Simplistic NJFET RIAA
- Thread starter Salas
- Start date
That RC Its not used in the pdf guide circuits as well. That ''prone'' to hum smells you had oscillations in those 1.2s. Making such regs P2P without oscilloscope is Russian roulette. You are quite adventurous to had done all those builds without scope and FFT I must admit.🙂
Well, if you remenber, I had big trouble with the "Optimae" version and V12 initial builds.
Some of them whistled and produced hum.
After various atempts, I figured a way to tame the circuit by placing a star GND near the EL output (-) leg, very close to the mosfet.
It can only be done p2p, otherwise you would need a severall layer pcb 🙂
I already built 10 of those with great success.
Some of them whistled and produced hum.
After various atempts, I figured a way to tame the circuit by placing a star GND near the EL output (-) leg, very close to the mosfet.
It can only be done p2p, otherwise you would need a severall layer pcb 🙂
I already built 10 of those with great success.
That is why I wrote ''adventurous''.😀 Anyway, first opportunity try to secure one now dirt cheap old analogue oscilloscope from some online auction. 20MHz will be plenty for most. But there are 50-100MHz around by the truckload. You will appreciate the security it gives you when building and debugging. Its the most classic thing to have along a DVM and a soldering iron.
Fancied myself a doctor I did, and operated on the patient. It was an emergency procedure to remove tip cleaner residue from the perimeter of the tip, to prevent inconvenience... Like a black market organ traffic doctor, I used the most primitive tools and an extensive vacuum of medical knowledge. The procedure appeared to go as planned, until one day the patient was whacked repeatedly to remove excess solder, which revealed a very thin trunk. It was not easy, watching the patient go... Eventual collapse caused by structural failure. A doctor never gets used to losing a patient...
I should take note to never operate on myself. 😉
- keantoken
I should take note to never operate on myself. 😉
- keantoken
Not really. There were some in the old pdf guide, but since then some things don't fit anymore.
I burn my fingers everytime I try to grasp a falling hot iron... Iron tends to fall from the workbench everytime I sumble on it´s wire 🙂
PS:
I did not try a ground plane.... I just made 20 or so layouts until I found the best working one. I implemented a "flying" star GND very close to output mosfet Drain.... I also experimented a lot on output caps placement until I got it working allright. Now I am sure I can do it repeatedly with success.
PS:
I did not try a ground plane.... I just made 20 or so layouts until I found the best working one. I implemented a "flying" star GND very close to output mosfet Drain.... I also experimented a lot on output caps placement until I got it working allright. Now I am sure I can do it repeatedly with success.
Just for fun, my latest implementation... I used an RIP DENON3300 CDP Case to place the benz riaa.
It uses 15.7nF FT-1 and V12R shunts.
The case is HEAVY... it even has two black plates (just to add weight) that were placed under the CDP PCB´s.
Sound is amazing.
It uses 15.7nF FT-1 and V12R shunts.
The case is HEAVY... it even has two black plates (just to add weight) that were placed under the CDP PCB´s.
Sound is amazing.
Attachments
Sondek / Ittok / DL103R / Audio Technica OCM3
My kids are teenagers now, and it is time to get a decent stereo system up and running. My stuff has been in boxes for a few years, and the only components that I plan on sticking with is my turntable / tonearm. The old integrated amp and speakers go to the kids.
So, I am thinking of this topology:
Linn Sondek/Ittok-->Simplistic NJFET RIAA-->Lightspeed LDR attenuator-->Pass F5 amplifier-->high efficiency speakers to be determined.
I have always wanted to have a moving coil cartridge, but they were kind of snob items back when I was in grad school. Now, they seem quite affordable. So, I am looking at these:
Denon DL103R 0.25 mV 14 Ohm ($379 from Jerry)
Audio Technica OCM3 0.4 mV 12 Ohm ("on sale" for $499" from Jerry)
Since I don't yet own either cartridge, is one to be preferred over the other, with respect to matching with my tonearm and the preamp? Which of these cartridges best meets price/performance?
