Stage Line 500W amp repair project

[WHONOES]

Looks interesting. If it's a free download then give it a try. If it's not what you want you can uninstall it and you have lost nothing.

Have a go!!

 

[bikemech]

I have downloaded it already, thats it on my laptop, thinking i can butcher a pair of headphones with a mic to make some leads, i am guessing it would only be 1 input chanel that the mic would normally use, any ideas on that ?

 

[bikemech]

Also has a sig gen built in that seems to work ok, i wonder if i could use the ear piece lead as the sig gen

 

[bikemech]

So sig gen set to 1000Hz, MIC reads 1000Hz, seems to work well so far

 

[bertus]

Hello,

Have a look at the specs of your sound card.
The circuit in post #429 has 5 V zeners to limit the output, but that may be to high for the sound card.

Bertus

 

[bikemech]

Hello,

Have a look at the specs of your sound card.
The circuit in post #429 has 5 V zeners to limit the output, but that may be to high for the sound card.

Bertus

I have no idea how i would find that out, i do understand there has to be some protection/current limit for the input on the MIC side, is that what that circuit was for in post #492 ?

Pete

 

[bertus]

Hello,

I have the number wrong, it is post #479.
It is made by Wendy (william before his transition).
Does the card have a line input?
That can handle more than a MIC input.

Bertus

 

[bikemech]

Hello,

I have the number wrong, it is post #479.
It is made by Wendy (william before his transition).
Does the card have a line input?
That can handle more than a MIC input.

Bertus

Hi, all it has is a headphone socket, but also works headpbones with a MIC if that helps,

Pete

 

[bertus]

Hello,

Is it the input of a laptop?
Wich brand and type is it?

Bertus

 

[bikemech]

Hello,

Is it the input of a laptop?
Wich brand and type is it?

Bertus

Yes it is , its a HP 250 G6, no other markings on it,

Pete

 

[WHONOES]

I assume the input to your sound card is via a 2.5 or 3.5mm jack. Ideally you would use some screened cable to make up and input lead.
Another alternative would be to use a BNC to 2.5mm jack plug that you can plug into your sound card and then you can use a regular scope lead with attenuators. See link below. You may be able to use them for the Sig Gen as well.

Pack of 5 BNC Female Jack to 2.5mm Plug RF Coax Adapter: Amazon.co.uk: Computers & Accessories

 

[bikemech]

I assume the input to your sound card is via a 2.5 or 3.5mm jack. Ideally you would use some screened cable to make up and input lead.
Another alternative would be to use a BNC to 2.5mm jack plug that you can plug into your sound card and then you can use a regular scope lead with attenuators. See link below. You may be able to use them for the Sig Gen as well.

Pack of 5 BNC Female Jack to 2.5mm Plug RF Coax Adapter: Amazon.co.uk: Computers & Accessories

Ahhhh, fantastic idea !!!, thanks @WHONOES i will look into that, would be much easier, would i still need some form of protection circuit so as not to overload the sound card, or is this built into the probes ?

Pete

 

[bikemech]

Just looked, that may not be possible, the BNC only has 2 points of contact, my headphone with MIC has 4,

Pete

 

[bikemech]

 

[WHONOES]

The probes will have attenuators in them. You can get them with 10:1, 100:1 or 100:1 all usually switchable between straight through and attenuated. If you can find some relatively cheap ones then buy a selection, it will save having to cobble together and calibrate your own.
It would also make sense to find out the input conditions of your sound card. If it is just a Mic I/P then it is probably quite sensitive. Some have Mic and Line I/P's.

 

[bikemech]

Could this be used then split into 2 BNC for standard probes ?

https://www.ebay.co.uk/i/1534487783...TABbm-Sm_fSrG8U1B_ZWNhsgOBn5k_0BoCvokQAvD_BwE

 

[WHONOES]

Ok. Just seen you Pics. Does make thing a bit more difficult. I suspect you would need to separate the input and output into 2 distinct circuits. You could break it out into a small Plastic or Ali' box with 2 BNC sockets in it.
I assume the Sig Gen is output via the headphone O/P?

 

[WHONOES]

Just seen you suggestion in #496. I think you would be better off sorting out which wires are which and going the route described in #497.
You also have to consider keeping the input screened which is best achieved as described.

 

[bikemech]

Ok. Just seen you Pics. Does make thing a bit more difficult. I suspect you would need to separate the input and output into 2 distinct circuits. You could break it out into a small Plastic or Ali' box with 2 BNC sockets in it.
I assume the Sig Gen is output via the headphone O/P?

Yes it is, sig gen output is via the LH earphone

 

[bikemech]

Would these work ok ?

https://www.ebay.co.uk/itm/193816364564