Simplistic NJFET RIAA

diyAudio Chief Moderator
Joined 2002
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Salas: Do I have to populatie R4 with 1.8K? It is a MM(MI) cartridge.

Is 1.2K good for R4? (I have already put 1.2K in :) )

R4 is 2.2k for the 43dB configuration. The rest is "don't populate Q2,R3, use 68R R2 and 5.6K 1W R13 for 43dB gain. Choose Q1 between channels from a 10.5-12.5mA range at 5% IDSS pair tolerance"

Follow the above exactly, else you will have bias and gain problems
 
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Joined 2012
not the best one but not bad either. I have a nice old Lenco L76 that I got from my old neighbour. Just had to renew the V blocks and clean it. Nice to do!

I own a cambridge audio 551p phono preamp that doesn't sound to good I think. So this is just for fun. no high end turntable ��
 
diyAudio Chief Moderator
Joined 2002
Paid Member
not the best one but not bad either. I have a nice old Lenco L76 that I got from my old neighbour. Just had to renew the V blocks and clean it. Nice to do!

I own a cambridge audio 551p phono preamp that doesn't sound to good I think. So this is just for fun. no high end turntable ��

Lenco can do very good music, especially the difficult tempo thing, no worries
 
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Joined 2012
Salas, you already helped me with another build some time ago so I have all the confidence in the world in the DIYAudio community. The previous build was the DCB1.... And she(yes it's a she) is still performing very, very good!

I am going a bit over the top with ths one, but he, it's a hobby!!! And it's fun!!!!!

making two separate cabinets( pessante from Italy ) with 10mm aluminium fronts.... I just love to go all nuts! haha!
 
Quiet has returned.

I should have realized when it was the right channel with the hum there was something going on with cartridge grounding but I did not.

Had installed the PHOENIX Eagle motor controller along with the Road Runner tachometer and did not realize it was connected with this SINCE at the same time I had changed out my tone arm wiring with the 24 gauge Western Electric wire recommended by Shirokazu Yazaki in this very interesting article:
Positive Feedback The BELDEN interconnect is very good and affordable for those of us who would rather spend silly money on a cartridge. The WE 16 gauge recommended for speaker cable is very good. Lots of neat ideas here.

So, I found that attaching a ground wire from the phono amp to the ground pin of the turntable's motor lead made it go away. Had been poking around for the last week and finally it occurred to me ...

Maybe this will be of use to someone else.

The PHOENIX combo on my LENCO is worth every penny. Beautifully engineered, thoughtful product. Had to use something since mine has a 50 hz motor here in 60 hz land. Had used a PS AUDIO P300 for this before it died. This is vastly superior. It backs off the the voltage once the platter is up to speed and the reduction in motor vibration is very audible along with have a platter spinning at 33.33_ rpm. That last digit will toggle occasionally and many times by the end of a record side it is reading a steady 33.333.

So back to analogue bliss with my SALAS phono amp and company.
 
I know! But I have it :) and it looks cool :))) It's a potted one..... :D:cool:

AS one who uses overkill power transformers with my SALAS for the same reason, I had them laying about, I would mount those big toroids Salas's recommended 1 meter away.

I am using EIs since they do a much better job of blocking AC line noises. The toroids welcome all of the noise to come right in. A good power line filter is a good (mandatory) idea with toroids - even better, an EI isolation transformer

All is compromise in audio - your bass response will probably be very good but there are many who would caution you might suck the life out of the rest of the spectrum but as TURBON says - you might as well give it a try.

I can assure you you will be delighted with the sound of this phono amp.
 
Disabled Account
Joined 2012
Ok, so I have done some reading regarding transformers..... Silly to put in the 500VA toroid so I will save it for another day.

You can get C-Core(expensive) EI-Core, R-Core, Double bobbin, you name it! All very good I guess.

But how about a supreme audio grade toroid from Toroidy in Poland. Very affordable and it looks like good shielding and good construction.

Anyone know these? I have used one in my Hiraga(600VA) and it sounds good.

But for this build I want the best.... well, the affordable best anyway.

Cheers,
Sjoerd