The Essential Role of Capacitors and Resistors Regarding Analog Circuits
Recently, I have come to realize the essentials of analog circuits to some extent. Especially for the past 15 years or so, I have accumulated a lot of experiences with capacitors and resistors used in signal amplifier circuits, and have even produced parts, such as Arizona Red, Blue, Green, and also the “Ultimate Ruby Mica” capacitor that actually boast excellent high-quality sound.
Looking back, in this long-term series from this Part 1 to Part 10, you could see that I’ve focused on and talked about the importance of these passive elements, which would be generally recognized in supporting casts rather than as active elements, such as tubes and semiconductors and circuit configurations, which should be the protagonists.
After all, my long audio journey for just a half century would be summarized as my own ”Capacitor Adventure” and ”Resistor Adventure”, but now, thankfully I'm finally able to conceptually or qualitatively understand the relationship between these passive elements and the sound quality of analog circuits.
Of course, the role of the capacitor is to have a filter effect that cuts direct current according to its impedance characteristics. However, as mentioned another chapter, the capacitor on the signal circuit consumes the signal component that should be transmitted originally in the capacitor due to the inherent resistance component, or delays the phase depending on the frequency by the inductance component.
In other words, the capacitors have the problem of losing the amount of information and modulating the phase, and so the most important item regarding the sound quality of the capacitors in the signal circuit would be the greatness of "transmitted information amount" including the accurate time axis, I think.
As I made clear in Part 9, the encounter with Ultimate Ruby Mica capacitor was shocking to me, and I was truly convinced that a capacitor with extraordinarily excellent physical characteristics was also outstanding in terms of sound quality. And my image of the sound quality of Ultimate Ruby Mica was just the capacitor with great “transmitted information amount”.
Well, regarding the resistors, as mentioned above the values of thermal noise and current noise are smaller would be directly linked to the better hearing quality.
Therefore, in the signal circuit, the quality of a capacitor should be represented by the level of the upper limit of the transmitted information amount and the noise of resistors determines the lower level of under the usual circuit noise.
I think that this difference between the upper and lower level limits should be called the “Audible Dynamic Range”, which cannot be expressed by the mere static S/N measurement data and specifications. The maximization of this dynamic range by using high quality passive elements with amazingly favorable sounding could only bring out the truly "Real-Sound", long looked for, I believe.
The 2nd Modification of Alan-san's & Roy-san’s Model 7 And Ryszard-san’s Model 7 Replica
On 30th last September, I recommended Alan-san to make the 2nd modification of his Model 7. It took about 3 years after I first modified it, and through these years, I have experienced mainly two findings, the one is the resistors with high value, which is a far superior vintage Allen Bradley solid carbon resistor, and some were used in the modification of Roy-san's Model 7 Replica.
These are IRC metal film resistors, RN70 and RN75 for the US military around 40 years ago. I have been adventuring, looking for a better sounding resistor with high value for a few years. But I just reached a goal, I feel.
My young friend, Jun-san, who developed an outstanding Class D solution in LA, and now Roy-san's good friend, also said to me that are really good parts in this present market. We can easily get the latest metal film resistors on Digi-Key or Mouser. We can easily come across 1/8 W, 1/4 W, but can't find truly reliable 1W and 2W types.
Noise level of the resistor depends much on the wattage value and of course, we need a higher wattage one. Fortunately, I have well known a few NOS parts shops in Japan, stocked a lot of vintage MIL standard parts that I already tried and experienced the sound quality. And sorry, there would be any generality for using such vintage NOS parts, I understand, but the modified Model 7 is a really unique one, and I have responsibility to improve the sound quality of the Model 7 as up-to-date as possible with replacing such resistors, I found.
One more finding is the "Ultimate Ruby Mica" capacitor. I have been requested by around 40 readers of Jeff's Place all over the world, and shared more than 550 pcs with them through one year.
Yes, this fact demonstrates how wonderful these mica capacitors are, I believe. Well, in the first modification, I used MC-DA mica capacitors, but I will replace all of them, the coupling and RIAA EQ with "Ultimate Ruby Mica". Especially, the phono EQ could be remarkably improved by the coupling, "Ultimate Ruby Mica" capacitors, newly set constant.
