped the idea fast,, IMO,, they are nothing like a real Guitar Amp.
Phil.
Nah; ever since I first got an eyeful of the Fender Cybertron (or somesuch?) as somebody who has built microprocessor-based systems for industry my first thought was "Who/how is going to fix it when it breaks?"
I'm often dealing with valve/tube amps that are 50 years old and still very repairable, but I'm also dealing with modern digital stuff of all sorts that use in-house and application-specific IC's that were literally unrepairable even when brand new. It's totally uneconomic to even take the back off for a look, and it gets worse from there. :duh
You know that the repair depot would simply have swapped the brain module, and once its more than a year old you can't even get that done.
You walk in to a repair shop (or Dick Smith) and ask for a "NEC D720101GJ/0340EPA12" 80-pin SMD* and may wonder why they fall over laughing. Even specialist suppliers like Wagners don't carry spare parts at this level. (* a real multi-USB controller)
So with these "Wunderboxes" you are generally a long way up a well known waterway in an unseaworthy vessel with no means of propulsion. xP
Hello, I thank all of you for your experience and input.y es, I agree that its above my knowledge to even try to work on this type of amp and I would take it to an experience person.I have tried to reset to factory settings and I went ahead and cleand and lubed any thing and every thing.I have noticed though that the noise gets louder when I turn up the wattage on the back of the amp. I went to trusty you tube and found were other people have the same probelm with thier vox.One peron freeze sprayed a IC and had some luck with it I think he said it was the final amp near a heat sink???? I know you get what you pay for.I didnt pay much. Ive made a few dollars with it so its all good. I just dont want to have to pay more to repair it than I payed for it .Well I need to get back to ,As the amp turns. Thanks again. adv
Hello,I tried crossing FX with another amp and the noise came through that amp also. So It must be in the pre-amp stage.Hell, I feel sorry for the people that have to assemble this amp in the first place. On youtube,under vox probelms or vox siren noise there is a sample of a amp doing almost what mine is doing, The helocopter is the same, but the siren sound on my amp is not as prominent. That is if anyone wants a sample of sound. Thanks ADV
Quote from: adv on September 24, 2012, 01:33:04 PM
Hello,I tried crossing FX with another amp and the noise came through that amp also. So It must be in the pre-amp stage.Hell, I feel sorry for the people that have to assemble this amp in the first place. On youtube,under vox probelms or vox siren noise there is a sample of a amp doing almost what mine is doing, The helocopter is the same, but the siren sound on my amp is not as prominent. That is if anyone wants a sample of sound. Thanks ADV
Sounds like it's time to build your own preamp and bypass the "fancy" one Vox used. Power amp, PSU and speaker should all be fine as is and you'd have a decent amp again.
Quote from: joecool85 on September 24, 2012, 02:25:32 PM
Quote from: adv on September 24, 2012, 01:33:04 PM
Hello,I tried crossing FX with another amp and the noise came through that amp also. So It must be in the pre-amp stage.Hell, I feel sorry for the people that have to assemble this amp in the first place. On youtube,under vox probelms or vox siren noise there is a sample of a amp doing almost what mine is doing, The helocopter is the same, but the siren sound on my amp is not as prominent. That is if anyone wants a sample of sound. Thanks ADV
Sounds like it's time to build your own preamp and bypass the "fancy" one Vox used. Power amp, PSU and speaker should all be fine as is and you'd have a decent amp again.
:dbtu:
@adv - could you post the link to the YT example please?
adv said:
QuoteHell, I feel sorry for the people that have to assemble this amp in the first place.
Don't worry that much, *this* is the "people" who builds such amps:
http://youtu.be/OO0c_PKDw7g
And this is the one who "hand solders" what can't be wave soldered:
http://youtu.be/AIwF1Hg65mg
Bye, I'm going to watch again my collection of "Terminator" movies.
I want to get used to the day when Machines Rule the Earth.
(A few years at most).
