Adding Ibanez ts9dx to 5f2 circuit

[Crate50watt]

Hey guys, I searched and searched but couldn't find any info anywhere regarding adding an effect "pedal" to an amp chassis. I like the way this 5f2 circuit sounds, but also like having a little more gain and distortion at lower volumes.
I have had a ts9dx pedal for years and I love it. So, I figured with my next build I would wire a stripboard up and throw one in a 5e3 chassis.
My question is, should I use a spst switch to turn on the 9v for the board and use the true bypass of the pedal (with the guitar input always going through it) or should I use a dpdt switch so that "on" sends signal and 9v power to the pedal and from the pedal to the amp, and "off" would be signal from the input, straight to the amp, going around the effect circuit. ( I wasn't sure if the 9vdc on one side of that switch would cause any noise on the signal which would be on the other side of the same switch)
My first inclination is input jack > effect board > amp with a spst switch to turn the 9v on/off and utilize the true bypass of the pedal circuit.
I didn't know if it would make any difference to use the dpdt to be able to completely go around the effect board...
Thanks team!

[HotBluePlates]

... I have had a ts9dx ... I figured with my next build I would wire a stripboard up and throw one in a 5e3 chassis. ... should I use a spst switch to turn on the 9v for the board and use the true bypass of the pedal ...

My limited understanding is the TS9DX doesn't have true bypass as part of the original circuit.  So you'd probably need to set up a switching scheme (either physical double-pole double-throw switch, or JFET switching) to route the signal through or around the TS9DX circuit.  You might want 3 switched circuits if you would like to add a status LED to indicate the pedal circuit is switched on.

I personally wouldn't switch the power on/off.  The pedal circuit only draws ~7mA, so as long as you create a 9vdc supply in the amp, keeping the pedal circuit always-on isn't a big power drain.  If I went to the trouble of putting a pedal circuit inside an amp chassis, I wouldn't run it off a battery I had to bother with replacing.

Personally, I'd keep the pedal circuit outside of the amp.  I have a few pedals I really like, but I wouldn't build them into any of the amps I've made if only because having them outside means I can plug any of them into any amp I use.

[Crate50watt]

My limited understanding is the TS9DX doesn't have true bypass as part of the original circuit.  So you'd probably need to set up a switching scheme (either physical double-pole double-throw switch, or JFET switching) to route the signal through or around the TS9DX circuit.  You might want 3 switched circuits if you would like to add a status LED to indicate the pedal circuit is switched on.

I personally wouldn't switch the power on/off.  The pedal circuit only draws ~7mA, so as long as you create a 9vdc supply in the amp, keeping the pedal circuit always-on isn't a big power drain.  If I went to the trouble of putting a pedal circuit inside an amp chassis, I wouldn't run it off a battery I had to bother with replacing.

Personally, I'd keep the pedal circuit outside of the amp.  I have a few pedals I really like, but I wouldn't build them into any of the amps I've made if only because having them outside means I can plug any of them into any amp I use.

If that is the case then I will probably use the dpdt switch, and just have the 9vdc on all the time. I am putting a 120v-9vdc converter in the chassis on the power end, so I'll just wire that up hot and use the dpdt switch for the two outputs (ts9dx, v1)

[HotBluePlates]

... I am putting a 120v-9vdc converter in the chassis on the power end ...

You could just use 2 resistors & a cap.

You have B+ inside the amp, and have develop relatively clean high voltage d.c.  Let's say it's 350vdc, and you need 9vdc for your pedal.  All you need is a voltage divider between the 350vdc point and ground (made of 2 series resistor), and you put a cap across the lower resistor to ground.

You know from before this divider should be able to deliver ~21mA without issue (a safe margin above what the pedal requires).  Assume the lower resistor will sink 14mA, 7mA will go through the pedal circuit, and the sum 21mA will go through the upper resistor.

350v - 9v = 341v
341v / 21mA = ~16.2kΩ (available in 2% resistors; a 5% 16kΩ resistor is likely close enough)
9v / 14mA = ~643Ω (642Ω is available in 1% & 2% resistors, but a 620Ω 5% resistor is probably close enough).

You'd want to attach this divider network to the filter cap feeding the screen of the output tube (plenty of current capability).  Use a 100µF (or higher) cap rated 16-25v (or higher) across the 620Ω resistor.

[PRR]

> 341v / 21mA

7.16 Watts. Needs to be a 14W part with lots of air around it.

Schematic I found shows full BOSS-like bypass.
http://schems.com/bmampscom/ibanez/ts9%20tube%20screamer.gif

Power demand may be 5mA-9mA depending on opamp and mods.

I agree this pedal should not be a built-in. At best I would sling it in a sack in the cabinet, to avoid clutter.

[Crate50watt]

... I am putting a 120v-9vdc converter in the chassis on the power end ...

You could just use 2 resistors & a cap.

You have B+ inside the amp, and have develop relatively clean high voltage d.c.  Let's say it's 350vdc, and you need 9vdc for your pedal.  All you need is a voltage divider between the 350vdc point and ground (made of 2 series resistor), and you put a cap across the lower resistor to ground.

You know from before this divider should be able to deliver ~21mA without issue (a safe margin above what the pedal requires).  Assume the lower resistor will sink 14mA, 7mA will go through the pedal circuit, and the sum 21mA will go through the upper resistor.

350v - 9v = 341v
341v / 21mA = ~16.2kΩ (available in 2% resistors; a 5% 16kΩ resistor is likely close enough)
9v / 14mA = ~643Ω (642Ω is available in 1% & 2% resistors, but a 620Ω 5% resistor is probably close enough).

You'd want to attach this divider network to the filter cap feeding the screen of the output tube (plenty of current capability).  Use a 100µF (or higher) cap rated 16-25v (or higher) across the 620Ω resistor.

I didn't even think at any point to just use the b+ and install a voltage divider. I'll probably cut a smaller piece of that g10 and mount it to the side wall of the chassis next to the power supply.
Is there any reason why I wouldn't just use a seperate 120v tap and a converter? Sounds like six or a half dozen of the other to me... Unless there would be feedback or interference?

[HotBluePlates]

... Is there any reason why I wouldn't just use a seperate 120v tap and a converter? ...

Probably more money & space.

PRR is right though that I didn't consider power dissipated in the resistors. That may be a mark against my plan.

[Ed_Chambley]

I do not remember the name of the amp, but Bogner had a ts9 circuit or 808 (cannot remember for sure) inside an amp and a tube overdrive.  Early 90's maybe.  First 3 channel amp I had played.  Nice amp, but I have not seen anyone else do it.  Lots of builders are using diode distortion and overdrive nowadays.
 

[silverfox]

I was going to do this myself and picked up a board and ordered the parts to stuff it; I've still got everything sitting in the drawer... I ordered it from Aion and was. at least, very pleased with the quality of the PCB; Also the board measures something like: 2x2 so it will fit just about anywhere. There are also other projects on that site that include voltage boost circuits that use a chip to get 18 volts for OP Amp circuits. Another great advantage from the site is: All the schematics and build manuals are available for free download...

https://aionelectronics.com/project/stratus-ibanez-ts9-od808-tube-screamer/

silverfox.