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USB MIDI KEYBOARD TO MIDI HARDWARE HOW TO

May 15, 2020One subject that comes up time and time again is "how to connect a USB MIDI keyboard to MIDI hardware". I've therefore decided to put up this post... It's not exactly difficult but at the same time, you can't take it for granted that the MIDI keyboard you've got your eye on, actually has well... MIDI ports. Just about every controller seems to be designed to plug straight into your computer and hence, only has a single USB port. Manufacturers tend to offer their controllers in versions with those little 5-pin DIN sockets but they're usually upgraded versions with for example, seventy-six keys instead of the sixty-one keys that you wanted and perhaps more to the point, the version that'll fit on your desk or that's within your budget. Oh! No MIDI port. In a market that has been increasingly dominated by computers, some might concede that it's hardly surprising that MIDI ports are omitted from modern (MIDI) controllers. On the other hand, for those of us that have a collection of hardware sound modules, synthesisers and drum machines, MIDI controllers without MIDI ports is kinda useless! Fortunately there's a potentially very simply and cost-effective work-around; introducing the MIDI USB host! So a MIDI USB host is basically a small box running embedded firmware that recognises any class-compliant USB MIDI controller. That middle bit (class-compliant) is really important. A MIDI USB host is designed to be switched on and left. There's no monitor, QWERTY keyboard or mouse attached and there's no way to access the 'operating system'. It stands to reason therefore, that connecting anything to it, should be immediately recognisable and that means that anything connected to it MUST be class-compliant. Well, fortunately most USB MIDI keyboards are just that but it's always worth checking. Several manufacturers make MIDI USB hosts but perhaps two of the most well known are those made by Kenton Electronics and MIDITech. Be expected to pay about 85 GBP for the former and 66 GBP for the latter. For the DIYers amongst us, I've chosen to include the USB Host Controller Board V2.4 in the image above. Available from https://www.hobbytronics.co.uk/ for a modest 16.20 GBP (at the time of writing), this kit is available in a variety of 'pre-blown' versions, with appropriate firmware put on to the 24FJ64GB002 microcontroller before it's sent out. One version makes this little board into a great USB MIDI host. You'll need to connect 5-pin DIN sockets, provide power and box it up yourself but for anyone who feels a little adventurous, this can be a very cost-effective solution. One point worth noting, is that these boxes require power and both examples mentioned above are equipped with USB power ports that are secondary to the USB port that's used to accept the connection from your USB MIDI keyboard. MONSTER MIDI INTERFACE A company called iConnectivity makes a series of MIDI interfaces that are superbly designed and particularly suited for the modern audio production environment. The MioXL for example, has ten (yes TEN) USB MIDI ports as well as a bunch of conventional 5-pin DIN MIDI ports and... it also supports RTP-MIDI via a RJ-45 connection. Fully configurable via software hosted on your computer, the MioXL also has an elegant OLED display providing an array of status information. Available for under 350 GBP, this is a seriously powerful interface that's designed to connect to just about anything that can carry MIDI. iConnectivity MioXL - The Mother of all MIDI Interfaces. WOW!!!! I'd love one of these! LATENCY Anyone working with digital audio will be familiar with something called 'latency'. Loosely defined as the time between a signal entering a digital system and leaving the same digital system, latency is basically the time taken to digitally process a signal. If that means simple analogue to digital or digital to analogue conversion, then even that process takes a finite period. This is not the case with analogue electronics although there does exist an almost analogous parameter called 'propagation delay' but let's not confuse things just yet, eh? When working with computers specifically, latency can be quite substantial as there's a lot going on in these boxes that we've all grown used to. Having said that, clock speeds and more efficient processing both in software as well as hardware, has reduced latency over the years and in most situations, it's not a real concern anymore. On top of that, manufacturers of audio interfaces introduced 'direct monitoring' a long time ago which was and still is a great work-around to the issue of latency. So going back to our USB MIDI host, it should be noted that by design, the smaller boxes are very simple and are designed to do one thing and one thing only. Hence, while latency technically still exists, simply by the nature of the beast, it is negligible. I use a Kenton Electronics MIDI USB host myself and I can assure you that if latency was an issue, I simply wouldn't bother....

ROLAND SUPER-JX UPGRADES

LCD BACKLIGHT REPLACEMENT

May 10, 2020A relatively common problem on older equipment, is the failure of the LCD backlight (or EL-panel). Often accompanied with a very high-frequency whine emanating from the LCD area of the gear in question, it's time to consider LCD backlight replacement. Here's a Roland GC-8 editor / controller for the massive Roland R-880 reverb (circa 1988). Without the controller, the R-880 which really is an awesome machine, is kind of useless as there's little out there to program it via MIDI. Roland GC-8 with original LCD backlight (pink) and new LCD backlight. Luckily and thanks to a company called backlight4you, LCD backlight replacement is now worth looking into to. A variety of EL-panels that are suitable for a whole bunch of older gear, is available at the company's website which is also full of other useful and related information. Their backlights are reasonably priced and arrive from Germany pretty quickly and in very stiff cardboard packaging. After fitting the replacement EL-panel, I powered up the unit to check. Wow! It looks great and on this occasion I got lucky and that bloody annoying whine has gone! IMPORTANT: As a backlight ages, its electrical characteristics change, These changes put a strain on a small component called an inverter which converts dc within the unit to high-frequency ac which is required to drive the EL-panel. As this components deteriorates, it starts to whine. In many cases, replacing the backlight will fix that problem but... not always. : ( If after swapping out your backlight, your unit is still whining, then backlight4you may still be able to help. Take a closer look at their website and you'll find a section on inverters. Designed to run from common voltages and power many of the EL panels that are sold on the website, these replacements are very reasonably priced. Replacement inverters might not be pin-for-pin compatible, especially with very old equipment but with a little ingenuity, you might be able squeeze a one in somewhere. Due to the low cost of replacement inverters, I would personally recommend swapping out the inverter when fitting a new EL-panel. Need help with a hard-to-read LCD? Drop me a line....

ROLAND MKS-70 POWER SUPPLY REPLACEMENT

May 2, 2020Guy Wilkinson's P0004 switched-mode power supply for Roland Super-JX Never thought I’d make a new friend over lock-down but I have recently struck up a relationship with Guy Wilkinson of supersynthprojects.com. While working on a very broken Roland MKS-70 that I have in for repair, I came up with the idea to design a MKS-70 power supply replacement but figured that after all these years, perhaps someone has already thought of this. After a few minutes of searching on-line, I stumbled across https://supersynthprojects.com. The work that Guy has done, is truly amazing. His power supply design is quite simply, elegant and I’m so impressed with his methodical record keeping. As it turns out, Guy seems to be a bit of an expert on several vintage machines. Anyway, having a Roland MKS-70 myself, one thing led to another and I’m currently in the process of building one of Guy’s P0004 switched-mode power supplies and installing his Super-JX OLED display module into my own MKS-70. It’s a bit difficult doing this during lock-down but I’ll keep you posted of progress. Guy Wilkinson's Super-JX OLED module. The background images show an actualSuper-JX OLED installed in a Roland MKS-70. Guy sells the P0004 switched-mode power supply bare PCB and the pre-assembled Super-JX OLED display directly but you'll need some competence to populate the former and fit either, into a JX-10 or MKS-70. If you're cool enough to admit that all of that sounds a bit too much for you, then please don't hesitate to contact me to discuss getting either (or both) fitted into your machine. NOTE: All prices include VAT (20%) but exclude shipping. This specialist stuff so I'll only order components when your payment has cleared. * If you're fitting the switched-mode power supply module yourself and your MKS-70 or JX-10 has a 2-pin IEC mains input socket, then you must replace it with a 3-pin IEC mains input socket. The replacement switched-mode power supply MUST be connected to earth as must the chassis of your Super-JX. ** The 3-pin IEC mains socket kit comprises the following: 1 x IEC 3-pin chassis socket. 3 x pre-cut heat-shrink strips. 1 x insulating boot for IEC socket. 1 x M3 earth tag. *** Includes earth bonding where applicable. It is paramount that if fitted, a 2-pin IEC mains socket be replaced with a 3-pin IEC mains socket and that the chassis and the P0004 are connected to earth. UPDATE - 10th MAY 2020 Last night I installed the assembled switched-mode power supply into my own Roland MKS-70. I'd already tested it outside the machine but I was still nervous. Hey, the MKS-70 fired up straight-away. The power supply worked just fine and quite honestly, if you're having issues with the power supply in your Roland MKS-70 or JX-10, then getting one of these is a no-brainer! Look, no transformer! Coooool. UPDATE - 12th MAY 2020 Took a while and was a bit tricky but the display got done and works absolutely brilliantly (pardon the pun). In fact it looks positively beautiful. Never knew what people meant when they referred to tech as "sexy". Now I do. I can't stop looking at it!!!! The Super-JX OLED module 'learns' the system's firmware so before I switched on the unit to test, I thought I'd drop in the Vecoven Super-JX flash module. Pressed the power button and everything powered up just great. UPDATE - 19th MAY 2020 Several days ago, I posted here that I'd keep you updated of progress on this project. I also suggested that I'd probably end up making a new post. Guess what? So, click here for more on Roland Super-JX Upgrades. ...

