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Altec 1592B repair, 1588B module, XLR pinout output etc

Recently i got a nice Altec 1592B mixer.

Each input requires a dedicated preamp/transformer module, for microphones there’s preamp, 1588B or preamp+12v phantom power, model 1588C.

I had to do a massive recapping job on the 1592B- the original caps values were all over the place-and i mean not only electrolytics-the only ones that were still measuring ok were the tropical fish and some of the lower values disc caps- though most of the electrolytics were good quality, Mallory or West Germany made, ROE (Roederstein). I replaced them all with Elnas (they seem to be the standard nowadays).

Also, the resistor after power transformer 7818 (that feeds part of the tone section, so if you have an unit that powers up but does not produce a sound, check for +18v at pin 6 of the tone board, that is linked to the power board after (out) the aforementioned 7818) was burned-clear sign that some damage had taken place. The schematic calls for a 10 Ohms resistor-i decided to put a 100 ohms substitute, much better.

Sounding good, i decided to recap also the 1588B module i have here (more are on the way, and when factory new, they were fitted with 3 modules).

After using a small screwdriver to pry the enclosure open, i took a look at this interesting blog (check it) for the schematic-i also took the time to sub the carbon comp resistors with metal film and yes-noise went down.

For your reference, here’s the resistors network:

Q1 and Q2 pinout:

Troubleshooting:

If the preamp is not working, check carefully the resistors-they break easily. One immaculate looking (inside and out, the spongy filler still in good soft condition, no leakages on the plastic screen etc) 1588B i have had a resistor broken at its base, and since the components are so squeezed together it was impossible to see it-i decided to test the transistors (thats why i took the q1 and q2 pics above) since everything was looking proper-and there-i spotted the broken resistor! The preamp would still burst in noise if i knocked the mic gently on the capsule, yet it wont amplify it properly. Thats the resistor connected to ground on the white wire-a pain to desolder too.

If you must desolder stuff, be patient-these boards wont take a 300 degrees hot iron-the circuit tracks will lift if you heat them up too much-use care.

Since someone over at the Tape Operator forum has raised the warning that the power supply may have been ill designed, i am powering it using an external psu (using the battery option), 24v dc.

Terminal: from left, my battery (external psu) connections (- and +) and pinout to wire an XLR balanced jack to the output: hot, cold and ground… in the mess between high and low impedance i went with, 600 ohms, good for any mixer or recorder input. PLEASE note 2 and 3 terminals are bridged (connected) at the terminal post. The signal is nice and strong.

I will not mod this unit, i like it as it is. Nice and retro sounding.

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TR707 TR727 reset, midi out, tricks etc

Reset your TR707 or TR727 to factory settings.. here is the buttons combination to give your drum machine a fresh new start and to check leds and screen, buttons.

Keep pressed CLEAR and INSTRUMENT/GUIDE and switch on the legendary (yes, legendary) drum machine.

All the lights will turn on, then step leds will blink one by one.

After the light show, press ENTER/CARTRIDGE to proceed with the screen test.

Press the buttons and see the relevant dots show up on the screen.

Switch off.

How to use the TR707 or TR727 to output midi notes, and use it as a midi controller to play other midi modules, samplers (bear in mind its defaut midi channel is 10):

STOP the pattern/track if it is playing.

Enter TRACK PLAY mode.

Holding SHIFT press INSTRUMENT/GUIDE and MIDI CHANNEL.

This procedure will mute the instrument’s internal sounds but will allow you to control external gear using the TR707 or TR727.

To revert back to default, using the internal sounds but NOT transmitting midi notes, and if you have a TR707/727 that is silent, just use the same keypresses again.

Common troubles with these machines:

PSU jack fail, power transistor 78M05 (can be substituted with 78S05), power supply section electrolytic caps.

Dim screen=check the power supply section.

Try different psu transformers too: Roland’s own are recommended, etc

These are machines that heal themselves.. put them aside for a while or leave them turned on for some time and they will fix themselves.

