Is the above layout up to date? I intend to build as soon as I receive the parts, but be in doubt because the schematic indicates the jump between terminals 1 and 2. Could you clarify this humble amateur?
Hi guys Forgive me but I'm new to these experiments. I'd like to try my hand at building this preamp but I'm not a great electronics expert so I ask you, if possible, the complete layout of connections to the various pots, jacks and switches? Thank you so much
The Zener is part of the power circuit, and is there to knock the current down from 26V. If you don't have any caps that are rated over 25V, I'd use the 20V Zener to make sure you don't get too close to blowing anything. If your caps are rated 35V or more, then either the 20V or 24V Zener should be fine.
A quick search revealed this: https://toshiba.semicon-storage.com/us/semiconductor/knowledge/faq/diode/is-it-ok-to-connect-multiple-zener-diodes-in-series.html#:~:text=Yes%2C%20it%20is%20possible%20to,lowest%20one%20among%20their%20specifications.
However - small signal audio circuit design often does stuff "wrong" (like using switching transistors for signal clipping, etc...) so honestly - you need to try it and see. If nothing melts: SUCCESS! Good luck!
I just opened that link and read it a little more carefully. It seems like using two Zeners in series is okay but if they are of different values (like a 10v and 12v, as you mentioned) the current that passes, and therefore, the voltage will default to the lower value diode.
So, what I believe that is saying, is that in order to get 22v with two diodes in series, you'll need 2x 11volt Zeners. A 10v and a 12v will effectively knock the 12v down to 10v - giving you only 20volts from the 2 diodes in series.
Built mine and the volume control attenuates when turned up & down. Looking at the schematic, I think swapping the Output & Volume 3 will fix it.
ReplyDeleteCan confirm, swapping the Output & Volume 3 rows makes it work great!
ReplyDeleteThanks for verifying and correcting the connections. Tagged!
Delete@CrackinTheShat are you getting 22V after the zener on this? I'm only seeing 9V. @fuzzhead Notice anything that might cause this? Thanks!
DeleteHmm, the layout looks good to me.:-/
Deleteow, I think on the trimmer legs 1 and 2 needs to be connected and not 2 and 3...
ReplyDeleteYes, thats right. But the trimpot will fullfil the same function,it is just reversed. I'll move the link as soon as I can.
DeleteIs the above layout up to date? I intend to build as soon as I receive the parts, but be in doubt because the schematic indicates the jump between terminals 1 and 2. Could you clarify this humble amateur?
ReplyDeleteThis comment has been removed by the author.
ReplyDeleteThe toggle spdt on off on doesn't change the tone for me stays the same no matter what setting
ReplyDeleteHi Fuzzhead!I hope you are well!I cannot find a 22v zener...Can i use something else?
ReplyDeleteHI guys build this but cannot seem to have any change when engaging the effect. I get 21 volts on row K, 18 volts at the trimpot/zener. What is wrong?
ReplyDeleteHi guys
ReplyDeleteForgive me but I'm new to these experiments.
I'd like to try my hand at building this preamp but I'm not a great electronics expert so I ask you, if possible, the complete layout of connections to the various pots, jacks and switches?
Thank you so much
Here is a diagram for how to handle your off-board wiring!
Deletehttp://tagboardeffects.blogspot.com/2012/02/offboard-wiring.html?m=1
Hi! can i use a 20v or 24v zener diode here? I don't have 22v...
ReplyDeleteThe Zener is part of the power circuit, and is there to knock the current down from 26V. If you don't have any caps that are rated over 25V, I'd use the 20V Zener to make sure you don't get too close to blowing anything. If your caps are rated 35V or more, then either the 20V or 24V Zener should be fine.
DeleteGot it, thanks!
DeleteHi! Can we put 2 zeners in series (for example 10v to 12v) to obtain the desired voltage? Thanks!
DeleteA quick search revealed this: https://toshiba.semicon-storage.com/us/semiconductor/knowledge/faq/diode/is-it-ok-to-connect-multiple-zener-diodes-in-series.html#:~:text=Yes%2C%20it%20is%20possible%20to,lowest%20one%20among%20their%20specifications.
DeleteHowever - small signal audio circuit design often does stuff "wrong" (like using switching transistors for signal clipping, etc...) so honestly - you need to try it and see. If nothing melts: SUCCESS! Good luck!
I just opened that link and read it a little more carefully. It seems like using two Zeners in series is okay but if they are of different values (like a 10v and 12v, as you mentioned) the current that passes, and therefore, the voltage will default to the lower value diode.
DeleteSo, what I believe that is saying, is that in order to get 22v with two diodes in series, you'll need 2x 11volt Zeners. A 10v and a 12v will effectively knock the 12v down to 10v - giving you only 20volts from the 2 diodes in series.
Hi! Thanks! I read it too but i think it refers to the Zener current and not the voltage.. I`m a newb though :)
Delete