DIYstompboxes.com

DIY Stompboxes => Building your own stompbox => Topic started by: Lost_soul on October 17, 2024, 04:00:26 PM

Title: Boss OC-2 Sabrotone problem
Post by: Lost_soul on October 17, 2024, 04:00:26 PM
there is a problem in the circuit that i can't figure out. When plugged in there is sound when bypassed and when the effect is on there is an intermittent sound along with some crackles and noises.
It's been 3 weeks and i can't figure out what's wrong. I thought about using an audio probe but idk the path i should take for the test.




(https://i.postimg.cc/LYXW2TXQ/IMG20241004182517.jpg) (https://postimg.cc/LYXW2TXQ)

(https://i.postimg.cc/sQNNXhGj/IMG20240930154454.jpg) (https://postimg.cc/sQNNXhGj)
Title: Re: Boss OC-2 Sabrotone problem
Post by: ElectricDruid on October 17, 2024, 05:49:49 PM
Welcome Lost_soul!

Sorry to hear your circuit isn't working. But if we don't have a schematic and some more information, we can't help much. In fact, there's a handy post here that tells you what we need:

https://www.diystompboxes.com/smfforum/index.php?topic=29816.0 (https://www.diystompboxes.com/smfforum/index.php?topic=29816.0)

Title: Re: Boss OC-2 Sabrotone problem
Post by: Lost_soul on October 17, 2024, 07:04:00 PM
Thank you! i am sorry it's my first build and my first post on the forum :)
i will definitely edit the post to have the schematic, the layout, the voltage readings or the ICs pins and transistors. and i will include what i did diffrent within the circuit.
but should i keep the post in this subboard or should i post it in the Building your own stompbox board?
Title: Boss OC-2 build Help
Post by: Lost_soul on October 18, 2024, 08:14:11 PM
Hello guys. For the past week i have been making my first vero build of boss oc-2 and it's based on sabrotone layout.
This is the layout for it:

(https://i.postimg.cc/Fk5bB6nk/Messenger-creation-6-CFAF490-D2-BA-4-AC1-8-EC3-9-BE456-F06116.jpg) (https://postimg.cc/Fk5bB6nk)

There is no schematic for this layout but there is a schematic posted on the sabrotone site and this is it:


(https://i.postimg.cc/PLvwn4DW/boss-oc2-true-bypass.gif) (https://postimg.cc/PLvwn4DW)

After i finished building it and then i connected it and tested it and boom, it doesn't work.
I used a dpdt switch as 3pdt switches are not available in egypt. So on bypass there is normal clean sound. When the switch is On, the sound is intermittent with a lot of loud crackles (like the sound when you unplug your guitar cable) and then suddenly sound goes off.

These are some shots of the build
(https://i.postimg.cc/DWRY7BMn/IMG20241019022825.jpg) (https://postimg.cc/DWRY7BMn)

(https://i.postimg.cc/kRRSqvL3/IMG-20241019-024117.jpg) (https://postimg.cc/kRRSqvL3)

And here is a mirrored photo of the solder side incase someone find it useful:

(https://i.postimg.cc/BX51Bp9b/IMG-20241019-024326.jpg) (https://postimg.cc/BX51Bp9b)


I made some changes in the parts.
First i used bf245 transistors instead of the 2sk30a ones as they aren't available in egypt (i know the pinout is diffrent and i solved this as in this picture)
(https://i.postimg.cc/mtxjhPjN/IMG20241019022804.jpg) (https://postimg.cc/mtxjhPjN)

The second change i made is that i used 1N4148 instead of all the diodes except for D6 and D7, i used a 1N5817 schotty diodes for those 2.

So i started trouble shooting and from my search i found out how to measure ic voltages although i don't understand a lot about circuits and stuff :-\  but i am trying my best.

So these are the ICs voltages compared to the ones on sabrotone website and the numbers are way off (mine are the ones in blue and the last column on the right is for IC5)

(https://i.postimg.cc/0rNdVL53/Screenshot-2024-10-19-02-46-14-79.jpg) (https://postimg.cc/0rNdVL53)

(https://i.postimg.cc/phS9Gcqb/IMG-20241019-024644.jpg) (https://postimg.cc/phS9Gcqb)

So idk what is the problem with this circuit. It's really complicated for me and i am still a newbie. I would really appreciate some help from experts here  :icon_neutral:

Btw idk if this matters but i tested the voltage on the pin of the audio socket that either input or output (idk if it's called tip or sleeve)
And it was ZERO volts.

I found that something called an audio probe that's easy to make is a great tool for trouble shooting so if i and the people here couldn't figure it out, i guess i will go that route.

