well. quite long to be honest. maybe 2m. yes i will decouple lokaly and also look at the impedance after all that cable and connectors but the loss should look like a resistor, a capacitor and a coil. at least at lower frequencies. With good connectors i whould asume 0.2Ohm, 300pF and 0.01mH.
here is a simulation of the loss in the connection cable if the pre filtered power supply would only supply the input circuit. i assumed the input circuit has a 150 Ohm input impedance over the whole audible range. i do not know the input impedance of your shunt regulators Salas. look only at the impedance plot because i used (misused?) a loudspeaker simulation program (AJ Horn)
Hi Salas,
I get an interpretation from your post it doesn't matter which LED colour we chose as the noise "depends on batch or model", do you have more information to your statement?
It's otherwise in general known the red LEDs have the lowest noise.
Cheers Michael
When I measure total noise floor on FFT in a stage referenced by strings of Leds, I have seen small differences between using generic Leds from different bags and sizes in same color, more than between colors. I have not done any survey and maybe the bypass cap has something to do with it, by not being always the same type.
A survey has been done in 2004 by member Christer. Don't know if the numbers are real because of the method being correct or not, but they are comparable by at least to have been taken by the same rig and method. Here we can see differences between types of same color between samples, and currents. There is a yellow that does better in higher current than some red for instance, and there is IR that does splendid in high current but beyond par with R,G,B at 5mA and lower. Not easy to generalize. Interesting towards the end in 2nd experiment too.
A survey has been done in 2004 by member Christer. Don't know if the numbers are real because of the method being correct or not, but they are comparable by at least to have been taken by the same rig and method. Here we can see differences between types of same color between samples, and currents. There is a yellow that does better in higher current than some red for instance, and there is IR that does splendid in high current but beyond par with R,G,B at 5mA and lower. Not easy to generalize. Interesting towards the end in 2nd experiment too.
what really hapened today was that we listened the first time to our new sytem here in Berkeley. i had designed new loudspeakers with a new crossover designed for a particular time domain behaviour. haven´t been able to build passive phase linear systems with the radiation pattern that i had in mind i started in the biginning of the 90th to think about artfully shaping the phaseresponse so that a sweetspot could be identified where time and energy whould be well balanced. as many researchers before me i found more problems in the bass. but that is not all what i can tell you. today we litened to a compleet chain designed by me and our american company. i was a great event and we got very fine sound. we had a Lyra Helikon SL cartridge in the new Immedia arm on the SG2 turntable. i had my Goldstandart Head Amp running on alcaline batteries and my Telepath RIAA stage on a regulated powersupply using blue leds as voltage reference. tomorrow we will change for the DIY MPP Head Amp on a second powersupply of the same construction. i tried it out in my home before i came here and noise was very low. with the ear on the speaker at medium to high volume my son cound hear a very faint "airy" hiss and a very faint low frequency hum, dark in colour. in the listenig seat my hearing is not good enough to hear the noise as distraction but i know that even better isolation and regulation could help the tiny signals to seperate better. anyway low level resolution WAS amasing in the Berkeley system. in my home i get enormous drahma but i must say that the american system already had incredible refinement and speed. i think beeing an open circuit without voltage feedback the MPP will be more sensitive to powersupply issues. i already found that stabilising the bias has paid of in sound and measurements and this is the version without "at least 30dB PSSR improvement when the cap is tied to the supply" and the LED:
by the way the goldstandart was set to a transresistance of 20 ohms and 200 ohms to ground from a balanced transimpedance instrumentation amp with output scaling for optimum dynamic range. the cartridge sees a constant ohmig resistance of 10 Ohm per leg + the parallel reference resistors. making them quite small in value optimises common mode rejection. the Helicon has a quite low output resistance and it did not sound compressed or high frequency wise challanged in any way. the sound had great speed and precission with surprising extention and bloom in the bass considering that the woofer cabinets have only 35 liters of volume and two 18cm drivers in parallel tuned to around 32 Hz so quite low compared to QB4 the most efficient desing with a linear near field response without peaking. i compensatet a bit with a freefield response that falls by 2 dB from 30 to 15.000Hz. due to the timedomain behaviour of the speaker there is aso a small energy peak in the fundamental range between 200 and 350 herz nicely compensating for the floornotch. we sat some 2.5 m from the speakers that have been ca. 3m apart angled to the ear. i call that medium nearfield. the experience is a bit more like nearfield than like farfield and has good imaging precission with an added bonus of some nice spaciness if the room allows. we set up the system in a caotically stuffed listening room that had never been seriously used before with lots of unpacked loudspeakers, electronics and software in the form of many nice vinyl recordings based mostly on pop, jazz and classic. most amasing was the speed, heft and slamm down to at least 32Hz on Däfos a 45 life recording with the ex Santana drummer. but it did not sound stupid ether. transparency and the feeling of endless resolution (somethig i start to call continuity) was the order of the day.
RC cartridge load
Hi Joachim,
sorry to be so late in reply about this issue, I just discovered this 3D.
I want just let you know that there is some work on the resistor + capacitor
load issue in the MC transformer world. I discovered it while reviewing the MySonic Stage 302 MC transformer, which you can see here:
http://digilander.libero.it/agostino.manzato/audio/reportage/mysonic/mysonic.html
together with some -too simply- simulations I did.
BTW, the sonic result was really impressive!
Ciao!
Tino
Hi Joachim,
sorry to be so late in reply about this issue, I just discovered this 3D.
I want just let you know that there is some work on the resistor + capacitor
load issue in the MC transformer world. I discovered it while reviewing the MySonic Stage 302 MC transformer, which you can see here:
http://digilander.libero.it/agostino.manzato/audio/reportage/mysonic/mysonic.html
together with some -too simply- simulations I did.
BTW, the sonic result was really impressive!
Ciao!
Tino
thank you for sending me that link, i will study it. to be absolutely honest i do not terminate the cartridge with any mathematical precission. my problem is often to get sound well quick under show and work condition so i simply do it by intuittion and experience until i am satisfied. do not underestimate the stick slip problem that can vibrate the arm quite badly in the presence of a theoretically good alignement. i found dynamicly changing mechanically systems hard to predict. it has to do with willpower not to give up until you "learn" the cartridje.
i know a bit about transformers. i designed the Audio Physic transformer with the legendary Pickatron company near Frankfurt. i used resistive damping on the scondary but soon moved out of that market because there was no market to speak of at that time
(early 90th) for a rather exensive and tempramental product. often people had hum problems that i never expirienced and a very engaged dealer with a good workshop sugested an improvement that solved the problem. anyway the review of the My Sonic Lab is very well done and looking at the specification of the top model my jaw drops when i calculate the posible gain in dynamic range especially at extremey low volume where the soul is in music. i do not meen to listen soft, just the contrary. to enjoy that dinamic range load volumes are good and will offend the ear much less because it is a very informative listen that does you sit at the edje of the sofa so to speak. i really whould like to hear that cartridje with an optimised phonostage. john curl seems to have the top mode around because he gave the same specs after asking. i am yeallous !
(early 90th) for a rather exensive and tempramental product. often people had hum problems that i never expirienced and a very engaged dealer with a good workshop sugested an improvement that solved the problem. anyway the review of the My Sonic Lab is very well done and looking at the specification of the top model my jaw drops when i calculate the posible gain in dynamic range especially at extremey low volume where the soul is in music. i do not meen to listen soft, just the contrary. to enjoy that dinamic range load volumes are good and will offend the ear much less because it is a very informative listen that does you sit at the edje of the sofa so to speak. i really whould like to hear that cartridje with an optimised phonostage. john curl seems to have the top mode around because he gave the same specs after asking. i am yeallous !
If you are interested I have tried to apply the RC load to my Tribute MC transformer, adding some more consideration, at this URL:
http://digilander.libero.it/agostino.manzato/audio/DIY/TributeMC/TributeMC.html
I'm very sorry to admit my ignorance... could you explain me what is the "stick slip problem"?
