I've had some very nice instruments come through the workshop lately. This one was a stand out for me. The @...
Posted by Elk Elektronik on Sunday, August 9, 2020
Monday, 17 August 2020
Midi Moog - repairs Elk Elektronics
Friday, 14 August 2020
BMC - FM Drum - build notes
sTART WITH the lowest profile components ..
usually IC sockets , resistors , etc
These are personal build notes just to help me trouble shoot should I have any probs.
As it turned out, this was a easy build.
cAPS next
the BOM calls for these:
0.002uf 1 Poly box type. ... 2nf or 2000pF
I'm using a 2.2nF cap
0.02uf 1 Poly box type ...20nF or 20000pF
I'm usinh a 22nF cap instead
.01uf 7 cheap ceramic disk....10nF (103)
sWITCHES next ... not sure how the panel and PCB link ??
Solder the pots to the PCB.
Time for the sole LED
Jacks:
IN - tip of the input jack
CV - tip of the CV jack
OUT - tip of the output jack and switch of the CV jack to allow self modulation
Modulation Waveform Selection switch:
MS - Top lug of switch
MC - Center lug of switch
MT - Bottom lug of switch
Output Waveform Selection Switch:
OS - Top lug of switch
OC - Center lug of switch
OT - Bottom lug of switch
For a ground connection, use the center wirepad of whichever power supply you're not using.
Nice !!!
Links
Manual BOM Build notes
http://www.bartonmusicalcircuits.com/fmd/
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For more Euro DIY builds click here:
http://djjondent.blogspot.com.au/2017/12/diy-index.html
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Repairing a Doepfer A-140 ADSR
Shit happens .
Remember, Red Stripe Down. !!!!
If this happens to you , don't panic.
There are only a few sensitive components.
Start by swapping out the ICs.
Thankfully they are socketed.
Just 2 of them:
This is a TL084.
Its a op-amp
This is a CD4001 CMOS chip
They are sensitive to static electricity, and is the most likely culpruit.
It's a quad 2-in NOR gate
I swapped it with one of these and the module worked again
You can :-)
Links
+ CMOS
+ Integrated circuits - packaging
+ Opamps - basic circuits
+ Synthesizer Logic Modules - The 7 gates
Basic 4 panel Buchla setup
He is considering a basic 4 unit setup.
These are some of my suggestions.
Just personal ideas ... I'm no expert but have had some experience over the last few years.
Of course he could just buy an Easel, which is a great way to begin as it has all the basic modules.
But if you're keen to buy modules, then here goes.
Before Buchla started producing half modules, this was always my preferred basic system.
It has what I feel to be the essential Buchla modules:
1. a VCO ... 261e
2. a envelope generator (EG)...281e
3. a LPG....292e
4. a SOU (source of uncertainity)..... 266e
The 261e VCO could be swapped for another VCO of your choice .... such as a 258, 259e,
or a 100 series such as the 158 or 144.
Basic system 2:
We have added two half modules the 291h & 292h.
These are the EG & LPG.
The SOU hasn't changed but I've added a preset manager module,
the 225e, which allows you to store presets and also adds MIDI to your system.
Basic system 3:
This is essentially system 2 but the 225e has been swapped for two half modules: the 202h (which is a adapter module) and the 225h which is a midi - CV interface.
Basic 4 is an evolution of the basic 3 configuration
We have swapped the 266e (SOU) for a 267e which adds a dual filter, but retains a basic uncertainity module.
Basic 5 drops the 202h (adapter module) and the 225h (midi-CV interface).
In its place we have the 225e midi-CV / preset manager.
If you come from the Euro world, you probably already have MIDI to CV converters
and might be tempted to drop any of the MIDI-CV modules.
But be aware that Buchla uses a different standard to Euro .. 1.2V/ Oct. and 10V gates generally.
Plus the CV and audio section are separated.
CV uses banana & Audio use Tiny jacks.
