■Budget portable digital drum machine with crunchy samples and a classic sequencer. Main panel features a simple LCD display, 15 buttons, 2 knobs and 16 trigger pads (no velocity).

■main core 8 bits CPU Roland R15179247 basically a HD6301 derived from classic 6800 manages 8 channels polyphony.Each voice features and assigned sample PCM which edit is limited to volume parameter and several polyphony restrictions :
- 1 tom per time (or timbale)
- rimshot OR clap
- 1 conga per time
- 1 cowbell per time
- crash OR ride. 

■SAMPLES wavetable is 128 KB ROM (at IC11) which contains 16 PCM samples at 8 bits depth 25 kHz rate .The internal samples are mostly standard drums from this era with some extra ethnic samples, very similar to Roland TR727 set.

■SEQUENCER the 505 features 2 recording modes:
- step mode
- real-time note insert.
Step numbers can be changed for other scale time (default is 4/4) and variable odd tempo.
Some classic edit functions such as accent, insert, copy or delete.
■SYNC internal frequency from 40 to 240 BPM or slave mode to external Midi clock. 

■ MIDI is limited to note on/off and 5 velocities and Pads can trigger assignable Midi notes (but no velocity).
NOTE: No sysex dump implementation.

■MEMORY :
- 48 ROM patterns
- 48 RAM patterns
- 423 measures
- 6 songs.
Patterns and songs can be saved only to tape using the appropriate interface. 

■ MODDING: a lot now including old circuit bending, retro lcd backlight, rom sample change (linn 808 dmx and more) 

■Country: Japan
Weight: 820g / 1lb 13oz (With Batteries)
Dimensions: 
305 (W) x 175 (D) x 75 (H) mm
12 – 7 / 16′ x 6 – 7 / 8′ x 2 – 3 / 16′

■Rear panel terminal connectors:
- main signal out
- headphones
- pedalswitch input for start / stop
- Midi interface
- tape interface
Power supply is a 9V external PSU 100 mA with -) plarity or 6 X 1.5V batteries.

■Preset rhythm composer
Sequencer
Tempo: 40 to 240
Tracks: 6 Tracks (423 Bars Altogether)
Step number: 1 to 16 steps

■Drum voices (16 voices)
Bass Drum
Snare Drum
Low Tom / Mid Tom / Hi Tom / Timbale
Rim Shot / Hand Clap
Open Hi – Hat / Closed Hi – Hat
Low Conga / Hi Conga
Low Cowbell / Hi Cowbell
Crash Cymbal / Ride Cymbal
Accent

■Controls and indicators
Start / Stop Key
Shift Key
Main Keys (1 to 16)
Enter Key / Accent Key
Clear Key
Mode Key
Scale Key
Back Key
Last Step Key
Forward Key
Instrument Select / Metronome Key
Last Measure Key
Pattern Group Key
Track Number Key
Tempo / Measure Key
MIDI Key
Level Key
Manual Play Key
Up Key
Down Key
Tempo Knob
Volume Knob
Tempo Indicator
Display Window

■Roland TR-505 rear panel connections
MONO / Stereo Out Jack
Stereo Out Jack (L)
Headphones Jack
Start / Stop Jack (DP – 2)
Tape In / Out Jack
MIDI IN Connector
MIDI OUT Connector
Power Switch
AC Adaptor Jack

■Included Roland TR-505 accessories
Batteries (UM3 x 6)
Cable (LP – 25)
Owner’s Manual
Rhythm Scores
Operation Table
Guide Book MIDI
AC Adaptor BOSS (PSA series)
Pedal Switch DP-2 

■ USER MANUAL DOWNLOAD

■ SERVICE MANUAL 

TR505 reset procedure:The following procedure can be used to clear the internal memory and reload the
factory settings:

1) Power on while holding down MODE and PATTERN GROUP KEY A .