Allen & Heath Brenell Inpulse One

You’re wondering why an obsolete drum machine that you may never have heard of has a page all to itself, in the top menu? Keep reading and find out!

This page originally predated WordPress, and featured some pre-loading audio files that would allow you to click and hear the pads of the drum machine. That’s kinda old-school crude; feel free to view the original HTML page here, where all the images and links will behave, but the fonts are kinda small for mobile.

It will try to download a load of audio files!

Back in 2002-2004 this page existed to try and find the machines in the wild, track down tapes and document an often overlooked bit of musical technology history, since when Allen & Heath have put their own pages in place for the Inpulse One:

The AHB Inpulse One

What is the Inpulse One?

The Inpulse One is a surprisingly rare drum machine featuring 8 velocity sensitive pads, playable with hands or sticks, plus an insanely easy to use drum sequencer, crude MIDI, SMPTE timcode implementation and 256KB RAM. Sadly only 140 or perhaps, even fewer were made before production ended, and finding parts, extra sounds or information is next to impossible.

AHB Inpulse One advertising

The current Allen & Heath page with original brochure and user’s handbook can be found here.

And their historic “Veterans” page is here – though their serial numbers are incorrect – I’ve been told that they started at 1000-1089 with a further batch of “around 20” made following MIDI improvements, which were retrofitted to many of the older units.

Since acquiring this some time ago, I’ve had contact with a few owners and the designer – it took some time before other working machines surfaced..

Sound on Sound retrozone

Well, it was an exciting day for me!

In 2004 my retrozone article appeared in the August 2004 Sound On Sound. In has not been possible to correct some small errors in print, because that would need a time machine and an argument with a production designer, but they are corrected on this page and will continue to be as more information is gathered.

The article is incorrect in that the Simon at Livingston Studios would have been Simon Bohanon, not Simon Jones (which could be a subconscious attempt by H2G2 to break out of my head in print).

I also referred to the Movement Drum Computer as the Larking Movement – from an old cutting/reference to the machine. I’m not sure if that was a reseller, or a forgotten company related to the Nascom-based drum machine, but I’ve been unable to find any further references – so assume that was wrong too!

Inpulse One people

Since this page was originally created in 2004, a few new bits of information have come up.

Contributors to the history, creation and understanding of the Inpulse One and in some cases information contained on this page include:

Allen & Heath Brenell people:

Glenn Rogers, MD
Alan Robinson – designer
Steve Bell – the mysterious “045” of Allen & Heath fame – the engineer that assembled the machines, hence the 045 stickers you’ll find inside them
Mike Clarke of Allen & Heath, who arranged permission for the media to be shared, and tried very hard to track down more information and technical documentation

Livingstone Studios people:

Nick Kinsey, owner of Livingstone Studios at the time
Simon Bohanon – who has clarified some more about the means of getting samples into the Inpulse One
Bob Henrit – sound engineer/consultant, Bob’s provided a great deal of insight into the system, and the machine I currently have awaiting restoration (for rather too long) is his. Not only a well-known drummer, Bob’s worked on other electronic drum systems since.

(quick plug: Robert’s got a book out – Banging On!)

Barry (Clempson?) – one of the consultants recording sound, who sent sample tapes to another person involved – Andy

Behind the sounds

Sounds were sampled for the Inpulse One using a combination of an Apple //e computer and an AMS DMX 15-80 – a studio grade delay unit with a fifteen bit sampling circuit. The memory of the AMS was read using a dummy memory card, by the Apple //e. Chances of me recreating this are slim, the AMS is still an expensive and rare device.

The samples were produced at Livingstone Studios.

Users of the Inpulse One:

It is fair to say that verified accounts of musicians using the Inpulse One are as rare as the machine itself. Naturally Robert Henrit is one user, as he created many of the samples for it. Bill Nelson is known to have used one on the iconic 1986 album “Getting The Holy Ghost Across“, now released on CD for the first time.

He discusses it in an interview with Sound on Sound in 1986 and hints at the long gestation and time taken for the machine to reach the market. At some point in history, I found a reference on usenet or a forum somewhere that suggested Ed Vargo of T.H.D used one, though can’t contact or verify that. 1045 I am fairly sure I bought from Mark Jenkins, an electronic/prog music producer in the UK. None of my recordings have been released.

What does an Inpulse One sound like?

The Inpulse One is now well over 30 years old, and it remains overlooked. For owners of the Teenage Engineering OP-1, I have produced a couple of drumkits ready to use with the sounds I have currently. These are clean recordings from a working Inpulse One, and are ready to go – compare them to the kits available from other machines of the era!

Free sample pack for OP-1

The Teenage Engineering OP-1

You can download the kits here, along with a list of instrument/sample names and keymapping.

