R5 is 0.1% TNPW from the start. The ones i ordered are 1206 size 250mW dissipation so it would be ok i guess
I don't think it will do anything related to the signal path there, its shunted by the reservoir cap to ground that power LED and its protection resistor anyway, but when getting a bunch of low current noise resistors for a build I think some would buy them all alike on a single move if they are not very expensive types.
One more thing i keep wanting to ask and always forgetting. My C3x is not MKT , its Rifa PPS. Is that ok ?
Yes. That one would be best if C0G in reality but the main consideration is to be small 5mm and 63V-100V. C0G is max 50V at 0.1uF in most vendors. Its just a peripheral cap to decouple the incoming wiring's inductance not to interact with the CCS.
I saw that the panel LEDS not to be too distracting needed about 1mA only or even less depending on usual ambient light in the installation room, black or silver panel, etc. Thus the 47K. Stays cool can bee 1/4W, and its still towards bright on a black panel for me. That value brings about 1mA if feeding from 45-50V RAW DC. This how bright to be thing is down to preference in the end of course.
Thats the reason of my question. I thought that a "lossy" cap would be better at decoupling. As far as i know pps is less lossy than mkt (i could be wrong though 😀). But since pps is ok, im happy ( no desoldering!)
Farnell has TDK 0.1uf C0G 100v smd in 1812 package at £0.75 and sells them at one piece. Worth a try i guess
Link (hope it works) : http://uk.farnell.com/tdk/c4532c0g2a104j320ka/mlcc-1812-c0g-100v-100nf/dp/1843173
Link (hope it works) : http://uk.farnell.com/tdk/c4532c0g2a104j320ka/mlcc-1812-c0g-100v-100nf/dp/1843173
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Lets explain the practice better for a bit. Why we put a decoupling capacitor near a load in general?
For filtering and local charge storage. In our case there is mainly a umbilical between the load and the bulk reservoir. Among other extra things like traces and connections.
The umbilical is long and sports parasitic stuff also. Small distributed R,L,C that can AC couple any possible interference across its length. We wanna shunt that noise to ground.
That is HF filtering very near the reg's entry point with the decoupling capacitor. Got its name from that. De-Couples to ground what's been coupled along a distance.
Now, the cable's parasitic L in particular can also block transient load current demand to the bulk reservoir. Just in case current is asked at high enough frequencies where our practical CCS is not effective anymore. A fast local charge is handy. The de-coupler is forming an HF CLC Π filter with any inductance between it and the bulk PSU cap in effect. Better not be some active component's parasitic capacitance instead where things can get unpredictable beyond insufficient.
Now why we care about that cap's qualities?
We should use a cap that stays capacitive over frequencies that our load may ask current, before that cap reaches its self resonance dip and starts behaving inductively. Small package short leads 0.1uF one can be effective up to several MHZ when put at the right place. If enough fast current will be demanded too, it must have the capacitance for that, but also be physically able to deliver it not blocked by its own high parasitic L. So its a toss between value and size when the demand is high both in volume and speed. That is why some times several same small ones are employed near fast chips.
Our case is just typical AF plus headroom though, and there is a CCS effective over quite a band. We care 99% about the filtering effect not the speedy charge. Not at all like a CPU running at a few GHZ that also varies its current wildly to really need heavy & scholastic decoupling. Any small cap that does not fail short in over-voltage like some Tantalum and ceramics do, will suffice. Still, good parts never do harm anyway. Lossy type would count if there were several bypass ones forming resonances which is not good to have at all than to try damp.
I knew about John Bicht and the engineering quality behind that arm. Now I know even more.
I wondered how it compared to RB300 (mine has threaded end, VTA, counterweight changed and rewired) as possible upgrade. SME 4,5 is a bit too much over horizon for me.
Your RB300 has to be better than stock. Counterweight upgrade is effective. The re-wiring is good in upgraded ones, it just tends to highlight the problems in stock ones. It think that pimped up RB300 tends to supplement better 70s-80s Linn like engineered sprung subchassis TTs when the better arms sound limited on those. You start with VPI Aries 1 (metal platter-perspex sucks) or Goldmund Studio class TTs entering the "modern era TT designs" and moving to their current offspring to worth investing in "super arms" IMHO.
An externally hosted image should be here but it was not working when we last tested it.
Ugly duckling. Made not only from old ideas, but not a modern design either, hehe.
He, he, sliced in half tennis ball suspension I see? Which TT is the platter etc. donor? Looks VPIsh?
Yes, that is a Benz! Gorgeous. Absolutely mad about that cart. Kudos to you both for the tip. Motor, drive, bearing, platter are from an old Lenco L75. Split top plate is from Netherlands and PTP fame. Idler wheel is from Hungary. Plinth material is german via UK. All assembled here. Lacks feet and some oil for the looks. Maybe a motor controller & platter damping and...
