DIY Audio Projects Forum
http://www.diyaudioprojects.com/Forum/

Forewatt psu
http://www.diyaudioprojects.com/Forum/viewtopic.php?f=9&t=6644
Page 1 of 1

Author:  Rog63 [ 06 Nov 2019, 15:07 ]
Post subject:  Forewatt psu

Hi,

Just testing the psu for my Forewatt build before installing it. I'm getting 299Vdc on the B+ after the 3k3 resistor and 93Vdc at the join to the heater psu. Input from the transformer is 220VAC. My circuit checks out with the diagram. Any thoughts as to why both B+ sides are so high? I haven't got the 10uF caps in yet.

Rog

Author:  Rog63 [ 06 Nov 2019, 15:13 ]
Post subject:  Re: Forewatt psu

I should have said the psu isn't connected up to the signal circuit yet.

Author:  Suncalc [ 06 Nov 2019, 19:28 ]
Post subject:  Re: Forewatt psu

Rog63 wrote:
... the psu isn't connected up to the signal circuit yet.
This is why the voltage is high. No load means that you're charging the caps to near the peak value of the sine wave.

In this case, 220 V-rms * 1.414 = 308V. So, you're not quite to the peak but very close (within 3%). The B+ should look much more reasonable with a load on the circuit.

Author:  Rog63 [ 07 Nov 2019, 12:10 ]
Post subject:  Re: Forewatt psu

Thanks Matt

I'll finish connecting it all up and check again

Rog

Author:  gofar99 [ 13 Nov 2019, 21:30 ]
Post subject:  Re: Forewatt psu

Hi, like already noted....voltage values are with the tubes in place.

Good listening
Bruce

Page 1 of 1 All times are UTC - 6 hours [ DST ]
Powered by phpBB® Forum Software © phpBB Group
http://www.phpbb.com/