U3 and U4 are the halves of the dual opamp.
This would be very simple to check, swap the opamp left to right.
Hello PierreQuiRoule,
the left DIP-switch is for resistor loading (MC), the right DIP-Switch is for capacitance loading (MM).
Greets
Dirk
Troubleshooting can be frustrating. If you have not done so already, flip the board and carefully inspect for solder bridges. It happens...
Next, set your Voltmeter to DC, ground the black lead, then probe and compare bias voltages between your known-good and faulty boards to verify that they are the same. Check supply rails, output, and both sides of R1 as a start.
Pearl 3 - Denon DL-S1 MC cartridge load 1000ohm seems to get close to the sound with SUT.
@bentconvert and all,
Dip # 8 and #6 did the job. #8 Took away nearly all of the whine, but there was still a very high-frequency whine (I mean very high). So I tried various combinations, and #6 took that away and did not affect the sound much...Of course, I read about number #8 for HOMC in the build docs, but did I remember ?noooo.....LOL! So many thanks to @bentconvert and @6L6 ..
The unit sounds significantly better than my older pre and I absolutely love the sound of the Hana! It's a whole new level of audio experience for me.
Dip # 8 and #6 did the job. #8 Took away nearly all of the whine, but there was still a very high-frequency whine (I mean very high). So I tried various combinations, and #6 took that away and did not affect the sound much...Of course, I read about number #8 for HOMC in the build docs, but did I remember ?noooo.....LOL! So many thanks to @bentconvert and @6L6 ..
The unit sounds significantly better than my older pre and I absolutely love the sound of the Hana! It's a whole new level of audio experience for me.
They are, yes.
On the good board, pin 4 to gnd is -15V and pin 8 to gnd is +15V. On the bad board I'm reading -6.8V and -.061V respectively for those pins.
10mm tall and nothing from the board is touching the chassis underneath.
Either side of R1 on the good board reads 5.525v and 14.08v and I got a big zero on either side of R1 on the faulty board. I'm checking for solder bridges and easy-to-find shorts and there's nothing I can see. I'll keep looking though.
Sigh. Yep.
Only checked those like three times. Or thought I did. I will swap and if you don't hear back from me, my problem is solved. As always, thank you so much for the help and suggestions. I'm getting better at this with everything I build, but sometimes the easiest oversights amount to literal silence.
Only checked those like three times. Or thought I did. I will swap and if you don't hear back from me, my problem is solved. As always, thank you so much for the help and suggestions. I'm getting better at this with everything I build, but sometimes the easiest oversights amount to literal silence.
Ok. Swapped the regulators to their proper positions and we're good to go. Records are spinning and music is playing. So far, the preamp sounds great. It replaces a Hagerman Bugle 2, which sounded amazing, but the Pearl 3 is already leaps ahead.
There is however some mysterious noise in the background - a mix of hum and other stuff. It's subtle when the volume is set at a reasonable playback level, but super obvious when there's no signal but the volume is turned up. I recorded an mp3 of the noise, with my iphone, about 2 inches from my speaker. Click here for it. The noise is in both channels.
Cables have been swapped, and it's still there. I've got some ferrite clamps arriving in a day or so, which might help. That said, if you've ever heard this noise and know what it might be, let me know. I'm so close on this - I just need that background to be quiet.
FWIW - VPI Traveler TT, Goldring E3 cart, Wayne's BA2018 Pre, and Aleph J amp.
There is however some mysterious noise in the background - a mix of hum and other stuff. It's subtle when the volume is set at a reasonable playback level, but super obvious when there's no signal but the volume is turned up. I recorded an mp3 of the noise, with my iphone, about 2 inches from my speaker. Click here for it. The noise is in both channels.
Cables have been swapped, and it's still there. I've got some ferrite clamps arriving in a day or so, which might help. That said, if you've ever heard this noise and know what it might be, let me know. I'm so close on this - I just need that background to be quiet.
FWIW - VPI Traveler TT, Goldring E3 cart, Wayne's BA2018 Pre, and Aleph J amp.