2019/12/08

Nakamichi SR40 STASIS Stereo Reciever

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Nakamichi SR-40 STASIS Stereo Receiver

An amplifier with a tuner released in 1987. My audiophile friend asked me to this amp if I could repair it.

gSR-40h has a STASIS power amplifier circuit. STASIS is a non-feedback type amplifier developed by Dr. Nelson Pass at Threshold.

Nakamichi received a patent license in 1985, and in the following year it was first commercialized in the power amplifier "PA-70 / 50" series. At that time, Threshold released only super-high-end products and licensed Nakamichi to develop products in the middle range and below.

There was no pre-main amp product at Nakamichi at that time, and the stereo receiver product with STASIS was the SR-40 (SR-4 in overseas), and it was a high-end model with a sales price of 148,000 yen. There seems to be a product called gSR-30 / 20h in the lower model.

Until this "SR-40" was manufactured in Japan, but the models after that seem to have been manufactured overseas, and the product quality seems to have deteriorated considerably. The successor model was renamed gTA-40 / 30 / 20h and was released until around 1990.

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At that time, stereo receivers were very popular in North America, and the market size was also large. In the catalog of gSR-40h, gThe Audiophile Receiverh and gRemote Control STASIS Receiverh are displayed and it seems that it was appealing as a stereo receiver for audiophiles.

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The appearance of the gSR-40h is so good that it cannot be seen by an audio product 32 years ago. The owner said that sound was coming out, but sometimes it was also mixed with noise.
However, I was drowned to turn on the power suddenly, so I opened the case and checked it.

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The lower board is the main amplifier board, and a fairly large heat sink is placed in the center.
Dust was piled up on the board, but no electronic parts were burned or burned out.
The old famous device Sanken 2SA1491 / 2SC3855 was placed in a 2 parallel configuration in the final stage.

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Since it is almost composed of discrete parts, the repair is a little easier.
However, this is the first time I have seen an amplifier with so many styrene capacitors. Styrene capacitors are famous parts because of their good sound, but they are very sensitive to heat (heat-resistant temperature is about 85C), so if a damaged part is found, it will be very difficult. Since it is already discontinued as a part, whether there is dead stock somewhere ...

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Since there is also an AM / FM tuner board on the front panel side, it is a fairly complex and high-density mounting. To improve the sound quality, it may remove the tuner circuit.

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The power supply has a large toroidal transformer, and the two large electrolytic capacitors were still safe.

I tried to leave it for a while after turning it on, but it did not generate any heat, abnormal vibration, or smoke. Because of the large heat sink, the temperature rise of the transistor is also mild.

When I was fine and put the music signal in the CD input and turned up the volume, the sound came out from the speaker properly. The main volume can be controlled smoothly without any rust, but the volume knob is quite heavy because of the motor control.

I also found that the display brightness of the AM / FM tuner was low, making it very difficult to see. When the FM antenna was connected, the signal meter was also displayed and the FM received sound could be played properly. I was surprised that the reception sensitivity was better than my FM tuner.

After a while, there was a symptom that sometimes the left channel was not output, but I found that the tone control volume seems to be poorly touched.

It seems to be mainly due to poor contact of the signal path, so it seems to be okay to not complete overhaul. For the time being, I'm trying to clean the contacts in questionable parts.

I've never heard of a STASIS amp, but it sounds like a high-end amp rather than a stereo receiver.
It's not particularly powerful, but it's a bit of a beautiful sound!

The reason why it was not popular in Japan was probably due to the product form of the receiver.

According to reviews from overseas users on the Web, the gSR-40 (SR-4)h has the impression that it sounds better than the gPA-50 (PA-5)h power amplifier with a STASIS circuit.

Around 1990, Nakamichi broke down in terms of contract with Threshold, and was unable to sell amplifier products with STASIS circuits.

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This gSR-40h is a complex implementation, so it would be troublesome to completely disassemble and clean it.@I got a service manual, so I would like to repair it in the meantime.B

Note (2019/12/11):
In the running test, sometimes the left channel was not output! Not only due to poor contact in the tone control section. I seem to have to overhaul it.
posted by toons at 23:58 | Audio

2019/12/05

Renewed my Pepper Mill - Cole & Mason Derwent

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Cole & Mason Derwent Pepper Mill

My Peugeot Pepper Mill, which I have been using for about 20 years, has become quite obsolete, so I bought a new one!

