Doepfer A-100SSB Small Power Supply/Bus Announced

A-100SSB is a combination of power supply and bus board with 8 connectors for A-100 modules. Planned for applications with up to 8 modules and a max. current of 380 mA. A-100SSB is available as ready built and tested unit.

A-100SSB Prototype I

These are the most important features:
- wide range mains voltage input 100-240V AC / 50-60 Hz
- IEC inlet on board for the connection of a suitable mains cable (a suitable cable has to be purchased by the customer locally)
- switching supply with +12V/380 mA and -12V/380mA for the operation of A-100 modules up to 380 mA total supply current
- safety cover at the bottom side (covers all elements that lead mains voltage)
- on board fuse
- 8 bus connectors
- LED displays for +12V, -12V and +5V (+5V are available only if e.g. the 5V adapter A-100AD5 is used)
- Dimensions: about 270 mm (length) x 55 mm (width) x 35 mm (height)
- several 3mm holes for mounting the unit on a rear panel or bottom plate

Planned for  ca. Oktober 2015 / ~ October 2015 /  for ~ Euro 75.00

Source: http://www.doepfer.de/A100SSB.htm

Avoiding Hum From Power Supplies

If you are buying a second-hand rack, or if you already have a Doepfer modular rack with a cheap alternative (non-Doepfer) power supply you should be aware of how to avoid the (minor) transformer hum that cheap PSUs generate.

In the area near those power supplies (bottom right) no modules should be assembled that are sensitive to transformer hum.
Doepfer recommends to assemble only control voltage modules in this area (e.g. LFO, ADSR, trigger delay, clock divider/sequencer, sequencer, slew limiter, MIDI interfaces and so on)
,but no audio modules (VCO, VCF, VCA, VCP, frequency shifter, ring modulator, spring reverb and so on)
Also don't put the A-178 Theremin modules near the power supply.

Doepfer Power Supply I ( PSU I )

This matters for some of the cheap alternative non-Doepfer power supplies, and for the old Doepfer versions with PSU I 
For new A-100G3/G6 cases (with original PSU II) this does not apply. 

Find out how to distinguish the old transformer (PSU I) from the new version (PSU II) at http://patchpierre.blogspot.nl/2012/07/doepfer-power-supplies.html

More info at http://www.doepfer.de/a100p_e.htm#A100P6

Quick Tip X : The Warm Up

Good performances need a good preparation and a warm-up.
That does not only count for sports-prestations, but also for your (eurorack modular) analog synthesizer.

2 Doepfer VCOs that could use a good warm up

If you are looking for getting the best out of your Doepfer A-100, understand that you need to give your system at least 20 to 30 minutes to warm up.
If you don't give it that amount of time, the tuning can/will probably be (slightly) off.

To be clear, it's not a question of the "A-100" warming up, but of the modules installed.
In some cases, the warm-up period of a module is mentioned in the manual or on the web-page of the module in question.

Especially VCOs like A-110, A-111-1, A-111-5, A-143-4 need a warming-up to become stable and reliable.
If no warm-up period is mentioned the VCO is stable very soon (like the CEM3340-based A-111-1).

The PSU type (Doepfer power supply I or II) has no influence.

Doepfer Power Supplies

There are 2 types of transformers used in the existing standard Doepfer A-100 racks and cases.

The old Doepfer power supply with a
rectangular transformer

If you are buying a secondhand A-100 rack, it might be useful to know how to distinguish the old transformer from the new version.

The newer version is a better version, more reliable and provides a steadier voltage that is better for your system, although i personally never heard any complaints about the old transformer besides the longer warming-up time.

The old power supply has a black or blue rectangular transformer, where the new power supplies have a round silver transformer.

The new Doepfer power supply with a round transformer

For a period during the transition (about 2 years) the customers could order both versions.
In any case all A-100 cases manufactured later than early 2005 are equipped with the new power supply, and all cases manufactured until about of 2002 are equipped with the old version.
For cases manufactured in 2003 and 2004 it depends which version has been ordered by the customer.

In any case the new power supply can be identified by a small label outside the case near the mains inlet.
It says "Power Supply II" unless it was removed by the user.

Source: Dieter Doepfer

Locating the A-100 Fuse

The fuse-box is located between the
power inlet and the on/off switch

It's pretty basic, but every once in a while i receive the question: "Where can i find the fuse on my Doepfer rack?"
I must admit i had to search for it too the first time i blew up a fuse.

The answer is quite easy.
On the backside of the G6 rack (and G3 rack and most other cases and koffers) you'll find the power supply and the On/Off switch.
Between these two there is a small compartment where the fuse can be found.

Use a small screwdriver to
slide out the fuse-holder

Always remove the power-cord before you are opening the fuse-box!

With a small screwdriver you can gently pull this fuse-box out of it's place and replace your A-100 fuse.
Check out the Doepfer FAQ to see what fuse-value you should use in your rack, depending on rack-size and country.

Fuse-holder with A-100 fuse