Tube preamp. coupling and output cap. Not sure about the coupling, but the output cap was failrly large, in the 3uF + range, i believe. Didnt pay much attention, but large one was easily noticed due to unusual shape that you get with Rike's. Small one was traditional shape. Ill ask him and see what he had in there before.
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Well Rickmcinnis its a hobby so one can just dig into what ever interesting problem that comes up on the table
While I was talking about it I was looking into the resistor component lists and I wonder what you have to say about some choices here.
My build is going to be for 2,5 mV Dynavector 10X5.
For R1, main cartload resistors I have 47k VARs. I am still thinking about what values to choose on Rx1-4. I have 6,8k VAR and also 18, 47 and 100k VARs
I also have VARs for R4 2,2k, R14 47k, R5 and R10 6,8k.
For R2 68R I have some Welwyn RC55D68RBB 0,1% 25 ppm 0,25W https://www1.elfa.se/data1/wwwroot/assets/datasheets/RC-series_eng_tds.pdf
For R6, R7 and R9 I have some IRC CAR5D1MBB 0,1% 25 ppm 0,25W https://www1.elfa.se/data1/wwwroot/assets/datasheets/qaCAR_data_e.pdf
For R8 47R I have either Welwyn RC55D47RBB 0,1% 25 ppm 0,25W https://www1.elfa.se/data1/wwwroot/assets/datasheets/RC-series_eng_tds.pdf
Or
Welwyn RC65Y-47RBI 0,1% 15 ppm 0,5W https://www1.elfa.se/data1/wwwroot/assets/datasheets/RC55_RC65_RC70_eng_tds.pdf
For R11 1,5k I have 3 choices:
Akane ohm RNM12TB 1K5 B E PB-FREE 0,1% 25 ppm 0,5W https://www1.elfa.se/data1/wwwroot/assets/datasheets/jjRN-Scan_data_e.pdf
Or
Arcol MRA0207 1K5 B 15PPM TA 0,1% 15 ppm 0,25W https://www1.elfa.se/data1/wwwroot/assets/datasheets/MRA_eng_tds.pdf
Or
Welwyn RC65Y-1K5BI 0,1% 15 ppm 0,5W https://www1.elfa.se/data1/wwwroot/assets/datasheets/RC55_RC65_RC70_eng_tds.pdf
For R12 120 R I have Arcol MRA0207 121R B 15PPM TA 0,1% 15 ppm 0,25W https://www1.elfa.se/data1/wwwroot/assets/datasheets/MRA_eng_tds.pdf
For R15 3,3k I have Akane ohm RNM12TB 3K3 B E PB-FREE 0,1% 25 ppm 0,5W https://www1.elfa.se/data1/wwwroot/assets/datasheets/jjRN-Scan_data_e.pdf
Or
Welwyn RC65Y-3K3BI 0,1% 15 ppm 0,5W https://www1.elfa.se/data1/wwwroot/assets/datasheets/RC55_RC65_RC70_eng_tds.pdf
Some of the datasheet links are the same since its different values in same series but for your convenience…
What do you guys think about my choices for resistors?
Dear Stajo,
I do not like the idea of paralleling resistors of different values so I am not installing Rx1-4. I think one is better off with the MC load resistor close to the cartridge so that is what I do. My input is connected to either side of the 47K resistor.
I used a mixture of MK132, TX2575, Shinkoh Tantalum, S102K (for R1 and R2 - TX2575 are not available in resistances that low), and a few good old Dales. I did not choose locations for brands - I just like the idea of mixing them up. Availability (other than the Texas Components stuff which were made to exact value) made the decision; not all needed values are available in all brands.
No hard science.
I must admit many of the brands you mention are not readily available here in the US.
I do not think I have long enough to live to appraise different brands of resistors in the various positions though I would respect one who would try. Whenever I have considered doing this the next thought is how the various combinations will react to each other and then I realize it is really impossible to find the best way. I will stick with a variety of resistors and caps and hope it blends well.
One other thing I have decided to do which I initially told myself I was NOT going to do is to replace the RIAA caps with the RELCAP RT polystyrene/tin foil caps from MICHAEL PERCY. He matched them for me and got really close to ideal values (as if that really means anything -using a variable air cap for the trimmer). They are quite large and I hope this does not introduce other problems.
For the little time I was able to listen to Michael's prototype - it was not attenuated (my system has no attenuators - gains have been set to work with the current phono amp) so it was too loud but there was a glassiness which I wondered might be from the stock caps. I have no idea but as I have said before I do not know when to leave well enough alone.
Hope to have my mishmash working soon,
Best of luck with finishing you build and your component selections.
Take care,
I have a few questions because it was very difficult in 1200 posts find what I need.
1. required voltage on the collector and emitter of Q3, which gives the best sound result?
2. what is the required voltage on C6 for best sound result
3. what is the required voltage on C4 for best sound result
4. I have FT3, Mundorf supreme, Jantzen silver, K40 and Siemens B33063 for C3 100nF. Does anyone compared some of this capacitors and which is sound result?
5. I have 3,3uF for output cap, Jantzen Silver, AudynCap Plus, Intertechnik KP-SN and Mundorf M-cap ZN. What is your recommendation that would provide the best sound.
I put 3x2sk170BL at input. Should i need 2sk369? I have both, but I have 2sk170 much more.
My turntable is Technics SL6 with original MM tonearm and i think the gain that i needed is between 40-43db
1. required voltage on the collector and emitter of Q3, which gives the best sound result?
2. what is the required voltage on C6 for best sound result
3. what is the required voltage on C4 for best sound result
4. I have FT3, Mundorf supreme, Jantzen silver, K40 and Siemens B33063 for C3 100nF. Does anyone compared some of this capacitors and which is sound result?
5. I have 3,3uF for output cap, Jantzen Silver, AudynCap Plus, Intertechnik KP-SN and Mundorf M-cap ZN. What is your recommendation that would provide the best sound.
I put 3x2sk170BL at input. Should i need 2sk369? I have both, but I have 2sk170 much more.
My turntable is Technics SL6 with original MM tonearm and i think the gain that i needed is between 40-43db
Attachments
This phono can work like MM and MC phono preamp. Because i put 3x2sk170 for lower noise. Dip14 socket is for change R13 and sorse resistors. R13 can be made with 3 paralleled resistors in dip14
2SK170 is not a problem, i have hundreds, and i can put with lower idss.
R13 i will define when i know voltage on Q3. Because i need voltages on Q3
2SK170 is not a problem, i have hundreds, and i can put with lower idss.
R13 i will define when i know voltage on Q3. Because i need voltages on Q3
3xK170 takes much bias nonetheless. Its a modification you did there. I will look into it bit later for evaluating the bias and the clip margins to let you know IDSS, Rs, R13 for MM & MC use, plus some check voltages. As for the 100nF use the Supreme and for output the Audyn + from your collection. But listen to those you have installed first for a comparison base.
The cascode must be wrongly oriented, or busted, or your R13 value is inadequate for your input stage bias.