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News: Analog real time strong pass audio filter. Mono version .
Insulated , balanced output.
Some assembly / delivery time on this item. Estimated price: € 350
******************************************************* A new idea in live analog audio background noise reduction / removal .
Strong pass audio filter, with adjustable setting of minimum pass level.
Bad input gives bad output , but there are exeptions when the output result depends on human hearing. Our
ears are not sensitive to volume change. 3dB is the absolute
minimum audio volume difference we can hear. 3dB equals to Signal voltage x2 or /2 , using a
linear scale.
By using our live strong pass audio
filter to eliminate background noise, all signals smaller than the minimun pass level adjusted by the user, are reduced by
a factor, typical 20dB or 100 times . This
noise cancelling function is strong, something you can really
hear.
Idea & solution by
Joar Falstad.
Jo Tech Service
No signal delay. No change in pitch, maximum volume or tone balance .
Measured audio volume reduction outside pass level: up to 100 x or 20db .
Line signals in consumer equipment has a standard max value : 0.316 Vrms
Tape , Tuner and Aux signals are normally close to the standard of line signals
Our live strong pass audio filter has a in / ouput limit of : 4Vrms
All versions for sale have galvanic insulated transformer output.
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Service & Repairs
A Pilot 240B for test and repair, just something to memorize.
This unik valve stereo amplifier is now back in action, after a long rest.
One of the best amplifiers in any class.
The Beard P35
and most other VALVE audio amplifiers have Direct Coupled audio signal inputs.
Note! DC audio signal inputs are not compatible with audio signal outputs found on modern preamplifiers or pc earphone output . A DCvoltage pulse of several volts from a pc or modern preamplifier at Power ON, to this type of signal input can overload and damage the valve in the input stage
Convert to AC audio signal inputs . Capacitors is a hint. Note! High Voltage inside the amplifier
Self oscillations in the amplifier.
Some input stage valves, mainly triodes, have internal positive feedback , this can be locally
neutralized.
You'll get the best overall result by doing just that, before adding
other oscillation cancelling parts in the input or feedback circuit.
Natural, non colored, high quality sound.
Even to day, a good quality VALVE amplifier has the best sound .
------------------------------------------- High end amplifier update Sony TA - 5650 Vfet pre & power amp
drifting bias fix.
Sony S2
Mosfet pre & power amp Great sound quality .
Hot inside, possible to fix.
Sony TA - 1120A
Solid state pre & power amp
Great sound quality .
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We are all most creative when we are "forced" to find a solution .
Some older ideas and solutions , composed at our workshop.
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******************************************************* Windows Program + industrial standard digital i/o hardware
Idea, design and programming by Joar Falstad Spot announcing machine, and more.
Speakers are included and arranged as group names. Latest USB-version has a capacity of more than 32000 patterns.
Manually speak to the addressed group.
Manually play a prerecorded message, to the addressed group of speakers. USB ver.
21 timecontrolled fixed announcements, will automatically Play a prerecorded message, to the addressed group of speakers. Timecontrolled announcements, w/separately file controlled speaker group addressing . Advanced spot announcing machine.
Sensor control will activate, log and play a prerecorded alarm message, to the addressed speaker groups.
Later version , USB
PC controlled.
Detailled schematic examples.
ISA demo version download
First ver : ISA Win95.
Latest ver : usb Win7 XP PC interface: Advantec USB 48ch DIO Inputs and Outputs: Advantech PCLD-8761 24 ch. input / 24 ch. output . Tested ok.
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******************************************************* Windows Program + industrial standard analog i / o hardware
Time and Masterfile controlled AD-DA conversion , Easy setup. Easy to run and control.
The Masterfile is generated by the program itself , as a linear "Unit Value" function from a Time ref to the next "Unit Value" at the next Time ref.
There is no limit in number of Time ref's from tne project start time to the final stop time.
PC clock is used to control the Time
First ver : ISA , Win95 . Early demo version download
Next ver : PCI , Win98 . Plug & Play.
We are now working on a USB ver in Win7
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Win 7 Program. USB - DMX hardware
For your own and PC safety: Use an insulated DMX USB interface .
Program has separate control of all spots . Not designed for disco.
Stage & other .
How to connect & more Free link to: Enttec compatible DMX open source VB6 program download . 1ch. to 512 ch.
Tested OK with : Win XP + VB6 runtime files + VB6 installed on your computer
Free download: DMX program . Compatible with most DMX controllers.
Tested OK with : Win XP + downloadable VB6 runtime files installed on your computer.
Enttec or compatible, like Splabs DMX.
Insulated USB - DMX controller. 1 - 512 ch.
Insulation USB to DMX output line connection : 1.5KV .
Internal 512 cannels memory w/repeat.
Works with most DMX programs. Ask us
Vingtor, Stentofon Old / obsolete intercom systems.
Replacements. Repairs.
Compact 32-2 / VMP32-2 Old / obsolete intercom systems.
Replacements. Repairs
This system is still used on ships.
NOTE!
Power OFF when plugging / unplugging any board.
If done with power ON, most IC's on the actual boardwill blow Some IC's are hard to find. Due to weak NOK we will now use Euro in our price list
Suitable stations.
Station indoor, desk or wall, w/handset : VMP 619
Cable from station VMP 619 to old modular 4pole wall socket , found on ships: € 20
GREEN LED = OK
Later systems, often used on ships. Replacements. Repairs.
Manufactured also today . Compatible with Vingtor & Stentofon wireing and stations.
NOTE!
Power OFF
when plugging /
unplugging any board inside the exchange.
If done with power
ON: the actual board is damaged beyond any repair
+ possible damage to other boards!
ACM-M-D-V2 is a later maritime model .
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******************************************************* Monacor Catalog
We are one of several Monacor suppliers in Norway.
100Volt line. Pa speakers & amplifiers . Monacor stage audio and DMX light equipment
Alarm systems , video , backup , ip adressing, wireless and more.
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Domain: Jotech.no ( registered on 20-03-2001 )
contact: Joar Falstad
phone: +47 99718408
Mail: mail@jotech.no
& falstad.joar@gmail.com
url: http://www.jotech.no
Company: Jo Tech Service Joar Falstad, Lykkmarka 53, 7081 Sjetnmarka, NORWAY
Some instruments in our workshop are not in use to day, but rare ones are kept for the history .
Rare VLF generator / service instrument. Band range: 10Kz - 60Kz .
From early 60'ties.
VLF Transmitter at that time in Norway : Noviken VLF Transmitter . 16.4 KZ
ULF / VLF Receivers was widely used in submarines, and some countries are still using them. Transmission is slow .
They was mostly used to receive coded messages , like new GPS coordinates .
It's advantage is that it works over wide ocean areas, also when the sub is submerged .
Now, sixty years later perhaps something new is in the making . At present China is working to develope "laser" satelites , able to detect
moving subs , even 500 meters below the ocean
surface .
A big car company has now taken the same domain name . " jotech "
To protect our site and keep it seen on the internet ,
we'll continue to add nice pictures , mostly from Norway.
Norway , Trondheim
Morning view from the car, at E6 in Rotsund .
Norway, Lyngen alps , Havnnes , Rotsund , Nordreisa
Norway, Ekne, Falstadberget
Nostalgy from the 70's. With Vital 15 feet
South Africa . Cape Town
South Africa . Cape Town
South Africa . Cape Town
South Africa . Cape Town
South Africa . Cape Town
Norway , Malvik, the ghost tree
History from mid 90's .
Windows95 , ISA controllers, homemade hardware , this project was initially made in Visual Basic 3 .