I found a circuit in this thread (page 266, post 2652) that uses the four 2SK170 JFETs, but I want to make sure that I am on the right track. Is this the right circuit (for me), or is there a better one?
My Sondek and Ittok are stock from 1988. Are they good enough for the cartridges? Do I need to perform any mods?
Also, any other words of caution or encouragement are welcomed. Thanks in advance to anyone that can help with this barrage of questions.
Andy
My kids are teenagers now, and it is time to get a decent stereo system up and running. My stuff has been in boxes for a few years, and the only components that I plan on sticking with is my turntable / tonearm. The old integrated amp and speakers go to the kids.
So, I am thinking of this topology:
Linn Sondek/Ittok-->Simplistic NJFET RIAA-->Lightspeed LDR attenuator-->Pass F5 amplifier-->high efficiency speakers to be determined.
I have always wanted to have a moving coil cartridge, but they were kind of snob items back when I was in grad school. Now, they seem quite affordable. So, I am looking at these:
Denon DL103R 0.25 mV 14 Ohm ($379 from Jerry)
Audio Technica OCM3 0.4 mV 12 Ohm ("on sale" for $499" from Jerry)
Since I don't yet own either cartridge, is one to be preferred over the other, with respect to matching with my tonearm and the preamp? Which of these cartridges best meets price/performance?
I found a circuit in this thread (page 266, post 2652) that uses the four 2SK170 JFETs, but I want to make sure that I am on the right track. Is this the right circuit (for me), or is there a better one?
My Sondek and Ittok are stock from 1988. Are they good enough for the cartridges? Do I need to perform any mods?
Also, any other words of caution or encouragement are welcomed. Thanks in advance to anyone that can help with this barrage of questions.
Andy
Peafarmer:
Surely to fully drive an F5 from this phono output you will need to add a 20dB gain line preamp. The F5 is only 15dB fixed gain. The 103R is a very good value cartridge, Merlin El Mago uses it on LP12 with Ekos I think, maybe he can tell you more. The Ittok with 11.5gr effective mass should be OK for the 103R giving ~9Hz resonance. Keep in mind that we found its standard compliance ~15, mass with mounting hardware ~9.45g, its coils ~19 Ohm each. All by our measurements in this thread. Use 220R load. About that AT cart I don't have any direct experience, no comment. As for what exact circuit to use, let me know your mean average IDSS of the K170BL batch you are going to have in hand when ready to begin and I will specify you the exact circuit and values then. Mean time go find a link in post#1 that leads to an instructions PDF and read it.
Surely to fully drive an F5 from this phono output you will need to add a 20dB gain line preamp. The F5 is only 15dB fixed gain. The 103R is a very good value cartridge, Merlin El Mago uses it on LP12 with Ekos I think, maybe he can tell you more. The Ittok with 11.5gr effective mass should be OK for the 103R giving ~9Hz resonance. Keep in mind that we found its standard compliance ~15, mass with mounting hardware ~9.45g, its coils ~19 Ohm each. All by our measurements in this thread. Use 220R load. About that AT cart I don't have any direct experience, no comment. As for what exact circuit to use, let me know your mean average IDSS of the K170BL batch you are going to have in hand when ready to begin and I will specify you the exact circuit and values then. Mean time go find a link in post#1 that leads to an instructions PDF and read it.
Yes, it has proper circuits for high output MC and MM there. Tells how to fix the HO/MC circuit for MM with just changing one resistor value. You may use a dip switch locally even if you will be exchanging the cartridges often.
Me I use P2P only. So you can imagine the answer.🙂
P.S. Forgot to mention there is a supplementary GB for the SSLV1.1 BIB board for regulators signing up currently in the group buys section if you want to avoid some work or layout headaches on the PSUs side of things. Each breakable board has two positive sections, plus a negative section.
P.S. Forgot to mention there is a supplementary GB for the SSLV1.1 BIB board for regulators signing up currently in the group buys section if you want to avoid some work or layout headaches on the PSUs side of things. Each breakable board has two positive sections, plus a negative section.