Friday, April 7, 2017

JBL Graphic Controller Preamplifier & Solid State Energizer Modification

Since 60's, JBL made several audio equipment.

Power amplifier : SE400S, SE408S, SE460, SE400, SE400E, SE401 and SE402

Integrated amplifier : SA600 and SA660

FM Tuner : ST860

And only preamplifier : SG520

All above have great sound and really match with vintage JBL speakers like they've claimed.

But now some components have expired and should be replaced.

Let bring them back to "better" life with high quality components.


SG520 Graphic Controller Preamplifier.


This SG520 just repaired before with standard Japanese components.





So I just replace standard capacitors with Western Electric paper in oil and RIFA electrolyte.






Better look & better sound with long life and high quality components.


Next was SE401 amplifier with Germanium power transistor & interstage transformer !

Top amplifier in picture is SE408S and bottom is SE401.


Indicated for JBL D50S8R (S508) Olympus.


This JBL amplifier was repaired too.


Replace components and treat power supply section.


Audio section with standard components.


After cleaned & replaced.




Seem JBL audio equipment have higher quality than we think before.

That's why some of Japanese guy still using these with their vintage JBL speaker systems.

Cheers if you are JBL fan and find them in reasonable price.

Wednesday, March 8, 2017

Sentimental Cafe's Loudspeaker System from Thailand

Sentimental Cafe' is the new cafe' in central of Bangkok Thailand.

Serve with coffee & music.

Me and my team had opportunity to select and set up speaker system of this marvelous place.

So I want to summarize and leave some information of speaker & crossover network here.


This cafe' stay on 2nd floor over Sentimental Friends Thai food restaurant.

Near Asia Hotel and Ratchathewi BTS Station.



Cozy and great coffee selected. 

Suitable for relaxation and make appointment with your good company.






This speaker system has 4 way drivers contain with 

Low frequency : Altec 416A in A7 cabinet (Below 300 Hz)

Mid frequency : YL D-55000 in Replica Western Electric 16A horn (300 Hz - 5 kHz)

Mid-High frequency : YL D-35000 in EL-800 horn (1 kHz - 5 kHz)

High frequency : YL D-18000 (Above 5 kHz)

Crossover network custom made by us follow frequency ranges above.



YL D-55000



YL D-35000



YL D-18000


Custom made crossover network for Sentimental Cafe'.


Almost use Western Electric 16 AWG wires for each drivers.


Inside wooden crossover network wiring with WE & Duelund wires.

From many know-how from Jeff Day blog.

We've select Solen standard inductor for low & mid and Jantzen litz wire inductor for high.

Ronken P61 film/paper in oil and WE paper in oil with WE film capacitor.

Result of the sound so remarkable. Can enjoy with almost kind of music.

That's our goal.





If anybody have a chance to visit Bangkok, please come and join us with music & coffee for you.

Cheers !!!

Friday, November 18, 2016

Marantz Model 1 Audio Consolette & Type 4 Modification

Marantz "Audio Consolette" also known as Model 1 is the one in list of collective items.

It is a beautiful mono preamplifier, so need "2" for using in stereo system.

It's adjustable for turnover and roll-off in record equalizer that Marantz 7C removed.

One of my friend has 4 pairs of Marantz Model 1, so he need to try 1 pair in "Real Sound"

like Marantz 7C that I've modified for him before.



3 of 12AX7/ECC83 for 1 preamplifier (mono).


It need external power supply like Marantz Type 4 that I mention in the end of this post.


Top view for both channels of original with many Bumblebee "an easier to leak" capacitors.




Bottom view of originals.




Rectifier section with carbon composition resistors that cause noise into system.


Components for modify both channels.

Arizona "Blue Cactus" capacitors, wet tantalum capacitors and high quality wirewound resistors.


Top view after modified.


All coupling capacitors using Arizona C50309 "Blue cactus".



Bottom view after modified.




Use wet tantalum capacitors for 12AX7 cathode bypass.


High quality resistors in rectifier section and add filter capacitor to final stage.


Change 47k cartridge loading resistor from 0.5W to 2W for more mellow tone.


And this is Marantz Type 4, external power supply unit for Model 1.

1 box supply to 1 channel Model 1. 


Use selenium rectifiers like all equipment in same era.

Selenium produces good tone but shorter life and cause toxic when it has failure. 




Modified by using STTH6112V2, great ultrafast & soft recovery diode for high voltage.

and good quality silicon bridge diode for filament voltage.


Parallel HV output with PIO capacitor, seem like bi-cap with first filter capacitor inside Model 1.


Better, can easily listen both Model 1 and Type 4 after modified.

Everything will be more better after run in for hundred hours.

Cheers !!!