Thank you and sorry for the long post :-\
Title: Re: Boss OC-2 Sabrotone problem
Post by: Elijah-Baley on October 19, 2024, 03:57:07 AM
Is it your first build and you start with this? I'm shocked! :icon_eek:

Don't worry.
There's a series of think you can check.
The picture can't allow to see all the spots, but you can check:
- Iif all the parts are in the right spot, resistors, caps, wires, IC, cut track, etc.
- Did you forget some parts?
- Check the orientation of the polarized cap, diodes and transistors (did you use some different parts?)
- Are the wires solder well? There some wires that touch some nearby stripe?
- Pass a knife between the stripes, sometime the solder makes some bridge between them.
- Check if all the cuts interrupt the stripes.
- Do you have doubt about the value of the parts?
(Use the multimeter to check continuity when you need.)


Maybe you did it all this, but do it again, sometime you have to check three or four time before you can find the mistake!

The sound you can hear over the noise is how the effect should be sound? Do you hear the octave and the pots working fine?
Title: Re: Boss OC-2 Sabrotone problem
Post by: Lost_soul on October 19, 2024, 05:09:24 AM
Yes it's my first build :)
I tried a fuzz factory before but i had no luck with it.

I checked all the things you said but maybe i need to check again.

The sound i hear is just normal guitar sound with no octave effect but with loud crackles like the sound when you unplug your guitar cable.

Btw i have made another post that has a detailed data of what i did and i included in it the IC voltages compared to sabrotone's measures.
The post is called (Boss OC-2 build Help). It's in the building your own stompbox sub :)
Title: Re: Boss OC-2 Sabrotone problem
Post by: antonis on October 19, 2024, 07:51:39 AM
Hi & Welcome..

Check short between 17E & 17F..
Can't say for sure but I think you've shorted 2 capacitors..
Title: Re: Boss OC-2 Sabrotone problem
Post by: Mark Hammer on October 19, 2024, 08:50:58 AM
I hate stripboard/veroboard.  Making a DC-2 is a worthy aspiration, but doing so on stripboard is probably one of THE last things I would ever consider attempting.  And if you had problems with a Fuzz Factory, you could/should expect even more with a DC-2.  There is a reason why the DC-2 includes not one, but two NE570 compander chips: because the risk of unwanted noise is so great....in spite of what one can only assume is Boss's well-planned layout.  Any stripboard layout of manageable size is unlikely to be especially amenable to keeping noise levels and interference low.  There ARE PCBs commercially available.  I would strongly encourage you to use one of those.  At the very least, they are nearly always well-legended, such that keeping track of parts installed and not-yet-installed is much easier to do.

Best of luck in your adventure.  Come back alive.  :icon_wink:
Title: Re: Boss OC-2 Sabrotone problem
Post by: Lost_soul on October 19, 2024, 08:52:34 AM
Quote from: antonis on October 19, 2024, 07:51:39 AMHi & Welcome..

Check short between 17E & 17F..
Can't say for sure but I think you've shorted 2 capacitors..

You mean because of the solder line in that spot?
I burnt part of the line where c8 is and so i connected the line again with solder over the burnt spot. I checked for shorts between 17e and f and there was no continuity.

Btw i made another detailed post including ICs voltages, what parts i changed in the layout (like diodes and transistors).
The post is called boss oc-2 build help if you wanna check it ;D
Title: Re: Boss OC-2 Sabrotone problem
Post by: duck_arse on October 19, 2024, 09:47:24 AM
have merged your topics. please pardon.

also, welcome.
Title: Re: Boss OC-2 Sabrotone problem
Post by: duck_arse on October 19, 2024, 11:18:37 AM
a small point on your jfets - are they BF245A, 245B or 245C ? the 'A' would be the closest match to the K30A.

Quote from: Lost_soul on October 19, 2024, 05:09:24 AMI tried a fuzz factory before but i had no luck with it.

well now, see, sometimes there is a pattern. perhaps if you start a thread [just the one, please!] help fix my fuzz factory, or something. go through the process of posting circuit and layout and photos of your build, voltage measure and parts notes, we might see something you are doing in both builds.

also, we need to see everything in the photos, all switches and pots and jacks, all resistor and caps connections, so we can check your wirings.
Title: Re: Boss OC-2 Sabrotone problem
Post by: Lost_soul on October 19, 2024, 12:20:46 PM
It was a Bf245C.

As for the fuzz factory, it didn't work because my soldering skills were bad i think back then.
I threw it away after several tries to figure out what's wrong with it :'(

RN i am finishing a zvex SHO as it's a very simple build and i am making it to see if it's gonna work.

As for this oc-2 build. I already posted the voltages for the ICs (you can find it above).
What should i do now to help you figure out the issue?

