lowering bias range
Moderators: pompeiisneaks, Colossal
lowering bias range
Hello, for an Express bias circuit how would I lower the bias range? This particular schematic has 100ks for the two bias resistors in the PI.Thanks!
Re: lowering bias range
You would raise the value of the 47K resistor that is connected to the bias trim pot.
Tom
Don't let that smoke out!
Don't let that smoke out!
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funkmeblue
- Posts: 485
- Joined: Mon Mar 13, 2006 4:17 am
- Location: akron, ohio
Re: lowering bias range
I was wondering if I was to change the 25k pot to 47k and the 47k resistor to 25k would that give me a wider bias range? I think that is what the climax has going on.
anything worth doing, is worth doing right
Re: lowering bias range
...assuming you can get a 47K potfunkmeblue wrote:I was wondering if I was to change the 25k pot to 47k and the 47k resistor to 25k would that give me a wider bias range? I think that is what the climax has going on.
By swapping a 50K pot for the 25K pot and a 22K resistor for the 47K you'll have the same "cold" limit, but more range. Both combinations = 72K. In other words, when you've got the pot a maximum R value, you're bias voltage won't go any colder. On the other end, you could make it too hot, so be careful. If you want more range on the cold side, you'll need to increase the fixed resistor.
Re: lowering bias range
I raised the 47k to 80k and it works great. Thanks!