And we should still get confirmation, that PSU-ground at output or audioground from BA2018-board is referenced to
earthground (from AC-inlet)?
Cheers
Dirk
earthground (from AC-inlet)?
Cheers
Dirk
Could you reduce your voltage swing (of the sinus- signal out of the generator) to anywhere around 500mv to 1V ?
Only to check if the clipping dissappears?
And is your PSU-ground at output of PSU / OV referenced to earthground?
Cheers
Dirk
Only to check if the clipping dissappears?
And is your PSU-ground at output of PSU / OV referenced to earthground?
Cheers
Dirk
Hello oloppolo,
my imagination is, that your BA2018 works properly - really.
I think the problems are in your measurement setup - and : you will have to make the connection from PSU-ground
at output of PSU to PE (protective earth) of the AC-plug. I read about the different plugs you use in Italy. Some have
no PE (2-pole), some have (3-pole). If you have EURO - norm plugs in your house it is easy. But please check with an
italian electrician! I don't want to be responsible for an accident.
And in this forum are so many members from Italy - a fast PM (private message) over the forum, and I am sure you will get
help. And from a native italian speaker. There is also the 'barrier' to communicate in a foreign language...
Cheers
Dirk
my imagination is, that your BA2018 works properly - really.
I think the problems are in your measurement setup - and : you will have to make the connection from PSU-ground
at output of PSU to PE (protective earth) of the AC-plug. I read about the different plugs you use in Italy. Some have
no PE (2-pole), some have (3-pole). If you have EURO - norm plugs in your house it is easy. But please check with an
italian electrician! I don't want to be responsible for an accident.
And in this forum are so many members from Italy - a fast PM (private message) over the forum, and I am sure you will get
help. And from a native italian speaker. There is also the 'barrier' to communicate in a foreign language...
Cheers
Dirk
Your BA2018 preamp works fine. Maximum voltage from an input to the preamp is LESS than 2v, even at 2v input, it would be like the preamp is at full volume! Set your signal generator to 1v and use the 10K ohm resistor for a load, the scope will show a very nice sine wave with NO clipping.
When I first started building electronic projects, USA had only L & N, no ground. I'm sure you can find information on the web or even this forum regarding safe operation with and without ground.
DON'T STOP NOW! This is a very nice sounding preamp, so put your boards back in the enclosure and wire up inputs and volume control. Then go listen to music.
+ UNO (translation : ONE) on Cubicincher and Elwood625
It would be a shame to give up... especialy when all is most probably working fine.
It would be a shame to give up... especialy when all is most probably working fine.
I think my DAC RCA output is specified as 2.1Vpp max. The 2.5V shown was RMS?
If 2018 linestage is expected to clip or not must depend on the gain setting (feedback resistor value) and the rail voltage?
If 2018 linestage is expected to clip or not must depend on the gain setting (feedback resistor value) and the rail voltage?
Yes, you are correct, the preamp can be built for either XLR (Balanced) or RCA (Single Ended). When built for XLR (Balanced), IN+ is used for XLR pin 2, with ground to XLR pin 1. The other half/channel has XLR pin 3 to IN- and XLR pin 1 to ground. You would need another BA2018 PCB for the other XLR channel. I built a Balanced version of the BA2018.
For RCA (Single Ended) you short IN- to ground for the ground side of the RCA input and IN+ for the "HOT" side (or center pin) of the RCA input. If you don't short IN- to ground when using RCA (Single Ended) the amplification is reduced.
As far as building during a full moon, considering your project works fine I don't think a full moon had any adverse effect. Your only mistake was measuring the BA2018 with 2.5 V input, you are NOT alone making this mistake. Very few of us builders are Electrical Engineers, I'm a retired Mechanical Engineer with DIY audio as a hobby.
Hi, I powered the input with my smartphone and I must confess that it happens as elwood625 said. There is no cutting of the sinusoid and the amplitude is multiplied by connecting in- and gnd. 🙂
The jumper is not shown as the jumper is not part of the schematic, which only shows things on the PCB. (And if you were building as balanced you wouldn't use the jumper.)
Some posts moved to their own thread - https://www.diyaudio.com/community/threads/modified-version-of-waynes-ba-2018-linestage.423279/Oscilloscope utility is UNDERSTATED. I used mine to diagnose a flow sensor problem with a lawn sprinkler system project at my Mom's home. A few months later, my younger cousin borrowed the scope to diagnose otto-isolator problems in his Florida HVAC system... He's a tradie that is sharp and eager to learn. The Scope can help you repair appliances and other things around the house. Must own!