Simplistic NJFET RIAA

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Batteries are about 27.5V unloaded. They are a little used so I expect about 30V loaded with fresh batteries.

I've got 3.6V across R4. I have a trimmer I can adjust if needed.

Thanks Salas.
3.5-4.5V cross R4 is acceptable and try center it at 4V. But its not practical to have a changing Rail+ due to batteries charge variations because it will keep you adjusting.
 
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Pretty much done with the small comps now. 369s and 170s are awaiting. Matching up the 369s tonight.

Everything populated so far is matched to the closest my instruments gets me.
 

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I have not heared the MRs yet but I think I know what I will hear or close by. Or maybe not, we will see. My rather unhopeful experience for all the hope-filled ones out there is no better capacitor then the next one for you if you dont know what you want to hear. In combination with the rest pile of stuff.

First of all: all the thingys (except look-feel-smell) you like when playin a kewl 8-incher is reproduction harmonics.

Anyways. My strategy is usually to blaspheme the system with kewl sound more up in the chain. I do like a good bunch of harmonics in my listening, but they are more easily controllable up there. Sometimes uglyer though.
 
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I have been listening to my Decca Gold Microscanner for a while now and had forgotten how good it sounds.BUT I cannot seem to get rid of an annoying hum which I cannot hear from my listening seat but is very noticeable when within a metre of the speakers.
I put my Xono clone back in the system and the hum is now only noticed with my ear against the speaker.
The FSP is wired/earthed as per the build guide as was my mc version which was hum free.
Just thought the original p/s was hard wired whereas I am now using the pcb and the transformer is an R core with its secondaries wired in series feeding both supplies on the pcb.Any advice as to how to get this beauty hum free gratefully received.
 
diyAudio Chief Moderator
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I have been listening to my Decca Gold Microscanner for a while now and had forgotten how good it sounds.BUT I cannot seem to get rid of an annoying hum which I cannot hear from my listening seat but is very noticeable when within a metre of the speakers.
I put my Xono clone back in the system and the hum is now only noticed with my ear against the speaker.
The FSP is wired/earthed as per the build guide as was my mc version which was hum free.
Just thought the original p/s was hard wired whereas I am now using the pcb and the transformer is an R core with its secondaries wired in series feeding both supplies on the pcb.Any advice as to how to get this beauty hum free gratefully received.

Try with one channel PSU on the transformer only. Check if the hum is there on the active channel still. If gone, then you need double mono or separate secondaries Tx as expected by the Raw PCB design. If the hum is there still then its something about the cart grounding.
 
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Yes the ground/return wires are effectively connected together at the back of the cartridge.
When I first used the Decca years ago it was in a Mission 774 arm with the original plastic mount which had just 3 pins on it so one channels ground wire was just left hanging and no hum.With the SME4 I have the hum whether I connect all 4 wires or just 3 and changing ground connections at the phono end of the arm cable makes no difference whatsoever.
I'll do a search and see if there is a thread.
 
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Im glad if it ends up where its supposed to:)

I have a question about R2,R3, im my case R2.

In the Notes 2SK369BL it says "Use corresponding resistor values for R2, R3 from this table..."

Under Gain it says: "For high MC cartridge 2-2,5 mV don't populate Q2, R3, use 68R R2..."

R2 :confused: