NAD: It's here! AFD100 in the house!

[Dmoney]

I'd imagine the steps in power are arranged in a way that would make it really hard for you to get bang on half way between.

I'm not sure it is, as I reckon that's the issue....

does this problem happen wherever you set the power level though? Like every time you set it, eventually you get this issue. Indicating that every time you dial it in you hit a half way point?
I'm just speculating because I'm interested.

As for input voltage, I wouldn't have thought it would vary by much more than +/- 20VAC? I've seen a small UPS used in a hotel to run a server that generated a input voltage graph against time. I had a friend who used one in his house as a power conditioner because his TSL kept needing repairs and it was another thing to try and fix it. He thought he had too much input AC.

You can get bias modulating tremolo effects. I was wondering if something like that might be going on.

[ToneMonkey]

Interesting point though - I don't have a way to measure the voltage coming out of the wall. Anyway the problem is random - day, evening - any old time. I'm not happy to use the amp at a gig though. Which makes the whole thing start to look a bit pointless unless someone can say categorically that the problem is <this> and we've done <this> to fix it.

Give me four grand and I'll get the whole neigbourhood studied for you.  I can tell you short term and long term voltage flicker, harmonic levels (which could actually be an issue with amps), all sorts really  :lol:.  When I'm seeing the boffin next, I'll see if harmonics could be affecting the amps.  Does the problem happen at consistant times?

Dmoney - Fairly sure that the UK is now 230V (+10% - 5%).  It used to be 240V (+5% - 5%) but we changed it to be in line with Europe....... as you can see, we didn't actually do anything, just fiddled the numbers a bit  :D

[Dmoney]

I was just going off that UPS I used to see. I couldn't remember what the peak was but I was just thinking 240v was average and 20volts either side of that seemed reasonable from memory. 240 + 5% is 252... so I wasn't far off  :)

[Twinfan]

does this problem happen wherever you set the power level though? Like every time you set it, eventually you get this issue. Indicating that every time you dial it in you hit a half way point?
I'm just speculating because I'm interested.

Nope - there seems to be a particular point on mine around 8:30 to 9:00 on the dial, which is home TV levels.  It only seems to happen on the quiter setting, so maybe it's one particular point that it's easy to get stuck halfway on?

[purpleplexi]

Are you using it at house level - i.e. in the 8.30 - 9 area? It's happened to me anywhere between fully down - 7 o clock and 9 o clock which is the next 'step'. If it's playing up it's really loud at 9 o clock even though that's supposed to be 1 watt. Like much too loud to use in the house. I know Marshall watts are bigger but...

When I got it back I was playing it at 9 o clock and it went from loud-ish to almost inaudible. I kept playing in the hope that something would break and identify itself but it came up again then went really loud and nasty sounding. That was the last time I used it.

I found a study that someone had done of power fluctuations in the national grid over a period of a week and they weren't very much. Average 230v which is right on the money, occasional short spikes up to 240 max and very occasional lows of 226 I think. Lost it now. I doubt that's it.

Twinfan on your youtube clip where have you got the master and the power control?

[Twinfan]

On that clip, power is about 9:00 and master around 6-7 I think - that's my usual home setting.  It's been really stable there recently, but it has been awful on that setting.

It's a really odd issue isn't it?  if mine starts playing up again, I'll certainly be mentioning the fact that I'm not the only one!

[ToneMonkey]

I found a study that someone had done of power fluctuations in the national grid over a period of a week and they weren't very much. Average 230v which is right on the money, occasional short spikes up to 240 max and very occasional lows of 226 I think. Lost it now. I doubt that's it.

It very much depends where you live and what's connected to your local network.  If you have a lot of industry on the same circuit (any of them from 66kV down really) then the issues can be quite apparent.  There are planning and compatability levels for voltage flicker and harmonics etc which should always be adhered to by industrial users, but this isn't always the case as they can often buy a new machine and plug it in without realising that it's a disturbing load.  This causes things to go what is technically described as "tits up"  :lol:

Personally I think it sounds like an issue with the amp(s) rather than the supply as the above happening for three different people is highly unlikely.  I'm still going to ask the boffins though as I'm curious more than anything else (although they cost over £150 an hour - each  :o, so it will have to wait until I have a meeting about something else).

As someone suggested (quite rightly) in another thread, have you tried kicking it?

[purpleplexi]

There's no industry in the area. I haven't kicked it yet but.......

[keith]

I haven't kicked it yet but.......

maybe this should apply to someone at Marshall

[Oli]

At Marshall, they probably have the same procedure for dealing with issues as we have at the company I work for (pro audio). There is a standard bench test which tests out the functionality of the amp, and if it passes this, it is deemed as 'working', as it meets the predefined standards set for the product. Unfortunately, these tests sometimes don't catch anything (ie, we have a product where a control is tested at it's maximum and minimum values.... but I've had one returned which were within tolerance, but the value in the middle was way out of spec)... i'm sure it's something like this, where on the bench it works fine, but when used in a 'real world' situation, there is something amiss. I'm sure that Marshall will take more notice when the same amp returns again-- especially on a limited run of units.

[Twinfan]

They claimed they play tested mine quite a bit, not just a bench test.  Mine was playing up a bit tonight but then sorted itself out.

I'm way confused  :?

[Dmoney]

Get it back there Dave. Maybe even get it shipped via Sounds Great and email Marshall direct with your serial number saying that you know other people having the same problem, and If it comes back faulty again then obviously it's going to upset you, but If it happens to other people It's going to reflect badly on Marshall, maybe even effect sales of the YJM.

I dunno. I don't mean hold them to ransom with threats of trolling ( ? ) or whatever... I'm sure you get what I mean. A gentle nudge.

By rights you're now entitled to a full refund, since the repair job isn't up to scratch, but I can tell you'd rather have a working amp.

[Alex]

On a new amp I'm pretty sure they would have to give you the money back if it keeps having problems. UK law says no, but EU says yes to that. It is a bit tricky though and will take some convincing. Still, by now that is probably what I'd go for: return it.

[Dmoney]

On a new amp I'm pretty sure they would have to give you the money back if it keeps having problems. UK law says no, but EU says yes to that. It is a bit tricky though and will take some convincing. Still, by now that is probably what I'd go for: return it.

I thought UK law said yes. At least it did when I checked with CAB over Sounds Great outsourcing a repair job on my Soldano which came back to me messed up.
The supplier (whoever that is) get one shot at fixing it or replacing it, and if it doesn't work then you are entitled to a full refund. In this case that would come from Sounds Great. You can't keep on being forced to take poor repair job, after poor repair job.

[Denim n Leather]

you got handed a lemon. Get your money back or a full credit. That thing is dogsh*t.