H2 V2 BUILD

[vdupham]

Maybe it's oscillating. J113 is not a very quiet fet, but mostly when used as a phono stage input,
otherwise we don't hear complaints.

Do you have a Gate resistor on the Jfet and an output Source resistor in series?

I made it exactly like schematic and pcb on firstwat website, last revision. But I use 100ohm 3296W not 50ohm.

 

[Tom369]

Ok, I will think about all of this and read more. I checked the resistance at the input and outputs of the H2 and got about 48K Ohms. Does that mean that the input and output impedance for the H2 is 48K? If I put a 50K volume pot does that mean the input impedance will go to 50K Ohms?
I am going to use a Geshelli Labs J2 DAC as the source but I am not really sure how to check the output impedance on that.

 

[vdupham]

Hi, what different sound when I use H2 like a preamp ? I am using single end connect L R GND, can I use H2? Because H2 need 2 RCA connection input.

 

[Nelson Pass]

2 rca with common ground for both in and out. Yes, that's the ticket,

 

[Tom369]

Hello All. Today I tried to connect the RCA jacks to the board but I have a problem. For example the output side of the board has 2 wires per channel. Output and ground. But don't I need to connect 2 RCA jacks per channel (black and red)? And since each RCA has 2 connections doesn't that mean I need 4 connection wires and not just 2? This might be simple but since this is my first build I really don't know what to do. Can someone please explain how to connect the RCA jacks? Of course the same issues goes for the inputs.
Thanks. Tom

 

[elwood625]

But don't I need to connect 2 RCA jacks per channel (black and red)?

No. One RCA for each channel, Red is right channel, black is left channel.

 

[elwood625]

Red RCA for right channel has two wires that go to it. Hot wire (+) to center pin of the RCA and ground (-) to the outer case of the RCA.
Repeat for Left channel.

 

[Tom369]

Hold on. I think I was having a little trouble with my brain. For some reason I was thinking this board gets connected to the speaks. But now by brain is working better again and I am remembering this gets connected to an amp. So yes 1 RCA per channel. Sorry everyone. Thanks for the reminder.
Tom

 

[dtaylo3]

Would an A23 battery be sufficient to power this?

 

[elwood625]

Not for very long, the spec sheet shows a continuance draw of 0.48mA, I would think the H2v2 would draw 5 - 10mA.

 

[viltsone]

How to get this H2 to work with a balanced in and a balanced out to active speaker (can not swap speakers wire)? Any other solutions to get a deeper soundstage and a vintage sound touch using active speakers set up?

Using 2SK209 or other JFET-s can we get the same effect?

 

[Mark Johnson]

Hi @viltsone , you will probably need to hire a skilled circuit designer and a PCB layout artist, unless you are able to perform those functions yourself (?). Another option would be to find a pre-made circuit board (eBay? AliExpress? Craigslist?) that includes balanced in and balanced out, and also operates from the same supply voltage as this H2.

 

[myleftear]

Not nonsense, just one piece backwards and a bit more detail needed, IMO.

If my corrections are nonsensical, pls correct me!

Ok, I got pretty (read: somewhat) close, didn't I?

 

[viltsone]

@elwood625 Did you tried to use H2 v2 generator in a balanced mode using 2 pcb boards? How that worked out? Did you changed speaker polarity also or in a balanced amp it works also if input polarity is changed?

Anybody else can comment that?

 

[DrDyna]

I was just going to ask the same question about building a balanced version.

Am I correct in assuming that the issue of the signal being inverted is easier to deal with in a balanced configuration by simply reversing pins 2 and 3 on the output side?

 

[elwood625]

Did you tried to use H2 v2 generator in a balanced mode using 2 pcb boards?

Yes, I built a Balanced version of the H2v2 using two PCB's, one per channel. In order to make it work, you need a distortion analyzer (I use REW software on my laptop), a good sound card and a very low distortion sine wave generator.
I used 5W 10K resistors to load the output and adjusted the two pots to give 1% H2 with the lowest H3 possible. This process takes me a couple of hours for each channel, once completed.

Did you changed speaker polarity

Yes, that was the easiest way, the adjustment for positive H2 is easier to make than negative H2 and provides lower H3. I learned how to do it when I made my Balanced B1 Korg preamp (still one of my favorites), it transformed the sound stage from my ALEPH J. I love how it fills the room wall to wall and ceiling to floor. Friends and family are amazed at the sound that combination makes.

The build itself is very easy, it's adjusting that takes time and patience.

 

[jameshillj]

For those that have a problem with changing the speaker polarity, you can just insert a 4 pole switch to the speaker lines, or a couple of relays if you wanted remote control ...

 

[Nelson Pass]

Or use banana plugs, easy peasy....

 

[viltsone]

Thank you for answers. I still do not have answer if this works if I am using balanced active speakers where I can not change speakers wires? I only can change balanced input polarity whats going to active speakers input.

 

[Nelson Pass]

Is the speaker input single ended or balanced?