ikoflexer said:
I don't know about the peak and roller coaster curve. Although great in dB region. I like soft trends. My guess is that a wee bit of capacitor imperfection, some layout reality, and a few cm of wire, will never let any reg do better than 100-115dB real life magic.
salas said:
The peak and roller coaster curve has appeared on absolutely all the regulators I have simulated so far, the Jung, yours, all, when the LC filter is inserted in the input. I agree with you that those number don't mean a thing in reality, with all of its imperfections. Ah well, at least it looks good on paper 😉
Better avoid then. It smells interactions. To the contrary, a cascode CCS surely helps on self noise, extending the good region of CCS performance a lot in frequency. But it is more of a hassle to implement. Good for low parts count are DN depletion Mosfets from Supertex.
The cascode doesn't seem to help at all. I might try just go ahead with this version to see what it can do in reality.
By the way, thinking back to your almost perfect scope trace... you got some major filtering before the regulator right? That might explain it, since the regulator does not need to work so hard; I only used an LC filter of about 8000uF and 150uH. In any case, I will report any good news here if I get the time do it.
By the way, thinking back to your almost perfect scope trace... you got some major filtering before the regulator right? That might explain it, since the regulator does not need to work so hard; I only used an LC filter of about 8000uF and 150uH. In any case, I will report any good news here if I get the time do it.
I only have 33R to 10.000uF. The Cascode maybe does not show in the sim. See Jung's FFTs for CCS comparisons. But what you are about to try has so much potential that the cascode is just a nice potential add on.
Hi Salas
Just did the GND mods as per your sugestion and the result is a better stereo image, better stereo integration and much better bass (detail - extension).
There are two issues that I need to deal with:
1 - The hum I am hearing is lower but always present... I can hear it when not playing a disc and the pot is half way up. It seems to me it is related with the regulation because it sounds like a motor running (a little faster than 50Hz).
2 - Everytime I cut the power to the Riaa (to do some mods) and power it up again, I need to wait for 5 - 10 minutes until it stabilizes. During this warm up period, I hear spitting and thunder coming from the speakers. I measured the DC offset in the output and it oscilates between 200mV and -40mV until it reaches 9mV and stays put.... Is this normal ?
Ricardo
Just did the GND mods as per your sugestion and the result is a better stereo image, better stereo integration and much better bass (detail - extension).
There are two issues that I need to deal with:
1 - The hum I am hearing is lower but always present... I can hear it when not playing a disc and the pot is half way up. It seems to me it is related with the regulation because it sounds like a motor running (a little faster than 50Hz).
2 - Everytime I cut the power to the Riaa (to do some mods) and power it up again, I need to wait for 5 - 10 minutes until it stabilizes. During this warm up period, I hear spitting and thunder coming from the speakers. I measured the DC offset in the output and it oscilates between 200mV and -40mV until it reaches 9mV and stays put.... Is this normal ?
Ricardo
1. Did you have it before in the other box? Your shunt is a new build? Try one way shielded to output rca gnd too instead of just wire.
2. No it is not normal to hear noises.
2. No it is not normal to hear noises.
Before I replaced all the rsistors in the Riaa, I did not have any of those power up noises.
The shunt is the same as before.
By the way the DMM reads in the output after power on, I believe there is some oscilation in the circuit until it stabilizes completely... The spitting thundering is the same I heard before when I did some mods in the DCP (new psu for the opamps) and latter I found there where some dry joints in the GND connections (now cured).
I believe I need to sit down and search for GND dry joints in the Riaa also.
BTW... The sound is unbelievably good right now.... Of course I miss the bass grip and detail of the CDP, but the high freq is so much better as well as the stereo image and presentation !
This can only be improved by changing the tonearm... I am using a SME 3009 II Improved (fixed headshell with 6.5g effective mass) and it is not the best choice for the MC ACE M Benz.
I would like your oppinion on the Roksam Nima unipivot.
Regards
Ricardo😉
The shunt is the same as before.
By the way the DMM reads in the output after power on, I believe there is some oscilation in the circuit until it stabilizes completely... The spitting thundering is the same I heard before when I did some mods in the DCP (new psu for the opamps) and latter I found there where some dry joints in the GND connections (now cured).
I believe I need to sit down and search for GND dry joints in the Riaa also.
