The neutrix D series XLR connectors can be mounted from the front or the rear, . when mounted from the rear, you only see the connecting receptacle portion. I agree, this is neater than seeing the rectangular faceplate as you do when front mounting
Very nice build itsikhefez. I like how you kept the wires nice and short. Any issues with hum or noise during your build process or was it quiet from the beginning? I’m about to start soldering on the Pearl 2 boards.
To go back to my power supply build everything is great now that I have the caps in. I also soldered in a .47ohm 3W resistor to each rail per 6L6’s suggestion. Now I am getting 30.8V on the + rail and 30.7 on the - rail. I expect a slight drop in voltage when loaded by the Pearl 2 boards but not much. I would think any transformer will experience voltage drop due to the load, not just Anteks. I have about 8 of them in various builds now and they have been performing well. The only “funny” thing here was the behavior of the diodes when not connected to the caps. I wasn’t expecting that. I really appreciate all the shared knowledge to help people like me along who are learning more and more from the community every day. Thank you!
To go back to my power supply build everything is great now that I have the caps in. I also soldered in a .47ohm 3W resistor to each rail per 6L6’s suggestion. Now I am getting 30.8V on the + rail and 30.7 on the - rail. I expect a slight drop in voltage when loaded by the Pearl 2 boards but not much. I would think any transformer will experience voltage drop due to the load, not just Anteks. I have about 8 of them in various builds now and they have been performing well. The only “funny” thing here was the behavior of the diodes when not connected to the caps. I wasn’t expecting that. I really appreciate all the shared knowledge to help people like me along who are learning more and more from the community every day. Thank you!
Hey, we are all learning something. Bridges produce a slight voltage drop. I got it!
The funny thing about the Anteks is the spec.
Most transformers that I investigate have secondary voltage designations that are low with respected to load. My Triads for instance.
From what I can see an Antek that produced a measured no-load voltage on the secondary of 32VAC would be named a 32-0-32 rather than the 24-0-24 volts of the Triad I tested. That's an important thing to know especially if a project calls for a 22-0-22 without specifying the manufacturer and the raw supply is feeding regulators that require more than a couple of volts to work properly.
By the way, did you install the bleeders too? I believe they would act as a pre-load load and yield a bit of a voltage drop too.
I've read that advanced regulators might benefit from such a pre-load too so that they perform better as source and sink of the variations they are intended to compensate for.
The funny thing about the Anteks is the spec.
Most transformers that I investigate have secondary voltage designations that are low with respected to load. My Triads for instance.
From what I can see an Antek that produced a measured no-load voltage on the secondary of 32VAC would be named a 32-0-32 rather than the 24-0-24 volts of the Triad I tested. That's an important thing to know especially if a project calls for a 22-0-22 without specifying the manufacturer and the raw supply is feeding regulators that require more than a couple of volts to work properly.
By the way, did you install the bleeders too? I believe they would act as a pre-load load and yield a bit of a voltage drop too.
I've read that advanced regulators might benefit from such a pre-load too so that they perform better as source and sink of the variations they are intended to compensate for.
Thanks! The issue of noise/hiss/hum is likely dependent on how much gain you have in your system and how sensitive your speakers are.
When the volume knob is set at a loud listening level, there is no noise/hum. You would need to put your ear physically on the tweeter to hear some hiss.
If you crank the volume all the way (no music playing...), then there is some audible hiss and a vague hum from 2-3 inches away.
So essentially, it is very quiet in my system.
@ itsikhefez, Glad to hear it's a great fit in your system. Looking forward to seeing how it pairs with everything in mine soon.
@ mhenschel, I haven't put the bleeders in yet, but will likely use something like 10K, 1/2 watt since I have some in my parts stash. So that shouldn't affect voltage much. Metal work for the psu case, cleaning up wiring, and installing LED's are next on my list. Then on to the Pearl 2 chassis and boards.
@ mhenschel, I haven't put the bleeders in yet, but will likely use something like 10K, 1/2 watt since I have some in my parts stash. So that shouldn't affect voltage much. Metal work for the psu case, cleaning up wiring, and installing LED's are next on my list. Then on to the Pearl 2 chassis and boards.
Wanted to close the loop and share the PSU in case its helpful for future builders.
Built per Wayne's schematic, case is Hammond 1455Q2202 with FPE panels.
Cable is 20AWG hookup wire. Use of cable gland reduces some cost of connectors and work.
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Thank you both !!
Both panels made by Front Panel Express.
Material is 4mm sandblasted/anodized aluminum.
You can cut the cost of the panels slightly with 2mm or 3mm panels instead
Both panels made by Front Panel Express.
