Simplistic NJFET RIAA

[Tham]

Thanks Salas .

[nicoch46]

Nick glad to know a secure source on sound of dl103r ....in the web 50% like - 50% dislike.....waiting more info vs 160 as I know how sound ....tube itch too


iko with jfet no dc on cartridge, the same with bjt ?

ps

95db !? new speakers ?

[ikoflexer]

Originally Posted by nicoch46

iko with jfet no dc on cartridge, the same with bjt ?

Doesn't matter, the MC still presents a low source resistance to the next gain block. Some bjts simply offer lower noise factor (a measure of both current and voltage noise) than the best jfets. But let's not worry about that.

[Salas]

Originally Posted by nicoch46

Nick glad to know a secure source on sound of dl103r ....in the web 50% like - 50% dislike.....waiting more info vs 160 as I know how sound ....tube itch too

ps

95db !? new speakers ?

Its a controversial beast as it seems on the tonearms of many. The basic 103 as I saw browsing a bit about it today, used to work on the Mission fine, back in its era, so the result is backed up by more experiences also. Tracked well in to the highest modulation of band 10 side 2 of the Telarc Omnidisc, so its a fact, they work together. There the 160 buzzed earlier and stronger. Maybe the high VTF and conical needle takes it better. Listened to it more today, its interesting I get no iritation from a totally new cart, so fastly and basically set on the TT. Even the DIY finger lift provides a little interface between 103R's not that rigid body, I did not tighten the aluminum screws hard also, as recommended by anecdotal experiences. I must go put my ear 10cm from the tweeter to hear the hiss from the sensitive speakers at highest level I replay, not max, even if I just use the standard 56dB simplistic version with just one SK 1st stage and R source C bypassed for 60-61dB gain. All went fortunate for me. This cart is well above 160's league, I hear this clearly. Its coherent and gentle with everything happening easy to hear too. Me I measure the resonances with FFT, the FR with the chosen loading, the noise floor, I know and can change the phono etc. so maybe I have better control and understanding of what I do than just guessing the system, as some web sourced anecdotal cart/arm/TT references, always I start with the test disc on FFT and phono gain, loading, earthing, and then go to music. I could tell and address the reasons if it would set and sound sub optimum. I had mass mounting interface plaques ready if the resonance proved high, mass ring for the counterweigh can make. Was just fortunate I did not need them. Although I will test a counterbalance mass ring so to have the counterweight nearer to the bearings since it takes to unwind it enough for the weight difference of the 103R over the 160. I will know more when it plays 50 LPs or so, but a good start is half the story usually.

P.S. My speakers were 95dB before, same speakers. PHL 6.5 inch mid.

[nicoch46]

good spin ,can sound only better ..

thanks, fine for me

PS with 95db put a 45 amp

[Salas]

No, its 4 Ohm in the upper bass to low mids, has double eliptical car woofers in closed lower separate box, takes 20W P-P to have grip. Its sensitive but not that light. The voice coils are heavy and the cones too. Stands 300W RMS max.

[massimo]

Thank you Salas, Ricardo and Nicoch for you comments about caps.
I'll go for Obbligato (Cout), FT-2 (interstage) and the pictured teflon "by Madrigal" plus some tiny PP film & foil Ero/Vishay KP1830 in // to reach the requested value in the passive riaa.
Russian and Chinese caps ordered today.

Yesterday morning I designed a 3D pcb a la Disco around the two biggest caps (to be placed under the board). Then, as Salas is going to play around a 4 2SK170s at the input in order to increase gain/reduce noise, I already extended the pcb to host the 4 input critters
It may become useful in a while.

[massimo]

Many years ago (1986), J. Hiraga sugested a simple mod for the Denon 103 in order to reduce body resonances. I performed this mod on my first 103 without open the cartridge with a sharp knife (and a big magnifier lens). Simple and effective.

(sorry for the quality of the picture)

[RCruz]

Hi massimo

Can not see the mod... would you care to explain in plain words ?

[RCruz]

Originally Posted by massimo

Thank you Salas, Ricardo and Nicoch for you comments about caps.
I'll go for Obbligato (Cout))

Hi Massimo

I am using 4.7u obbligato gold and these sound very good.... you must let them burn for a while because initially they are quite rough.