It would be the theme of Modification of Model 7, Part 9. In my understanding, with this 2nd modification, the true potential of the PX25A (DA30) mono SET will be apparent.
This 2nd modification was completed successfully, and it was returned to Alan-san at the end of last year. And just on the 2nd of the New Year, 2021, I got the first impression from Alan-san that:
“I am so happy that you invited me to join you with your Model 7 Adventures, I feel so blessed and lucky to be on this journey with you! I am noticing changes in the sound of the Model 7, it is so enjoyable to be a patient observer of this birthing process! My brother was by yesterday and stated, “What’s different, the sound has always been enjoyable and live; now I am in the room!” I said, “oh, okay! ”Then I shared with him the new Real Sound Adventure that is in progress!!”And on the 11th, almost 10 days later, it seems that some aging has progressed."
“Thank you for your kind assistance with new version of the Model 7. I very much enjoyed seeing the figures of the transformation, it looked to be a very delicate endeavor. Thank you very much for sharing this transformation with me, I am very grateful! We have been enjoying the Real Sound Version 2 Adventures of the Model 7, it is really fun to listen and feel close to you! Thank you for the tube recommendations, these are really elemental and organic additions to the mix. The gestalt of the whole has brought a deeper level enjoyment for me, settling into the grounding octave of my soul. It is relaxing and humbling to be one with the performers that are safely entering our room, thank you! Warmest Regards.”
It was strange feeling, but I was even happier because Alan's impression was exactly what I expected. I also felt this version of the upgrade might go beyond the level of only improving sound quality, and I could immerse myself in music quite naturally.
Well, in this early January, Ryszard-san, who has been also an eager reader of Jeff’s Place, contacted me from Poland and very seriously wanted me to build up a system of the modified Model 7 and a pair of WE310A drive GEC PX25A(DA30) mono SET.
In our discussions that followed in the mail, I understood, Ryszard's thoughts were very serious and sincere. Also, when I heard that his current speaker system was a highly efficient “Avantgarde”, and his plan to build a speaker system with Altec units in near future, I imagined that his liking would match the direction of the sound I have been aiming for. And so, I decided to accept Ryszard's request.
First of all, since it was premised on modification, I started looking for Model 7 at a reasonable price as much as possible. Fortunately enough, in less than a week, I was able to find and bid successfully for a Model 7 Replica in good condition for him on the Japanese auction site.
After that, parts collection progressed relatively smoothly, the modification was completed at the end of March, and it was shipped to Ryszard-san by DHL in early April. And on 13th, I got his delightful first impression:
“Hello Yazaki-san, I have already received the packages today (Monday). They arrived very quickly and, luckily, nothing was damaged. You secured everything very well - thank you VERY much!"
"I’ve already connected the equipment and started listening (my daughter and wife also enjoyed the music for a while). We all noticed very big and positive changes in the sound of my set - these changes exceeded my expectations."
"First of all, I immediately noticed that the soundstage went deeper and wider. We can hear the sound of instruments or voices, which resembles listening to live performances / concerts much closer than before. I now hear more detail in recordings I know quite well and am surprised to discover new elements."
"In the case of one album (Oscar Peterson + Stepfane Grappelli + Joe Pass + Mickey Roker + Niels Henning) - a live concert from 1979, recorded in Denmark - when the audience applauded, we felt as if we were at the concert ourselves and applauded as well."
"So much for just the first day of listening, and yet you mentioned that the equipment will get even better over time. I wanted to emphasize once more how much I appreciate that you made such a major modification for my sake, which embodies some of your great knowledge and experience. Without it, I doubt I could have ever experienced such quality. And, luckily for me, this isn’t even the end of our cooperation. Thank you very much, I am finally beginning to understand what you meant by the term "Real-Sound".Greetings, Ryszard”
Nishikawa-san, my closest Japanese friend, often talks about this kind of thing lately, and this is what he said after listening to my old but latest version upgrade Model 7 K. Of course, he's a very credible person who has been involved with audio for as long as I have, both professionally and personally.