Free sample pack for Novation Circuit

Since I use a Circuit as a jumping off point most of the time, the Inpulse One samples are generally resident all the time; here’s a Circuit pack with the factory synth patches and sessions, plus the Inpulse One drum samples from factory ROM and recovered from data tapes.

Please note: I do not own the copyright for any materials other than my own presentation and articles – the sound files and data are the original works of Allen & Heath or the team at Livingstone Studios and related consultants and suppliers to the Inpulse One.

I have been given permission to redistribute these for the purposes of helping Inpulse One owners find new sounds, and keeping the history of this unusual drum computer alive.

Whilst I’m sure no issues will arise from any fair use of these creations, do not copy and resell them in commercial sample libraries.

Will we track you down? It’s unlikely, but I do regularly search for new information, forum posts and mentions of the system.

If you want to share this with other drum machine enthusiasts, please link to this page so the full story is told. That’s all I ask.

AHB Inpulse One user registry

Serial NumberSpecificationConditionOwnersLast seen
1015Functional, recently servicedRobert2004, eBay - £140
Contact form, March 2020
1021Fail FF error
Has manuals
Ian Barr, UK
MatrixsynthMatrixsynth - June 2016
1025No MIDI In?WorkingAndy at EMISEMIS Synthesizer MuseumEMIS Synthesizer Museum
1042ROM 5WorkingAlan Rideout2004
1044MIDIFaulty pads (sounds like the same issue as mine!)Vintageworks NLJune 2020
For sale on eBay, €950
1045-M256K RAM
Working/mintMark Jenkins, IIRC
Xavier Piednoir, FR
2008 (my old machine)
1058256K RAM
Erratic pitch
Pads 1,4,6 not working
Battery probably due again
Bob Henrit
May 2020
1072MIDIUndergoing restorationCyJune 2020, UK
1073Working, but may need serviceGary2004
16461Post MIDI retrofit?Not working 2008-12, unsureSteve Graham, NZPossibly the one in this book:

Mystery unit2011 - eBay Germany
UnknownAlan Robinson (designer)
When booted the Inpulse One gives the ROM version after “INPULSE 1” and before “SONG 1”.
So far no 64K machines have been confirmed; the 256K upgrade is easy with 8 socketed 256K x 1 DIPs that remain easily found.
The ROM is stored on 8 EPROMs (with a 9th MIDI EPROM) – backing these up would be wise as the EPROMs age.

The Inpulse One sound tapes and samples

In 2002 Mike Clarke, Technical support of Allen & Heath was assisting me in finding tapes/data – and did find a copy brochure and manual, which Allen & Heath still host on their website. He gave me permission to redistribute tapes for Inpulse One users, so I am trying to find as many as I can.

Where available, the table below will have both the sound sample in AIFF form and the data from the tape – the data files for this website are not recorded from the tapes, but have been loaded into my Inpulse One, then resaved as a single set of data. At the moment these are large AIFF files – if smaller formats preserve the data’s ability to load over the tape interface they’ll be used in future.

Factory Sounds
Data Name2K Block CountSound name/AIFFDownload
PAD 1 Ride Cymbal
PAD 2 Crash Cymbal 
PAD 3 High TomTom 
PAD 4 Mid TomTom 
PAD 5 Snare Drum 
PAD 6 Bass Drum 
PAD 7 Hi-Hat Closed* 
PAD 7 Hi-Hat Open* 
PAD 8 Low TomTom 
These sounds are contained in ROM on the Inpulse One
Download as a set of data to load from tape.
*note: The Factory Hi-Hat sample seems to contain both Open and Closed variants. Samples cannot be loaded into the switched position selected by open/closed on the front panel or via footswitch, and if the Hi-Hat sample is copied from one pad to another, the Open/Closed switch works on all pads. It may be theoretically possible to create new samples that work in the same way. I may have transposed the two cymbals.

Loading sample data from tape is fun, and involves a lot of tweaking of levels to get it right. If you can find one in good order, an old home computer tape recorder with a speaker that works during playback even when an earphone lead is connected will make all the difference.

If you have a real Inpulse One you can use the tape data files to load the samples by connecting the line out of your computer to the machine. The recording quality should make it relatively reliable compared to magnetic tapes…

Tape Load Error on AHB Inpulse One

Tape One

9 Percussion Sounds, supplied with Inpulse One originally.
Data Name2K Block CountSound DescriptionDownload
000124Crash Cymbal 
00024Agogo Bell 
00033Cowbell 1 
00043Cowbell 2 
00061Wood Block 
00071Shaker 1 
00082Shaker 2 
Tape One is MISSING - if you find a copy of it or the samples from it, please get in touch.

