Tag Archive for analog audio

Tokyo International Audio Show 2014

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Between 23rd-25th of September, Tokyo International Forum hosted the 32nd edition of TIAS (Tokyo International Audio Show). This year’s exhibition had about 31 exhibitors and some interesting lectures however it was set in the middle of the week and even with a national holiday on 23rd I’m sure many could not make it.

2014東京インターナショナルオーディオショウ

This year there were some interesting products from Ocean Way, Daniel Hertz, Wilson Benesch, Constellation Audio and DartZeel that i got a chance to listen and inspect visually, but the rest were pretty much same ol’ same ol’. I will get into some details with some of these units and for the rest i kindly ask you to visit the gallery below.

Bowers & Wilkins

In the B&W room i saw displayed details of the top mounted tweeter used in CM6S2 and CM10S2. You can see what the Decoupled Double Dome technology is and the back chamber.

Also pictured is crossover of the smaller models in the CM series. We can see B&W uses first order filters and Mundorf capacitor.

B&W, Bowers & Wilkins, CM Series, Decoupled Double Dome Tweeter, Crossover, CM10S2, CM6S2

B&W, Bowers & Wilkins, CM Series, Decoupled Double Dome Tweeter, Crossover, CM10S2, CM6S2

B&W, Bowers & Wilkins, CM Series, Decoupled Double Dome Tweeter, Crossover, CM10S2, CM6S2

B&W, Bowers & Wilkins, CM Series, Decoupled Double Dome Tweeter, Crossover, CM10S2, CM6S2

B&W, Bowers & Wilkins, CM Series, Decoupled Double Dome Tweeter, Crossover, CM10S2, CM6S2

B&W, Bowers & Wilkins, CM Series, Decoupled Double Dome Tweeter, Crossover, CM10S2, CM6S2

B&W, Bowers & Wilkins, CM Series, Decoupled Double Dome Tweeter, Crossover, CM10S2, CM6S2

B&W, Bowers & Wilkins, CM Series, Decoupled Double Dome Tweeter, Crossover, CM10S2, CM6S2

B&W, Bowers & Wilkins, CM Series, Decoupled Double Dome Tweeter, Crossover, CM10S2, CM6S2

B&W, Bowers & Wilkins, CM Series, Decoupled Double Dome Tweeter, Crossover, CM10S2, CM6S2

B&W, Bowers & Wilkins, CM Series, Decoupled Double Dome Tweeter, Crossover, CM10S2, CM6S2

B&W, Bowers & Wilkins, CM Series, Decoupled Double Dome Tweeter, Crossover, CM10S2, CM6S2

B&W, Bowers & Wilkins, CM Series, Decoupled Double Dome Tweeter, Crossover, CM10S2, CM6S2

B&W, Bowers & Wilkins, CM Series, Decoupled Double Dome Tweeter, Crossover, CM10S2, CM6S2

Wilson Benesch

My attention was caught by their Endeavour Loudspeaker first because it features an isobaric bass alignment, something you don’t see very often and second because the enclosure is made from composite carbon material.

In a speech, i was able to capture, they talk about the advantages of composite materials to reduce enclosure resonances and they state their design philosophy. There is also translation in Japanese.

Wilson Benesch Endeavour

Wilson Benesch Endeavour

Wilson Benesch Endeavour

 Ocean Way

This year they brought the Montecito Reference Monitor System. A 3 way design all aluminum diaphragms so the tweeter dome and the midrange and bass driver’s cone is made of aluminum. The tweeter is loaded by a wood waveguide.

What i liked about this loudspeaker is the high diameter midrange, a 10 inch unit and, in my opinion, a very good choice for crossover points, 160Hz and 1.6kHz.

Ocean Way Montecito

Ocean Way Montecito

Ocean Way Montecito

Ocean Way Montecito

Ocean Way Montecito

 

 

Gato Audio

AMP-150 and CDD-1 were displayed and i really found their aesthetics very pleasing and interesting. The amp is pretty powerful rated at 150W/8 ohms/channel.

Gato Audio AMP-150, Gato Audio CDD-1,

Gato Audio AMP-150

 Gato Audio CDD-1,

 

 Accuphase

Their room was impressive as always with some really good speakers to showcase their electronics. They setup a demo of PS-520 Clean Power Supply unit and i would like to mention it here. For more pictures please check the gallery.

Accuphase PS-520 demo

Accuphase PS-520 demo

And the system they used with Magico Q3 speakers

Accuphase System with Magico Q3

 

Daniel Hertz

I got to see the M8 Speaker System this year. This high efficiency loudspeaker can be used as nearfield monitors with an 8 inch mid-bass driver and a compression driver in a 2 way bass reflex alignment. I was able to get some closeup shots of the drivers.  Crossover point is at 2kHz and one speaker weights 25kg.

Daniel Hertz M8 Speaker System

Daniel Hertz M8 Speaker System

Daniel Hertz M8 Speaker System

Daniel Hertz M8 Speaker System

 

These were some of the things i liked or i was anticipating to see. Please visit the gallery below for more pictures. I hope you enjoy it.

 

Microphone Preamplifier Part 1: Restoration

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Some years ago, i got my hands on an old and obscure mono mixing console. It was labeled just as PM5200. It wasnt of much use to me so i tore it down and salvaged parts for my own projects.

The other day i was looking through my things and found the mic preamp modules from that console and i thought this would be a great weekend project. I remember i used one of the modules for a guitar recording rig. Battery powered and with a transformer input it worked very well with Shure SM57.

The circuit uses only solid state discrete components and uses capacitor coupling. It allows for 3 gain settings and a nice line in/mic feature.

Original Mic Preamp Module

Original Mic Pre PCB

I do like the shield. 1mm thick steel.

You can see the original module with the busted gain setting. First i had to do is to reverse engineer and draw a schematic. It wasn’t very difficult, old PCB single sided, resistors all 500mW clear marked. You can see the schematic below:

PM5200 MIC PRE Original Schematic

 

With +/-15V the circuit draws about 10mA so its running pretty hot.

T101 along with D101, D102, R109, R110 for a constant current source. T102 and T103 form a long tail pair. You can attack it with balanced/unbalanced signal. You can use an input for more feedback or if you use the inputs together you can get a nice line in input with about 10x gain. T104 and T105 forms the main voltage amplification stage.

Next i took down all the components. Nothing was worth keeping.

MIC PRE PCB

MIC PRE PCB2

 

I changed the NPN transistors to 2SC2240 from Toshiba. I really like these transistors in audio applications. PNP transistors i used BC559C, low noise and i have alot of these.

Also i replaced R119 with a multiturn pot of 5k in value. I hope i can get rid of the last coupling capacitor. We will see. One thing that surprised me was the lack of any power rail decoupling on board. I added 2 100n MKT caps.

Modified Mic PReamp

Modified Mic PReamp PCB

 

After that i recorded frequency response which you can see below. It is pretty linear with just 1dB dropping at high frequency.

PM5200 Mic pre frequency response

 

In next part i will explore some improvements and just put it in a box, add controls and make it ready to be used.

Thank you for visiting.