Stereomour build question

[jwrossie]

I am building my stereomour at this moment. I got a question about the power supply PC board assembly, in the manual they talk about 1N4007 rectifiers and I got two UF4007 in my kit. Is it safe to use these?

 

[Doc B]

Yes, they are fine. In fact they are a little better than a standard 1n4007.

 

[jwrossie]

Yes, they are fine. In fact they are a little better than a standard 1n4007.

Thanks Doc!

 

[jwrossie]

I Finished my build!

I just did resistance check, all ok.

But between A1 en A4 I measure 2V AC instead of 2,5V AC (same for C1 and C4)
That's more than 10-15% , what to do?

All the voltages are all good to.

 

[Paul Joppa]

What is your power line voltage? Does your meter measure more accurately than 2 volts AC, such as 2.0 or 2.00 volts?

 

[jwrossie]

237 Volts is the measurement out of the powerline voltage.

And my meter gives 2.0 volts AC.

Is this a big problem? What do I need to hear/see/missing out with this 2.0 volts?

I am listening to the amp at the moment but it is playing fine.
The 2A3 tube don't light up, only the 12AT7 is visible lighting up, the 2A3's are getting warm though.

 

[Paul Birkeland]

I would imagine it's a meter issue.  At 2V AC, your DC voltages at pins 1 and 4 of the 4 pin sockets would drop noticeably. 

 

[jwrossie]

I think it is, my meter isn't a fluke but a cheap-ass one.

Just to be sure, here are my VDC measurements:
A1 58
A2 364
A3 0
A4 58

C1 57
C2 364
C3 0
C4 57

 

[Paul Joppa]

Those are just about perfect.

Many meters don't handle low AC voltages very well. Sometimes (not always!) the specifications have a hint buried in them somewhere.

 

[jwrossie]

Those are just about perfect.

Many meters don't handle low AC voltages very well. Sometimes (not always!) the specifications have a hint buried in them somewhere.

So if the VDC are 'just about' perfect it's assumeble the 2.0v AC must be 2.5v AC and the problem is my meter?

 

[Paul Birkeland]

So if the VDC are 'just about' perfect it's assumeble the 2.0v AC must be 2.5v AC and the problem is my meter?

Yes, at this point, that's a reasonable assumption.

 

[jwrossie]

So I borrowed a Fluke multimeter and the results are good  .

So my own multimeter has problems with measurements of low AC volts.
Paul you were right!

Thank you.

 

[Paul Joppa]

Thanks for posting, that was a valuable confirmation for us!