Should i make an audio probe and see where the signal cuts off or something?
Title: Re: Boss OC-2 Sabrotone problem
Post by: Lost_soul on October 19, 2024, 01:47:40 PM
@duck_arse i finished the zvex SHO and it's making the same freakin crackle noise that the oc-2 does with no effect sound. Maybe it's a problem with my offboard wiring?
I checked all rows for a solder bridge with a multimeter and there was none!
I did it based on tagboard fx compact layout.
Title: Re: Boss OC-2 Sabrotone problem
Post by: antonis on October 19, 2024, 01:49:03 PM
Sorry but your posted build doesn't correspond to layout posted.. :icon_wink:
Title: Re: Boss OC-2 Sabrotone problem
Post by: Lost_soul on October 19, 2024, 01:54:38 PM
How so antonis?
Title: Re: Boss OC-2 Sabrotone problem
Post by: antonis on October 19, 2024, 04:39:04 PM
Too late here (and too much tsipouro) but collumns 17 & 18  dont coinsidece,, :icon_wink:
Title: Re: Boss OC-2 Sabrotone problem
Post by: amptramp on October 20, 2024, 07:50:40 AM
One caution that shows up here all the time is that transistor pinouts may not be the same as you would expect.  Quite often, we have seen transistors with an EBC pinout be replaced with transistors with an ECB layout and nothing works.  The same happens with SDG JFET pinouts and SGD pinouts.  Check what you ahve carefully.
Title: Re: Boss OC-2 Sabrotone problem
Post by: duck_arse on October 20, 2024, 10:15:33 AM
Quote from: Lost_soul on October 19, 2024, 01:47:40 PM.... it's making the same freakin crackle noise ....

ah-hah! progress. so instead of fuzz facktry help me, call the new thread SHO don't go, please help, or something. start with the sho and we might learn you some debug and fault findings.


the BF245C is way way away from the 2SK30A for equivalence. I've had a handfull of 'C's' looking for a circuit use this last 20 some years.

[edit :] you got me again.
Title: Re: Boss OC-2 Sabrotone problem
Post by: duck_arse on October 20, 2024, 11:05:14 AM
Quote from: antonis on October 19, 2024, 04:39:04 PMToo late here (and too much tsipouro) but collumns 17 & 18  dont coinsidece,, :icon_wink:

I agree-ish. on the parts side photo I can see C6 is fitted, but in the solder side photo those holes are blank. shenannigans?
Title: Re: Boss OC-2 Sabrotone problem
Post by: antonis on October 20, 2024, 02:33:08 PM
Quote from: Lost_soul on October 19, 2024, 08:52:34 AMI checked for shorts between 17e and f and there was no continuity.

If you say so... :icon_wink:

(https://i.imgur.com/6bLzsvR.jpg)
Title: Re: Boss OC-2 Sabrotone problem
Post by: Lost_soul on October 20, 2024, 04:32:33 PM
Quote from: antonis on October 20, 2024, 02:33:08 PM
Quote from: Lost_soul on October 19, 2024, 08:52:34 AMI checked for shorts between 17e and f and there was no continuity.

If you say so... :icon_wink:

(https://i.imgur.com/6bLzsvR.jpg)

I just checked them and that's not a solder bridge.
I will be testing the Circuit tomorrow with an audio probe but idk what is the path i should follow from the input to the output ;D
Title: Re: Boss OC-2 Sabrotone problem
Post by: Mark Hammer on October 21, 2024, 08:39:49 AM
Wait a second.  I'm confused.  Is this about a DC-2 or an OC-2?  Big difference.  The thread title says OC-2 but the initial images are clearly DC-2.  What are we talking about here?
Title: Re: Boss OC-2 Sabrotone problem
Post by: Lost_soul on October 21, 2024, 09:49:25 AM
Quote from: Mark Hammer on October 21, 2024, 08:39:49 AMWait a second.  I'm confused.  Is this about a DC-2 or an OC-2?  Big difference.  The thread title says OC-2 but the initial images are clearly DC-2.  What are we talking about here?

It's an OC-2 ;D
What images are you talking about?
Title: Re: Boss OC-2 Sabrotone problem
Post by: Mark Hammer on October 21, 2024, 11:12:08 AM
Now I'm REALLY confused.  There was another thread, with a DC-2 title that was collapsed into this one, if I'm not mistaken.  When I saw the picture in the first post, admittedly only a quick glance, it seemed to have more chips than I would have expected for a drive circuit but something close to what a DC-2 would have (with quad op-amps replacing duals).  I'm beginning to think I misread BOTH threads on my smaller tablet screen as D when it was an O.  Damn aging eyes!
Title: Re: Boss OC-2 Sabrotone problem
Post by: idy on October 21, 2024, 11:28:44 AM
Welcome, and I salute your bravery.
Have you read/watched videos on soldering skills? The right tools are important, the right temperature and solder.
Foundation skills avoid so many problems.
And this is a very hard circuit for strip board.