SQ-RSEout Space Echo Impedance Balanced Output

[Bo Deadly]

Did you desolder any of the wires of the main echo board? My first guess would be that you didn't reconnect those wires perfectly or you have introduced a short or solder bridge or something of that nature. Did you take before pictures?

Check continuity / resistance of things with your meter. Start with the the main echo board wires. look at the schematic and find a point on the echo board that you know should have continuity to some point at the other end of those wires to confirm that they are connected correctly and they have 0 resistance. Check signal wires like between the jumper replacing C72 and JIN. Check resistance between JV+ and ground. And so on. Clearly you have a mistake somewhere. You just have to find it.

Another thing to try would be to disconnect the RSEout supply at solder lug 16 and see if the supply goes back up to 17V. Of not double down on checking those main echo board wires.

The RSEout board is very thick and the pads are small which is prone to cause a bad solder joint because the board takes more heat to get the solder to wick around. This is particularly true of the ground pads because of the ground plane. So look carefully for bad solder joints.

 

[craigmorris74]

Did you desolder any of the wires of the main echo board? My first guess would be that you didn't reconnect those wires perfectly or you have introduced a short or solder bridge or something of that nature. Did you take before pictures?

Check continuity / resistance of things with your meter. Start with the the main echo board wires. look at the schematic and find a point on the echo board that you know should have continuity to some point at the other end of those wires to confirm that they are connected correctly and they have 0 resistance. Check signal wires like between the jumper replacing C72 and JIN. Check resistance between JV+ and ground. And so on. Clearly you have a mistake somewhere. You just have to find it.

Another thing to try would be to disconnect the RSEout supply at solder lug 16 and see if the supply goes back up to 17V. Of not double down on checking those main echo board wires.

The RSEout board is very thick and the pads are small which is prone to cause a bad solder joint because the board takes more heat to get the solder to wick around. This is particularly true of the ground pads because of the ground plane. So look carefully for bad solder joints.

Thanks for the reply!

I didn't take before pictures because my unit looked exactly like yours, so I've been using those as a reference.  The only wire I disconnected were the 3 wires from the switch, and the signal and ground wire fro the filter PCB.  I've checked those and they all show continuity.  I check all the ground points from the back of the RSE board to the chassis, and the show a good connection.  Would I need to check from the front side of the board too?

If it makes any difference, I took the signal from the jumper at C72, and it's just as distorted there as what coming from the jack on the RSE board.

I just lifted the wire from lug 16, and the voltage is still 14.7V.

I'm guessing I messed up a connection elsewhere on the board.  I'll try to do some more tracing and find where.

EDIT-For some reason the meter started moving again, and I'm getting clean signal at the input of the RSE board when I put signal in at the first three jacks, but I only get a low bassy signal when I plug into the PA jack.

 

[Bo Deadly]

EDIT-For some reason the meter started moving again, and I'm getting clean signal at the input of the RSE board when I put signal in at the first three jacks, but I only get a low bassy signal when I plug into the PA jack.

If conditions have changed, then you should describe in greater detail what the current problem(s) are now.

 

[craigmorris74]

If conditions have changed, then you should describe in greater detail what the current problem(s) are now.

Now if I attach the RSE board, when I turn the unit on, I initially get signal, but it faces rapidly to nothing.

 

[craigmorris74]

Now if I attach the RSE board, when I turn the unit on, I initially get signal, but it faces rapidly to nothing.

After testing a bit more, I'm sure the main problem is in the RSE board.  I bought some extras, so I'm just going to build a new one and do a better job soldering this time.

 

[Bo Deadly]

Like I said, that board is really thick and the holes are small. So when you solder a part, you need to actually hold the heat there for an extra few seconds so that the solder really wicks down into that hole. This is especially true of the holes connected to the ground plane because that really absorbs the heat of the iron. I just did another PCB through OSHPark for something else and I deliberately made the holes bigger and ordered the thinner boards. The default OSHPark boards are stupidly thick.