Hello Roly, Thanks for the response.
http://www.youtube.com/watch?v=loSllHtY9q0 This is close to what mine is doing but just the opposite in sound noise. Mine is the helocopter 1st and then a slight siren noise not as prominent as this amp on y/t. P.s. Turn your sound down this guitar player will rattle your brains. Thanks adv
http://www.youtube.com/watch?v=loSllHtY9q0 Hello Roly this is similar to what my amp is acting like, the hellocopter sound first then a slight siren noise not as prominent as in this vid though. ADV
Hoooo Boy, that's the worst case of whatever it is I've ever heard. :duh
Seriously 'tho, that's not analogue so forget the suggestions written below the vid about cleaning connectors and broken valves - that has one serious digital headache. It's not two sounds but one, a software loop that starts off short and gets longer, sliding rapidly down in frequency until you get the "helicopter" putt-putt. Even if I had the circuit of the digital effects area it would still be mainly guesswork, and it's not just out of your class, it's out of ours too.
What I can say is that it seems to be a generic failure, a common failure in older Vox's, but it could be anything from a surface mounted device coming unsoldered to an internal silicon failure. I am certainly not advising you do this, but if I really had to try and fix this one thing to try would be removing the whole Fx PCB and putting it through a solder reflow oven, but this is almost certainly not going to be practical.
It could be as simple as requiring new electrolytic caps in the power supply, but that's a pretty long shot.
As a generic I expect that Vox knows all about it, 'tho they may not admit it, but if you talk to their service department, reference the vid, you may get lucky and get a definite answer and a proposed fix (like buy a whole new PCB costing lebenty-leben dollars). Sorry to be pessimistic, but I've been watching this one coming down the turnpike for a couple of decades now.
All I can suggest is that you e-mail Vox's service department and see what they have to say. :(
Go for it. But I have to say about generic faults, they may be aware that some 100-pin LSI chip has weak solder, but each of those 100 pins will have a different effect upon the operation of the amp. It won;t be like pin 47 is always what comes loose. And a lot of problems are caused by lead-free solder. It grows "tin whiskers" which can cause shorts to adjacent parts, and they can be ANYWHERE, so knowing you may have tin whiskers doesn;t really help narrow down the location. Wish I had better news.
Hello, Thanks be to all with your in put. Man that robot was 21st century.LOL!After reading that I should build my own pre-amp. Sounds like a plan.Would it be possible to gut this ss amp and build a good tube amp out of that chassis and cab? What could I salvage off of it that would interact with atube amp? I think i will do some home work and investigate another alternative. Once again I do thank you all for your experience and advice. ADV :dbtu:
I'd keep the SS amp if possible, or build a simple new one fed from its salvaged PSU and if possible attached to its heatsink.
I mean, that thing is *optimized* for SS !!!
And would feel *very* free to experiment with the preamp.
Post a couple gut pictures.
Voxman almost lynched me over on the Valvetronix site for raising the same concern about digital amps and digital equipment in general some years ago. But the longevity of digital circuits really is their main problem. Once it goes, it goes. We can prolong their life by hoarding amps, and swap circuit boards and that will keep us going for a while, but eventually we will run out of functional boards. This is also a major concern in respect to digital synthesizers. I own an Ensoniq TS-12 packed with specialized chips, and I know that one will go too eventually. In the synth area, things started to get problematic about the time the DX7 was launched.
This is really a shame, because my AD120VTH head sounds incredibly good. Vox did a really good job on the models in this amp.
But my trusty 1964 AC30 will live forever. So will my 1967 Vox Conqueror solid state. And my MiniMoog. And my Hammond organs.
Or any 100/150 years old piano :dbtu:
A DX-7 is "my main man", so I'm keeping my fingers crossed. My general experience with Yammy electronics is that they are pretty solid.
A friend has an Ensoniq ESQ-1 sampling synth which was a lovely instrument but has a pretty crappy 3.5 inch 360kB disk drive, and when you couldn't buy 360kb disks any more...
