Soldato
Sometimes if the the centre tap of the secondaries isn't grounded properly you get all sports of strange things going on...
*** The DIY Audio Thread ***
- Thread starter -Ad-
- Start date
Soldato
As in, earthed? I might have to try that...
edit: misunderstood I think, I thought you meant the bolt through the middle of the transformer.
Soldato
mike that's a beaut...what's the power output on that?
Soldato
p4radox, what transformer set up does the amp10 use? is it dual secondaries or center tapped. Make sure to check the ceramic coating is stripped from the secondary cable of the transformer if there are grounding issues. What are the voltages like before the rectifier and after. Is the fuse the supplied and appropriate for the uk, i know my lm3886 requires a differant fuse for operation here in the uk, here it needs a 2A slow blow and in the US it needs a 3A standard but not sure what the 41HZ kits require.
Soldato
Erm...
The transformer has dual secondaries. I'm only using one.
I'm still not really clear what constitutes a "grounding issue". Why would there be ceramic coating? It looks like tinned wire ends.
No idea, I've been turning the thing off straight away when my "bulb fuse" in series wit the primary glows very brightly.
A 500mA slow blow is recommended for testing unfortunately I only had 3 250mA fast blow fuses to hand. I wired them in parallel... and they all blew...
Thanks for the replies
Soldato
Post some photos of your wiring, transformer, amp terminals and other bits. The transformer secondaries are fine with tinned ends, some do not come with this and you have to remove the coating on them and tin them yourself. The coating is to stop the many windings of copper wre shorting on each other.
Looking at the pcb for the AMP10 you should be using both your secondaries on your transformer, the AMP10 takes a plus and minus rail to function, each secodnarie powers each rail or you can use a single trafo for each rail. If you are using 2 trafos in your set up then your ok but if you have a single trafo your missing a rail. Gets some pics up as it will help greatly!
Fat blow may be no good, some amps have a surge at strt up, its only for a split second but its enough to blow the fuse if it isnt sufficient, the circuitry will be built to handle this but the fuse will need to be picked specificly with this in mind, if the surge lasts longer than usual then the fuse will blow, if it is only short then the fuse compensates. You really need some slow blows. Get down to the local high street electronics store, there something like £1.50.
Looking at the pcb for the AMP10 you should be using both your secondaries on your transformer, the AMP10 takes a plus and minus rail to function, each secodnarie powers each rail or you can use a single trafo for each rail. If you are using 2 trafos in your set up then your ok but if you have a single trafo your missing a rail. Gets some pics up as it will help greatly!
Fat blow may be no good, some amps have a surge at strt up, its only for a split second but its enough to blow the fuse if it isnt sufficient, the circuitry will be built to handle this but the fuse will need to be picked specificly with this in mind, if the surge lasts longer than usual then the fuse will blow, if it is only short then the fuse compensates. You really need some slow blows. Get down to the local high street electronics store, there something like £1.50.
Last edited:
Soldato
Thanks for your reply again damian. From what you're saying, I must be doing something embarrassingly wrong! Here's how I've got it wired:
How do I use each secondary winding for each rail?
How do I use each secondary winding for each rail?
Soldato
the terminals of the amp voltage inputs, do they have two holes for wire or one sinlge hole
Soldato
should do the trick 
you may have blown your regulator or may not but the way the trafo is wired you did indeed have grounding issues, the as the rail was not earth because the earth was on the other rail. Easy mistake to make
This is presuming that each terminal onm the pcb has two seperate slots on were each wire can go un effected byt the other, im finding it hard to make out from the pictures on the site, get some pics up before you do anything if you can!
you may have blown your regulator or may not but the way the trafo is wired you did indeed have grounding issues, the as the rail was not earth because the earth was on the other rail. Easy mistake to make
This is presuming that each terminal onm the pcb has two seperate slots on were each wire can go un effected byt the other, im finding it hard to make out from the pictures on the site, get some pics up before you do anything if you can!
Last edited:
Soldato
Right, well I can blame the godawful instructions for that one then. The entire dual hole jumper is simply labeled as "transformer input for + rail".
I suppose I could have really done with a bit more knowledge on how a rectifier actually works, but the way you've posted it does appear to make sense.
I suppose I could have really done with a bit more knowledge on how a rectifier actually works, but the way you've posted it does appear to make sense.
Soldato
ok found some pics up on the site of the terminals, this is definatly the correct wiring, only thing that it will depend on is the transformer and the layout of the secondries, ie what wires go with what for each secondrie ( this must be correct) it should state on the side of the trafo though you should have this rite anyway. This should no doubt solve your problems and nice its only a quick rewire aswell! doesnt matter which secondrie runs wich rail as long as there paird properly with there respective 0. Post back with results
Soldato
Okay, rewired and ready to retest. I have a nasty feeling one of the rectifiers is fried, but if this looks okay I'll give it a shot anyway:
Soldato
Spot on Love the ghetto wiring, looks like something right out of my portfolio!!!
Where did you purchase the traffo?
Love the ghetto wiring, looks like something right out of my portfolio!!!Where did you purchase the traffo?
Last edited:
Soldato
Still sweet **** all. Light bulb lights up brightly, which I'm fairly sure it shouldn't after the caps have charged so I switched it off straight away.
The transformer was from that shop that means "quick". Probably a competitor in some respect. It weighs a bout 4kg
The transformer was from that shop that means "quick". Probably a competitor in some respect. It weighs a bout 4kg
Last edited:
Soldato
Is you primary wired correctly, take a snap of the side were the sticker is for me, the web sites close up is pure tripe! Hve you measured the secondries on you trafo to double check the output?
Just realised something, the bulb will stay lit constantly, its before the amp in the cuircuit so its going to be constantly fed with mains supply. if there is a problem it absorbs the extra current and it should blow so your proberbly safe mate and overly concerned, your cuircuit is proberbly fine
Just realised something, the bulb will stay lit constantly, its before the amp in the cuircuit so its going to be constantly fed with mains supply. if there is a problem it absorbs the extra current and it should blow so your proberbly safe mate and overly concerned, your cuircuit is proberbly fine
Last edited:
Soldato
I have:
Live -> bulb -> brown -> violet -> grey -> Blue -> neutral
Soldato
There's a solid 31V AC on the secondaries when open-circuited.
Soldato
Yes its all wired fine, are the fusing blowing now? if not id say your good to go, the bulb will stay lit, is it any brighter than if it was in a light fitting on the ceiling?
Soldato
No, it's about as bright as you'd expect really. I'd just read this on 41Hz forums:
thomaseliot said:
Soldato
Best way to tell, ill grab a bulb from my living room and wire it to my working lm3886! give me 5