Hi I'm looking for an existing design DIY friendly for a shelter 501 0.4 mV output. My current tube phono stage has 44 dB gain with 78 dB SN. There three main designs in this forum collectively have over 6000 posts. With so many circuit diagrams produced, in the end i didn't know what i was looking at and whether it was a functioning circuit. Ideally id like some switchable gain steps as well as adjustable loading. I prefer discrete components unless there are going to be a number of transistors, then an op amp makes some sense as i prescribe to the kiss concept..
Hoping some one can point me to the right option.
Hoping some one can point me to the right option.
The K.I.S.S concept in your case,could be a moving coil cartridge transformer from a reputable maker( Sowter,Jensen). I pressume that your phono stage has mm only sensitivity,compatibility.A suitable choice , between 1:10 or 1:37 ratios,based on the output resistance of the Shelter and the input resistance of your current phono will do it.
B.L
B.L
Thanks for your input. The transformers are an expensive option way beyond my budget presently. The cartridge is a stretch by itself.
I had in mind the Hiraga pre pre or leach. Some one claimed better versions exist but i cant find the schematics.
Jaochim has posted so many circuits i'm not sure what the latest\best\working MC head amp is.
I had in mind the Hiraga pre pre or leach. Some one claimed better versions exist but i cant find the schematics.
Jaochim has posted so many circuits i'm not sure what the latest\best\working MC head amp is.
Why don't enter in this thread Simplistic NJFET RIAA & ask to Salas:
http://www.diyaudio.com/forums/analogue-source/129126-simplistic-njfet-riaa.html
Also for regulators thread Simplistic Salas low voltage regulator & ask Salas too:
http://www.diyaudio.com/forums/powe...listic-salas-low-voltage-shunt-regulator.html
You can do the same like mine Phono MC for Denon DL103R with 60dBs & I will assure very good success only must follow Salas advices.
If you want to use your tube MM other solution is to buy Hagerman Piccolo MC without RIAA, has selectable gain & load impedance as desired.
http://www.diyaudio.com/forums/analogue-source/129126-simplistic-njfet-riaa.html
Also for regulators thread Simplistic Salas low voltage regulator & ask Salas too:
http://www.diyaudio.com/forums/powe...listic-salas-low-voltage-shunt-regulator.html
You can do the same like mine Phono MC for Denon DL103R with 60dBs & I will assure very good success only must follow Salas advices.
If you want to use your tube MM other solution is to buy Hagerman Piccolo MC without RIAA, has selectable gain & load impedance as desired.
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Just a head amp to go in front of your existing tube mm pre amp, I only know 2 solutions:
-Commercial I know only Piccolo from Jim Hagerman (I built a couple with BG & some exotic resistors, one with PSU another with batteries & both sounds very good).
-DIY Hiraga, It's an old design I do it with batteries, sounds very neutral & it's easy to do, do you have the schematics? if not I will search to post.
-Commercial I know only Piccolo from Jim Hagerman (I built a couple with BG & some exotic resistors, one with PSU another with batteries & both sounds very good).
-DIY Hiraga, It's an old design I do it with batteries, sounds very neutral & it's easy to do, do you have the schematics? if not I will search to post.
Here is the Sowter page.Think that, before going into the strange ways of buying or diy-ing something,that ultimately will not solve your "kiss" requirements.Start saving some money
http://www.sowter.co.uk/acatalog/SOWTER_TRANSFORMERS_PHONO_CARTRIDGE_TRANSFORMERS_30.html#a136
The non dynamic examples,that you say,is a case of unmatched impedances,
or a anaemic system.
Since you know the qualities of your setup,only your opinion and a test with your phono preamp counts.Do not forget,that you are listening to your system,and it is yours and only yours to enjoy.
You have lucky, Salas posted a pre pre without RIAA has gain x10 so you can use your MM, see link post 3695:
http://www.diyaudio.com/forums/analogue-source/129126-simplistic-njfet-riaa-370.html#post2195178
Schematic:
http://www.diyaudio.com/forums/analogue-source/129126-simplistic-njfet-riaa-370.html#post2195178
Schematic:
Attachments
Regarding the 2SK170, it is a very good fet for this purpose.
On schematic you can omit the 47 ohm.
You have also to select with care the ouput capacitor because, due to a very large freq.response at lowfreq. you may have an acoustic feedback or you can see a large movments of woofer.
With the trafos, due to the fall of response (gentle) at low freq. this will not appaer.
Ciao
Walter
On schematic you can omit the 47 ohm.
You have also to select with care the ouput capacitor because, due to a very large freq.response at lowfreq. you may have an acoustic feedback or you can see a large movments of woofer.
With the trafos, due to the fall of response (gentle) at low freq. this will not appaer.
Ciao
Walter
No, he can't as it is. He must bring R2 down to 330R and then delete R1. Will gain a bit of SNR from that but not much because the FET itself is going to be noisier from running more current, and will lose linearity due to lack of degeneration. Its an option to listen and decide.
Its gradually cutting already below 20Hz with 0.47uF on 47k MM input. I would not advise less than 0.33uF else it cuts too early. Plus the MM stage is probably doing it already. We don't want to pile up much phase shift.
Regarding the noise , in the range between 1 mA until 10 mA we have the best performance about the equivalent input noise voltage.
On datasheet you can also see that the noise figure is costant (for different frequencies) from 1 mA to 8 mA.
In addition, in my opinion, is much better (in case we have a risk of acoustic feedback) to have more fall at frequencies below the 20Hz. With 0,47 uF and 47k ohm we get about 7 Hz at -3dB; with 0,33 uF we have 11 Hz.
At those frequencies the phase shift is not so important; we have to consider the right frequency resonance of the arm/cartridge system and the imperfections of LP (ondulation and out of the center) that are more important to check.
Ciao
Walter
On datasheet you can also see that the noise figure is costant (for different frequencies) from 1 mA to 8 mA.
In addition, in my opinion, is much better (in case we have a risk of acoustic feedback) to have more fall at frequencies below the 20Hz. With 0,47 uF and 47k ohm we get about 7 Hz at -3dB; with 0,33 uF we have 11 Hz.
At those frequencies the phase shift is not so important; we have to consider the right frequency resonance of the arm/cartridge system and the imperfections of LP (ondulation and out of the center) that are more important to check.
Ciao
Walter
3.5mA ID, 5V VDS is the rather most quiet for a 2SK170BL in my experience. The coupling capacitor can be fixed in context with what high passes are created in the MM stage that follows. Depends on the isolation of each turntable , the size of the speakers, room modes, floor construction for events like footfall etc. Surely someone can check some coupling values and the impact of subsonic rumble on a system as a whole. The phase shift unfortunately starts higher than the -3dB turnover in first order HPF.
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