Amplified Zener

Started by craigmillard, August 20, 2017, 07:09:39 AM

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craigmillard

Hi all, I'm looking to use a amplified zener on the center tap of a b+ to drop some voltage but don't have the right voltage zeners, can I series a few together to get the right voltage but only use one transistor still? I think I can??

The circuit is Merlin's but similar to the MOSFET follies b+ reducer

Thanks

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R.G.

R.G.

In response to the questions in the forum - PCB Layout for Musical Effects is available from The Book Patch. Search "PCB Layout" and it ought to appear.

craigmillard

Thanks RG,

found your post here just a second ago too!
http://music-electronics-forum.com/t36150/

thermionix

Is this for a tube amp?  Is it fixed bias?  Is the bias supply drawn from a tap on the B+ secondary?  Just be wary that the zener trick will also reduce your bias voltage a great deal, and you'll need to increase your bias set resistor to compensate.

craigmillard

Cheers thermionix, i saw that gotcha but its a cathode bias'd custom build, just with a junk box transformer!

Just working out how to attach the parts to a turret/ p2p build!:)

thermionix

Roger that.  But you know the rules, pics when done!

craigmillard

Hi guys, a bit of a follow on question!:) the amplified zener works great but I have realised I could do with a vvr circuit to lower the volumes down to bedroom levels! So I was going to implement Merlin's power scaling circuit which is similar to

http://www.tdpri.com/attachments/img_3043-jpg.412507/

Which is great but I want to limit the top end of the voltage as well, ie so it is always scaled a bit, replacing the amplified zener circuit! Is it as simple as puting some resistance to the the top of the 1meg pot?

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PRR

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craigmillard

Quote from: PRR on August 27, 2017, 08:47:06 PM
Yes.
Thanks prr! Going to wire it in tonight:)

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