Tape Two

15 Percussion Sounds
Data Name2K Block CountSound DescriptionDownload
P.00304Conga D 
P.00332Timbali Rim (dampened) 
P.00346Timbali Rim (opened) 
P.00351Clave A (low) 
P.00361Clave B (high) 
P.00392Milk Bottle 
P.00413Tin Tray 
P.00423Hand Claps A (tight) 
P.00433Hand Claps B (loose) 
0053Tabla Rim 
0068Tabla (open) 
0073Tabla (damped centre) 
Complete Tape Zipfile - with samples and data.
Tape Two is COMPLETE

Tape Three

4 Cymbal Sounds
Data Name2K Block CountSound DescriptionDownload
P.001914Chinese Cymbal 
P.002014Crash Cymbal A 
P.002114Ride Cymbal A 
P.002214Ride Cymbal B 
Complete Tape Zipfile - with samples and data.
Tape Three is COMPLETE

Tape Four

4 Cymbal Sounds
Data Name2K Block CountSound DescriptionDownload
P.002314Ride Cymbal C 
P.0045151/2 Open Hi-Hat 
1/2 Open Hi-Hat Closed 
P.002514Crash Cymbal C 
Complete Tape Zipfile - with samples and data.
Tape Four is COMPLETE

Tape Five

Drum Sounds
Data Name2K Block CountSound DescriptionDownload
P.00103Snare A 
P.00188Oil Filled Tomtom 
P.00122Snare B 
P.00133Snare C 
P.00144Snare D 
P.00404Aerosol Can 
P.0017810" Tomtom 
Complete Tape Zipfile - with samples and data.
Tape Five is COMPLETE

Tape Six

Snares 1
Data Name2K Block CountSound DescriptionDownload
SN112Killersnare! Heavy doubled snare 
SN216Mid snare with reverb 
SN34Mid snare dry 
SN412Electrosnare + reverb 
SN54Flam, military. Use with SN6 
SN62Beat, military. Use with SN5 
SN712Metallic Electro + reverb 
SN82High snare 
Tape Six is MISSING - if you find a copy of it or the samples from it, please get in touch.

Tape Seven

Bass Drums and Bits
Data Name2K Block CountSound DescriptionDownload
BD11High, Tight Bass Drum 
BD22UM, Bass Drum, doubled live sound 
BD33Live, sloppy, windy Bass Drum 
BD42Muted Jazzer 
CAB12Hard Cabasa 
F-POP1Finger Pop 
CAB21Octave Up Cabasa 
Tape Seven is MISSING - if you find a copy of it or the samples from it, please get in touch.

Tape Eight

Electro Snares 2
Data Name2K Block CountSound DescriptionDownload
EL18Various Electronic Snares 
EL27Various Electronic Snares 
EL311Various Electronic Snares 
EL52Various Electronic Snares 
EL616Various Electronic Snares 
EL712Various Electronic Snares 
EL85Various Electronic Snares 
Tape Eight is MISSING - if you find a copy of it or the samples from it, please get in touch.

Tape Nine

Egyptian Sounds
Data Name2K Block CountSound DescriptionDownload
000112Various Egyptian Sounds 
00036Various Egyptian Sounds 
000412Various Egyptian Sounds 
00052Various Egyptian Sounds 
00068Various Egyptian Sounds 
00073Various Egyptian Sounds 
Tape Nine is MISSING - if you find a copy of it or the samples from it, please get in touch.

Tapes Ten & Ten A

Guitar Power Chords 1
Data Name2K Block CountSound DescriptionDownload
G1.C19Tuned C "Power Chord" 
G2.C12Tuned D "Power Chord" 
G3.C20Tuned E "Power Chord" 
G4.C20Tuned F "Power Chord" 
G5.C20Tuned G "Power Chord" 
G6.C20Tuned A "Power Chord" 
G7.C18Tuned B "Power Chord" (Tape Ten A) 
Tapes Ten and Ten A are MISSING - if you find a copy of it or the samples from it, please get in touch.

Tape Eleven

Guitar Chords 1
Data Name2K Block CountSound DescriptionDownload
GTR.C8Tuned C "Chunk Chord" 
GTR.D6Tuned D "Chunk Chord" 
GTR.E6Tuned E "Chunk Chord" 
GTR.F6Tuned F "Chunk Chord" 
GTR.G6Tuned G "Chunk Chord" 
GTR.A5Tuned A "Chunk Chord" 
GTR.B5Tuned B "Chunk Chord" 
Tape Eleven is MISSING - if you find a copy of it or the samples from it, please get in touch.

