Good question AndrewT,
As you know I'm not an EE, a possible solution wil be connecting all RIAA grounds ina a star gnd & this star gnd to the gnd plane? or better could you suggest any solution? or tell that isn't a good idea use a gnd plane for a fono RIAA...
Also can use star gnd for the pcb & over the pcb a sheet of mumetal connected to gnd covering all the RIAA....
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Hi Ricardo,
So better avoid gnd plane in phono RIAA, but about to add a mumetal sheet over the phono RIAA connected to gnd to shield EMI/RFI?
The mumetal can be purchased at diyhifisupply
Ultraperm MUMetal Shielding Sheet 0.15mm, 31.5cm x 19.5cm 80% nickel | Diy HiFi Supply
Price 21.00USD each sheet of 31.5cm x 19.5cm
Photo:
An externally hosted image should be here but it was not working when we last tested it.
What about to design and create a GB for a Universal Salas Phono RIAA pcb 2 layers?
Ok Sir,
I'm "Everyone else should keep their hands/minds off that topic"
But I bad supposed that the ee can help us...
Another way is to group the signal ground all together (Rloadx, R2, C10, C2,C3, R5, R8) in bus and refer it to star ground. Moreover, D4 alone, C5&R6; C6&R7, C9&V1 (star point). Now from 13 to (only) 5 links.
Ricardo: I'm working on a similar pcbOne side, can be etched at home.
In this case, do you connect R8 to R7 and then to star ?
Hi Merlin
I have no experience with that material but I am using an internal ferrous shield in my last build with great effect.
It is a plate between the riaa boards and the TX separating the case in two.
The shield must contain iron otherwise it does not work (aluminium and copper do only minimal changes so constitute no good shields)
I have no experience with that material but I am using an internal ferrous shield in my last build with great effect.
It is a plate between the riaa boards and the TX separating the case in two.
The shield must contain iron otherwise it does not work (aluminium and copper do only minimal changes so constitute no good shields)
I do agree with Andrew: no ground plane, leave it for HF stuff. It makes a big cap with lower tracks and, sometime, ad antenna.
Ricardo: when finished, I'll publish the pdf. My idea: dual jfet input RIAA + dual SSRegs v1.2 in a single side (with few jumpers) pcb 21*10 cm aprox, but I must ask Salas a question about C2/C3 in the v1.2 before finalize my design
R7/R8 togheter and then to star point: absolutely not. R8 belongs to signal ground, while R7 to power ground (and thus can be joined to C6).
Ricardo: when finished, I'll publish the pdf. My idea: dual jfet input RIAA + dual SSRegs v1.2 in a single side (with few jumpers) pcb 21*10 cm aprox, but I must ask Salas a question about C2/C3 in the v1.2 before finalize my design
R7/R8 togheter and then to star point: absolutely not. R8 belongs to signal ground, while R7 to power ground (and thus can be joined to C6).
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The passive filter is very prone to noises due to parasitic capacitances.
When I use perfboard, i get the best results by removing the unused copper islands between the riaa filter components.
I also notice that the board must be totally free of flux in that area otherwise some noise appears.
PS: I read about submerging the built board in isopropil alcool would get rid of the flux completely but I did not try it because I am afraid the alcool might affect the components.
When I use perfboard, i get the best results by removing the unused copper islands between the riaa filter components.
I also notice that the board must be totally free of flux in that area otherwise some noise appears.
PS: I read about submerging the built board in isopropil alcool would get rid of the flux completely but I did not try it because I am afraid the alcool might affect the components.
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Ricardo, I use this with good success
An externally hosted image should be here but it was not working when we last tested it.
