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Bias Trim Pot?

Started by nimane9, January 12, 2015, 05:54:09 AM

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nimane9

Hey everyone,

I'm looking at building the silicon Fuzz Face clone from madbean.

It says that I need a bias trim pot. Would https://tubedepot.com/products/trim-pot-for-bias-level work for that?

And also, what does it even do?

Thanks.

selfdestroyer

Quote from: nimane9 on January 12, 2015, 05:54:09 AM
Hey everyone,

I'm looking at building the silicon Fuzz Face clone from madbean.

It says that I need a bias trim pot. Would https://tubedepot.com/products/trim-pot-for-bias-level work for that?

And also, what does it even do?

Thanks.

The lead spacing will be to big for the FF PCB. You should try to get Bourns 3362P (or clones).

http://www.mouser.com/ProductDetail/Bourns/3362P-1-253TLF/?qs=izR6mho4f8X2Z56KYjpczw==

Cody

TGP39

Hi Ninane9.. The bias trim pot will adjust  how much voltage reaches your collector of the Silicon resistor (Q2 in this case). When you build this fun circuit you can see just how much the sound changes when you turn the bias trimpot.  The general goal will be to achieve close to 4.5 volts on the collector, but you may like the sound at a different voltage. These tips and more can be found on the build guide as Brian always lays out easy instructions to follow.  Hope this helps and let us know how it turns out. Steve.
Follow me on Instagram under PharmerFx.

selfdestroyer

Quote from: TGP39 on January 12, 2015, 07:26:43 AM
Hi Ninane9.. The bias trim pot will adjust  how much voltage reaches your collector of the Silicon resistor (Q2 in this case). When you build this fun circuit you can see just how much the sound changes when you turn the bias trimpot.  The general goal will be to achieve close to 4.5 volts on the collector, but you may like the sound at a different voltage. These tips and more can be found on the build guide as Brian always lays out easy instructions to follow.  Hope this helps and let us know how it turns out. Steve.

Thanks Steven for explaining that. I jumped on the datasheets for the trimmers and totally forgot to address the second question.

Cody

nimane9

Quote from: selfdestroyer on January 12, 2015, 06:07:21 AM
The lead spacing will be to big for the FF PCB. You should try to get Bourns 3362P (or clones).

http://www.mouser.com/ProductDetail/Bourns/3362P-1-253TLF/?qs=izR6mho4f8X2Z56KYjpczw==

Cody

Thanks man, I appreciate the help. Do you think http://www.taydaelectronics.com/potentiometer-variable-resistors/trimmers/6mm-top-adjustment/20k-ohm-ohm-trimpot-variable-resistor-6mm.html that would work? It appears that they don't have 25k trim pots, but they have 20k and 30k. Would either of those be an acceptable substitute?

Thanks.

Quote from: TGP39 on January 12, 2015, 07:26:43 AM
Hi Ninane9.. The bias trim pot will adjust  how much voltage reaches your collector of the Silicon resistor (Q2 in this case). When you build this fun circuit you can see just how much the sound changes when you turn the bias trimpot.  The general goal will be to achieve close to 4.5 volts on the collector, but you may like the sound at a different voltage. These tips and more can be found on the build guide as Brian always lays out easy instructions to follow.  Hope this helps and let us know how it turns out. Steve.

Awesome, that really clears it up.

Thanks.

TGP39

Follow me on Instagram under PharmerFx.

nimane9