Because of the milspec they conform to, the RN series are rated at 1/2 the dissipation they can actually do. Which is to say, an RN55 is a 1/4w CMF55 with lead tin solder, non magnetic leads, but otherwise identical even though the RN55 says it’s a 1/8w resistor on the datasheet.
An RN60 is a 1/2W resistor that says 1/4w on the datasheet.
As Mike says, the Vishay SFR and MRS are the “normal” pass labs resistors with stripes. Also a fantastic resistor.
An RN60 is a 1/2W resistor that says 1/4w on the datasheet.
As Mike says, the Vishay SFR and MRS are the “normal” pass labs resistors with stripes. Also a fantastic resistor.
Although we digress from the purpose of this thread, I believe this to be correct, but have not seen data. I adjust the loading on the fly (dale resistors on a rotary switch next to the phono input) and can definitely hear a difference. More loading (lower resistance) would reduce the range of coil movement, and tends to "tighten" the image. I find the presentation indeed to be dryer, and complex orchestral pieces to be more intelligible (less distortion?). Less loading (higher resistance) would allow the coil to travel further within the magnet field. Van den Hul describes the creation of an artifact "phantom central image" (sorry I don't have the reference at hand where he explains this). This is distortion, but not necessarily of the unpleasant kind. I would describe this as a touch of "bloom" and less loading can sound quite nice on simple music like female vocals and guitar for example. Generally though I don't bother and leave my moving coil cartridges loaded at a few hundred ohms, away from the extremes. YMMV.Yes, I know......it was just a bit of "nerd thinking".......like when you load a dynamo/generator it gets harder to turn. So I thought that the needle would see just a little bit more mechanical resistance when the coil is loaded
@rhthatcher The Yageo resistors are a fantastic product, would be very happy to make a Pearl with them, it world perform perfectly. The only complaint I have is the blue background makes them slightly more difficult to read the stripes than some, but that’s a minor quibble at best.
A great point! Wayne mentioned this in his BA talk, which is the reason he used them and also why they’re currently unobtainium. I’m thinking I’ll build my P3 with some 550/450s from my stash and swap them out some for the 851s next year when they’re scheduled to be back in stock. I’ll see if I can measure or hear a difference, assuming the rework doesn’t introduce some thermal drift / difference, and assuming my measurement rig is stable enough to consistently measure a difference I’m expecting to be very small.
Hello All,
I purchased a few ZTX851 (14) on ebay, I also placed a back order at Mouser.
Any thoughts about the need to measure / sort for good candidates for the SS parts.
I also placed an order for TTA004B's and TTC004B's for the output pair. Again any need to measure / sort these parts?
I am looking at a breadboard of the JFET / op-amp front end to measure for distortion and noise.
What is the target current setting for the J112 Q9?
Yes this entertainment / for fun.
@olen measurement is part of the fun.
Thanks DT
I purchased a few ZTX851 (14) on ebay, I also placed a back order at Mouser.
Any thoughts about the need to measure / sort for good candidates for the SS parts.
I also placed an order for TTA004B's and TTC004B's for the output pair. Again any need to measure / sort these parts?
I am looking at a breadboard of the JFET / op-amp front end to measure for distortion and noise.
What is the target current setting for the J112 Q9?
Yes this entertainment / for fun.
@olen measurement is part of the fun.
Thanks DT
The bipolar in the capacitance multiplier and cascode don't need sorting. (The ZTX) Also, as both @Mark Johnson and @jackinnj mention, there are lots of very suitable parts for these positions. The 851 are really just the super-duper turbo chrome plated hot rod parts from the J.C. Whitney catalog. Remember the exact same input stage has been made in both the previous Pearls and some of the Pass Labs phonostages using the ZTX450.
The A004 and C004 are in the feedback loop of the 2nd stage, so they don’t need any matching.
Not sure about the current sink target, that’s on my list of questions.
D1 is a voltage reference and not a light bulb, it needs to be a normal red LED. The kits are going to use LTL-1CHE.
D3 is just a light bulb, use whatever color you want, and if you want to wire it up to your panel, go right ahead.
The A004 and C004 are in the feedback loop of the 2nd stage, so they don’t need any matching.
Not sure about the current sink target, that’s on my list of questions.
D1 is a voltage reference and not a light bulb, it needs to be a normal red LED. The kits are going to use LTL-1CHE.
D3 is just a light bulb, use whatever color you want, and if you want to wire it up to your panel, go right ahead.
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Is it because the 851 has high current capabilities (5A continuos, 20A peak)?
Applications only mention "Emergency lightning circuits".
https://docs.rs-online.com/e409/0900766b80d2ee1d.pdf
Applications only mention "Emergency lightning circuits".
https://docs.rs-online.com/e409/0900766b80d2ee1d.pdf
What opamp has been used as U1 in BA boards?Here's a sneak peak of a stuffed board 6L6 had at BA23 that I posted in the BA23 thread. I was lucky enough to be sitting in the front row and snagged a pair of boards from Wayne