This September TIAS was held at its usual place, Tokyo International Forum Building from the 25th to the 27th.
I took some pictures so i will share these with you but before that i want to say that this year i really liked the Esoteric room. Tannoy Kingdom Royal sounded great.
Accuphase room remains, though, my favorite this year too. These guys really know how to setup an audio system and i really liked their speaker selection. This year they had Tannoy Canterbury, Focal Maestro Utopia, TAD Compact Evolution One and Franco Serblin Accordo.
This year’s surprise was the Air Tight AL-05 Bonsai speakers. I could not believe the low frequency extension and the impact these small speakers had. People in the room were getting close to the speakers to see if the sound is coming from there. Amazing.
That’s about it, sorry if the pictures are not that great, I really have no idea how to use a camera.
I got a used Hartke A25 Bass Combo recently and it was in good condition but the pots needed cleaning so i decided to show you what is inside this little combo.
Once i took out the amp i noticed the power stage is actually using discrete transistors which is really really nice. The codes are not so well visible but i think it uses 2sd2058 and 2SB1366.
The opamp used is the JRC 2068 and a JRC 13700 is used for limiter (can be replaced with LM13700)
I also liked that the transformer is well shielded. After I cleaned the potentiometers I tested the unit and sounded great. I took some measurements to see the effect of the equalizer, range and center frequency.
I measured the output of the speaker from 50cm away and the speaker about 50cm from ground.
First i compared CD input with instrument input. Note that CD input is not affected by any of the controls, not even the master volume.
Red trace is the CD input and the other trace is the instrument input
Next i tested the equalizer controls.
The above is the bass control. We can see it is centered around 100Hz and indeed it has 30dB control range. Blue is +15dB setting, Red is -15dB setting.
Midrange seems to be center around 700-800Hz and again the control range is about 30dB. Blue is +15dB setting, Red is -15dB setting.
Treble center frequency looks to be 2kHz. The range is close to 30dB again. Blue is +15dB setting, Red is -15dB setting.
I also measure the direct output of the amp to see the frequency range of the preamp. It is quite linear as you can see below.
I can say it is well built and it has a nice tone. It doesn’t go that low but if placed on the floor it can be quite satisfying. In the future i will look more at the speaker and the enclosure as i think it can be improved a bit.
It has been a quiet period but a very busy period, very active and very fruitful. I will be launching the projectryu.com site soon with tons of free resources for the audio hobbyist.
Getting back to the title of this post, i would like to present a few improvements and a concrete design as a pedal unit. If you don’t remember about the Lagger project let me put the links below in case you want to check it out.
As a quick summary, Project Ryu Lagger is a guitar effect pedal that slows down the attack of the guitar (or any instrument for that matter) just like an automated volume pedal.
It does this with a VCA (Voltage Controlled Amplifier), based on the LM13600/LM13700. The fade in envelope is created with a ramp voltage generator that controls the VCA and this generator is triggered by a digital circuit created with a Microchip PI18F1320 MCU.
The digital signal conversion and rectification is explained in a previous article, please read it at the link below:
The new version i will present today was adapted as a real pedal with a 3 pole footswitch.
Another change was in the ramp generator replacing the 100k potentiometer with a 10k one since the other two pots in the circuit are 10k. This last change also implies changing some capacitor values. Please refer to the new schematics below:
I am pretty satisfied with this pedal so i have created the PCB for this circuit. The PCB gerber files and the MCU firmware is available for free as usual to subscribers in the next newsletters. If you are not a subscriber yet please register in the form to the right.
Some things to consider if you plan to design your own PCB is good shield of the LM13600/13700 input pins. It is good to surround it with ground plane like below:
With the new modifications on the ramp generator circuit the min – max values for attack control is 0.1s and about 1.4s. Below is the ramp waveform measured, this is actually the control voltage of the VCA:
1. full counter clockwise attack pot setting:
Horizontal resolution: 50ms/div
2. full clockwise attack pot setting:
Horizontal resolution: 200ms/div
Below is a screenshot that shows the triggering of the ramp generator, the red trace is the input signal:
As you can see modifying the attack control will adjust the length of the fade in effect. The trigger control adjust the input level above which the ramp generator is triggered. This is to prevent noisy pickups or other pedals used in front of the Lagger to trigger the effect.
The level control adjusts output gain from between +6dB to a max of +24dB so it is capable of a high amount of gain. In the measurement below voltage gain is 14 with an output voltage of 3.6V peak to peak (yellow trace). As you can see there is a bit of saturation happening.
