Yocto 808 building tips

  
Some tips and notes on how i built my TR808 clone, the marvellous Yocto 808 project!

Buy the kit and subscribe to the forum here: http://www.e-licktronic.com/en/content/25-yocto-tr808-clone-tr-808

yocto hlf kit received

I do not think it is a difficult nor long build – i spent a couple of hours at every day off on it, for about a month.
The excitement of being able to own an 808 drove me, and gave me the needed focus and patience boost.

yocto genesis (09)

When building the Yocto, it is very important to measure every component before soldering it.
I decided to buy the resistors needed each time I was going to start a new section. This relieved me from measuring hundreds of resistors in one tiring session, putting them in order all at once, etc.
I bought a paper note book on which I would position the components, writing down their value and taping them, as I prepared for each part of the build. This helped me double check them before and while soldering them to the boards.

yocto tips notebook

I decided to socket all the IC’s and the noise section transistor.
The germanium diodes provided in the half kit are rare, treat them with care. I cut the curvy terminals to have a straight lead as per this picture.

yocto diodes
Check the pictures I am posting here to note certain ic’s position.
I made the mistake of putting all the pots at the end, do not do it, it is a mess. Just follow the build guide-do it as recommended, at the end of each section.

Remove the encoders’ tabs before you solder them in! 

 

cut this part of the two encoders and the tempo pot
 
Please note that you do not have to cut the lead cables at the end of the build (i did it!), what Vincent meant in the last paragraph of the build guide is, you can make them shorter.
I had some issues with the flat cables, aka they broke, so i socketed them too. It is advisable to have a suitable enclosure ready before you get to link the two pcbs with flat cable, otherwise having the boards moving around will cause them to break. I would recommend you to buy this brand and sku: TE Connectivity-fsn-3a-10-3″ ribbon cable. They are the best. I socketed the connection point as per picture here, and i just slid the ribbon cable in the sockets-it works great.

yocto genesis (32)
Usually the boards sit a bit shallow in the enclosures, do not use led covers and cut them about the height of the sequencer’s coloured buttons.
Use 5mm spacers to lift the board up and have it sit properly, the keys will stick out properly through the holes.. More on that further down..

(see pic at the top of the post)

A few more tips to build the yocto, not a mod guide by any means, more like a ‘watch out for’ list, for instance where to look if you would like to change the value of some resistors to change the tuning of the instruments.. and other useful things to know as you go along.

A lot of these ideas are to be found in the yocto forum, but here is whatever I found essential to complete the build without headaches.

For a more in depth mods’ list, google dsl-man yocto mods.

Side note: please take note of these mods that allowed me to fine tune my build-i am not implying that these will be needed for your build, but keep these in mind: 

Hats noise filter:  for R58 use a 1K trimmer, multiturn

Cymbal noise filter: R56, use a 1K trimmer, multiturn

Cymbal decay: R93, use a 470K trimmer

Clave filter: R322, use a 20K trimmer

Clave decay: R313, use a 470K trimmer

SD noise filter: R202, use a 50K trimmer

TM1 and TM2 better adjustment range (Cowbell): at R44 put a 100K resistor, R45 put a 68K.

I put them on a veroboard or two, see at the bottom of the guide..

Also make sure you have many SC828 transistors to choose from for the noise generator!

THE NOISE SECTION
As opposed to the building guide, a more effective functionality of the noise generator can be achieved with this mod, as per the official Roland service manual (page 15):
R 129 use a jumper instead of the resistor listed
R 131 100k
R 127 10uF electrolytic: see this pic for correct orientation (positive side left)

  
R 130 22pF in parallel with resistor 130 (it means on top of the resistor, using the same soldering points – check the pic, i soldered it on the other side of the board)

I socketed Q35 as it is a very substantial part of the noise generator.