ROLAND MKS-70 REPAIR

March 19, 2020Recently, this gorgeous vintage analogue Roland MKS-70 synth module came in for repair. The MKS-70 is basically the rack version of the Roland JX-10 keyboard synthesiser, which itself is essentially two JX-8Ps. Often refereed to as the Super JX, the JX-10 and the MKS-70 ooze analogue tone and both deliver pristine sound quality. Check out more details and some sounds here. Anyway, the customer said that it wasn't powering up properly with just a flash briefly appearing on the display and then nothing. Well, let's see if we can get this ol' girl singing again.. Apart from being a giant classic analogue synth, the MKS-70 like the MKS-80, has hinged circuit boards which means that it opens up quite nicely. Having said that, if you need to get at the 'CPU' board (the service notes refer to this as the Assigner board, for some reason), you really do need to disconnect and remove the lower analogue voice board. Switched-mode power supply for Roland MKS-70 Before I did that, I checked the voltages on the power supply which were all about 25% more than they should be. Eek! Hope no serious damage has been done. I'll keep you posted on this fix but please bear in mind that I'm respecting the COVID-19 lock-down so it may be a while before I'm back. In the meantime, please check out MKS-70 power supply and OLED display replacements here. If you've got one of these, I'd love to know! If it needs a little TLC, then just contact me....

PLASMA MUSIC SALE 2020

March 18, 2020Last year, I started to downsize my recording facility and so a lot of stuff is now up for grabs in my Plasma Music Sale 2020. It's not just studio gear but drums, cymbals, guitar and keyboard stuff, video cameras, computer equipment and live performance gear like complete PA systems, mixing desks, powered monitors, multi-track recorders, amps, radio mics and so much more. Some of it's old and some of it is relatively new but either way, it's all been lovingly looked after while I've had it and most of the stuff is in pristine condition and it all works perfectly. Please do check it all out my Plasma Music Sale 2020 here before it all goes on eBay! If you need more information about a specific item or just not sure about something, then please don't hesitate to contact me. NOTE: I haven't bothered with an on-line shop. Seems a bit over-the-top. To date, buyers have been quite happy either paying via PayPal, bank transfer or cash on collection....