Bellow are two videos showing signal traces using sine waves at 1kHz, one video triggering the effect manually and the other with the effect triggered by the input signal.
Project Ryu Lagger is one of my favorite pedals, i really like this effect and the latest version allows for a great deal of control for the guitarist in sustaining the effect or muting by simply applying muting effects with the palm for example.
For DIY-ers this project is of moderate complexity but you can subscribe or comment here and i will try to offer any assistance i can. Remember to read the Disclaimer though.
Here is the parts list for this project:
C1, C8, C15
C13, C14, C16-C18
R2, R6-R12, R15, R22, R23, R26, R28
R5, R29, R31, R32
R13, R14, R24
3 pole foot switch
I hope you enjoyed reading this article as much as i enjoyed building this pedal and hope to hear from you. To the subscribers, the newsletter will be sent in a few days with Gerber files for PCB and MCU firmware and a couple more details about this construction.
Here are 2 sample sounds of the effect played by one of my guitarist friends:
This sure was a pretty full period audio-wise. Lots of events all over the world and im glad to say i pushed forward new developments with Project Ryu.
CEATEC Exhibition as expected was held this month and i was looking forward to some new audio products. Looking around i found Tamura Booth showing off their transformers. In a glass box they also had one of their vintage jewels. Take a look:
Next interesting booth was Pioneer’s. A lot of demo DJ setups and noise but in a corner i found TAD. Nothing new here but i could snap a couple of driver close-ups of the Reference One Speaker System. Also they displayed the Compact Reference CR1MK2 but i got to say i was more attracted by a TL-1601a they had in between.
Next to TAD, Pioneer Professional (… i know) showed their PA speakers. GS-WAVE Series sure look promising and it is a pretty interesting move for Pioneer to go back to the old days of PA with the concept for this series. Pictured below is the WAV-LENS, mid-high speaker featuring acoustic lens and can do a whooping 145dB peak. Coaxial 2″ drivers, 250W MF and 160W HF and dispersion measures 110 deg H and 50 deg V.
Technics had a very nice room, showing a bit of their history, had 2 listening rooms and they presented their Reference System R1 Series. Products were displayed with inside view as well.
The R1 Series has 3 components, SU-R1 Network Audio Control Player (aka Preamplifier), SE-R1 Stereo Power Amplifier and SB-R1 Speaker System.
Technics SU-R1 Control Amplifier is a 17kg preamp featuring Technics Digital Link (a digital connection between Technics Components) and it is powered by two R core power transformers.
Technics SU-R1 Control Amplifier
Technics SU-R1 Control Amplifier
SE-R1 Stereo Power Amplifier sure looks like it can handle the work load. Normally Technics tried to come up with something different and even if IMHO they really lack imagination naming these technologies, i really appreciate their effort. So SE-R1 features JENO Engine (Jitter Elimination and Noise-shaping Optimization) … [great name guys!], GaN-Fet Driver, (now this is something worth looking into) and LAPC (Load Adaptive Phase Calibration).
Technics SE-R1 Power Amplifier
Technics SE-R1 Power Amplifier
The third component of the R1 Series is the SB-R1 speaker system. Now in the past Technics has proven its speaker design ability with some really amazing products. Now on this blog i don’t really want to write subjective impressions on sound so if you are curious about this system go ahead and find a place where you can listen to them. And this goes for any system from any brand, its your money, if your willing to spend it go and decide for yourself.
What i can do is give you some pictures and info on how these systems are built. So back to Technics SB-R1, these speakers claim 100kHz , and they reach that but at -16dB! Oh well… so lets just throw away the specs and look at what we have here.
We have 4 x 16cm drivers in 2 separated bass reflex enclosures (2 per enclosures), we have 1 coaxial MF/HF unit which looks pretty interesting in its own isolated closed enclosure.
Below you can see a cutout through the speaker and some details like crossover board. As you can see there are no exotic components in the crossover.
Technics SB-R1 Speaker System
Technics SB-R1 Speaker System
Technics SB-R1 Speaker System Inside
Technics SB-R1 Speaker System Inside
Technics SB-R1 Speaker System Crossover
Technics SB-R1 Speaker System Coaxial Driver Exploded View
All in all it was a really fun show and Kaihin Makuhari is a great place with lots of cool futuristic buildings. I hope you enjoyed these pictures and that you will visit again soon.
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.
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.
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.
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.
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.
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.
And the system they used with Magico Q3 speakers
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.
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.
I had the chance a couple of days ago to talk with professional drummer Joe Costello from Arizona, USA.