At the time of first consideration, the leading candidates were Peugeot and Japanese IKEDA.

I thought that a pepper mill with an orthodox stone mill structure was not interesting, so I decided to choose one with a completely different mechanism.

So, I chose the Gourmet Precision series Pepper Mill of the UK Cole & Mason.

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Cole & Mason pepper mills are chopped with a sharp carbon steel blade instead of grinding pepper with molar teeth.

Therefore, the grinding feeling is surprisingly light and we can grind a lot of fine pepper.

At first tried grinding, it was much easier than Peugeot, so I made too much ground. In addition, this mechanism is a permanent warranty.

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It is much larger than my current Peugeot, its height is 19cm and its thickness is 4cm even at the narrowest part, so the hold is very stable.

The upper stainless steel part is a rotating knob that can be pulled out and refilled with new pepper.

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Pepper grinding roughness can be adjusted in 6 stages!
It can be set to any size from super coarse to powdery. The silver part with the Cole & Mason logo is the size adjustment ring.

A new Peugeot's pepper mills are also equipped with the gU'SELECTh roughness adjustment function. I compared to that products. But I abandoned it because the adjustment mechanism part of the molar gap was likely to cause a new failure. It seems that the size adjustment ring part is easily damaged in the Web information.

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I tried to grind sample pepper with Cole & Mason at each roughness setting. This is a setting where the roughness increases from the upper left to the right, and the lower right is the most coarse setting.

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In this result, there is a change due to the size setting of the roughness adjustment. The finest pepper is possible with Peugeot, but it will not come out unless the molars are tightened firmly, and a very strong turning force is also required.

Next, I tried the finest ground pepper with Cole&Mason and Peugeot 2 models (12cm, 16cm).

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All of the pepper mills are infinitely thin and have little variation.

However, Peugeot is a very rough level of setting that tightens the adjustment screw all the way and turns the knob. On the other hand, Cole & Mason was able to grind very easily even with the finest setting (1), so I thought it was clearly superior. If it is set to grind with the same level of power as Cole & Mason, Peugeot will be quite coarse.

In addition, I tried the coarsest ground pepper as well.

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Peugeot was ground with the adjustment screw completely loosened (the limit between the knob and the main body is about 2mm, which is the limit to grind). On the other hand, Cole & Mason grinded normally with the coarsest setting (6).

Cole & Mason can grind very coarsely, but Peugeot can only grind to a certain extent and there are many variations in size. Peugeot is determined by how the spacing between the molars is opened, so it requires a trick to operate the adjustment screw and knob, and it seems that it is not very good at super coarse grinding. (The Peugeot gU'SELECTh product may have improved these.)

I would like to use Cole & Mason and Peugeot for a while and will move to Cole & Mason completely if there is no problem.
posted by toons at 19:25 | diary

2019/12/03

Autumn leaves around Shugakuin in Kyoto

Last weekend, I went to see the autumn leaves around Shugakuin in Kyoto.

A 5-minute walk to the east from Shugaku-in station of Eizan train, there is "Sagimori Jinja" shrine. I took a detour on the way to "Manshuin" temple.

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Go through the precincts of "Sagimori Jinja" shrine and head further east. At the end of climbing a long steep slope, there is "Manshuin" temple.

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If I didn't take a detour, I regretted that there was a little more sun light and the red contrast of the autumn leaves was good.

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hManshuinh temple is a famous place for the autumn leaves along the outer bund, but now it had become a fallen leaves carpet. If it was already a few days earlier, the carpet would have been more bright red.

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On the way back, the sunset over Nishiyama mountain seen from the middle of the slope was beautiful.

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posted by toons at 19:08 | diary

2019/12/02

Expof70 Commemorative Park

I went to the Expof70 Commemorative Park yesterday.

The Expof70 Commemorative Park was built on the site of the Japan World Exposition 1970. It has about 260 Hectares. In the huge park, there are a part of facilities of the Expof70, such as the Japanese Garden and the Japan Folk Crafts Museum, Osaka.

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It is a view from the observation tower of Solado (forest aerial observation path).

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posted by toons at 10:10 | diary

2019/11/30

Big ginkgo of gBukojih temple in Kyoto

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Due to the coldness recently, the big ginkgo of gBukojih temple had fallen considerably.

The kids playing with fallen leaves looked very happy.

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posted by toons at 23:59 | diary

2019/11/27

"Oike-zakura" blooms!

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"Oike-zakura" has bloomed again this year!

It is a single cherry tree in the corner of the Kyoto Oike Soseikan, called "Oike-zakura".

It is a cherry variety that blooms when it gets cold. It begins to bloom from now and continues until early spring. It will delight us with this lovely pink flower this winter.
posted by toons at 15:38 | diary

2019/11/25

Autumn leaves at "Kinkai Komyo-ji" and "Shinyodo" temple in Kyoto

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Yesterday, the weather forecast was rainy, but fortunately it was cloudy. So, I went out to a nearby autumnal spot in Kyoto.

Along the northwest of Marutamachi Higashioji, I went to "Kinkai Komyo-ji" temple.

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This gate can be climbed for viewing and overlooks Kyoto city.

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I walked to the northwest and went to "Eisei-in" temple. There was a nice garden.

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Furthermore, I walked a little to the north and went to the famous spot of autumn leaves, gShinyodoh temple.
It was close to sunset, so there were few tourists.

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posted by toons at 07:23 | diary

2019/11/24

Autumn leaves at Bishamondo temple in Kyoto

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I went to see the autumn leaves at Bishamondo temple in Yamashina, Kyoto.

Due to the cold weather until yesterday, the mountains around Bishamondo temple were also changing to colored leaves.

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Once a small temple that only local people know, but since it was introduced on CM video, a lot of tourists came.

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Just at the autumn leaves festival, music dedication was taking place.

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posted by toons at 07:30 | diary

2019/11/22

PEUGEOT Pepper Mill disassembly and cleaning!

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My PEUGEOT Pepper Mill.

It is a pepper mill that has been used for more than 20 years. A French automobile manufacturer, Peugeot, has been spun off and manufactured as a family business.

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Peugeot's pepper mill is a staple in restaurants around the world. The model on the right side seems to be discontinued.

Recently, the pepper grind is not stable and the adjustment screw tends to be loose.

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Short type 12cm pepper mill.
I used it for white pepper before, but now I use it with coriander. The usage frequency is relatively low.

It can be disassembled simply by loosening the two screws.
A very simple structure when you remove it! The shaft is a bit rusted, but the grinder's mill teeth are still alive.

The Peugeot grinder mechanism consists of double-toothed helical teeth. Pepper grains are cut into the outer teeth, guided to the bottom and fixed, and then finely crushed by the inner teeth.

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Cleaned with absolute ethanol, it is completely clean.

Next, a 16cm pepper mill.
Since it was mainly crushed black pepper, the usage frequency is quite high.

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The shaft is also rusted and the mill teeth are worn away considerably.

This may be the reason why the adjustment screw is loosened quickly while crushing pepper.

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For the time being, it was cleaned with absolute ethanol and assembled.

Peugeot's pepper mill is made of wood, and the grinder mechanism is fixed with wood screws, so if it is frequently disassembled, the screw holes on the main body side will soon hurt. There is a limit to the number of disassembly and cleaning.

The 16cm pepper mill seems to be at the limit of use, so I need to procure a new one.

I will investigate how far the current Pepper Mill has evolved and choose a high quality one.

posted by toons at 22:22 | diary

2019/11/21

New updated - "Vocalise Scope" ver 4.4

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"Vocalise Scope" was updated to ver 4.4.

"Vocalise Scope" is a new diagnostic vocal pitch-visualizer for iPhone. It has also the recording function with the pitch analysis.

It can display your vocal pitch in real-time. It will assist you visually for training your a cappella vocals and practice of Passaggio. Please be exploited to improve the ability for your singing.

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If you are interested in this app, please click the following link to display on the product information of App StoreTM.

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posted by toons at 18:38 | News