Maybe.. I used the cheaper mean well module and caps listed on the bom. The power supply section is working well. Even with my very ugly soldering of the surface mount components..
I’m keen for you to get yours playing music with the J113 JFETs to prove that section works too. Give me some hope!
I’m keen for you to get yours playing music with the J113 JFETs to prove that section works too. Give me some hope!
Yep, just confirming that the less expensive supply works well. The medical grade one hiccups and does not seem to like all the caps. If I remove a few caps it works well but since the less expensive is working properly, no need to change anything.
Algar, I would omit that medical grade smps from the BoM. I think it must be too borderline for charging the cap bank.
On to the real testing now!
Algar, I would omit that medical grade smps from the BoM. I think it must be too borderline for charging the cap bank.
On to the real testing now!
Mine is dead silent when output directly through headphones, even on max volume (except for a bit of ringing until the nutube settles after the switch on).
You shouldn't be getting hash noise but it could be from the LDR. Where does the LDR source power from?
I was reading this article regarding noise from an LDR and found it interesting:
Tortuga Audio LDR3 Volume Control: Measurements & Review
Having put my build to one side in frustration some weeks ago I started following the thread again and decided to try the cheaper smps as mentioned recently. Smiley face time as now things switch on; nutube glows blue and voltages are within a smidgeon of the values they should be with T7/8 adjustable with the trimmer. I now need to get it cased and have a listen over the weekend. Thanks Avtech for your previous advice.
@Marra
It was the same issue on my side and the cheaper SMPS got it working. Other SMPS should be removed from the BoM.
@avtech23
I have the same issue with a 23 steps 50K attenuator but I suspect the IPS from my test amplifier causing this issue when coupled to this preamplifier. I will test and report back.
Thanks
Do
It was the same issue on my side and the cheaper SMPS got it working. Other SMPS should be removed from the BoM.
@avtech23
I have the same issue with a 23 steps 50K attenuator but I suspect the IPS from my test amplifier causing this issue when coupled to this preamplifier. I will test and report back.
Thanks
Do
Will let you know once i received and swap the resistors, now finding an enclosure for it.
I didn't crank up full volume to listen for noise yet, but at my normal listening level, it was quiet, i did not hear any "Shhhhhh" noise, only the usual slight hum that is coming from my M2X.
Have you tested it with shorted inputs to verify whether the noise is internal or external?
Any SMPS or CFL nearby? I had awful noise on one amp that was caused by one of those cheapo little plug-in USB charger cubes.
Swapped the 392k for 332k.
I didn't pick up any significant difference between the two. So i just leave the 332k intact.
At max volume, without music, there is a very slight "shhhh" noise, similar to that of a valve set, but a lot hell lower than my valve preamp.
There is something very musical about this preamp as compared to the rests of my sets,
I actually enjoy this set very much.
I didn't pick up any significant difference between the two. So i just leave the 332k intact.
At max volume, without music, there is a very slight "shhhh" noise, similar to that of a valve set, but a lot hell lower than my valve preamp.
There is something very musical about this preamp as compared to the rests of my sets,
I actually enjoy this set very much.
. Had a listen to a couple of cd's yesterday; very pleased with the sound. Will have a proper listen this afternoon through the PMC's.