BTW... The sound is unbelievably good right now.... Of course I miss the bass grip and detail of the CDP, but the high freq is so much better as well as the stereo image and presentation !
This can only be improved by changing the tonearm... I am using a SME 3009 II Improved (fixed headshell with 6.5g effective mass) and it is not the best choice for the MC ACE M Benz.
I would like your oppinion on the Roksam Nima unipivot.
Regards
Ricardo😉
"I miss bass grip and detail of the CDP"
EHEH digital fake 😀
Nima is good ,but your tonearm and cartrigde are good stuff better tweeks , my TT after two days of setting sound a lot better...
BUILD a Pass amp..... F5 or miniA
PS with my OB I lost the bass grip but I gain the music!!
EHEH digital fake 😀
Nima is good ,but your tonearm and cartrigde are good stuff better tweeks , my TT after two days of setting sound a lot better...
BUILD a Pass amp..... F5 or miniA
PS with my OB I lost the bass grip but I gain the music!!
Unipivot arms are great, achieving much with simpler construction, hence having a lower price tag normally too. But I hate the jittery handling when moving them across the vinyl, selecting tracks.
Ricardo, hunt for those noise issues you got after so many substitutions and soldering at your leisure, with clear head. Since they were not there before, they will be taken out again somehow. I still recommend you to try your shielded wire that you use for input, in the same way for output too. It may lower your hum further.
They had a very nice analysis about low noise regs over at the solid state section forum by professional level engineers, me and Iko took part, and an easy to implement suggestion came up for our shunt too. I have it on test. Seems positive for now. Will extend and confirm my listening, and I will let you know if we got an easy shunt mod to adopt or not, soon.
Ricardo, hunt for those noise issues you got after so many substitutions and soldering at your leisure, with clear head. Since they were not there before, they will be taken out again somehow. I still recommend you to try your shielded wire that you use for input, in the same way for output too. It may lower your hum further.
They had a very nice analysis about low noise regs over at the solid state section forum by professional level engineers, me and Iko took part, and an easy to implement suggestion came up for our shunt too. I have it on test. Seems positive for now. Will extend and confirm my listening, and I will let you know if we got an easy shunt mod to adopt or not, soon.
Hi nicoch46nicoch46 said:
Can you suggest some tweeks for my arm/cart combo?
Does any of those preamps have caps in the signal line ?
salas said:
Hi Salas
I am sure I will get rid of the noises.... very soon I will get some russian Teflon caps and so I will review all the connections.
Do you mean I can upgrade the existing shunt, or must I build a new one ?
I love these steps forward.....
Ricardo
No rebuild for no one. Just a replacement of a resistor for a JFET. Silly to do. 1 minute mod. Only wait a couple of days, I have to make sure its a true upgrade for sound or not.
which TT you have ?
speaker ?
first)tray bypass the preamp
start to thinks better diy power amp
speaker ?
first)tray bypass the preamp
start to thinks better diy power amp
My Salas RIAA is finally finished!
First, it is totally silent through 96 db speakers, without proper connection of tonearm wire shield. The sound as far I can say is excellent! I have not make a proper audition yet, but I it is very promising.
The output caps are temporary 22uF bypassed. Maybe order some auricaps 3.3uF today.
Also I gave the schematic to a friend of mine to built it, he is has no internet and he is amazed too!
Thanks a lot Salas.
George
First, it is totally silent through 96 db speakers, without proper connection of tonearm wire shield. The sound as far I can say is excellent! I have not make a proper audition yet, but I it is very promising.
The output caps are temporary 22uF bypassed. Maybe order some auricaps 3.3uF today.
Also I gave the schematic to a friend of mine to built it, he is has no internet and he is amazed too!
Thanks a lot Salas.
George
Attachments
Ricardo ,post on vinylengine , a lot helps....
http://www.vinylengine.com/library/sme/3009.shtml
you can found a lot protractor , find near you a print service for plastic cover
contact audio origami ,I have the oil kit , fine service and info ,you can work on motor psu and rfi filter (add to phono too) and so on
sorry can't helps more , no time for my diy stuff 🙁
best
http://www.vinylengine.com/library/sme/3009.shtml
you can found a lot protractor , find near you a print service for plastic cover
contact audio origami ,I have the oil kit , fine service and info ,you can work on motor psu and rfi filter (add to phono too) and so on
sorry can't helps more , no time for my diy stuff 🙁
best
