Ah, I see it now, thanks! I missed the solder-dot at far right which shorted them together.
M2 (and M2x) need 3V RMS at the Edcor transformer primary, to produce full rated output power into an 8 ohm load. Do you think this circuit will be able to drive 3V RMS into the Edcor transformer? The article on the First Watt website shows a graph that only goes up to 2V RMS output.
_
M2 (and M2x) need 3V RMS at the Edcor transformer primary, to produce full rated output power into an 8 ohm load. Do you think this circuit will be able to drive 3V RMS into the Edcor transformer? The article on the First Watt website shows a graph that only goes up to 2V RMS output.
_
Attachments
Just finished my H2 V1 build. Thought I’d share my challenges.
Took a few hours to stuff, adjust and wire it into a Hammond box. I’m not fast – an experienced builder could probably knock it out much quicker. On my initial test, one of the channels went silent after a few seconds of playing.
I checked continuity between the PCB outputs and cables – no issues.
Checked DC voltages – no issues
Swapped the JFETs (I used sockets). Problem remained on the same channel - so not the JFETS.
Inspected my soldering and found I missed one lead
. Soldered this – no change . All the other solder joints looked good with no bridging.
Reflowed all of the points on the problem channel. Problem solved! Just because it looks OK doesn’t mean it’s actually OK.
I don’t have a distortion analyzer, so I used the chart from the “H2 HARMONIC GENERATOR - DIY VERSION 1” article and targeted for 1.0% to 1.5% distortion. I have 90 dB speakers and listen at low levels, so thought a bit higher on this curve may be appropriate.
As for initial listening impressions… I found the differences subtle. A bit more airy and bright. My wife said she liked it better before. She liked the “airy” part, but not the brightness. She said it sounded like the treble had been turned up too much. I’m on the fence. Might need to tinker with the voltages more.
Either way, it was a fun project. And a big thanks to NP for the kit!
Took a few hours to stuff, adjust and wire it into a Hammond box. I’m not fast – an experienced builder could probably knock it out much quicker. On my initial test, one of the channels went silent after a few seconds of playing.
I checked continuity between the PCB outputs and cables – no issues.
Checked DC voltages – no issues
Swapped the JFETs (I used sockets). Problem remained on the same channel - so not the JFETS.
Inspected my soldering and found I missed one lead
. Soldered this – no change . All the other solder joints looked good with no bridging.Reflowed all of the points on the problem channel. Problem solved!
Just because it looks OK doesn’t mean it’s actually OK.I don’t have a distortion analyzer, so I used the chart from the “H2 HARMONIC GENERATOR - DIY VERSION 1” article and targeted for 1.0% to 1.5% distortion. I have 90 dB speakers and listen at low levels, so thought a bit higher on this curve may be appropriate.
As for initial listening impressions… I found the differences subtle. A bit more airy and bright. My wife said she liked it better before. She liked the “airy” part, but not the brightness. She said it sounded like the treble had been turned up too much. I’m on the fence. Might need to tinker with the voltages more.
Either way, it was a fun project. And a big thanks to NP for the kit!
Many thanks for the circuit and kit Nelson and 6L6.
I used H2 (no volume control, standard build, gains, swap outputs terminals for negative phase) in line between a CD player and Whammy. I set H2 to 1% from the chart in the article. The distortion seemed excessive and volume level is much lower than without H2. Both channels are similar. Does this make sense ?
Going straight from the CD to Whammy sounds great.
Could the problem be gain? If so why would with H2 sound lower and not higher ? Is it destructive interference with whammy ?
I can calculate 14db gain difference between the two input voltage divider options. Perhaps I will try unity gain next.
Thanks in advance for any suggestions.
I used H2 (no volume control, standard build, gains, swap outputs terminals for negative phase) in line between a CD player and Whammy. I set H2 to 1% from the chart in the article. The distortion seemed excessive and volume level is much lower than without H2. Both channels are similar. Does this make sense ?
Going straight from the CD to Whammy sounds great.
Could the problem be gain? If so why would with H2 sound lower and not higher ? Is it destructive interference with whammy ?
I can calculate 14db gain difference between the two input voltage divider options. Perhaps I will try unity gain next.
Thanks in advance for any suggestions.
That is not what Mr Pass suggested in his article about the H2 V1.
I quote: (Point number 5 right at the end)
"Remember to reverse the phase on the speaker connections to the amplifier."
I've got both. I prefer the B1 as I find the H2 has a little too much effect on the sound.
I haven't played with the pots on the H2 other than setting it up originally, so I'm reserving judgement until I get around to playing with it fully.
Gonna have a couple of weeks isolation coming up soon, so plenty of time to play then!!
I haven't played with the pots on the H2 other than setting it up originally, so I'm reserving judgement until I get around to playing with it fully.
Gonna have a couple of weeks isolation coming up soon, so plenty of time to play then!!