yocto noise section mod betternoise section yocto 808 mod

ACCENT
C 27 1n2 for 1ms pulse, needed for an effective accent

BASS DRUM
R 165 tuning resistor

SNARE
R 234 47k (positioned in the Low Tom section)
R 188 check its position carefully
R 195 tuning resistor 1
R 196 tuning resistor 2
R 202 noise filter resistor

yocto toms

yocto genesis (14)

LOW TOM
R 231 to lower pitch, use a 4k7 resistor (or increase value to lower pitch)

MID TOM
R 257 tuning resistor

HI TOM
R 284 tuning resistor

yocto genesis (16)

CLAVE/RIMSHOT
R 312 tuning resistor
R 315 tuning resistor
R 334 and
R 373 are part of the Hand Clap circuit, although they are to be found here

HAND CLAP
R 342 and
C 137 may have a solder bridge, it is ok
Do not rush to solder the BA6110 ic, it is better to socket it and add it at a later time, please check the picture here to have it positioned correctly.

yocto genesis (29)

COWBELL
R 63 decay resistor 1
R 65 decay resistor 2

CYMBAL
Look at this section before trying to find the position of the components. It is L shaped.
R 56 noise filter resistor 1
R 58 noise filter resistor 2 (this is in common with the HiHat)
C 6 and
C 42 and
C 44 and
C 46 I did not have any 22nF caps in my stash so I used, 27nF instead.

INPUT OUTPUT BOARD

Please note the position of this IC

yocto genesis (30)

yocto genesis (22)

Before you put the keys in, make sure your enclosure will let them stick out properly (as stated before, they sit a bit shallow), and use spacers the right height to suit your eclosure.. As described here..

Before you put it in the enclosure

Prep the enclosure by screwing the spacers in the front panel- i used 5mm spacers but 10mm spacers’ screws (aka the ones that came with the mouser order) that go in for like 3/4 of the spacer’s lenght. Screw the top panel side all the way in through the spacer. 

Please note there are two sides to the spacer, one is hollow and the other flat. You want to have the hollow part as receptacle to screw the pcb side in (aka at the back of the front panel) as much as you can (it is not much, a few mm’s but that will suffice to have the pcb steady in place). This means, flat side of the spacer on top.

Look at the picture:

 

top panel screw: screw the spacers in flat side up, hollow side down
 
Nuts of the two encoders will have to be placed on top of the front panel not below.

My Yocto fired properly first off.
I made all the trimmer’s adjustment upon finishing it.
I am very satisfied by the result. Vincent has been very helpful too, and the YOCTO forum is an invaluable resource.

yocto genesis (26)

Thanks Pawluk for the sturdy enclosure!

2016 02 222

Also, if you feel inclined, i would suggest you add a little daughterboard to fine tune the noise generator, to allow for correct voicing of the snare, hats and cymbal (check out the relevant resistors above and swap them with trimmers)..


I arranged them on a small veroboard and i am very happy with the results!

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12 thoughts on “Yocto 808 building tips”

  1. This is a question not a comment. What do you mean when you say you used a noise filter resistor, and a tuning resistor, I’m not familiar with these types of resistors. Good work by the way, this helps guys like me who are not as experienced as some others like yourself. I built a Sonic Potions LXR last month, and a XoXbox in January, so the next step seemed like the Yocto, the more parts the better, I love to solder and sort things.

    1. They are just common resistors. They are labelled this way for the use they have in the circuit.
      Id like to build an LXR too! By the way, Vincent of E-licktronic just announced (yesterday) the NOVA-a great TR909 clone!

      1. Ah! That one is from an old amplifier.. I dont know the codename or brand of that particular item..

      2. I would just like to add, that it’s better to get knobs that use a screw, some of them (i seem to remember the tempo especially) were quite wide in shaft diameter and did not suit all knobs (bought a couple of real nice plain black ones and did not fit!)

    1. πŸ‘‹ i bought a new soldering iron for the project and i seem to remember it was a 35w. Solder was the old school solder.. they dont sell the new green stuff here.

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