since preamp is in the TT case i have no heareble hum, just some white noise at max volume, but well below the record one, and not heareble at normal level, even with ear close to speaker. is your preamp in some enclosure?
as i promised - after few days listening and fine tuning cartridge load finished at standart 47k (with MM) everything beyond makes sound sharp. in series with 10p ceramic caps, not making sence added to preamp input capacity, but maybe blocking some HF noise, i don't know, but difference is audible.
there is a lot to do, like PSU case and mounting it in TT, adding some weight to back of arm (correct VTF with concorde cartridge is reached with counterweight at the end of pipe, touching the lid at the record end) and adjusting subchassis suspension, with TT level platter is not and vice versa.
as i promised - after few days listening and fine tuning cartridge load finished at standart 47k (with MM) everything beyond makes sound sharp. in series with 10p ceramic caps, not making sence added to preamp input capacity, but maybe blocking some HF noise, i don't know, but difference is audible.
there is a lot to do, like PSU case and mounting it in TT, adding some weight to back of arm (correct VTF with concorde cartridge is reached with counterweight at the end of pipe, touching the lid at the record end) and adjusting subchassis suspension, with TT level platter is not and vice versa.
I used my analog Tektronix 2225 scope and was no way to save images. I was supposed to use iPhone camera to capture screens, but curiosity to find the problem and fix it actually won.
The only thing left is uploaded to the forum file with noise recording.
However, I still have all boards on my table and bad cap there too. I can send you the whole setup with trany if you want to learn it in deep.
Not big deal with $20 shipping forward-back.
Please let me know.
Sent from my iPhone using Tapatalk
You are following a custom approach there with a related circuit based on the discourse of this thread using your stashed ready parts which seems successful enough for your purposes and it looks like you know what you are doing. I can't give you much value additional input since its not the standard circuit or power supply and way of installation but I guess you could relax your gain a bit since its high output MM you use so to benefit in the hiss and overload margin departments a bit. 40dB will be plenty for your cartridge.
Sure, Andrew, but if there wasn't one fitted, and you fitted one yourself, does that still count?
RCDs have been the most incredible leap forward in this respect. If your house doesn't have all of the sockets go through one, I suggest getting one fitted. If 30mA of live is routed to EARTH, it will trip and save your life - good to know in the event of an old cable breaking loose etc.
I will keep the PE, as it seems to be quiet(ish) with both PE and chassis GND both attached. Still some work to do. My biggest problem is that I have a metal and carbon fibre arm that literally floats above the arm carrier on a cushion of air, with no real way to connect them, without compromising the whole air bearing implementation. It's a big source of buzz too - an aerial if you will.
I discovered how good RCD/RCBO were at protecting housholders in my last house.
As a result, when I designed and built this house, I included 5 power socket ring main. Each of those rings has it's own RCBO. I have a 6th ring to my main listening lounge. I don't want it switching off if leakage reaches the 30mA trip value.
BTW, the RCD/RCBO should not have leakage reaching 25% of it's rating during normal use. This limits the amount of filtering permitted on each RCD.
hmmm, i made U-turn
took all stuff out TT and restored it as it was. dont want to cut possibility for other cartridges, preamps etc.
cascoded first stage this morning, now listening one side and going to work.will update soon
I am struggling to hear the differences of resistor loading, to my surprise.
I have the exact same cartridge as in the excellent "Load the Magnets" article that Salas recommended, about resistor and capacitor loading with MM cartridges, specifically the Shure M97xE, their latest flagship.
Perhaps my listening equipment is too old?
I know that my hearing cuts off like a light switch at 14 Khz. I know it because of this rather excellent video on the subject. (My 3 and 9 year old boys can hear all of these sounds.) I'm 42 and have the typical high treble hearing of a 42 year old, it seems.
https://www.youtube.com/watch?v=VxcbppCX6Rk
I have:
R1 100K = 100K
Rx1 47K (+R1 = 32K)
Rx2 91K (+R1 = 48K)
Rx3 220K (+R1 = 68K)
Rx4 330K (+R1 = 77K)
From my short test, I'm struggling to tell the difference between R1 (100K) an R1+Rx1 (32K). Is that normal?
I have the exact same cartridge as in the excellent "Load the Magnets" article that Salas recommended, about resistor and capacitor loading with MM cartridges, specifically the Shure M97xE, their latest flagship.
Perhaps my listening equipment is too old?
I know that my hearing cuts off like a light switch at 14 Khz. I know it because of this rather excellent video on the subject. (My 3 and 9 year old boys can hear all of these sounds.) I'm 42 and have the typical high treble hearing of a 42 year old, it seems.
https://www.youtube.com/watch?v=VxcbppCX6Rk
I have:
R1 100K = 100K
Rx1 47K (+R1 = 32K)
Rx2 91K (+R1 = 48K)
Rx3 220K (+R1 = 68K)
Rx4 330K (+R1 = 77K)
From my short test, I'm struggling to tell the difference between R1 (100K) an R1+Rx1 (32K). Is that normal?
Ah yes, I know that there is filtering on Youtube at around 18Khz, but I'm assured by my kids that the 15khz and a couple more are audible as a sine, and not just the clicks I can hear. So, I know that my ears are 15Khz dead
I've done sweeps to confirm. 14Khz seems to be my limit. It's horribly high anyway - we're not missing much
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With the arm earth disconnected there is a slight increase in hum. I haven't tried with the PE removed.
youtube test is incorrect, i don't know why, played it via airplay trough pioneer vsx-528, 16Khz are something like present, but not exactly and nothing above. with signal generator (software and hardware) i hear up to 17, can distinguish if 18 are present or not, but is more like feeling and nothing above. so if the test was ok i would hear 17 am i?
am i?
This is my experience, in tests, you may have hearing losses above a certain frequency, but you do perceive the information above where you're cut off is. It may be our brains working on unperceived information or something like that.
youtube test is incorrect, i don't know why, played it via airplay trough pioneer vsx-528, 16Khz are something like present, but not exactly and nothing above. with signal generator (software and hardware) i hear up to 17, can distinguish if 18 are present or not, but is more like feeling and nothing above. so if the test was ok i would hear 17
How old are you? The test I linked to (in 1080p) has predicted the age of several people I know from age 3 to 70. My 9 year old can hear up to 19Khz. For me, I just hear clicks from 15Khz above.
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