Thanks a lot! That is because I'm not a hi-fi journalist, but I'm reviewing good components for my personal joy. Unfortunately the MySonic was too expensive for me and I didn't buy it
(the same happened with the Kronzilla amp).
Ciao!
http://digilander.libero.it/agostino.manzato/audio/audio.html
interesting, you combine a sharp sounding mica (i like sharpness so no critique) with a rather mellow ricken. if you did that by purpose results can be stunning because you tune it to your liking and that makes listening fun and easy.
how can i explain stick slipping ? well you see when they cut a laquer, that laquer can be brand new send the same day from the factory or having been stored in a freezer or even under less favourable conditions. different suppliers have different recipies or do not always supply the same quality so the experienced cutter has no choise than to cut the record in an angle that may not be the ideal 22° or what have you but makes posible that a continous string of debree is sucked into the vakuum tube. at any other angle the chance is much higher that the cutter stylus starts to "jump" and distroyes the continuity of the string. i really have language problems her because it is a rare art with it´s owm language and that may differ in germany or other places you know better. i just got so curious when i saw that and asked what VTA they cut and the answer was silence. so it can happen you set your cartridge to 22° VTA with a microscope and track that "naturally cut" record that does not care a damn **** about the VTA. the cartridge may experiene some uncomfortable fricktion and shaking and although it may not literally jump out of the groove can nevertheless put the arm in motion because compliance is not infinitesimal small.
how can i explain stick slipping ? well you see when they cut a laquer, that laquer can be brand new send the same day from the factory or having been stored in a freezer or even under less favourable conditions. different suppliers have different recipies or do not always supply the same quality so the experienced cutter has no choise than to cut the record in an angle that may not be the ideal 22° or what have you but makes posible that a continous string of debree is sucked into the vakuum tube. at any other angle the chance is much higher that the cutter stylus starts to "jump" and distroyes the continuity of the string. i really have language problems her because it is a rare art with it´s owm language and that may differ in germany or other places you know better. i just got so curious when i saw that and asked what VTA they cut and the answer was silence. so it can happen you set your cartridge to 22° VTA with a microscope and track that "naturally cut" record that does not care a damn **** about the VTA. the cartridge may experiene some uncomfortable fricktion and shaking and although it may not literally jump out of the groove can nevertheless put the arm in motion because compliance is not infinitesimal small.
Ooops... No, I didn't make it by purpose. Sorry
( I was curious to try the Riken resistors which I never tried before, and the place where I bought the Soshin SE99 (do you know any place in EU where I can find some of them? I need some good silver mica caps for bypassing and maybe also some 0.22uF or 0.47uF for decoupling) was selling also Riken resistors. I'm a fan of tantalum resistors (like Shinkoh) but have not compared them to Riken in that Tribute transformer. By the way, that RC-loaded step up seems to work better with my old Koetsu Red than with the Benz LP...
OK thanks. I think the practical solution is to set the VTA listening more good records than
only one or two...
Ciao!
save me some if you buy them out !!!!! i have no idea who makes them and found with surprise that they are not magnetic like the standart Siver Mica Cornell Dublier. i use the Cornell Dubliers if i have a desire for speed and leading edje definition. unfortunately that comes with an alien aftertaste sometimes that interprets the signal more then it let it though without commend and that makes listening more challanging. it sharpens the edjes somehow. the blue micas do not have that problem but the are also not able to "improve" the signal. i found them great for miller compensation and RIAA trimming. they do no damage to an already fine system
Oh yes that's correct, I do remember Christers research of some diodes and their noise levels, I think I had red LEDs in my back-head because I did read many times on this forum that was sometimes pointed out as low noise, maybe it has become the preference for many because of the better price in comparison to especially IR LEDs, no real advantage by any other LED, and red is quite nice colour too and good visual indicator the circuit is "working".
Another thing that would be interesting is to measure the spectrum of noise as an even spread of noise spectrum pattern would be preferable.
Another thing I am wondering about is the Re of LEDs, Zeners are noisier but have fairly high Re so a capacitor in parallel works quite well.
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