"I had always thought that the basis of audio is speaker selection. But recently, I understood that if the power amp is great, any speaker can sound fun. And now I truly realized once again how much the preamp controls the sound quality of the power amp and also the system including speaker."
For about Roy-san’s 2nd modification of Model 7 Replica, a truly wonderful story was waiting for me. It took some time due to the coronavirus epidemic, but Honda-san, my old friend and the best professional engineer we can hope for, took over Roy's 2nd modification.
The thing is, Roy-san and Honda-san have been getting along with and having deep respect for each other in these past few years, becoming familiar each others love for music, life style, and they both live in California.
So, this time, I only prepared the parts kit and sent it with the circuit diagram for modifying to Honda-san. Anyway, I highly value the reference design of the innovative Class D amplifier called AMP4 with outstanding musicality that Honda-san developed 15 years ago in the International Rectifier era and so I really wanted him to experience the sound of the masterpiece of tube preamplifier, moreover, which will be replaced with the best passive parts available in the world, including rare and valuable NOS.
Well, I heard it directly from him that Honda-san truly excited to see the parts kit and enjoyed the process of this modification. At the end of July, all of Honda-san's work was completed and handed over safely to Roy-san.
The following is a passage from the mail sent by Honda-san to Roy-san on 5th of August, and he seems much excited about the results of this modification too.
“Dear Roy-san, Thank you for sharing your first impressions. I got very excited to know that the new adventure is bringing a new dimension of listening enjoyment. It seems that the modification had brought much more depth to your system. Even in my system with stock JBL 4320, I could “see” a sound image floating on the canvas, even at very low volume levels, that impressed me a lot in the first five seconds. Hope the phono issue is not in the 7.”
Then, a month later, on 3rd of September, Roy-san completed the steady burning process and gave us a summary of his impression so far.
“Dear Yazaki-san and Jun-san, I apologize for taking so long to report back to you. It took me awhile to get my tonearm repaired. I also wanted to give some time for the resistors/capacitors to break in. The sound has improved dramatically! It is much more open and spacious than before. Dynamics are improved as well – my Quads sound a little more ‘horn-like’ now and they track dynamic range better. Nuance and texture are improved as is localization within the soundstage. There is an increased sense of realism as a result for the above. Yet the sound is never harsh or strident. It is still smooth and effortless. Lower bass has better coherency and definition – it integrates better with the mid-bass now. The sound is simply more life – like and satisfying. Good vinyl is now extremely good. My sincere thanks to both of you for this amazing upgrade. Such a pleasure!! Sincerely.”
After all, you could see, all of my friends, Alan-san, Ryszard-san, Honda-san, and of course Roy-san expressed exactly the same positive impressions about this version upgrade, even though they enjoy each different audio system.
On the Japanese side, we, Nishikawa-san, Kajiwara-san, were so surprised that we also felt just the same thing, and since then Alan-san and I often talked about how to describe the sound of the latest state in detail, when the sound was so natural and real, it was only a fun time for us, but we could only realize that it was too difficult for us to express our excitement with all the words.
We also agreed, when the sound reached that level, where music and audio are completely fused, there would be no longer a desire to do a so-called audio listening reviews.
In any case, I was truly impressed and moved by the wonder that my friends living in various points of the globe had almost common experiences. Thankfully, I enjoy my whole life. Making things for specific small number kindred-sprits in various countries would be far more desirable for me now rather than producing products for an unspecified number of customers as before.
As you might have known, I had been a professional engineer of manufacturers for a long time, and involving in development a lot of kinds of audio and video equipment. But I realize my essence or identity is as a "Craftsman", who wants to dig deeper into the already matured analog technology.
Well, I’d like to insist again that if we want to look for authentic analog technology, we should listen deeply to the wisdom of past ancestors found in vintage supreme equipment such as Marantz Model 7 and also the remarkable NOS parts, forgotten in the flow of time.
I take my hat off, and hang my head on the efforts and consequences of those ancestors.
