Tayda tube screamer

[Mgt280y]

Evening all,
Thought as I'm ordering parts I might as well try a few of there pcbs as well
Just putting a tube screamer together based on taydas TS808 Bom

Wanted to try a little mod but Tayda don't produce the schematic for their boards so not 100% confident I know what I'm doing lol

What I wanted to do is in the diode department is to have a toggle to switch between say silicon/germanium/LED

At a guess I'm thinking I run wires from the pads of d1 and d2 to a daughter board where there would be the alternative diode arrangements and a toggle to switch between them.

Just don't know how to do it, could someone draw the layout/what's connected to what in order for this to work
Any help much appreciated

[thermionix]

I have one of those Tayda 808 boards on the way, my first one from them.  Hoping there are no issues, I didn't search for reviews before buying.  So fingers crossed for both of our builds, lol.

A clipping diode toggle switch can be added without a daughterboard.  You can just have the diodes mounted on the switch itself, or run from the switch to the board.  There are different ways to do it.  You might mount the LEDS on the board (highest Vf), and alternately switch Si and Ge in parallel, shunting the LEDS.  You can use a SPDT or a DPDT switch.  It's simpler if you think of each diode pair as a single component.

[Mgt280y]

I have built the guv'nor pcb from them and am really pleased with it great tone nice pcb only criticism is 1590bb is the smallest enclosure.

Is there a diagram of how the pads are wired to the switch, also putting the clipping on the toggle what's the maximum number of options.

thanks dan

Just thought would using a rotary switch be better

[ShOrEbReAk]

hey

I recently bought and built one. they are good but make sure you put the right value components in, dont ask me how I know this, as it came out quiet sounding. I changed everything needing replacing but it is still a little quieter than my normal signal but still could be my fault. I just bought a pcb from guitar pcb site to compare and will let you know when i get to finishing.

troy

[Kipper4]

Google is your friend when it comes to "clipping diodes on a switch"

ergo;
http://www.muzique.com/news/diode-clipping-switch/

[thermionix]

Just thought would using a rotary switch be better

You could use a rotary switch, but they tend to be quite a bit larger than the little mini toggles.

[Mgt280y]

Yeah this is what I'm looking for

https://flic.kr/p/QXjN7W

So using this which pad on the pcb is
In
Out
Ground

https://flic.kr/p/QMAxTE

Thanks

[Mgt280y]

Anybody?

Can't get my head round this
I continuity tested all four pads and they connected opposite as you would expect running 2 diodes back to back but can't tell where the signal in and out are doesn't help I can't completely populate board until I sort this as pots will cover solder pads so at the min circuit isn't compete to test for continuity or I meight just be overthinking it all 

[thermionix]

I can't tell how the pads on your PCB are connected because I can't see the traces.  The clipping diode switch diagram you posted above is different from a tube screamer, the TS clippers are in the feedback loop of the opamp and do not connect directly to ground.

If you just put the LEDs on the board, you can hook two wires to the ends of one of them (either one).  Run those wires to the two middle lugs of a DPDT ON-OFF-ON (or ON-ON-ON) toggle.  Between one outside pair of lugs on the switch, run a pair of Si diodes anti-parallel.  Between the other outside pair of lugs on the switch, run a pair of Ge diodes anti-parallel.

[Mgt280y]

Right ok that makes a bit more sense,
Just to clarify it's a wire from each leg of 1 LED to the centre lugs Dpdt
I take it the signal will still take the route of least resistance so if either on (outside positions) when engaged will be the preferred route?
Thanks

[duck_arse]

the diode with the lowest forward voltage wins. so, leds are the default/fallback, somewhere between 1V7 and 2V4 ish. then comes the silicon, at about 600mV, then the Ge at 200mV or something. electrons are lazy, they seek the easist route - if the Ge's (or Si's) are switched in, the leds will pass no current.

[thermionix]

Right ok that makes a bit more sense,
Just to clarify it's a wire from each leg of 1 LED to the centre lugs Dpdt
I take it the signal will still take the route of least resistance so if either on (outside positions) when engaged will be the preferred route?
Thanks

[Mgt280y]

Nice 👍 thanks