Simplistic NJFET RIAA

diyAudio Chief Moderator
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3.0.12

I have tried to search for it and found other linked places but you tube says its not available to my country due to copyright restrictions.:dead: I know what video you mean now, have seen it before, but I don't remember the specific TT. Someone else maybe can tell. There was also a self made turntable there with the motor on an off the self tripod.
 
Hi Salas, my RIAA is running in well...powered by a v2, it is really quiet with a transparency that I have not heard of before. I had a 1000uF cap across the 33R resistor and now have sufficient gain for my 0.2mV output Supex 909 mc cartridge. However, I have to turn the volume control almost all the way up for normal listening, and it picks up a pop sound whenever a fluorescent light in the house is turned on and off.

How do I get rid of this nuisance? Could a cap across the power line helps?
 
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Nice to know it plays well. Bravo. Its not a little thing that you have no hiss for 62dB gain. You start with a next to nothing 0.2mV and you boost it 1250 times! You have a buffer preamp stage, can't do anything there, but can you set your amp for say 3-6dB more gain? What is the sensitivity of the speakers?
Its a starter transient that from the light. The route is the mains, logically. I would try to filter the mains first thing, as you say. V2 has a lot of bandwidth, and surely can pass it. I would not think is going through the Riaa directly, it does not have much bandwidth because of the very Riaa HF filtering. I am no expert on advanced mains filtering, Jon Risch one is a DIY stalwart, here modified a bit by Fikus. But a 0.1uF X2 type mains cap across the phono transformer primary and another 1uF across the secondary, would not be a bad idea to test for a start.
What quality 1000uF cap did you use in the end? Is it still a smooth sound regardless the generic components? Does it stand up to your CD source?
 
Hi Andrew,

Thanks for the advice. It is both annoying and scary to hear such loud pop at loiud listening level. Hope to get rid of it soon.

Hi Salas,

It is quite amazing not to hear hissing at such volume setting. I had a Rubycon ZL across 33r resistor for the additional 5dB gain. With stock components (and a 4.7uF Elna Starget NP output cap), I am hearing excellent width and depth. Voice is clear and low on sibilance. Violin is natural sounding. Would have loved a more full bodied midrange that I think can be improved with proper RIAA caps, inter stage cap and output cap.

Compared with my Shigaclone/Monica 3 DAC powered by a v2, they are almost equal in terms of noise level with the vinyl set up generally sounding more organic (in voice, etc) with better bass extension and slam.
 
franky phono reload

:cool: :smash:
 

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diyAudio Chief Moderator
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@Tham

Very nice so far. Even impressive. You did not tell me if you can modify the T amp's gain and what is the SPL sensitivity of your speakers. ...And any photo?

P.S. As you know from others in this thread, this is a very component quality responsive circuit, you will have lot of tuning fun when you will start playing with them.
 
Hi Salas,

Using a Charlize T amp. Not sure if I can increase the gain at all. Speaker is a Coral 8A40 fullranger in an angular spiral horn enclosure coupled to a pair of diy subwoofers and recently added vintage Coral supertweeter for a truely fullrange speaker system. Sensitivity shall be around 96dB.

Can take some photos later but will have to learn how to load it here.