Simplistic NJFET RIAA

[alexkosha]

Some one asked here about test points connectors for TP1, TP2 and GND...
I used these loops found in Mouser about 2 years ago. Unfortunately, I trashed receipt and do not have P/N. You might find these by picture on eBay...

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[bucurb]

Hi Salas,

I fixed the earth screen.

Congratulation it's very nice your phono preamplifier!! (Chapeau bas!...)

 

[42001]

Thanks!

 

[bucurb]

You are welcome!

 

[42001]

Salas, what could be done if I think that the high's could be more crisp? I have the feeling of "missing" some bandwith. It's not too much, but I think it could be better.

Can point me in the right direction?

 

[Salas]

I have asked you if C2y maybe much for your cart. Take them C2y out. If too crisp after that put new C2y at half the value of the now used.

 

[42001]

C2Y's are now 200pF. Combined with the 15nF C2 cap, that is is what I went for.

Did I make a misstake with those? I did not know this was cartridge dependant....

 

[42001]

PS: Polystyreen or Silver Mica?

 

[Salas]

Because MM and rather soft now I would go Polystyrene

 

[Salas]

C2Y's are now 200pF. Combined with the 15nF C2 cap, that is is what I went for.

Did I make a misstake with those? I did not know this was cartridge dependant....

You never know before testing. 200pF proved bit much in your case so go nothing or lower C2y in any order that is easier for you and judge the balance now that you are somewhat familiar with the integration in your total system room included

 

[42001]

Ok thanks!

I have some 100pF polystyrenes in stock

Can I ask you an off topic question? Or should I PM you for that?

 

[Salas]

If completely off topic better PM me

 

[42001]

You have PM

 

[Salas]

Yes that was a completely off topic technical question about your friend's system. I have answered you, check.

 

[42001]

Yes that was a completely off topic technical question about your friend's system. I have answered you, check.

That's why I asked

 

[42001]

Just ordered the Clarity Caps for C3 47nF is the way to go I think!

 

[Salas]

OK Clarity are good option. Are you going to exchange for the 100pF Polystyrene tonight? Those 200pF you put, what kind of dielectric material they use?

 

[42001]

These are the ones that are in now: http://www.hificollective.co.uk/components/amtrans_amch.html
I will replace them when the clarity caps arrive with polystyrenes 100pF. Not tonight... no time :-(

 

[Salas]

I looked them up and I see DF 0.1% at 1kHz spec. Lying next to me as we chat Wima FKP2 1nF 100V 0.000 DF Wima MKS2 1uF 63V 0.003 DF on my LCR at 1kHz

 

[Salas]

Maybe those AMCH are doctored polypropylene "tone" caps to soften the usual rough edges in many systems but not needed in yours or its just the value that does the slight softening business, you will know in practice. Don't destroy their pins when pulled maybe they will come handy in combination with the Clarity C3 or not. Change the Orange Drop C3 when time comes, but put pins for C2y so you can experiment without lifting the boards with empty, polystyrene, AMCH. Even without pins the pads are plated through so you can just touch solder and the connection will be complete to both layers.