Joe holds a degree in music performance and has played with many artists throughout the years, some of the best contemporary jazz musicians. Ben Wolfe, Joe Magnarelli, Jerry Weldon, Tom Harell, Papa John DeFrancesco, Paul Mark and The VanDorens are just a few of them.
Joe is at the core of two projects, The Joe Costello Syndicate, a band that plays live at various events and a jazz band called The Joe Costello Project.
Take a second to visit Joe’s website, you can find there more information about his projects, his gig calendar and a contact form for any questions you might have for Joe.
There are many vintage drivers that posses a great timbre, used in many legendary speakers but after many years their motor is demagnetized to a point that they lost their output and the impact on midrange and high frequencies.
This is true especially with Alnico magnets since they are prone to demagnetization. Revitalizing these magnets can be very hard, it is for sure not something a DIY-er can do.
In these cases converting the motor to a field coil motor can be a very sensible solution. It will never demagnetize and it can offer other advantages such as adjusting the motor force for specific applications.
Someone has a pair of JBL 2220H which he loves and uses them in a Front Loaded Horn. However, in this horn, the midrange above 400Hz is not very detailed and asked if somehow a field coil motor can spark some life in that band.
Output in this region is influenced primarily by mass of moving assembly (cone, voice coil, surround, spider, dustcap etc) and the strength of the motor. Since changing the cone mass would mean altering the timbre of the driver the only option is to change motor strength.
If we increase the electro-mechanical coupling factor BL, we will notice a rising response characteristic with frequency. This is because the output of the driver will rise but lower frequencies will be tamed down by an increased impedance in that region.
This is a very good characteristic for drivers intended to be used in Front Loaded Horns because it will compensate for the natural low pass filter of such horns. This LPF is created by the air trapped between driver’s cone and the throat of the horn. At low frequency this air has mass and all of it is pushed into the throat but as frequency rises the air becomes compressible acting like a compliance and not all the air will be pushed into the throat. This compliance is a reactive element and acts as the low pass filter. Fortunately our rising frequency response characteristic will compensate for this effect and equalize the system to a flat response.
JBL 2220H has a strong motor already with a BL of 22.5 Tm, Re of 5.7 ohms and B of 1.15 T. Being a 15 incher however, there is room for a bigger one, a field coil motor. In the JBL specs sheet we see that the gap height is 9 mm and voice coil height is 7.2 mm so we are dealing with an underhung design with a ceramic magnet.
The motor i am proposing is a 180mm in diameter and 80mm in height. It has the same 9 mm gap height but it can reach a flux density B of 1.6T with a 1010 steel structure. As we will see, this will boost the midrange frequency of the driver so that it will respond better in a FLH.
With a 4 inch (100mm) voice coil i considered a 40mm cooling vent with large flange to eliminate any noise. It also features a T shaped pole piece for field symmetry around the gap as you can see in the image below.
The below graph shows the theoretical flux density curve with a 13 mm range, that’s +/- 2 mm outside the gap. In reality the value will be a little lower @ 1.5T due to imperfection of the joints between metal parts as opposed to the 1.7T on the graph.
To determine the new BL we have to know the length of wire in the gap on the JBL 2220H. The original BL is 22.5Tm and a B of 1.15T, this means that L=22.5/1.15=19.5m. With the new motor we have a B of 1.5T and this results in a BL of 29.25Tm Very Powerful!
The field coil used is a low voltage one <30V so that power supplies should not pose any problems. The graphs above were acquired with 26W delivered to the field coil. Considering careful ventilation this should not pose any heat problems.
I simulated the new driver in a 100L closed box to see how the response compares to the original. The result is shown below. The response rises indeed to about 5-6dBs from 220Hz up.
As you can see a field coil motor not only will solve the problems of old weak motor but it can also give you the ability to tune the driver to a specific application. By lowering the current in the field coil you can get to the original parameters of the driver. By not modifying the mechanical side, the cone, the suspension system we also maintain the original sound characteristic, the timbre of the driver.
I hope it was interesting and thank you for visiting.
About a month ago i reversed engineered a mic preamp module from an old console. If you don’t remember please refer to the article here. After i rebuilt the modules with newer components i decided to build a nice 2 channel preamp with them.
Below you can see the circuit for the unit. M1 and M2 are the modules presented in part 1.
As you can see it splits a 12V rail into +/-5V duble rails. I did this because i wanted to make it more mobile so i can power it from a big battery.
Below you can see my example of chassis.
This preamp doesn’t have a phantom power although you could easily add a +12V phantom power. In this regard it is best suited for dynamic microphones.