DCB Cable

[Sajid Awan]

Does anybody know where I can get a DCB cable for my Roland Juno 60?

[Larry Hendry]

Sajid Awan <rac...@gate.net> writes:

>Does anybody know where I can get a DCB cable for my Roland Juno 60?

No, but they are easy to make.... They are a standard 15 pin computer
connector that I was able to buy with no problem... and the cable only uses
about 3 or 4 of them I think... I have the diagram here somewhere...
The cable needs to be sheilded.
If you are interested in making it, Eail me and I will look up the specs
for you... I got them on the phone from Roland.

[Ricard Wolf]

This is what I found out from the documentation for the Roland OP-8
DCB <-> CV/gate converter:

+++
Ok, for all you DCB lovers out there...I've finally got my act together
and found the connection diagrams for the DCB cables...

This information comes from the OP-8 manual. The OP-8 is (was) a device
for converting 8 CV/gate signals to a DCB signal for the JP-8.

According to the manual, Roland made two cables: H172 and H165. H172
is a uni-directional cable for connecting one Juno-60/Jupiter-8 to another,
so you could play one from the other, but not vice versa (without
turning the cable around). It did not carry the VCA/VCF/VCO analog
control signals.

The H165, on the other hand, is probably what you need to connect a
Ju-60/JP-8 to an MSQ-700 or whatever. It is a bidirectional cable, including
the VCA/VCF/VCO signals.

Because of the way DCB works, you cannot connect to synths with the H165;
the manual says you'll get regeneration. This is because (at least on the
Ju-60), DCB information entering the synth is echoed on the output.

The connectors for the cables are Amphenol DDK 57-30140 . (It's what I
call a "small centronics" connector, for those of you familiar with
parallel connectors on printers).

The signals at each end are:

1. RX: Busy
2. RX: Data
3. RX: Clock
4. Ground
5. TX: Busy
6. TX: Data
7. TX: Clock
8. UNREG (don't know what this is, it's unconnected in the OP-8)
9. Lower VCA CV
10. Upper VCA CV
11. Lower VCF CV
12. Upper VCF CV
13. VCO-2 CV
14. VCO-1 CV

The cables are connected as follows:

H172 (uni-directional, no CV):

1. - 5. (busy)
2. - 6. (data)
3. - 7. (clock)
4. - 4. (ground)

H165 (bi-directional, CV connected):

1. - 5. (busy I)
2. - 6. (data I)
3. - 7. (clock I)
4. - 4. (ground)
5. - 1. (busy II)
6. - 2. (data II)
7. - 3. (clock II)
8. - 8. (UNREG)
9. - 9. (VCA lower)
10. - 10. (VCA upper)
11. - 11. (VCF lower)
12. - 12. (VCF upper)
13. - 13. (VCO-2)
14. - 14. (VCO-2)

The connector pins should be written on the pins, otherwise, here's an
ASCII diagram:

\--------------------------------------/
\ 7 6 5 4 3 2 1 /
\ 14 13 12 11 10 9 8 /
\--------------------------/
(viewed from outside of rear panel on DCB device)

Notes:
* I don't know what UNREG is for. It is unconnected in the OP-8; my guess is
that it's an unregulated voltage output for external devices.
* RX means receive, i.e. for the reception of DCB signals. Note that this
means that RX-data and RX-clock are inputs, whereas RX-busy is an
_output_ (handshaking). (The converse is true for TX (transmit)).
This doesn't affect the cables, but may be good to know if you're
fiddling around with other hardware...
* I don't know whether the Juno-60 can receive the CV signals (which I
assume are used for modulation). The OP-8 manual mentions that cable
H165 is designed to connect the OP-8 to a Juno or Jupiter, however,
you can also use the H172 cable with the Juno. Since this cable
lacks CV signals, this might imply that the Juno can't receive
them. Perhaps someone with a Juno schematic can
help...I haven't tried it out on mine...

+++
--
Ricard Wolf / | \ / | /- email: ric...@axis.se
Axis Communications AB /__| \/ | \__ uucp: axisab.se!ricard
S - 223 70 LUND / | /\ | \ Tel: +46 46 19 18 63
SWEDEN / | / \ | \__/ Fax: +46 46 13 61 30

[Larry Hendry]

Pins 1-7 connected as shown in the previous post are all that is needed
for the Note on/off & damper data to and from the Juno 60...
HHmmm... didn't have the CV connections in the cable I had.. Not sure either
if the Juno recognized / transmitted it... I know my pitchbend did not
work thru the DCB....
One other note for those considering the MD-8 DCB/MIDI converter... It has
a transmit channel selector, BUT the receive of the Juno60 is OMNI and
not channelized by the MD-8... I solved this problem with a ANATEK
poket filter
;)
Happy J-60ing... I sold mine years ago and still miss it...

[Thomas C Butcher]

> a transmit channel selector, BUT the receive of the Juno60 is OMNI and
> not channelized by the MD-8... I solved this problem with a ANATEK
> poket filter

While the default operation mode of the MD-8 is OMNI, you can connect a
MIDI cable to the OUT and the IN of the MD-8, put the MD-8 into
MIDI<=>DCB mode, press a key, then change the MIDI channel. THis
sequence puts the MD-8 into POLY mode.

Tom