So it sounds like you could have a bad solder joint. If a solder joint isn't quite making contact, it can work temporarily and then oxidation literally builds up in real-time and causes things to fail. It might be that you could just reheat and add a touch of solder with fresh flux to each joint on your existing board. Then check the continuity of things with your meter. Clean it with 99% isopropyl, polish the surface and around parts with a lens wipe and some plastic tweezers and visually inspect with a magnifying lamp to make sure the solder joints are good. Or take a picture with your phone in bright sunlight and look at it in high res on your computer.

 

[craigmorris74]

Like I said, that board is really thick and the holes are small. So when you solder a part, you need to actually hold the heat there for an extra few seconds so that the solder really wicks down into that hole. This is especially true of the holes connected to the ground plane because that really absorbs the heat of the iron. I just did another PCB through OSHPark for something else and I deliberately made the holes bigger and ordered the thinner boards. The default OSHPark boards are stupidly thick.

So it sounds like you could have a bad solder joint. If a solder joint isn't quite making contact, it can work temporarily and then oxidation literally builds up in real-time and causes things to fail. It might be that you could just reheat and add a touch of solder with fresh flux to each joint on your existing board. Then check the continuity of things with your meter. Clean it with 99% isopropyl, polish the surface and around parts with a lens wipe and some plastic tweezers and visually inspect with a magnifying lamp to make sure the solder joints are good. Or take a picture with your phone in bright sunlight and look at it in high res on your computer.

Yes, I tried to solder that board like I do normal boards, and I think that's the problem.  I'm going to build a new board today or tomorrow, and solder in one part at a time, and make sure the solder flows all the way through.

 

[Dreams]

Just ordered some. Will report back when I get one installed. Thanks!

 

[craigmorris74]

I built a new RSE board, being extra careful soldering each component, and got my RE201 back up and running. It is much more useful as a studio tool now!  Thanks again Squarewave for this project.

 

[Bo Deadly]

Great. Glad you got it working.

 

[emrr]

FINALLY got around to ordering one. Now to gather the other bits!

 

[bgrugle]

Are there any common problems that people have encountered with this mod? I'm having trouble with it.

When I have the JV+ connected to eyelet 16 I get 4V, but I get the correct 16V when not connected. No input or output with the mod installed either. I've re-flowed my joints, but I have to imagine that I've done something wrong on the board? Or is there a connection somewhere that I've done incorrectly?

I have JV+ going to eyelet 16, signal from eyelet 23 going to JIN, and the ground from the PA jack and the signal shield going to JGRND. Those combined grounds go to an existing ground pin on the footswitch jack. Is there a specific ground those leads should be going to? Also have the three switch points going to the corresponding switch pins, and the pins connected along their poles.

I've checked continuity and all seems good, so I'm unsure of where to start troubleshooting. Thanks for the help!

 

[abbey road d enfer]

What happens if you remove the opamp? I hope you've socketed it...

 

[bgrugle]

What happens if you remove the opamp? I hope you've socketed it...

haha definitely, have made that mistake before. Never again.

I'm getting the correct 16V without the opamp. It's a TI RC4580IP, bought new from Mouser. I swapped it out with a second new one and got the same result, though, so it's probably not bad. Is the NE5532 or the NJM4556 preferred?

 

[abbey road d enfer]

haha definitely, have made that mistake before. Never again.

I'm getting the correct 16V without the opamp. It's a TI RC4580IP, bought new from Mouser. I swapped it out with a second new one and got the same result, though, so it's probably not bad. Is the NE5532 or the NJM4556 preferred?

Changing for 5532 or 4556 wouldn't change the outcome.
You have to find why the opamp draws too much current.
I would look at shorted pins at the opamp.

 

[bgrugle]

Changing for 5532 or 4556 wouldn't change the outcome.
You have to find why the opamp draws too much current.
I would look at shorted pins at the opamp.

Yep, found a short between two pins that shouldn't have been there, and now it's working wonderfully. Thanks so much for the help!

 

[thomasdf]

Would this mod work on a RE150 ?

 

[abbey road d enfer]

Would this mod work on a RE150 ?

It should. However you may have to re-tune the bias trap, depending on the actual bias frequency in the RE150. You need an oscilloscope to do that.