Table of Contents

• Part 1: Intro­duc­tion and Hard­ware Overview.
  • About this series
  • What’s in the box?
  • What’s on the board?
  • Con­nec­tor Pinouts
  • A Pro­to-Blofeld and Devel­op­ment Board?
  • Hard­ware Comparison
• Part 2: »nano Pock­et« – Ultra Portable Synth Mod­ule (DIY)
  • Con­cept and Objectives
  • Mod­i­fi­ca­tions
  • Free­ing up Space on the PCB
  • Pow­er Supply
  • Midi Sig­nal Routing
  • User Inter­face
  • Com­ing up next

Adver­tised as an expan­sion board for CME UF mas­ter key­boards and intro­duced over 15 years ago, the nano is one of the less­er known Wal­dorf synths. Nev­er­the­less, you can still buy a new nano from cer­tain retail­ers. And it was only recent­ly when this lit­tle device caught my atten­tion again.

In fact, the nano is not even a Wal­dorf prod­uct, since at the time of its intro­duc­tion in 2006, Wal­dor­f’s res­ur­rec­tion from insol­ven­cy was still pend­ing [read more about Wal­dor­f’s his­to­ry]. And it is not an editable syn­the­siz­er either. Shipped with plen­ty of pre­sets, it only lets you tem­porar­i­ly tweak a few para­me­ters. But you can­not you store your mod­i­fi­ca­tions or cre­ate com­plete­ly new sounds.
This lim­i­ta­tion, and the fact that it was tar­get­ed towards a nar­row range of CME key­board mod­els might be among the most impor­tant rea­sons for the nano to nev­er gain pop­u­lar­i­ty. Last but not least, the microQ Phoenix edi­tion and the espe­cial­ly the Blofeld which arrived in late 2007 made the nano look very unat­trac­tive. But hey, it’s not about looks and pop­u­lar­i­ty here!

The offi­cial doc­u­men­ta­tion was pret­ty sparse when it orig­i­nal­ly came out. And as of mid-2021, there is still almost no infor­ma­tion avail­able. So let’s dig deep­er and change that, shall we?

About this series

Over the course of the next weeks I will explore the nano and share my insights with you. My main moti­va­tion here is curios­i­ty and the desire to learn more about DSPs and the prod­ucts of my favorite synth manufacturer.

I have already ana­lyzed the nano’s cir­cuit­ry, stud­ied tons of datasheets, and com­pared the nano to oth­er Wal­dorf machines. Anoth­er out­come is a DIY project I called the “nano Pock­et” – prob­a­bly the world’s small­est sound mod­ule with Wal­dorf sound. More on that in Part II. Cur­rent­ly, I am inves­ti­gat­ing the capa­bil­i­ties of the nano’s synth engine. This will be sub­ject of a lat­er article.

Part 1:

Intro­duc­tion and
Hard­ware Overview.

Part 2:

»nano Pock­et« – Ultra Portable Synth Mod­ule (DIY Project).

Part 3:

In-depth Synth Engine Analy­sis
and com­par­i­son,

What’s in the box?

To get more famil­iar with the nano, here is what you get if you buy one. 

The nano comes in a sur­pris­ing­ly large box which can accom­mo­date the wide rear pan­el for the CME UF key­board, a print­ed A4 man­u­al, and a gen­er­ous amount of foam. The nano mod­ule itself is actu­al­ly quite small (74mm x 114mm, includ­ing TRS jacks) but it’s pret­ty well equipped.

What’s on the board?

Connector Pinouts

Con­nec­tor	Pinout	Remarks
(14) JST-XH‑6 con­nec­tor: pow­er sup­ply / Midi input	1: Midi in (3.3V low-volt­age TTL, 5V tol­er­ant)* 2: not con­nect­ed 3: Ground 4: +12V 5: +12V 6: Ground	*: Cau­tion: Pin is direct­ly con­nect­ed to the DSP. Pro­tect from elec­tro­sta­t­ic discharge!
(15) JST-XH‑4 con­nec­tor: pow­er supply	1: Ground 2: +12V 3: +12V 4: Ground
(16) Foot­print for 5‑pin DIN jack: opto-iso­lat­ed Midi input	1: n/c 2: n/c 3: n/c 4: Vref 5: Midi in	Either use this con­nec­tor or (17) if you want to use the nano with a Midi inter­face or Midi keyboard.
(17) JST-XH‑2 con­nec­tor: opto-iso­lat­ed Midi input	1: Vref 2: Midi in	Either use this con­nec­tor or (16) if you want to use the nano with a Midi inter­face or Midi keyboard.

A Proto-Blofeld and Development Board?

