With the inputs shorted, the H2 is the cause of the ringing. C1 is supposed to prevent ANY DC on the output. Since you have 50 mV, I would replace it.
Just so I'm clear on this, the 9V battery for a power supply had no noise/ringing? Both channels?
Do you have access to a 12V battery, to try?
Just so I'm clear on this, the 9V battery for a power supply had no noise/ringing? Both channels?
Do you have access to a 12V battery, to try?
I will replace C1 and give it another go. Unfortunately I don't have access to a 12V unless I were to run several AAs. Perhaps these "friends" I can make might have one.... 💩
This is a very simple circuit regarding parts that could cause an unwanted noise two capacitors and a JFET per channel. You already have the correct power supply and the filter is icing on the cake.
I will do some experiments with one of my four H2 kits, putting in some simulated faulty caps, and see what's up.
New C1 caps in, triad power supply, WHINE IS GONE!
Thanks so much for the guidance, now I have to spend some time with this.
Cheers!
Thanks so much for the guidance, now I have to spend some time with this.
Cheers!
I'm curious what was wrong with the caps now. Are they the ones that were recommended?
Great to hear it's fixed.
Great to hear it's fixed.
If you're not great at soldering things, you may have incidentally ended up damaging the capacitors. It happens. Who knows how many transistors I fried when I was 14.Yes they were the ones from the BOM on this pdf
I swapped them out for same and away the whine went. Probably something I had done wrong from the start.
Anyways it works perfectly now and I'm excited to give it a solid listen.
Thanks for the kindness
Have built both the H2 and H2Rev1 generators but am not trained in electronics.
Has anyone built a balanced version of the H2? Don't remember is there were posts or a thread. Would be interested in DIY instructions for a novice.
Has anyone built a balanced version of the H2? Don't remember is there were posts or a thread. Would be interested in DIY instructions for a novice.
NOT me...but someone?! I understand that running balanced is designed to mitigate noise but is second harmonic affected the same way?
So I guess it would need to be designated "Hno2" or some such. 😵
So I guess it would need to be designated "Hno2" or some such. 😵
Balanced output has the inherent property of cancelling even order harmonic distortion. This will never perfectly cancel out as upper and lower legs of a BTL circuit are never perfectly identical. But it will give the sound a different signature die to relatively higher odd order harmonics. Probably considered to have more “bite” vs original. You could add asymmetry to the circuit by making one leg purposefully different than the other leg. That will restore some of the natural 2nd character.
Yes, that's what I meant. But since the whole point of this thing is to add second harmonic, it seems kind of pointless to build it balanced.
This insight into the downside of balanced operation, at least as it affects the H2, is much appreciated. Thanks!
Do you want balanced inputs or balanced outputs or both? There are ways to manage that, without messing up the second harmonic.
Yes, using the top and bottom half of a CFP in Class A provides balanced output and a dominant second harmonic. See clever design by Aksa here:
https://www.diyaudio.com/community/...2-transistor-se-class-a-headphone-amp.338656/
Balanced output into 49ohm load 2Vpp:
https://www.diyaudio.com/community/...2-transistor-se-class-a-headphone-amp.338656/
Balanced output into 49ohm load 2Vpp:
