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DIY Stompboxes => Building your own stompbox => Topic started by: nickbungus on January 31, 2019, 03:14:52 PM

Title: Boss CE2 Trim
Post by: nickbungus on January 31, 2019, 03:14:52 PM
Hi

I have built a Boss CE2 using the tonepad layout only to realise I dont have a 10k trimmer.  I do have a 20k timmer.  Was wondering if I could sub it?

Its in the power section to bias the 4.5v (VR3)

(https://www.electrosmash.com/images/tech/ce-2/boss-ce-2-power-supply.png)
Title: Re: Boss CE2 Trim
Post by: ElectricDruid on January 31, 2019, 05:10:28 PM
Yes, you could sub it.

It'll be a bit more sensitive than the 10K trimmer, so you'll have to be more careful when tweaking, but it ought to work.

It will also affect the impedance of the bias voltage a bit (15K/15K vs 10K/10K) but I doubt that's significant.

It's not ideal, but it'll work in a pinch.

HTH,
Tom
Title: Re: Boss CE2 Trim
Post by: nickbungus on January 31, 2019, 06:22:35 PM
Thanks Tom as always.   I got itchy fingers while waiting for a response and put it.  I've got signal but no effect,  so it's debug time
Title: Re: Boss CE2 Trim
Post by: thermionix on January 31, 2019, 07:06:49 PM
You could tack on a 20K (22K) resistor in parallel.
Title: Re: Boss CE2 Trim
Post by: GGBB on January 31, 2019, 07:51:47 PM
Could also jumper the two 4k7s R27 R28 so that your voltage divider stays close to original 10k/10k.
Title: Re: Boss CE2 Trim
Post by: antonis on February 01, 2019, 05:02:54 AM
Quote from: ElectricDruid on January 31, 2019, 05:10:28 PM
It will also affect the impedance of the bias voltage a bit (15K/15K vs 10K/10K) but I doubt that's significant.

C18 will take care of it..  :icon_wink:
(although you're right about insignificant ratio raise, Tom..)

Quote from: GGBB on January 31, 2019, 07:51:47 PM
Could also jumper the two 4k7s R27 R28 so that your voltage divider stays close to original 10k/10k.

It will call for a multiturn (X10 plus) trimmer and flexibly steady hand, also..
(we may like to believe we live in an analog world but our motor neurons impulses are sent in digital form..) :icon_smile:
Title: Re: Boss CE2 Trim
Post by: Fender3D on February 02, 2019, 07:54:02 AM
Quote from: MADONNA
'Cause we are living in analogical world
And I am a digital girl
You know that we are living in analogical world
And I am a digital girl

:icon_mrgreen: