2019/09/29

SONY Blu-ray Disc Recorder "BDZ-X95"

BDZ-X95.jpg

Sony's Blu-ray Disc recorder high-end machine released in 2008.

It was the popular model of the time with high-quality video circuit "CREAS", and became a hot topic even with the failure of Seagate HDD.

It malfunctioned due to HDD system error. I tried to disassemble it and repair myself, but eventually gave up.

The top plate is made of 4mm aluminum, and the HDD has a rubber-damped pedestal and a copper spacer.
By the way, I will use this aluminum top plate in place of the insulator of my CD player, and I am thinking about what the copper spacer can be used for.

Introducing each part of the dismantling.

# All boards
S.jpg

# System board
CPU.jpg

HDD
HDD.jpg

# Video Encoder/Decoder
EncDec(CREAS).jpg

# Digital tuner
Tuner.jpg

# Video signal I/F
Comp.jpg

# LED
Button_LED.jpg

# Display
Front_Disp.jpg

# Power supply
Power.jpg
posted by toons at 08:11 | diary

2019/09/28

Got FoodSaver FM2000! - its noise level?

foodsavor-fm2000.jpg

As a new kitchen tool, I got the vacuum packer gFoodSaver FM2000h.

I've wanted this tool since purchasing the low temperature cooker gBoniqh.

There are various manufacturers of vacuum packers, and their performance and price are very different. In the past, I used a semiconductor vacuum device, so I know how it works. But the consumer products is proved to be incomparable to expensive professional products with vacuum chambers. For the time being, I decided to choose a product that seems to be reasonably durable next to performance.

I finally selected FoodSaver's gFM2000h. FoodSaver has the US No.1 share, but it seems that the cost performance is not so good because a special pack is required.

foodsaver-MF2000-040.jpg

This product has a lot of accessories such as handy sealer, vacuum fresh box, special pack roll, bottle stopper, etc., so it is quite profitable.

gFM2000h is designed to perform vacuuming and sealing automatically, so it may be packed with air remaining due to malfunction of the pressure sensor.

In fact, I think that the manual method that can perform vacuuming and sealing by separate operations is more certain.

Ay first, I tried to make rice into a vacuum pack to check the packingoperation of FM2000.

foodsaver-MF2000-test-1.jpg

The important point of FoodSaver products is to set the rough side inside the original pack roll to the lower side. On the other hand, it seems that vacuuming process tends to fail.

foodsaver-MF2000-test-2.jpg

foodsaver-MF2000-test-3.jpg

The rice vacuum packed in a tick has been successfully completed.

There are rumors that the vacuum packer is quite annoying and cannot be used at night, so I tried to measure the noise level during vacuuming.

I use the sound level meter app " Sound Level Analyzer PRO" that was measured at a distance of 30cm from "FM2000".

foodsaver-MF2000-sla.jpg foodsaver-MF2000-sla-tc.jpg

According to this measurement result, the maximum noise level during vacuuming with FM2000 was 68.7dBA, and the average of 10 seconds at the last vacuuming was 65.4dBA.

As the degree of vacuum increases during the vacuuming process, the noise level gradually increases. But it turned out to be much quieter than I had imagined in advance.

Looking at the results of statistical analysis, the noise level with higher occurrence is 62 dB, which can be said to be steady noise during vacuuming.

foodsaver-MF2000-sla-sa.jpg

Furthermore, looking at the frequency analysis results when the noise level is maximum, it seems that the main component of the noise is around 500-1000Hz.

Since there is no peak at a specific frequency, there is no harshness in the sense of hearing. Unless midnight, FM2000 seems to be usable normally.

foodsaver-MF2000-fft.jpg

I would like to use it for frozen storage of food, but the special pack is quite expensive, so I need to search a cheap alternative. Well, FoodSaver products are major, so the SNS reviews will be very helpful.
posted by toons at 17:50 | Environmental noise

2019/09/22

SANSUI AU-907 Limited

a907LTD-front.jpg

SANSUI AU-907Limited

Released in 1994, the third-generation limited products of Sansui 907 integrated amplifier.

Equipped with a HYPER -X balance circuit, it featured a clean sound in the mid-high range of Toshiba's old MOS-FET (2SK405 / 2SJ115). This is still popular as the best sounding device for audio power MOSFETs along with Hitachi 2SJ49 / 2SK134.

Last night, after a long time, I tried to play an analog record to adjust my 2way speaker, but the amplifier was out of order and no sound was produced (CD direct input was sounded).

This morning, I opened the top plate to clean the inside, and after removing dust for the first time in several years, it started to sound normal.

# Inside of amplifier
a907LTD-inner.jpg

# 6mm thick aluminum bonnet with copper powder coating
a907LTD-topplate.jpg

# Left channel power block
a907LTD-left.jpg

# Right channel power block, preamplifier section (black box at right end)
a907LTD-right.jpg

# Power block (large power transformer with a total weight of 13kg)
a907LTD-trans.jpg

It was a total weight of 34kg, so I was concerned that it would hurt my waist when placed on the floor, but there was enough reward to clean it!
posted by toons at 03:15 | Audio

2019/09/20

MarkAudio OM-MF519 vs OM-MF5, Fostex speaker frequency characteristic comparison - extra edition

Extra edition report of my handcrafted speakers characteristic comparison.

I tried to measure the frequency characteristics of MarkAudio OM-MF519, last year's model OM-MF5, and some FOSTEX products under the same conditions as much as possible.

The amplifier volume position was the same, pink noise, and the measurement position was fixed at 1m on the axis, but the height of the unit was adjusted precisely, and there were a difference of several centimeters.

This was measured frequency characteristics with RTA app "Audio Frequency Analyzer".

OM-MF519 double bass reflex vs OM-MF5 bass reflex

# MarkAudio OM-MF519iDuct 15cm + 2.5cmj
OM-MF519.jpg

OM-MF519(3).PNG

# MarkAudio OM-MF5 (Tw is removed.)
OM-MF5.jpg

OM-MF5(3).PNG

As expected, the rich bass of OM-MF519 double bass reflex!
It seemed that the level around 30-50Hz is higher than OM-MF5 bass reflex.
For hearing, the left handed sound of the piano was resonated deeply. The loudness of the contrabass was also rich. And the mid-high range resolution is quite high, and the sound image localization was good due to the narrow baffle.

On the other hand, OM-MF5 bass reflex feeled like being pushed by energy. Since 60-100Hz was the same level as the mid range, the force of the base went up here. Full orchestra was a little difficult, but it was more suitable for Pops and Jazz.

The OM-MF519 double bass reflex was a 12mm front MDF, so I intended to reinforce it, but I found that the top plate was vibrating a little.

Since OM-MF5 bass reflex had 18mm side plate and bottom plate, it may be affected by the difference in rigidity.

Compared to the playback sound of two speakers, I prefered the normal bass reflection.

And measured other speakers under the same conditions!

Fostex FE83n
FE83n.jpg

FE83(1).PNG

Fostex FE83n mini bass reflex, installed in the enclosure in the Ontomo MOOK appendix.
The sound pressure level was the same, and the low frequency response was attenuated gently from 100Hz, making it easy to hear.

Fostex M800
M800.jpg

M800(2).PNG

2016's Fostex M800.
This box was a simple square shape, but the inside is actually elaborate. It had a hard reinforcement and air venting duct port, but was almost a sealed design.

The low frequency response feeled better than FE83, but was less conservative than OM-MF5. Since the sound had a peak in the high range of the unit, there were a feeling that it will be a little audible, such as a scratching sound. The low range was neutral and sound power can be put in as it fully.

Each units and boxes had very different characteristics and sounds. How far I can get to my favorite sound is a long way off.
posted by toons at 02:12 | Audio

2019/09/19

MarkAudio "OM-MF519" Speaker assembly Part 7 - frequency characteristics

OM-MF519_DB_1.jpg

After painting, I played a lot of music with this speaker for sound aging.

My personal impression is that the bass sound is very loud despite the 8cm full range. This is probably due to the bass enhancement effect of the double bass reflex.

# frequency characteristics (distance 1m, Pink noise, measurement by RTA app "Audio Frequency Analyzer"j
OM-MF519_DB_freq.png

However, looking at the frequency characteristics measurement above, it seems that the elasticity and tightness are retreating compared to a general bass reflex type, probably because 125-200Hz is slightly depressed. In a sense, 100Hz or less is too high.

Next, I adjusted the length of the second duct and examined how the frequency characteristics changed.

# Original duct (15cm)
duct-original.png

duct-original.jpg

I prepared a paper pipe with a slightly smaller diameter and measured it in units of 2cm.

The level of 100Hz decreased in the duct +2cm. It may be the effect that the duct area is slightly reduced.

# Duct +2cm
duct-2cm.png

duct-2cm.jpg

After that, the length of the duct was increased by 2cm, but no significant change was observed. It is also possible to pick up ambient noise.

# Duct +4cm
duct-4cm.png

duct-4cm.jpg

# Duct +6cm
duct-6cm.png

duct-6cm.jpg

# Duct +8cm
duct-8cm.png

duct-8cm.jpg

# Duct +10cm
duct-10cm.png

duct-10cm.jpg

# Duct +12cm
duct-12cm.png

duct-12cm.jpg

As a trial, I changed the length of the upper and lower ducts extremely. But, it did not be much different from closing the duct.

# Duct +2cm, +10cm
duct-10cm-2cm.png

duct-10cm-2cm.jpg

These results was not clear, so I have to try several times with different dates. I try listening with a duct length of + 4cm for a while.
posted by toons at 03:20 | Audio