Basic 6
If you have got this covered then swapping the 225e for a 206e would be a great choice.
You have added a mixer & retained the preset manager.
I hope these ideas help you make a good decision.
Cheers J
Saturday, 8 August 2020
Happy 808 Day
This drum was introduced in 1980.
There were just 12,000 made and production was stopped in 1983 when some of it's parts (faulty transistors) became impossible to restock.
The TR stands for "transistor rhythm".
Unlike the Linn LM-1 Drum which used samples, this created sounds with analog circuits.
It's actually a synthesizer which focuses on making drum sounds
Thank you "Mr. Nakamura" for the analog voice circuits and "Mr. Matsuoka" for the software.
You've heard the TR 808 on countless records and it's been "cloned" again and again.
.... the best form of flattery
Thursday, 6 August 2020
ARP 2500 - 1046 envelope generator & eloquencer
Triggering the ARP's envelopes is a bit tricky if you are using eurorack, as most modules put out only 5V gates & triggers. This is usually not enough.
The Eloquencer sends out 8V gates - good enough to trigger the 1046 EGs
You need to adjust the gate length from the Eloquencer.
Most of the old ARP gear seems to want +10V but will usually act on +8v.
yOU CAN trigger the EG from either the upper matrix or lower matrix
The upper matrix allows you to treat the 1046 as if it is 4 "basic" EGs
Use the lower matrix if you want to use the 1046 as two "combined" EGs
When the Trigger Mode switch is in the Multiple setting you need both gates & triggers to activate an envelope. In the single mode, only a gate is required (T not needed).
If you apply another trigger signal while the gate is still present the cycle
will restart. ..a good way for creating multi-peak envelopes.
The 1046 QUAD Exponential Envelope Generator is actually a ARP 1003 & 1033 in a single module.
The 1003 has the stages: Attack, Initial Decay, Sustain, Final Decay
The 1033 has the stages: Gate Delay, Attack, Initial Decay, Sustain, Final Decay
The main difference between the two is the addition of a gate delay
As a side note, the ARP 2600's envelopes also can't be triggered with most eurorack gate/trigger modules. The ARP 2600 uses a gate range of 0-10v
The Gate & trigger output of the ARP 2600 keyboard is +10V
The FuzzBass TTSH gate booster is a useful module to have. In addition to the need for a 10V gate, the 2600's ADSR circuit has a retrigger function.
This requires a 10V trigger signal. This allows
you to reset/restart the cycle when you press a second key (without disabling the gate signal).
I can also clock the eloquencer (slave) from the ARP 1027 sequencer's clock (master).
The 1027 clock sends triggers not gates.
Links
+ More about the 2500's EGs
MFOS Bi-polar Power supply
i'VE built an earlier one & it works well.
It uses LM78XX/LM79XX or LM78LXX/LM79LXX regulators
That is, it uses an AC output wall wart.
DO NOT USE A DC OUTPUT WALL WART.
These are the parts needed:
| 1 | LM7812 +12V Voltage Regulator | LM7812 | U1 |
| 1 | LM7912 Voltage Regulator | LM7912 | U2 |
| 2 | Resistor 1/4 Watt 5% | 2.4K | R1, R2 |
| 6 | 1N4004 General Purpose Rectifier | 1N4004 | CR1, CR2, CR3, CR6, CR4, CR5 |
| 6 | Capacitor Electrolytic | 3300uF | C1, C2, C3, C6, C7, C8 |
| 4 | Tantalum Electro (35V) | 1uF | C4, C5, C9, C10 |
| 1 | 9 to 12 VAC Output Wall Wart | 12VAC Output | |
| 1 | Optional SPST Switch | SPST |
Tantalum capacitors -- they are polarized.
Links:
http://musicfromouterspace.com/analogsynth_new/WALLWARTSUPPLY/WALLWARTSUPPLY.php
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For more Euro DIY builds click here:
http://djjondent.blogspot.com.au/2017/12/diy-index.html
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