Lit­tle is known about the specifics of the nano. When inter­viewed by Ger­man Sound & Record­ing mag­a­zine, Ste­fan Sten­zel point­ed out that the nano is “relat­ed to the microQ […] but with func­tion­al lim­i­ta­tions” and that they had been “using exist­ing hard­ware and soft­ware com­po­nents” [source: “Sound & Record­ing” 09.2006: nano test and inter­view with Ste­fan Sten­zel]. I will cov­er the synth engine in a lat­er arti­cle and try to find out more about it.

Here, I will focus on the hard­ware aspects. As it turns out, the nano is much clos­er to the Blofeld than to the microQ in this regard (see com­par­i­son table below and my Wal­dorf Synth Hard­ware page).
In hind­sight, Ste­fan’s state­ment seems due to the fact that the the inter­view took place well before the Blofeld was announced.
To me, the nano appears to be an inter­me­di­ate step, a Proof-of-Con­cept while design­ing a new cost-effec­tive synth plat­form – a kind of “Pro­to-Blofeld” if you like. It is not unlike­ly that the nano had also served as a Wal­dorf-inter­nal devel­op­ment board, hav­ing all these debug con­nec­tors which are not used with the CME UF keyboard.

Hardware Comparison

To bet­ter under­stand the nano’s posi­tion I have com­pared it against the microQ and the Blofeld.

	microQ (MQMB12B + MQBP12)	nano (MMT V2.3)	Blofeld (BFMB V1.41)	Blofeld, Blofeld Key­board (BFMB V2.04)
DSP	1x DSPH56362	1x DSPB56731	1x DSPB56731	1x DSPB56731
Exter­nal DSP RAM	3x 2 Mbit SRAM	n/a	n/a	n/a
Option­al Expan­sion Board	2 addi­tion­al DSPs + RAM	n/a	n/a	n/a
Main MCU	MC68331CPV20	n/a	MC9S12UF32PBE	MC9S12UF32PUE
Exter­nal Main MCU RAM	2x 1 Mbit SRAM	n/a	n/a	n/a
Non-volatile mem­o­ry	1x 4 Mbit Flash	1x 512 Mbit NAND Flash 1x 256 Kbit ser­i­al EEPROM	1x 512 Mbit NAND Flash	1x 512 Mbit NAND Flash
Aux­il­iary MCU(s)	n/a	n/a	n/a	Blofeld Key­board only: MC9S08GT8A
Sam­ple Rate	48 kHz	44.1 kHz	44.1 kHz	44.1 kHz
Audio Out­puts	6 chan­nels	2 chan­nels	2 chan­nels	2 chan­nels
Audio Input	yes (stereo input)	n/a	n/a	n/a
DAC	1x AKM AK4527 Mul­ti-Chan­nel Codec for ADC and DAC	1x AKM AK4384 2ch Delta Sig­ma DAC	1x AKM AK4384 2ch Delta Sig­ma DAC	1x AKM AK4384 2ch Delta Sig­ma DAC
ADC	Mul­ti-Chan­nel Codec for ADC and DAC (see above)	n/a	n/a	n/a
Line Ampli­fi­er	3x NE5532 (one per stereo out­put) 1x TL072 (stereo input)	1x NE5532 (stereo output)	1x NE5532 (stereo output)	1x NE5532 (stereo output)
Head­phone Amplifier	LM8272MM	LM1877M	LM1877M	LM1877M

For a more detailed com­par­i­son, please find the tables on my Wal­dorf Synth Hard­ware page.

His­tor­i­cal­ly, Microwave II and Q based machines were built around gen­er­al pur­pose Motoro­la chips from the mid and late 1990s:

• DSP56303 (Microwave II/XT/PC, ear­ly Q and Q Rack revisions)
• DSP56362 (microQ, lat­er Q and Q Rack revisions)
• MC68331 MCUs
• Aux­il­iary PIC16 con­trollers (Microwave II/XT/PC, Q and Q Rack)

These chips only have lit­tle inter­nal mem­o­ry, so exter­nal mem­o­ry was unavoid­able for synth appli­ca­tions. RAM and Flash chips in the mid/late 1990s had low capac­i­ty and bulky pack­ages. As a result, Wal­dor­f’s synths typ­i­cal­ly con­sist­ed of a dense­ly pop­u­lat­ed main board (with four cop­per lay­ers) and mul­ti­ple daugh­ter boards for front pan­el, rear con­nec­tors, dis­play. This all added to com­plex­i­ty and pro­duc­tion costs.

In con­trast, the DSP56371 used for the nano (and lat­er also for Blofeld, Stu­di­o­log­ic Sledge, and Hart­mann 20) is specif­i­cal­ly tar­get­ed towards audio appli­ca­tions. It is improved in mem­o­ry capac­i­ty, clock speed, foot­print, and pow­er con­sump­tion. But it is not high-end and con­sid­er­ably stripped down in I/O (i.e. the ports for­mer­ly used by Wal­dorf for their expan­sion cards and exter­nal mem­o­ry). As a con­se­quence, cer­tain lim­i­ta­tions affect­ing a synth engine’s voice count and mem­o­ry-inten­sive effects like delay or reverb are to be expected.

