Mark Levinson No. 33XL

If you send a questionnaire to all audio enthusiasts in the world, ask them to list the most impressive Hi-End audio brands. Mark Levinson (hereinafter referred to as ML) will definitely be one of the top answers. Perhaps many audio fans can't agree with the ML's "too" accuracy, neutrality or even "no taste" sound, but it is absolutely impossible to deny the advanced structure of ML audio products, the perfect industrial design, production and quality Strictly, it is still second to none among HiEnd audio manufacturers today.

For DIYer, it seems that it has nothing to do with ML's industrial design and product management, but there are many references to the structure of ML audio product design, especially ML's "highest reference standard". No.33XL post level (No.33XL is a special number for Taiwan agents, hereinafter referred to as No.33). Let us first look at the "set" of post-amplifiers of No. 33 launched ten years ago (1995). First of all, it is a mono production (so I say "a set"), the height is half the height of each person, and each channel weighs 136 kg. Is the output power of such a large and heavy set of rear stage very large? In fact, it is not too large. It only has 300 watts per channel at an 8-ohm load, but its output power can be doubled from 600 watts at 4 ohms and 1200 watts at 2 ohms to 2400 watts at 1 ohm. The large power supply and current output are the design priorities of No.30.

Looking at the picture inside No. 30 below, you can find that two super giant toroidal transformers (each with a capacity of 2.45kVA) and 12 giant power supply filter capacitors (each with a capacity of 39,000μF) occupy the interior of No. 33 Most of the volume can be seen.



You may also find that the appearance of No. 33 is a "stand up" upright design, which is very different from the appearance of ordinary audio equipment. In fact, this is considering that its super large size is placed horizontally like a traditional amplifier. ", Will occupy a very large audio-visual room area. But in fact, the accompanying benefits are actually worth learning for DIYer. First, after changing to an upright design, the area of ​​the heat sink on both sides is greatly increased, the width of the heat sink is greatly reduced, and the increase in the height of the heat sink improves the heat convection efficiency, so the heat dissipation efficiency is greatly improved. As for beauty, it is regarded as a side benefit.

Secondly, the three-dimensional architecture design allows No. 33's three main circuit boards to surround the power supply module configuration. Have you noticed that No. 33 is "almost completely without wiring"? The top input stage and the voltage gain stage circuit are directly connected in series with the pin header, while the power output stage circuits on both sides of the board intersect the voltage gain stage in a 90-degree vertical manner, and are also directly connected with the pin header. In addition, we all know that the power supply module is the "core" of the post-amplifier. The main circuit boards wrap the power supply in the center, which also allows each circuit board to obtain power with the shortest path. It also reduces the interference caused by power transmission.

Another feature of No.33 is the "AC Mains RegeneraTIon". DZ netizens know that in addition to the sufficient power supply for the power stage of the post-stage amplifier, the driver stage (voltage gain stage) circuit The stable power supply is also not negligible, so most manufacturers or DIYer will design additional voltage regulator and separate power supply for the driver stage. ML did more than that on No. 33. They think that the general commercial power has too much noise, which has a great negative impact on the voltage gain stage that requires a pure power supply, so ML designed this unique "AC power supply "Rebuild" the circuit, the rectified and filtered DC DC through the power supply line, and then input an AC oscillating line to create a more pure AC, and then through a rectification and filtering and voltage stabilization, the resulting "pure and pure" DC power The four voltage gain stages for No. 33 are used.

Caption: This is the front and back view of No. 33 "AC Power Rebuild" circuit board. You can find that "AC Power Rebuild" has a separate power transformer, rectification and filtering. For this circuit board alone, ML also Practicing three-dimensional planning and configuration, including the first AC rectifier diode set on the other side of the bottom circuit board of the power transformer, and the combination of the stabilized power crystal directly through the heat sink and the circuit board, all help Significantly shorten the transmission path and simplify the assembly process.

Caption: No. 33 is the top view after removing the top cover. The front green circuit board is the input stage circuit, the rear yellow circuit board is the voltage gain stage, and the "stacks" of power crystals are in the four corners on both sides.

Caption: No. 33 fully symmetrical and fully balanced voltage gain stage circuit board is the most important signal processing core of the whole machine.

Pictured: No.33's output stage crystal is directly combined with the heat sink. This picture shows only the "one side" of the mono channel. No.33XL mono power output stage uses 60 power crystals, 15 pairs of push-pull complementary output for each of normal phase and reverse phase, in order to achieve the goal of completely balanced design from beginning to end.

Picture: No.33 uses two super-large toroidal transformers each with a capacity of 2.45kVA. From the CD records in the picture, you can know how huge these two transformers are! var check_allow = "/d/Api/iscantalk.html"; var add_url = '/ d / article / write /'; function CheckLogin () {now_uid = ''; var ElecfansApi_checklogin = '/ webapi / passport / checklogin'; var logout_url = "{: U ('Login / logout')}"; var logout_url = 'http://bbs.elecfans.com/member.php?mod=logging&action=logout&refer=front'; $ .get (ElecfansApi_checklogin, function (data, textStatus) {if (data! = "") {EchoLoginInfo (data); CheckEmailInfo (data); data = $ .parseJSON (data); now_uid = data.uid; / * var login_content = 'write an article