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 NEW  Matt presents bias and operation data for the 6V6 tube in SE operation - 6V6 Single-Ended (SE) Ultra Linear (UL) Bias Optimization.

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It is currently 20 Nov 2019, 05:33

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 Post subject: Forewatt psu
PostPosted: 06 Nov 2019, 15:07 
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Joined: 11 Sep 2019, 10:56
Posts: 13
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


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 Post subject: Re: Forewatt psu
PostPosted: 06 Nov 2019, 15:13 
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Joined: 11 Sep 2019, 10:56
Posts: 13
I should have said the psu isn't connected up to the signal circuit yet.


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 Post subject: Re: Forewatt psu
PostPosted: 06 Nov 2019, 19:28 
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Joined: 06 Apr 2009, 10:08
Posts: 1594
Location: US Pacific Northwest
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.

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 Post subject: Re: Forewatt psu
PostPosted: 07 Nov 2019, 12:10 
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Joined: 11 Sep 2019, 10:56
Posts: 13
Thanks Matt

I'll finish connecting it all up and check again

Rog


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 Post subject: Re: Forewatt psu
PostPosted: 13 Nov 2019, 21:30 
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Joined: 04 Jun 2008, 20:59
Posts: 4050
Location: Arizona, USA
Hi, like already noted....voltage values are with the tubes in place.

Good listening
Bruce

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