YAQIN MS 34 D upgrade - udoskonalenie

[neixian]

in case you don't understand Polish:

In this film, I will present an upgrade, which means an enhancement of the amplifier working in my audio system. I chose a tube amplifier instead of a transistor one after listening to and comparing the mentioned options. I consider the tube amplifier as the input stage. We replace the tube in the input stage. We replace the tube in the input stage. We replace the tube in the input stage. We replace the tube in the input stage. We replace the tube in the input stage. We replace the tube in the input stage. of the 6J1 type. I replaced it with a German-made AEG EF95. After changing this tube, I clearly noticed an improvement in resolution and clarity of the higher frequencies, that is, the high tones. Next came the replacement of the tubes for the high frequencies, that is, the high tones. I replaced the original 6CA7 power tubes with Tung Sol EL34B. These tubes were manufactured in Russia by this company. As a result, the amplifier achieved a clear improvement and freedom in the emerging sound. I consider this replacement beneficial. When replacing the tubes, I relied on opinions, as not everyone can afford to buy multiple sets of tubes just to select the right one and leave the others in a drawer.

Next came the electronics of this amplifier. At the very beginning, the potentiometer is, of course, in operation. The original one, although almost new, was already crackling. I replaced it with an Alps potentiometer. It was very difficult to obtain and its price was also very high. Note that there is an error in the schematic. There are capacitors working at a short distance from the potentiometer, which are not marked in the diagram. I replaced the poor-quality originals with high-grade Mundorf capacitors. This is the first one. And here's the second one. I significantly reduced the rotation speed of the potentiometer, as I found the original rotation to be exaggerated. Next, I dealt with the power supply. I replaced it with significantly larger capacity and higher breakdown voltage. These are T4 and T4 additionally placed in a free space of this amplifier. The capacitors are Nippon Chemicon, protected in parallel with Janssen Audio capacitors, each with a capacity of 0.1 microfarad. Additional capacitors are protected with 20 kOhm resistors. The total capacity of these capacitors at this point is about 6000 microfarads, compared to the original approximately 1300. This replacement greatly improved the sound quality, especially at higher power levels. This is understandable.

I then replaced the diodes in the power supply circuit. I replaced the original diodes with fast Schottky diodes, BAY26C type. I didn't notice any changes in the sound output. The next step involved the electrolytic capacitors directly connected to the anodes of the low-power high-frequency tubes. The capacitor labeled as 101. I replaced the original 22 microfarad capacitor with a 330 microfarad capacitor from Samyang. It seems to me that the amplifier also improved its sound quality as a result. Another electrolytic capacitor in the power supply circuit is labeled as 114 and its twin 113. These capacitors, T, work directly in the power supply circuits of the grids of the EL34 power tubes. The capacitors originally had a capacity of 330 microfarads, here they are 6800 microfarads. It also seemed to me that the quality of the sound output significantly improved. The T capacitors, as well as the anode capacitors, were protected with capacitors. This anode one is Janssen Audio with a capacity of 0.1 microfarad, and the T capacitor is Pilcore with a capacity of 3.3 nanoFarads. These grid capacitors were also protected with Pilcore capacitors with a capacity of 3.3 nanoFarads. I then replaced the electrolytic capacitors in the amplifier control circuit, labeled as 119, 120, and 121, with capacitors of much larger capacity. Also from Samyang. These capacitors were also protected by 3.0 Pico capacitors. To extend the filament heating time of the tubes, I replaced the original 100 microfarad capacitor with a 220 microfarad capacitor, labeled as C122. At this point, the filament heating time increased to about 45 seconds. This time seems sufficient to me. The capacitors working in the power circuits of the tube filaments were bypassed with a Janssen Audio capacitor with a capacity of 0.1 microfarad, to increase the alternating current flow through the tube to the ground. This replacement didn't seem to bring any sound improvement effects. The capacitors working in the high-frequency grid circuits of the low-power tubes, that is, the input tubes, were replaced with standard-quality ones, also from Janssen Audio, labeled as ZKP. These are capacitors labeled as 102 and 103. The red capacitors here are the ones working in the inter-stage signal circuit between the low-power and high-power tubes. These are crucial capacitors. I replaced them with mid-range Janssen Audio Superior ZKP capacitors, labeled as 104 and 105, on the diagram. All the work I did in the electronic amplifier was done using silver-added solder. The replacement of these components resulted in a significant improvement in the sound emitted by this amplifier. I believe that the work I did here was truly worthwhile. And now let's take a closer look at the aforementioned work. Fast Schottky diodes. Electric capacitors in the power supply circuit and their bypasses. Additional capacitors for low-power tubes. Anode capacitor of a low-power tube, Samyang, along with a protective Picore capacitor. The inter-stage signal capacitor between the low-power and high-power tubes. Superior Z-Cup Alps potentiometer along with signal capacitors. Electrolytic capacitors in the power supply circuit of the amplifier control system, also from Samyang. The amplifier cooperates with the GP-LAMI TI5000. The efficiency of the speaker is about 93 dB. This is important because a relatively low-power amplifier, 50 Watts RMS, like this one, works in a room with a volume of about 80 cubic meters. Quietly. When turning the potentiometer to about 3.4, there's no talking in the room. And the sound spreads around 300 meters in a circle around the house. I replaced the flimsy casing with a thin steel sheet back with a thick aluminum one. This way, the amplifier looks much better than the original. Finally, something about finances. They are unavoidable. Just the tubes alone cost around 550 złoty at the moment. The Alps potentiometer is just under 200 złoty. Signal stage capacitors are about 200 złoty. Electrolytic capacitors in the power supply, also about 200 złoty. Sheet metal about 100 złoty. Altogether, all of this amounts to about 1300 złoty. Adding the amplifier purchase itself, we're looking at around 3, 200 złoty. However, for this price, we get a really good-class amplifier that produces fantastic sound. It can easily compete with much more expensive amplifiers, both the originally tube-based ones and the transistor ones from a higher price range. I wish everyone good luck with such projects, and of course, great satisfaction. I derived a lot of satisfaction from these endeavors. Thank you for your attention. And great satisfaction. I derived a lot of satisfaction from these endeavors. Thank you for your attention.

[jacojaw]

Dobra robota! Zostały jeszcze do wymiany kable sygnalowe, oryginalne są fatalnej jakości

[jerryjohnson]

Hello, I have a yaqin ml-20L that has no sound out of the speakers, but has small sound out of the headset. what do you think the problem is, and do you sell upgrade kit for that model ?

[brackyy]

Gdzie udało się kupić lampy sterujące AEG EF95? Super robota.

[polishmotorfan]

Dobra robota, jaki koszt modyfikacji sumaryczny? Dziś kosztuje ten wzmacniacz 3300 około.