What to do after i finish recap?

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rg12

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Joined 2010
#1
Hello
I just finished recapping my whole amp and then i saw a thread in another forum about testing using a bulb and pmv (dunno what it is).

What is a PMV? what is that test with the bulb?

I just connected my amp to the whole system after every few caps that i replaced to make sure everything is fine and thats it.

Did i do something wrong? do i need to let it play for a while? i replaced more than 30 caps!
 
#2
It's a Poor Man's Variac. Use a power strip and install power box to install light bulbs. You start with a low watt bulb hook amp up to it. If it glows bright you have a short. Then just keep stepping up the bulb watts.
 
#5
If everything is fine you don't need it.

It's a useful tool when repairing amps as any fault (such as output transistors conducting heavily) will light the bulb, which limits the overall current saving any disasters such as blowing transistors.
 
#6
So why does the bulb need to be changed every time to higher watt?

Is there such thing as breaking in the amp after recap? i heard something
about playing music for a few hours or something...is there anything true to this?
 
#7
rg12 said:
So why does the bulb need to be changed every time to higher watt?

Is there such thing as breaking in the amp after recap? i heard something
about playing music for a few hours or something...is there anything true to this?
Click to expand...

A 60 or 100 watt bulb is usually all that's needed, personally I'd never work my way up in wattage... you know if the thing is OK,

Break in... again personally no... it doesn't happen. Silicon, as in IC's and transistors doesn't change, neither do resistors. Caps do change slightly (electroylitics) when first used but it all settles down very quickly... seconds only... as the cap "forms".

Others will disagree I know.
SY had a brilliant answer,
http://www.diyaudio.com/forums/digital-source/171998-op-amp-swapping.html#post2283818
 
#9
For other users:
If the bulb lights brightly then something is shorted or mis-wired inside the unit. (with no audio signal at the input)
You start with a low wattage bulb, to limit damage is something is bad.
Later you may use a high wattage bulb with high level audio signals.
 
#12
rg12 said:
Banned? i can't imagine a good reason for such a stupid decision...
Click to expand...

Not stupid, it's just not thought through.

Energy saving lamps give the same light output for around one fifth the consumption, trouble is they are no good for dimmers or some triac controlled switching applications.

So yes, stock up if you use them.
 
#14
oshifis said:
100 Watt light bulbs are banned in the European Union 🙁 It's time to conserve a stock over there until it's too late...
Click to expand...

Why, who uses 100 W bulbs anyway (for the normal purpose which is to light a room etc. ) ? I don't like things to be banned but 100W bulbs produce way too much heat for normal armatures and they are too bright too. Most armatures accept 60W max.With the current energy prices using 100W bulbs in a normal household will give an unsatisfying feeling when the electricity bill comes in...

LED lighting is very promising at the moment. It took some years but now they are to be compared with normal bulbs. They consume much less power but the amount of light cannot be fully compared with bulbs (yet). Way more reliable than halogen or any other form of electrical lighting and more pleasing for human eyes too. Still like HID lighting though 🙂
 
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