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Simplistic NJFET RIAA
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Old 12th July 2014, 12:54 PM   #12941
Salas is offline Salas  Greece
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Quote:
Originally Posted by stajo View Post
Edit. Found some Pana 450V MKP. Should do? http://www.mouser.com/ds/2/315/ABD0000CE47-179957.pdf
Just don't use anything worse than roughly a Wima MKP4/10 equivalent.
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Old 12th July 2014, 01:03 PM   #12942
buzzforb is offline buzzforb  United States
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I heard them for the first time the other day. Unfortunately I do not have a basis for comparison, as it was the first time i heard that piece of equipment and they were already in. THE owner seemed to love the change.....FWIW.
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Old 12th July 2014, 01:48 PM   #12943
RCruz is offline RCruz  Switzerland
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Quote:
Originally Posted by buzzforb View Post
I heard them for the first time the other day. Unfortunately I do not have a basis for comparison, as it was the first time i heard that piece of equipment and they were already in. THE owner seemed to love the change.....FWIW.
What equipment was it and where did the caps go ? What values ?
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Old 12th July 2014, 01:54 PM   #12944
buzzforb is offline buzzforb  United States
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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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Last edited by buzzforb; 12th July 2014 at 01:57 PM.
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Old 12th July 2014, 02:47 PM   #12945
buzzforb is offline buzzforb  United States
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Should get to listen to this latest version tomorrow.
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Old 12th July 2014, 02:48 PM   #12946
rickmcinnis is offline rickmcinnis  United States
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Quote:
Originally Posted by stajo View Post
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/a...es_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/a...CAR_data_e.pdf

For R8 47R I have either Welwyn RC55D47RBB 0,1% 25 ppm 0,25W https://www1.elfa.se/data1/wwwroot/a...es_eng_tds.pdf

Or

Welwyn RC65Y-47RBI 0,1% 15 ppm 0,5W https://www1.elfa.se/data1/wwwroot/a...70_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/a...can_data_e.pdf

Or

Arcol MRA0207 1K5 B 15PPM TA 0,1% 15 ppm 0,25W https://www1.elfa.se/data1/wwwroot/a...RA_eng_tds.pdf

Or

Welwyn RC65Y-1K5BI 0,1% 15 ppm 0,5W https://www1.elfa.se/data1/wwwroot/a...70_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/a...RA_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/a...can_data_e.pdf

Or

Welwyn RC65Y-3K3BI 0,1% 15 ppm 0,5W https://www1.elfa.se/data1/wwwroot/a...70_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,
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Old 12th July 2014, 04:53 PM   #12947
Salas is offline Salas  Greece
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If the stock treble caps ain't smooth enough in a certain system you can simply increase their value a bit than changing brands.
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Old 12th July 2014, 07:17 PM   #12948
stajo is offline stajo  Sweden
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What is the current per channel?
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Old 12th July 2014, 07:33 PM   #12949
Salas is offline Salas  Greece
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The integrated regs draw 90-100mA from the raw DC rails per channel.
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Old 13th July 2014, 03:42 PM   #12950
impuls is offline impuls  Yugoslavia
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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
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