I fell in that same trap. You are likely good to go. Changing the resistor doesn't make the voltage change that much. But you effectively lowered current as intended
Why? You would still have to measure the pot at whatever setting it is at, put it in circuit, measure voltage through it, do the math to determine how much additional resistance to add. You won't see the voltage suddenly be correct as you turn the pot or however you increase the resistance. I had the same thought, until I put in correct resistor value and saw voltage not correct ...it won't be, but current is.
Yes. You are radioactive man right?Here's another data point. When I have the Pearl 3 plugged into Korg B1 and nothing plugged into Pearl 3, I can increase the loudness of the hum by waiving my hand over the open RIAA. If I touch the chassis of the Pearl 3, the Korg, or the Aleph Jzm, the hum gets a little quieter.
Maybe I'm emitting EMI?
Perhaps I'm being selectively blind, looking at Jim's build guide step 27 says nada about LED resistor, Step 27 Stuff Semiconductors.
Very simply, so audio ground only touches the chassis at one single location, which is what eliminates ground loops in the audio path.
@Toys4Boys
two observations:
step 27 is not step 25
The JFET-resistor combination is a constant current source. the resistor is chosen to set the current you want. A long time ago in the Audio Amateur Richard Marsh specified particular diodes to do this kind of thing... pick the diode according to the current. i.e 1N5314. But these are expensive.
two observations:
step 27 is not step 25
The JFET-resistor combination is a constant current source. the resistor is chosen to set the current you want. A long time ago in the Audio Amateur Richard Marsh specified particular diodes to do this kind of thing... pick the diode according to the current. i.e 1N5314. But these are expensive.
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with a matched resistor in the package I would assume (so the user doesn't have to futz around).
Convenience at a price.
Wait, hang on everybody… What LED are we talking about??
The panel lights are light bulbs only. The dropping resistors are on the PCB, R26 on the RIAA boards, R11 on the PSU. No additional dropping resistor required.
Step 25 shows adding wire to the LEDs so they reach the panel.
The red LED on the RIAA board (D1, pn# LTL-1CHE) is a diode voltage reference for the output stage that happens to light up. There is no resistor for the red LED.
The panel lights are light bulbs only. The dropping resistors are on the PCB, R26 on the RIAA boards, R11 on the PSU. No additional dropping resistor required.
Step 25 shows adding wire to the LEDs so they reach the panel.
The red LED on the RIAA board (D1, pn# LTL-1CHE) is a diode voltage reference for the output stage that happens to light up. There is no resistor for the red LED.
Always good to bring that up, as it’s confusing, for sure!
If the LED are inserted backwards they will just fail to light, but will not be damaged.
If the LED are inserted backwards they will just fail to light, but will not be damaged.
Yes, that was my dodo move. Got fooled by plus sign.
Guide even points out to not be fooled by capacitor plus sign for LED. Still got me...but I'm not as bright as the rest.
Guide even points out to not be fooled by capacitor plus sign for LED. Still got me...but I'm not as bright as the rest.
I thought that they lit up initially, is 20v too much for the LED's?
I'm still curious as to why it was 120Hz vs 60Hz. Is there an obvious explanation?
I'm still curious as to why it was 120Hz vs 60Hz. Is there an obvious explanation?
This is my first time ever dealing with an RIAA phono preamp. I had no clue how sensitive they are. When tapping gently on the input wire made an audible tapping in my speakers (sounds like when you tap on diaphragm of a stethoscope), I then began to understand how truly sensitive they are.
I guess in an ideal world we should use metal blanking plates for XLR holes and also perhaps covering up the cooling grate with fine steel mesh on top and bottom plate. Could help eliminate noise paths as those are certainly openings in chassis?
Are the Nuetrik XLR blank plates metal? I made some 3D printed plates, but obviously not gonna help with EMI.
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Measure the voltage across the LED once you connect to the right way round. 😎
It is extremely difficult to discern 120 vs 60 by ear. Show me a scope photo and we'll talk. Also because of the 60hz mains and the prevalence of lots of recited widgets plugged into the outputs all around you house ,he most obvious being LED light bulbs and CFL, the 120hz noise exists strongly as well.
Although I am in the early stages, I have psu package from Randy, and waiting for the kits to be available in the store. While I was at a local hi-fi repair shop in our area and I came across an Ariston turntable that was the shop owners go to player until he bought a more recent TT with automated features.
As I do not plan to use the Pearl 3 exclusively for listening entertainment, I thought the fully manual Ariston (not a lot of bells and whistles) would be a nice starting point and do me well when I wanted to use it. I will have to buy a cartridge for it and the shop owner liked the Denon 103 MC he was using with it. Shop owner wants $800 Cdn, so I thought that was reasonable. Since I know little about TT, I did some research on Ariston/Linn heritage and it seems good quality. I welcome any comments on my upcoming purchase.
Thank you for your time.
MM
As I do not plan to use the Pearl 3 exclusively for listening entertainment, I thought the fully manual Ariston (not a lot of bells and whistles) would be a nice starting point and do me well when I wanted to use it. I will have to buy a cartridge for it and the shop owner liked the Denon 103 MC he was using with it. Shop owner wants $800 Cdn, so I thought that was reasonable. Since I know little about TT, I did some research on Ariston/Linn heritage and it seems good quality. I welcome any comments on my upcoming purchase.
Thank you for your time.
MM