Build Your Own Clone Message Board

I built the 27V Boost yesterday afternoon and had trouble with it...

The build went well, pretty quick considering I never made a small-format pedal before.

In bypass, everything is fine.

When engaged, the led lights, but no sound... UNLESS I strum very hard which causes a very sharp, staccato screechy sound, then immediately back to silence.

Today's plan is to look at everything with a magnifying glass (again), reflow solder (probably) everywhere...

If that doesn't work, I will be taking pictures and checking voltages on the ICs to post-up later.

But, in the meantime, I was wondering if those symptoms indicate anything obvious I should be focusing on.

Funny thing is, I was documenting this build on video and now I will also be documenting some troubleshooting...

This is always a good plan, and generally the first thing I recommend. But we've been seeing a rash of IC-related issues of late, particularly with charge pumps and TL072 op amps....and this circuit has one of each. So I'd get a set of DC voltage readings on the pins of each of the IC's and report them here. See left side of the image below for the numbering of the pins.

_________________
“My favorite programming language is SOLDER” - Bob Pease (RIP)

My Website * My Musical Gear * My DIY Pedals: Pg.1 - Pg.2

OK, figured I would start here... listing pins 1-4 on the left and 8-5 on the right....

My power supply was delivering 8.91

TL072CP
5.51--7.96
5.32--5.37
5.01--5.39
5.41--5.37

7660S
8.91--8.91
4.99--7.10
0.00--6.56
4.91--4.88

I am not so good at reading the schematics yet, but something on that 7660S should have about 18V, right? And a -9V? ALL of those are +V... sorry about the dashes, those are not negatives.

Hopefully taking pictures shorly...

https://drive.google.com/drive/folders/ ... sp=sharing

That should be a link to 4 pictures I hope look good enough to judge my work...

The charge pump definitely looks bad, but the TL072 may be as well, so contact sales@buildyourownclone.com and ask for replacements for BOTH. Tell 'em DVM sent you.

_________________
“My favorite programming language is SOLDER” - Bob Pease (RIP)

My Website * My Musical Gear * My DIY Pedals: Pg.1 - Pg.2

Thanks, DVM! Email sent. I appreciate your help!

Just curious, any way to test the ICs before soldering them in to make sure they are good (esp since I have read about others having trouble with them)? Or maybe it is really best just to test them IN the circuit. I bought a solder sucker, so i hope I am ready for whatever happens.

Probably the best way to do this would be to have a pedal with a socketed charge pump that you know works correctly and test a new CP in that. This would allow you to confirm good audio performance as well as the correct pin DC voltages. A BYOC Silver Pony or Green Pony would be perfect for that purpose, they're both great boost/overdrive combo pedals, and the kits are very reasonably priced.

_________________
“My favorite programming language is SOLDER” - Bob Pease (RIP)

My Website * My Musical Gear * My DIY Pedals: Pg.1 - Pg.2

I have a green pony, so I could test the 7660 in that (yes, it is a great pedal, except I plan on modding the capacitors sometime to change the norm/thin/fat frequencies slightly... I think I remember reading some suggestions from you on an old post that made a lot of sense).

What about testing the TL072? is that similar enough to the 4558 in the GP to plug it in there?

Thanks again, very appreciated!

Yes, absolutely. They're both general purpose dual op amps.

_________________
“My favorite programming language is SOLDER” - Bob Pease (RIP)

My Website * My Musical Gear * My DIY Pedals: Pg.1 - Pg.2

Everything is back together and working well with the new ICs installed! Honestly, I was too impatient to test them first... and also, my de-soldering skills are nothing to write home about... but it works and it is one hell of a clean boost. Had to name it "High Voltage" in honor of the final chorus of Dirty Deeds by AC/DC!

Thanks again, my pedalboard is done for next week's gig! Including capacitor mod on the green pony!

Great! Go rock that board!!

_________________
“My favorite programming language is SOLDER” - Bob Pease (RIP)

My Website * My Musical Gear * My DIY Pedals: Pg.1 - Pg.2