Tag Archives: old

Roland SH1000 recapping

Sometime ago i bought Roland’s first ever synthesizer, for about a quarter of what it goes for these days-it was in dire condition, mind you. The control panel rusty and battered, the silkscreen on a couple of spots barely readable.

I always believed mint condition items belong to museums, not being fit for use, abuse and misuse.. i feel the same way about vinyl records-people who wrap them in polypropylene covers from day one and treat them as if they’re going to break anyday soon.. good grief

I must say that although i truly love the instrument- i also fit the Kenton cv/gate control board a year ago, i rarely ever used it.

The other day i took it out for a spin and the tuning was way off, it was drifting. It wouldnt even span an octave-it was that bad.

Time to recap, i thought, and pulled out the Elnas, the Nichicons and the soldering iron-i figured i’d give a refresh to the power filtering section, part of what the service notes call the “Pulse Sheet Assembly”..

Before
I also upgraded the caps from 35v tolerance to 50v

Just a note: although the unit was in working condition, albeit out of tune, most of the 1uF caps on this board, were off their nominal capacitance-the 2.2 uF cap measuring a whooping 8.5 uF! Of the big 1000 uF caps, two were measuring 1200something uF, whereas the other two were still closer to the 1000 mark-and they all showed low ESR (40+ year old caps!). The three tantalum capacitors on this board were still working great, their value as per specs.

I fired the synth after recapping this board-the sound was a bit more definite, but the tuning was still off.

I decided to check the VCO board, pictured above. But, alas, no electrolytics there to substitute. I checked very carefully the board-and there it was, staring at me:

Polarity is negative at diode soldering onto the board

The diode+resistor combination to the upper far right of the board: the diode was broken in two!

The schematic calls for diode, 1S2473.. i checked a few diodes I had, and landed on a 1N4148 as a fitting substitute!

And.. yes now it IS tuned! The snipped diode was the issue!

Assorted pics of the wiring at the back of the oscillator board

Ace Tone FR8L recapping and external psu, trigger mods

Assorted pics of the actual boards.. might be useful to someone.

That good old recappin’ blues:

Since one of the boards was GLUED to its standoff, i had to solder some caps on top of the older ones.. now one of the caps had leads so short i thought it might be useful to remind myself where does each lead went (see pic w scribble).

And the odd freaky transistors that didnt have its legs cut off (and indeed they were perilously almost touching)

The FR8L can produce 13 drum sounds-and very crispy too, thats why i decided to modify it..

Circuitbenders.co.uk’s trigger module: wires aplenty, but this will allow me to trigger each drum sound from a midi to trigger highly liquid board, that has been assembled back in the day to control my fr3-a build/mod and brilliantly carried out by circuitbenders.co.uk (you can see it HERE and HERE TOO).

The trigger board for the fr8l can be ordered HERE but remember, stock is limited.

Please note a male/female hex spacer (m3 22mm) is needed to screw the trigger board to the existing hex nut.

I decided to put the trigger input jacks in an external box-lots of fun soldering all the tiny jacks!

External PSU mod:

From an idea by circuitbenders.co.uk

READ ABOUT IT HERE

Due to the nature of the machine it is best to reduce background noise as low as possible-and an external power supply may be a better power source than the provided transformer since the filtering in the power supply section is basically nil.

I had to make a quick mod here so if you may, bear with the crudeness of these connections-i was also low on cables so pardon the lacking colour scheme..

Remove the transformer (WARNING: Dangerous voltages around this area)

First of all take a nice picture or two of where the transformer cables were originally.

The plastic thing where the red orange and black wires go is a diode bridge-check the schematic from the FR8L service manual, it has to be removed along with the transformer. We’ll reuse thosw wires so just cut them and leave them hanging for now.

Then when everything has been unscrewed and cables cut, make a bridge connection between the two pins of the on off switch at the tagboard end (pink cable).

Red and orange cables soldered to the positive side, grey cable connecting all black leftover cables to the negative side.

To attenuate noise from using a switching psu i put a choke in series with the positive pole, and a 2200uF 50v capacitor in parallel between + and – like this:

Remember the resistor between + at the psu and the orange cables (you can barely see it in the picture because i used some spare shrink tubing to prevent shorts).

🙂

Akai S612 sampler

I opened my newly acquired Akai S612..to check for spiders and animal residue from its previous owner – i was intrigued by the “cassette interface”. Mine was screwed behind a closed metal door.

I realized right away it is the same cassette port as the Commodore 64.

And yes, you can save, verify and load your samples using an old (non)trusty tape Datassette!

I sampled a sound, got some tape to record, went fast forward 004 counts on the tape counter, pressed rec and play and then pressed save on the Akai panel. Red light, it’s recording.

Counter reading 044, the Datassette automatically stopped. I rewound the tape, switched off the Akai (remember with these old machines it is better to switch them off before plugging or unplugging devices from serial ports..), on again and Load. Pressed play on tape, and yes. It’s working. Easy.

No need to buy the MD280 rack to load discs on the S612.. you just need a Commodore Datassette (clean its heads and fix azimuth before doing anything)!

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.