Simplistic NJFET RIAA

[merlin el mago]

Originally Posted by RCruz

I got 25x10-6cm/dyne for Mission effective mass of 5.5g, Denon 103r mass of 8.5g and 0.5g screws + dust.

Can this be correct ?. How does it feel to touch the cart tip with a light finger compared with a "normal" MM feel ?

I am used to the stifness of the B&O MMC 20EN that has a 30 compliance and it is quite easy to move the cantilever with a light finger.

You can use some heatsink to increase arm mass

[gjfim]

follow up to posts 4066 and 4067

Salas- thank you for your response. I misread the layout and inserted all the transistors backwards. I reversed the transistors and now have good sound.

Two questions:
1) I have not altered values of R7 and R11, as you suggested in post 4067. Should I make these changes?

2) My cartridge output is around 5mV. Can I decrease R2 to get about 6db more gain, without increasing distortion? I am running RIAA into 6db gain preamp, then into F4. If I can get more gain from RIAA, then I can eliminate preamp.

Thanks for your help and sharing your knowledge and excellent designs.

Gary

[NPower]

Originally Posted by merlin el mago

Now you know where to look for the bug, good luck & let us know.

Thank you Merlin, for sure I will post the results

[Salas]

Originally Posted by gjfim

follow up to posts 4066 and 4067

Salas- thank you for your response. I misread the layout and inserted all the transistors backwards. I reversed the transistors and now have good sound.

Two questions:
1) I have not altered values of R7 and R11, as you suggested in post 4067. Should I make these changes?

2) My cartridge output is around 5mV. Can I decrease R2 to get about 6db more gain, without increasing distortion? I am running RIAA into 6db gain preamp, then into F4. If I can get more gain from RIAA, then I can eliminate preamp.

Thanks for your help and sharing your knowledge and excellent designs.

Gary

Good. It kinda dawned on me you reversed by the way you posted the voltages. That is why I insisted on orientation guide.
1. Post the now voltages around Q5 and I will let you know.
2. Stage two carries the burden, but since it has high degeneration in your case (R6 47R) you may have some slack till objectionable distortion. Go R2=33,22,15,10R step by step and judge volume increase VS distortion increase. Last step is +6dB from what you got now.

P.S. After finished, tune down your C3 to 15.6n. See if it is preferable to you. My then model with 'lost constant' in the inverse feed looks like it has to be revised, I use a tuned Lipshitz now and it seems more correct to my ears. LOST has finished, they have gone to heaven.

[Salas]

Originally Posted by merlin el mago

Small aluminum DIY finger lift, a ton of dust & Polyolefin heat shrink surely change the FS

Will look in to that again with more test records, I can't disassemble the thing now and weigh the extras exactly, I listen to records. If there is more weight in those extras it may really is 10-20cu. Surely more in 10Hz terms than what Denon gives as 100hZ dynamic by large.

[merlin el mago]

What's cu?

Yes in 10Hz will be between X 3 times or more. As you said one time is a strange animal the Denon DL103-R.

[Salas]

I have run again even higher resolution on several tracks, and in one channel there is a 8.3Hz sideband that the octave scaling was weighing towards. Without scaling I see 10.8Hz in both channels plus that sideband on one channel. So its 16cu (cm/dyn) when the mounting extras are assumed +2gr. Mind a rough guide x3 what Denon gives in manual. In my sample x3.2.

[merlin el mago]

That's perfect, is very near mine cart compliance combo with arm that is 16,5cm/dyn, possible due to the fact that I have more arm mass or simply mine cart is newer than your cart....

[Salas]

I also run THD on same 300Hz track that I saw some measurement in online free press test for some EUR1000 cart and the Denon showed 40% the distortion. He, he.

[merlin el mago]

Well implemented the Denon DL103-R it's very difficult to beat & if we regard the price it's impossible to find something similar this nice bargain.

Do you see some measurements THD 300Hz in online press test for the best considered carts: Koetsu, Air Tight, Vdh, Clearaudio, Transfiguration, etc. it's only curiosity to know how near is the Denon DL103-R?