Ulti­mate­ly, it allows for design­ing more stream­lined and more eco­nom­ic prod­ucts. The nano can be con­sid­ered as a pre­view for what even­tu­al­ly became the Blofeld: a great sound­ing and inspir­ing syn­the­siz­er for the mass­es. A machine which is still in pro­duc­tion and sell­ing after almost 15 years – at approx­i­mate­ly the same price point. In con­sumer elec­tron­ics, espe­cial­ly in the syn­the­siz­er mar­ket, this is an out­stand­ing achievement!

Table of Contents

• Part 1: Intro­duc­tion and Hard­ware Overview.
  • About this series
  • What’s in the box?
  • What’s on the board?
  • Con­nec­tor Pinouts
  • A Pro­to-Blofeld and Devel­op­ment Board?
  • Hard­ware Comparison
• Part 2: »nano Pock­et« – Ultra Portable Synth Mod­ule (DIY)
  • Con­cept and Objectives
  • Mod­i­fi­ca­tions
  • Free­ing up Space on the PCB
  • Pow­er Supply
  • Midi Sig­nal Routing
  • User Inter­face
  • Com­ing up next

Concept and Objectives

1. Portable with a form fac­tor as small as pos­si­ble – ide­al­ly have every­thing fit into a 2.5″ HDD case
2. Sim­ple user inter­face for select­ing built-in sounds (requires micro con­troller, encoder, but­ton, and a display)
3. 5V sup­ply from a pow­er bank or USB charg­er, avoid spe­cial cables or voltages
4. Midi input via stan­dard 5‑pin DIN plug or 3.5mm-TRS to DIN adapter
5. Keep exist­ing 1/4″ line out­put con­nec­tors and inter­nal amplification

Suit­able HDD enclo­sure: ICY BOX IB-256WP

• Stur­dy alu­mini­um body with plas­tic slide-in module
• Dimen­sions: 77mm x 113mm x 20mm (with­out sil­i­cone bumper)
• Inter­nal PCB with USB–SATA adapter can be removed for gain­ing some extra room

Freeing up Space on the PCB

Power Supply

When con­nect­ed CME UF key­board, the nano is sup­plied by a sin­gle 12 V rail. While the Opamp and the Head­phone Ampli­fi­er need this volt­age for prop­er out­put lev­els, the rest of the active com­po­nents only require 3.3 V (DSP: 3.3 V and 1.25 V).
In its orig­i­nal con­fig­u­ra­tion, a com­mon mode choke, two 56 Ohm resis­tors in par­al­lel, and fil­ter capac­i­tors pro­vide high fre­quen­cy sup­pres­sion. A dual lin­ear volt­age reg­u­la­tor then gen­er­ates the required 3.3 V and 1.25 V. As a result, dur­ing idle oper­a­tion, the nano con­verts about 0.9 W into heat in the pow­er sup­ply sec­tion alone. Since there no big cop­per area which could act as a heat sink, these com­po­nents as well as the 330 µF elec­trolyt­ic capac­i­tor get very hot. Espe­cial­ly in case of the capac­i­tor, this could result in accel­er­at­ed aging.

For the »nano Pock­et«, I made some mod­i­fi­ca­tions: A boost con­vert­er gen­er­ates 12 V from 5 V. A 12 V sup­ply is not nec­es­sary any­more and the »nano Pock­et« can be pow­ered by a USB charg­er or USB pow­er bank. Even if the input volt­age is at the low­er lim­it of the USB spec­i­fi­ca­tion (5 V – 10%), 12 V can be gen­er­at­ed reli­ably. From the 12 V rail, a cheap MPS MP2307DN based buck con­vert­er (search for “HW 187” or “Mini-360” and read Dr. Gough’s arti­cle) gen­er­ates 5 V for the dual lin­ear reg­u­la­tor and the Arduino. There might be bet­ter alter­na­tives but it cer­tain­ly does its job.

At first glance it seems like unnec­es­sary com­plex­i­ty step to boost 5 V up to 12 V and then step down to 5 V again. But it turned out to be nec­es­sary since with input volt­ages low­er than 5 V, the lin­ear reg­u­la­tor can­not reli­ably pro­vide 3.3 V. For the DSP you want to ensure that a sta­ble 3.3 V sup­ply is avail­able before the 1.25 V sup­ply. Oth­er­wise, there is the risk of a latch-up which can dam­age the chip which hap­pened to me dur­ing my experiments.

Midi Signal Routing

User Interface

…

Coming up next

…