Maybe.

Roland CR8000 buttons repair made easy

Roland Compurhythm drum machine CR8000 with faulty or worn buttons.

Sounds a lot like the TR808, but a design fault makes these buttons useless after a while.

You will have to pull the plastic covers first, to reveal the spring and rubber dome under which we will drop a bit of conductive paint..

To pull the plastic part you need to push the sides using a screwdriver or two like on this video:

Youtuber The Imp Of The Perverse has made a few vids of his restoration-he used my method too, check them

SammichSID Novation Zero SL mkii template

Those geniuses at Novation shipped this controller with a couple of software disks but alas, no TEMPLATE EDITOR for people who dont use a pc to make music.

Download the template editor program from their support pages, connect the Zero SL to your pc via usb, switch it on and fire the software. Press Global options on the SL, choose mem protect off.

Load the syx file provided by yours truly:

Masuto’s SammichSID template 😊

and then.. select

Press Write, and bob’s your uncle.

I saved it in location 20 (empty) and made it the startup template.

To use the drumpads to send cc (mod depth 1,2,3,4,5,6) on the novation zero SL you must first press REVIEW and then use the drumpads-you will see their assigned value increasing because we are using them as step switches.

For your reference, heres a crudely PAINT assembled wildcard:

Happy knob twiddling!

Creating a drum program on the Akai S900

Ok this is as basic as it gets, but still it’s nowhere to be found on the actual Akai S900 manual, since it deals mostly with pitched sounds and how to spread them on the keyboard.

How do you make a drum program from recorded samples on the Akai S900, and play those sounds from a controller in midi in?

Well, first of all you must understand what a keygroup is.

The keygroup is the number of samples in the program. Or something like that.


Here the guide, how you do it, step by step:

-press the function button sample rec, press “letter” function and enter the name of the new sample, scroll down and set the sample rate: choose 16000 for best definition (it will be punchy nevertheless) then scroll the page down until you can assing that specific sample to a key on the keyboard- I normally start from A1. For easier operation, use a keyboard plugged in the midi in port.

-record sample.

-press edit sample function, since they are drum samples you dont want any scaling of the single hits so deactivate any transpose function, then set the sample start and end points.

Scroll the page down and choose (right arrow twice) to discard whatever is before the start and after the end points (aka sample truncate).

-press edit program and choose (right arrow) the name of the sample you just recorded.

At Program screen 03, KEYGROUP,  add one more keygroup to the total keygroups by pressing + on the COPY line. Then scroll page down, assign the keygroup to the sample you just edited, and set the sample pitch range-since it is a drum sample, you want the range to be of just one key, so set it to the key you assigned upon recording for both range figures. If you assign it to another key, the sample’s pitch will be affected. You will not be able to listen to the sample as you do this so make sure you write down what note the sample was assigned to.

-press save, scroll down page to (right arrow twice) save prg and samples.

That’s it, plain and simple, easy guide to make drum programs on this legendary sampler.

Remember to drive the inputs a bit when recording-i always record at 16000 (best quality) but sometimes in a drum kit i like to have also low fidelity drum hits, so i record also some kicks and snares at like 8000-they add some dirt, just dropping them in the pattern, they add character.

Akai S900 disk drive replacement

Since keeping it strictly old school is a must, i decided NOT to go the Gotek/ HxC floppy drive emulation route to make up for my S900’s broken floppy disk drive.

Which disk drives can be used to replace the Akai S900 floppy drive? Theres a page on gearsluts with a few suggestions, but i felt the info was a bit messy and not really clear (a few yes this works, some no-nos etc).

I took an old amiga 500 external floppy disk drive and yes it works on the akai S900-just be careful about the header’s orientation. It is a drop in replacement. It can format and use modern HD floppy disks too.

So in a nutshell: amiga 500 floppy disk drives can work as a replacement for the Akai S900 sampler.

Just a piece of info from Masu.