If I could get my claws on it today I'd consider trying to knock up something like an Arduino as a fake FDD-to-SD card, or similar. I think it was Z-80 based, while my E-MU Proteus/1 has a 68000 inside, so you at least have some idea of what you are dealing with; but when it's an in-house anono-chip... :-\
Maybe that amp is trying to send a fax somewhere?? I recently had an AD30VT amp where luckily the speaker was the only thing bad. I decided to look in the amp just out of curiosity and pulling off the knobs loosened/cracked a couple pots. So I now have to take the whole thing apart... :trouble
The stems pulled right out of the pots and I had to replace them, but they had legs that bent around. Very proprietary pots and so I clipped off the legs. I soldered the legs onto replacement pots, and that was actually fun. Like a MacGyver repair technique that this amp really deserves. So I got the thing all patched up and working. Sold that amp and now I don't think I will ever touch one ever again.
Playing the amp the decay of the strings was vibrating in some sort DSP way that just kills my heart. For loud playing the amp is ok. If you have any level of dynamics to your music then these amps do not do justice at lower dynamic playing level.
Quote from: Roly on October 05, 2012, 01:17:25 AM
A DX-7 is "my main man", so I'm keeping my fingers crossed. My general experience with Yammy electronics is that they are pretty solid.
Me too. I have two original DX7, and a TX802. I once had a TX7, but it literally went up in smoke at a gig.
Quote from: Roly on October 05, 2012, 01:17:25 AMA friend has an Ensoniq ESQ-1 sampling synth which was a lovely instrument but has a pretty crappy 3.5 inch 360kB disk drive, and when you couldn't buy 360kb disks any more...
Ensoniq were particularly fond of custom chips, making them particularly hard to repair. Floppy drives don't make things easier.
Quote from: Roly on October 05, 2012, 01:17:25 AMIf I could get my claws on it today I'd consider trying to knock up something like an Arduino as a fake FDD-to-SD card, or similar. I think it was Z-80 based, while my E-MU Proteus/1 has a 68000 inside, so you at least have some idea of what you are dealing with; but when it's an in-house anono-chip... :-\
Actually a really good idea! While I still had a functioning floppy drive, I took all my old Macintosh OS7-8-9 floppies and transferred the contents into images on my present HD. You can have a lot of floppies on a modern HD! The idea is to make them available to a virtual OS9 machine some day.
A similar thing could be done with the Ensoniq floppies. But as far as I remember, you need a special DOS-program to even read those discs and control the drive. But, if you overcome that problem, then using something like Arduino to present the machine with a virtualisation of the floppies is a really good idea.
So why do I hijack the thread to talk about this? Because, maybe a similar hi-tech type approach is the future of rescuing our DSP-based amps. If we can get a future electronic device - similar to the Arduino, but likely more powerful of course - to simulate the software running the Vox amp simulations, then maybe we would be able to virtualise the Vox software, and repair these amps with replacement boards made of such general purpose template boards. A good idea in fact!
/Frank
Quote from: Frank
Playing the amp the decay of the strings was vibrating in some sort DSP way that just kills my heart. For loud playing the amp is ok. If you have any level of dynamics to your music then these amps do not do justice at lower dynamic playing level.
A kind of step-wise granularity? This reminds me of a project I did with the original AY-series "toot-bang-whistle" chip that only had 8-bit amplitude control. Sounded okay up high, but at the tail of a decay it sounded like it was falling down a flight of stairs - bumpbump bump bump bump ...
Spotted a TX-7 in a junk shop a while back and was sorely tempted, but they were asking far too much for it, even if the cassette interface is still a proposition. Left it a couple of months and went back to make them an offer they would be silly to refuse, but it had gone.
I've just bought a little Arduino-based thing called a
LeoStick (http://www.freetronics.com/products/leostick), and while I once did a truckload of F-8, 6800, Z-80, and CP/M, I'm not quite sure why (apart from the fact that they are only $A30).
I wouldn't be afraid of trying to reverse engineer the OS ROM's from an ESQ-1 if I had one, but unless it turns up scratching at the door (which is possible but pretty damn unlikely) then it's all a bit theoretical. But as a general concept for gear that is up the beach due to unobtainium (e.g. Boss DM-1 with a dead Reticon CCD/BBD) it's certainly an approach worth keeping in mind.