Hi,
I just built my new amp yesterday, using a nc122mp module and a ghent audio case.
When I first powered on the amp, I got a very loud hum in the speakers. (>10m audible)
As soon as the preamp was turn on, no more hum noise.
Then I tested the amp alone (without any xlr plugged in, only speakers out) and still had the noise.
So I once again checked my solders, and notice a little lug on the xlr socket, near the pin 1.
After some readings, I decided to solder the pin 1 with this chassis lug, and the noise mostly disappeared, when no XLR cable is plugged.
If I plug the XLR cable again, the noise is back, and if I "move" the xlr cable, the noise changes.
Now, I've a few questions:
I just built my new amp yesterday, using a nc122mp module and a ghent audio case.
When I first powered on the amp, I got a very loud hum in the speakers. (>10m audible)
As soon as the preamp was turn on, no more hum noise.
Then I tested the amp alone (without any xlr plugged in, only speakers out) and still had the noise.
So I once again checked my solders, and notice a little lug on the xlr socket, near the pin 1.
After some readings, I decided to solder the pin 1 with this chassis lug, and the noise mostly disappeared, when no XLR cable is plugged.
If I plug the XLR cable again, the noise is back, and if I "move" the xlr cable, the noise changes.
Now, I've a few questions:
- when I compare with same ncore/ghent audio builts pictures on the net, nobody solder the pin 1 with the chassis lug. Is it needed ?
- I used thermal compound between the case and ncore module (not the full area). Maybe it "breaks" the ground connection, so it's why I needed to solder pin1 with chassis lug ?
- when reading the "Legacy pin 1 problems" whitepaper on hypex site, I understand the good solution is to solder the pin 1 to chassis, and no connection between audio circuit and pin1.
But in the ghent audio case kit, the pin 1 should be soldered to J4.3 and J4.14 (GND).
Do I need to bypass it, and only connect pin 1 to socket ground lug ?
- Do I need to soldier pin1 to chassis lug in the XLR cables too ?
Last edited:
Another question:
Is there a way to remove the "pop" on power on ?
If I use standy spms instead of full power off/on the amp, will it help ?
Thanks
Is there a way to remove the "pop" on power on ?
If I use standy spms instead of full power off/on the amp, will it help ?
Thanks
PLEASE don't be offended by this... but looking at your picture I believe your problem could be poor soldering... Sorry, but you wouldn't be the first guy to fall victim to cold solder joints, dry solder joints or just plain poor technique.
Not offensed, my last solder was 25 years ago at college, and never was very talented anyway 🙂
I struggled with speaker connectors.
For XLR, I think it was quite ok.
Whatever, how can I verify my solder joints?
Multimeter check seems ok.
I struggled with speaker connectors.
For XLR, I think it was quite ok.
Whatever, how can I verify my solder joints?
Multimeter check seems ok.
Try to make a grounding plan, so you see all connections. Then we can discuss your project and give hints where to improve.
Practice soldering outside of the amp!
Anyone can learn it, you do not need talent, just have to see the necessity of any single connection being perfekt.
Take some left over pieces of wire and what ever is flying around to get the edge of soldering.
Clean the tip in some cotton cloth,
apply enough heat,
pre-solder both components before making the final connection.
No soldering skills = no skill to build a good amp. Such easy!
Practice soldering outside of the amp!
Anyone can learn it, you do not need talent, just have to see the necessity of any single connection being perfekt.
Take some left over pieces of wire and what ever is flying around to get the edge of soldering.
Clean the tip in some cotton cloth,
apply enough heat,
pre-solder both components before making the final connection.
No soldering skills = no skill to build a good amp. Such easy!
I practiced before, making a pair of XLR cable. 😅
First I pre-solder the wire, then the XLR pins, and finally solder them together.
I think the last step was not so good: I put the wire in the XLR pin, then put my soldering gun on top, and 2/3 seconds later it was soldered.
For the speaker connectors, it was really difficult to pre-solder the connector. The tin didn't 'glue' to the connector, and I had to retry multiple times.
Solder the wire to the connector was complicated too, I had to let the gun a long time before it worked.
I think my gun is not very efficient.
It's an eBay 50$ basic model, with temperature control (but sure it doesn't work.)
First I pre-solder the wire, then the XLR pins, and finally solder them together.
I think the last step was not so good: I put the wire in the XLR pin, then put my soldering gun on top, and 2/3 seconds later it was soldered.
For the speaker connectors, it was really difficult to pre-solder the connector. The tin didn't 'glue' to the connector, and I had to retry multiple times.
Solder the wire to the connector was complicated too, I had to let the gun a long time before it worked.
I think my gun is not very efficient.
It's an eBay 50$ basic model, with temperature control (but sure it doesn't work.)
Being a beginner myself, I can‘t give you specific advices but you may read about good solder here: Eutectic Solder - diyAudio Guides
And find some guides about soldering technique.
HTH david
And find some guides about soldering technique.
HTH david
Wow, good guide (so it seems to me)
Only that by scrolling through, I missed details about soldering finesse. 6l6 (I believe) has a great description, or check YouTube...
Do yourself a favour and buy a good soldering station, if you plan on doing more diy, I bought a used Weller WTCP51, and it's perfect for my needs, you can get all spareparts and alot of different tips.
3 Soldering mistakes beginners make...
1) Not enough heat. When you touch the tip of your iron with solder it should melt immediately. When you tin wire you should see the solder flow into the strands evenly.
2) Not enough solder. Solder isn't meant to cover a tiny spot where you plan to put the wire. It should "tin" the entire surface of the connector. Then you tin your wire. Put a little fresh solder on your iron then all you need to do is hold it in place until the solder flows together,
3) Not enough time. Especially on circuit boards, you should hold your iron on the junction of the board and the lead for a couple of seconds. Then apply solder so that it flows evenly across the board and lead. Then stay on it for a couple of seconds to make sure the flux and any air pockets are eliminated from the joint.
There is a certain knack to good soldering. It's a learned skill, but fortunately it's not really all that difficult...
Common Soldering Problems | Adafruit Guide To Excellent Soldering | Adafruit Learning System
1) Not enough heat. When you touch the tip of your iron with solder it should melt immediately. When you tin wire you should see the solder flow into the strands evenly.
2) Not enough solder. Solder isn't meant to cover a tiny spot where you plan to put the wire. It should "tin" the entire surface of the connector. Then you tin your wire. Put a little fresh solder on your iron then all you need to do is hold it in place until the solder flows together,
3) Not enough time. Especially on circuit boards, you should hold your iron on the junction of the board and the lead for a couple of seconds. Then apply solder so that it flows evenly across the board and lead. Then stay on it for a couple of seconds to make sure the flux and any air pockets are eliminated from the joint.
There is a certain knack to good soldering. It's a learned skill, but fortunately it's not really all that difficult...
Common Soldering Problems | Adafruit Guide To Excellent Soldering | Adafruit Learning System
Generally... with a magnifying glass. The signs of a bad joint are usually visible.