Material is 4mm sandblasted/anodized aluminum.
You can cut the cost of the panels slightly with 2mm or 3mm panels instead
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I like your build and it's similar to mine in the size of the case and the close quarters of the wiring and boards, although your's is way nicer 🙂
When I turn up the volume slightly passed normal listening level, I get hiss and hum that I can hear 3 feet from the speakers. My cart is .3mv and I have the Pearl set up at 65db of gain, is that too much and causing the issue? I think I am getting some voltage issues because when I switch to another input on my receiver from the Pearl input I get a loud squeaking noise.
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There are a few variables here, I can't say for sure why yours would be noisier.
To start, we both may have different "normal listening levels", so our baseline to inspect the level of hiss could be different.
Mine is built with 55dB, so the extra gain could contribute as well. If you have sufficient range in your volume put with 65dB (say, if you are at mid-level with your preamp at normal listening levels), then it would be worth a shot bringing the Pearl down to 55dB.
Lastly, the RN55D resistors mentioned in the PDF and in the sample BOM are 100ppm.
Wanye wrote in the Pearl documentation:
Now, I wouldn't recommend replacing your resistors and I have no idea if this actually makes a difference, but I thought it would be worth pointing out for future builders when starting from scratch.
To start, we both may have different "normal listening levels", so our baseline to inspect the level of hiss could be different.
Mine is built with 55dB, so the extra gain could contribute as well. If you have sufficient range in your volume put with 65dB (say, if you are at mid-level with your preamp at normal listening levels), then it would be worth a shot bringing the Pearl down to 55dB.
Lastly, the RN55D resistors mentioned in the PDF and in the sample BOM are 100ppm.
Wanye wrote in the Pearl documentation:
Trying to address this, I went with RN55E (25ppm) resistors, and RN55C (50ppm) where "E" was not available.
Now, I wouldn't recommend replacing your resistors and I have no idea if this actually makes a difference, but I thought it would be worth pointing out for future builders when starting from scratch.
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The ppm in that spec is temperature coefficient. The noise spec does not change with the various coefficient characteristics and is given as .10 uV per V or less, depending on actual resistance.
Still, points for using the super tight ones.
Still, points for using the super tight ones.
PSU working!
Got the PSU up and running this weekend,
+ & - 30.5 unloaded, I’m using the antek AS0522 transformer and the store universal PSU.
My CRC resistors are 10R, can drop the resistance if I need a bit more voltage at the regulators once it’s loaded by the pearl boards.
Thanks for all the help so far!
Got the PSU up and running this weekend,
+ & - 30.5 unloaded, I’m using the antek AS0522 transformer and the store universal PSU.
My CRC resistors are 10R, can drop the resistance if I need a bit more voltage at the regulators once it’s loaded by the pearl boards.
Thanks for all the help so far!
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Got mine together last night, but it doesn't sound right. The symptoms sound similar to what others have diagnosed as a bad Q2--distortion and clipping. How can I test to confirm that this is the problem before I break out the solder sucker and replace those MOSFETs?
However, it is sounds like the same problem I had with my buddy's Pearl 2, which sounds totally fine with his table and cart (Sota + Grado). Mine is a Rega Planar 6 with an Ortofon blue. I have 47k on r19, tried 100pF, 150pf and omitting c22, r15 is jumped, c13 is jumped, c8 omitted, c21 omitted, c7 omitted. I checked all the pads for solder bridges. Power supply puts out a steady exact +/-31V. The offset is as close to 0v as I can get it (hovers between +/- 1 mV). R4 and R33 read +/- 23.9v, respectively.
What is going on? Feeling pretty frustrated.
What is going on? Feeling pretty frustrated.
First, are you absolutely sure the turntable/cartridge is tracking properly? Everything aligned and tracking weight on the heavy side of recommended?
Yeah, I'm almost certain the turntable is tracking properly. It sounds great with an NAD phono and fine with the built in phono on my surround sound.
What are the reasons behind omitting C21 and C7?
I don’t recall reading about these in the thread, perhaps you can point me to the discussion for each?
C7 was mentioned to cause some instability and is recommended to not populate.
C21 though.... have not seen anything to omit that.
C21 is in the BOM as a 22uF ELNA Silmic II, maybe thats your issue.
The only other caps potentially omitting would be the output caps in case you do the R14 mod and are sure of ~0mV DC
C21 though.... have not seen anything to omit that.
C21 is in the BOM as a 22uF ELNA Silmic II, maybe thats your issue.
The only other caps potentially omitting would be the output caps in case you do the R14 mod and are sure of ~0mV DC
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