Thank you for your answer. 
I am now gathering and matching parts for the riaa 43db version, and I am using a Tonghui TH2821A 10KHz LCR meter with kelvin test probes and a Fluke 87V and a Fluke 73II for testing and matching.
I am using russian silver mica caps for the riaa circuit. The caps are spot on 47nF and 15.330 nF (I soldered several together to get it these values).
Regarding resistors I have followed the posts and bought Shinkoh resistors. What about the 1M resistors as I have not fund any Shinkoh in this value, what about Amtrans amrg? Are there any other resistors that will match the Shinkoh, Z foil, Caddock maybe as the 47K input resistor?
I will post some photos as the work evolves.
With kind regards and thanks once again for all the help this forum has given me
Martin
I am now gathering and matching parts for the riaa 43db version, and I am using a Tonghui TH2821A 10KHz LCR meter with kelvin test probes and a Fluke 87V and a Fluke 73II for testing and matching.
I am using russian silver mica caps for the riaa circuit. The caps are spot on 47nF and 15.330 nF (I soldered several together to get it these values).
Regarding resistors I have followed the posts and bought Shinkoh resistors. What about the 1M resistors as I have not fund any Shinkoh in this value, what about Amtrans amrg? Are there any other resistors that will match the Shinkoh, Z foil, Caddock maybe as the 47K input resistor?
I will post some photos as the work evolves.
With kind regards and thanks once again for all the help this forum has given me
Martin
Since you are going towards the more ''organic'' flavored parts, use Amtrans 1M. For the load resistor Shinkoh and all you mention give subtle results of their own, its more about cooking them parts for some favorite overall flavor than finding equivalents. The more neutral and informative of all those is Z foil. Important is the 47K bridge resistor between input stage and RIAA too.
It is not so easy to chose parts and I assume I will be testing and changing resistors quite a bit in the months to come, but that is also some of the fun with DIY
. The cost of it all is the down side, and since the Shinkoh 47K is not so easy to come by in 0.5W I really would like an alternative (I have them in 1watt but the matching is not good). Maybe the Z-foil will be the way to go, I am really are not certain? regarding interstage cap that will be an russian FT-3 100nF. And since I allready have some K75-10 2.2uF caps and some FT-3 220nF, maybe I will use these for output cap. Any oppinions on what would be the right way to match components will be appriciated. Are these components maybe to "soft" sounding?
The bridge 47K resistor needs have best tolerance so use Z foils there. The input load puts no particular tolerance demands so use the 1K Tantalums there. Mixing the Teflons and the Z foils which are clean but not harsh with the ''mellower'' ones produces some balance. Never go one sided in total because it gets boring tonally.
components and matching
I am really looking forward to testing the riaa I can hardly wait. But what about the 6.8k resistors should these be z-foil as well or maybee somthing completly different. I have heard and read that the Shinkoh to is on the top shelf, but as you say it is all about getting a balanced sound.
With kind regards
Martin
I am really looking forward to testing the riaa I can hardly wait. But what about the 6.8k resistors should these be z-foil as well or maybee somthing completly different. I have heard and read that the Shinkoh to is on the top shelf, but as you say it is all about getting a balanced sound.
With kind regards
Martin
resistors and capacitors
Yes getting resistor value spot on by connecting them in parallel is smart, I will be doing this with 2.4k to get the 1.2K value that I only can find in 1W when it comes to Shinkoh. I will try to keep values matched between the two channels. And if I get it right, the 47k, 6.8k and 1M regarding riaa is important to get in dead center. Well there will be many resistors that will be surplus stock after I am finished.
Is there anyone that have other recommendations, and what about output capacitor? I have both the 220nF and the 100nF FT-3 that could be used, along with K75-10 and K73-16. Any recommendations and suggestions is greatly appreciated.
With kind regards
Martin
Yes getting resistor value spot on by connecting them in parallel is smart, I will be doing this with 2.4k to get the 1.2K value that I only can find in 1W when it comes to Shinkoh. I will try to keep values matched between the two channels. And if I get it right, the 47k, 6.8k and 1M regarding riaa is important to get in dead center. Well there will be many resistors that will be surplus stock after I am finished.
Is there anyone that have other recommendations, and what about output capacitor? I have both the 220nF and the 100nF FT-3 that could be used, along with K75-10 and K73-16. Any recommendations and suggestions is greatly appreciated.
With kind regards
Martin
I have received today one nice aluminum box for my RIAA preamp. How to proceed with grounding the case ? My pcb's (preamp, shunt) and RCA connectors will be isolated from the case but i think will be good to have the case connected to ground. Also where to connect the ground wire that comes from TT ?
I usually reference the chassis with a single wire from the VinGND point at Riaa board. After that, any grounding post non insulated to chassis can ground the TT. Without a referenced chassis hum goes up, so its not an option, its a must. Did you find out what went wrong last time and your phono became silent by the way?
Oh, that situation shame on me, it was a human error. On the dau before a changed several interconnects and i was trying to use the wrong end of an interconect
That's way i had all voltages correct
Also i received some Mundorf Mcap 0.1uf/630v for interstage connection.
I'm so nervous to see the case populated with pcb's.
shame on me, it was a human error. On the dau before a changed several interconnects and i was trying to use the wrong end of an interconect That's way i had all voltages correct
Also i received some Mundorf Mcap 0.1uf/630v for interstage connection.
I'm so nervous to see the case populated with pcb's.
I do have 0.1 uF FT-3, but I was hoping to get a use for the 0.22uF 200V FT-3 that I have and these were cheaper to. Regarding mixing resistor and caps I just ordered Shinkoh, Z-foil, and 1M AMRG in matched pairs. I also have some PRP and Takman in cabon and metal film so getting it togheter with the "correct" mix is the next stage. The Salas BIB 1.2 shunts worked just perfect. What resistors did you use in the 1M riaa?
PS! the riaa is primaraly intended for a sme III with a shure V15III.
Yes, simply supreme because my audio chain is not so high end and think i cannot hear so subtle differences. I ordered also some Vishay 1837 15nf and 0,1uf.
1845 are 5% at their best tolerance J variance. You would need an LCR to check them out. 1837 would be care free.
You can check that the regulator is trouble free by using the oscilloscope on AC input and 5mV/div, 10uS. Looking for a clean straight line on the screen with probe between B+ and GND. No small frequency riding, no noise hash. If you make an inverse-riaa input filter to very tight tolerance spec and you got a function generator you may check 1kHz square waves are good also. That will prove good Riaa shape. Our phono uses Lipshitz Riaa classic, no extra supersonic pole. Just for fun testing, not really to worry about when with tight Riaa caps and resistors in the phono, has been tested before it gives compliant Riaa if made well.
You can check that the regulator is trouble free by using the oscilloscope on AC input and 5mV/div, 10uS. Looking for a clean straight line on the screen with probe between B+ and GND. No small frequency riding, no noise hash. If you make an inverse-riaa input filter to very tight tolerance spec and you got a function generator you may check 1kHz square waves are good also. That will prove good Riaa shape. Our phono uses Lipshitz Riaa classic, no extra supersonic pole. Just for fun testing, not really to worry about when with tight Riaa caps and resistors in the phono, has been tested before it gives compliant Riaa if made well.
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