Inside the AHB Inpulse One

Allen & Heath make mixers that are designed for serious, long-term service. The Inpulse One did not attempt to break away from that format. Remove the screws holding the two control panels, and you will be faced with this:

Inside the AHB Inpulse One

To the best of my knowledge, there are no custom chips in the system.

Replacement ROMs could be available through AHB; if they are, or they give me permission to dump the ROMs in my own system, I will provide images and details here of how to blow your own to avoid bit-rot.

That white battery almost directly in the centre is apparently the cause of death for many Inpulse Ones, btw – I intend to have mine replaced ASAP as a preventative measure. The Inpulse One is built like a tank, so the soldered battery is not really a big drama as long as the traces aren’t damaged.

To replace the Inpulse One battery:

  1. Unplug the Inpulse One. The PSU electronics are exposed, so it’s not just for protection of the machine.
  2. Undo the four screws on the side of the control panel. Lift the panel to one side, the earth cable on the left (machine facing you) limits movement so be careful.
  3. Undo the six screws on the side of the drum pad panel and depending on the state of your machine, either the three screws on the top or the three screws under the shield at the back, near the output ports.
  4. If you have undone the three visible screws on the top, be very careful, slide the panel towards you just enough to reach the three black screws securing the output board.
  5. Slide it back, and refit the three screws securing the output panel to the drum pad panel.
  6. The top panel is now attached to the drum machine by one earth wire and two ribbon cables. The ribbon cables can be detached by pushing the two clips outwards – they may be stiff, but be cautious and steady. The pins will lift straight out if you do this correctly. I usually disconnect the ribbon cable at the output board in both cases.

The image below shows why you want to lift the output board AND the top panel together, even though the three black screws are partially obscured. This is the output board in place, with four ribbons linking the pad boards to the output board and the earth wire linking it to the chassis. These ribbons are also on the least reinforced areas on the machine.

AHB Inpulse One output board ribbon cables

Also, see that capacitor? Don’t touch the contacts. Seriously.

Whilst in there, check the condition of the pins on the connectors – 1058’s were badly corroded.

Now remove the MIDI board. Two screws go through plastic standoffs, then a small locknut secures it on the lower right corner. Unto the ribbon cable from the port on the PCB, noting orientation if it’s not already marked, detach the ports (they should be labelled In and Out) and take it away. Remove the short plastic standoff from the stud as it gets in the way of detaching the ribbon cables, but don’t forget to refit it.

Now you have the MIDI PCB out of the way you can detach the power cable – mine has a bent pin that looks like a factory mod to disconnect part of the board or avoid issues with an unused pin. Orientation is VERY important on this!

Detach the two ribbon cables from the computer board linking it to the DMX board – the larger one can be very stiff.

Replacement battery for AHB Inpulse One

Finally, remove the black screws securing the computer PCB to the chassis. The battery is a commonly available 3.6V Mempack, for which Varta and others make direct replacements. It’s easy to solder as the board is straightforward, and unless you’re incredibly unlucky leakage won’t have hurt the machine, and any damage in that area can be repaired.

Battery in an Inpulse One

Reassembly is the reverse, with the caveat that you need to watch those ribbon cables, and remember to put the screws through the MIDI board and slide the longer 2 standoffs on before refitting. I take pictures at every stage.

Still having trouble?

A common error message on the Inpulse One

This is not an exhaustive repair guide, but some erratic behaviours I have seen include:

Entire front panel flashing, refusing to boot: Poor connections to power, battery coming up to operating charge, and 100mA 20mm Fuse on Power Supply PCB.

Drums not working, but everything else looks good: -5V fuse (400mA 20mm, on rear of machine) blown.

Inpulse One ports - individual outs, trigger in and MIDI

Patterns not programmable: Refer to the manual – after erratic junk gets into the memory, it can play up – delete patterns. You can only step-sequence a pattern of 4 bars or less.

Unusual pitch behaviour: This should not happen, but the corrupt memory as the battery fails can also cause MIDI mapping issues and similar.

  • Press HOLD and 0, then tap a pad – the key range assigned will be displayed.
  • Press “RES” to reset, then press FROM – on your MIDI keyboard/controller, press the key you want to start a range from.
  • Then press TO on the front panel, and the corresponding end of range note on the MIDI controller.

Pressing Pat and the two pitch keys will enable pitch changes from MIDI. It’s a bit odd, but kinda works.

Inpulse One steps and sequencer

Simplicity Itself. The step-time pattern arranger on the Inpulse One offers a degree of user-friendliness I have yet to encounter in any other bit of 80s equipment.

If you know of an Inpulse One, own one yourself, or have tapes, advertising material, reviews or other material relating to it, drop me an email on this form.

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.