Phoenix, MOBO & SMR MKII assembly help needed

Hello synthlovers,

My name is Ronny and i like to make electronic music and i needed some nice warm bass. After listening to a lot of bass synths i stumbled upon the Shruthi (Phoenix, Tubeohm). What a sound!

What a project!
I have never soldered before. i am very messy, but i thought this project would learn me patience, accuracy and it couldn’t hurt to get a little handy with a soldering iron.

Soo, i started with the MOBO ( Motherboard) and i made a lot of mistakes. I had to pull a few things out and resolver etc. Messy.
I haven’t been able to test the board but here is the result:
I wonder if anyone can see if there are any mistakes i made.
had to remove picture because of forum rules. I will upload this one after i get permission*

After finishing this part of the assembly i started on the SMR MKII filter board. I was more cautious this time and i thought i did everything correct. BUT after i hooked up a power supply (Moog 9V as in picture), and got the multi meter (as seen on picture), but i’m getting strange readings. It’s supposed to be 5V or -5V but i get 1.2, 2,5. Very low and i guess not any minuses.
Here two pictures with my board, adapter and multimeter. Can anyone see something is wrong?

! had to remove picture because of forum rules. I will upload this one after i get permission*

I appreciate the help.


You forgot the jumper wire next to the power inlet. Also, If you want to get any voltage on the -5V, you will need to insert the LT1054 in its socket.

Edit: Maybe move this topic to the “discontinued products” section?


It might be better with the LT1054 in place in the IC socket but it’d have been easier to insert it before soldering the electrolytic caps… :wink:
As a general rule, you always start from the lower parts (diodes, resistors) and finish with the highest (regulators, electrolytic caps).

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Yeah…Didn’t see that one. :sleeping:


And thank you for helping.

So, i just bridge a wire on the sw22 like this?

Very nice that you guys are helping out a noob⛷

Yes, that’s how you should solder the bridge.

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It should read +5 v


This should be -5V
Am I measuring correctly?

This is my multi meter

What are you powering the board with?

on wich mode should i set my multimeter?

On 20 in V DC mode.
Did you put the LT1054 ?
Could you measure the AC adapter alone ?
It is rated 9V 400 mA but it will tell us if it is regulated or not.

You have your multimeter set to the hFE (transistor test) mode. That is wrong. You want to measure a voltage.
Why don’t you set it to the DC (not AC!) voltage mode? Set to to 20V-, that should do the trick :wink:

I suggest you watch a youtube video on multimeter basics. (Knowing how to measure stuff is crutial to finding an error)

And don’t put the LT1054 in backwards, it blows very easily. :slight_smile:

TheSlowGrowth got the last piece of the puzzle, I think. The multi-meter isn’t in the correct mode in your last set of pictures. After that, you should be in good shape. Also, a general tip on building your first synth - TAKE YOUR TIME! I know it seems obvious, but using care to get it right the first time will pay off in the long run. I rushed through building my Anushri a few years back, and didn’t have the skills/ experience / patience to get it functioning for a couple years. The build instructions are really well made, so follow them closely and you’ll be done before you know it. Have fun, Shruthi-1 is a fantastic little box. That reminds me, I should bust mine out and jam on it soon…

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Is this correct?
It should be 5V. So, it’s wrongly measured or the board is messed up.

I looked up an Lt1504 and it looks like an metal lasso. It’s not included in the kit. Why do I need it. Was it for the bridging of the SW22? I used a piece of wire for that.

How do I measure voltage on the adapter? Like this?

Haha. I take my time and Take breaks. Go on YouTube and try to educate myself. There is nothing else on my mind than this assembly.

But now I’m really stuck. So I hope for some help.
I will later post pictures of the motherboard. Man, that is a real mess💩

Sorry, typo…
You want a 8 pin IC with LT1054 on it.
Should look like that:

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