OK GOOGLE SWITCH ON MY COMPUTER

March 1, 2020Occasionally I build a batch of things which I put up here for sale. It's not worth me puting up an on-line shop just yet, so if you want anything, just contact me. Anyway, recently I built a bunch of smart momentary switches which will allow you to turn on your computer from your Google Assistant or Amazon Alexa. Just say "OK Google, switch on my computer" or "Alexa, switch on my computer" and it just happens! This item is basically a kit comprising some parts which need to be attached to the header on the motherboard inside your computer. Hence, this kit is ONLY suitable for computers which have an accessible motherboard and a standard motherboard header. UNFORTUNATELY THIS KIT IS NOT SUITABLE FOR LAPTOPS, TABLET PCs, STICK PCs AND MACs. Since parts need to be attached to your computer's motherboard, a basic proficiency of working with computer hardware is required. If you're not confident to open up your computer and move a couple of bits around, then either find someone who is or think again about buying this. Included is a small ABS box which contains the electronics and which has an integral USB lead for power, a USB power supply, a standard PCI back-plate (this should fit most ATX sized cases) and a connection cable which connects the box to your computer via standard 3.5mm jack plugs. Oh and a link to download full instructions (in UK English only, I’m afraid), are also included. I can't exactly call this box an OK Google switch on my computer box! Instead, I'm just calling it 'SMS' which stands for Smart Momentary Switch. OK GOOGLE, OPEN MY GARAGE DOOR Yes, that's right! I make a version of this gadget which can be used to open and close your electric garage door via your Smart Home (Google Home Assistant or Amazon Alexa). So how much do they cost? £69 including postage to UK mainland. That's a bit more than I'd like but I hand make these myself in small batches....

BEHRINGER DEQ2496 REPAIR

February 26, 2020On the bench today is a Behringer DEQ2496 repair. This is the third generation of 'Ultra-Curve' from the well-known German manufacturer. The DEQ8020 and DEQ8024 were both 2U units but in 2005, Behringer released the super high-specification 1U DEQ2496. These extremely high-quality and versatile processors do a lot more than graphic equalisation. Amongst the machine's function is a real time spectrum analyser. You can purchase a Behringer ECM8000 calibration microphone and quickly and easily set up the graphic to 'compensate' for room acoustics, for example. There's also a mired of other functions such as parametric eq, dynamic eq, dynamic processing and time delay, to name but a few. With digital inputs and outputs (S/P DIF on TOSLINK and AES / EBU), the analogue side of the DEQ2496 is balanced and boasts a fantastic dynamic range with its 24-bit / 96 kHz conversion. Finding popularity amongst hi-fi enthusiasts and audiofiles, the latest and current Ultra-Curve is of course also very popular with PA hire companies, recording studios and even in musicians' instrument rigs. So, unreliable power supply, then? No, definitely not! The date code on the one that's on the bench today is July 2006. That makes in almost fourteen years old and quite honestly, it's done bloody well, in my humble opinion. The repair to the power supply takes just over an hour. The parts cost about twenty quid and in no time, the machine's going to last another fourteen years, at least. 🙂 So, if you're in need of a Behringer DEQ2496 repair, don't hesitate to give me a call. Check out the Behringer DEQ2496 Ultra-Curve here....

UNBALANCED TO BALANCED CONVERTER

February 17, 2020Many musicians, engineers and producers appreciate why signals should be kept as 'hot' as possible. High signal levels can reduce your noise floor and of course a lot of professional, studio equipment is designed to run at +4dBu (about 1.25 volts). What many might not appreciate is the virtue of also running balanced signal lines. Running an analogue audio signal over a balanced line severely increases immunity to noise. I won't go into the physics of just why that is yet, although I'll no doubt end up adding to this post at some time in the future. Unfortunately there's a lot of older gear out there including stuff we all love dearly, which has unbalanced +4dBu outputs. The Marshall JMP-1 that was featured in a recent post, is a prime example. The Roland RSP-550, an excellent nineties multi-effects processor, is another example. Unbalanced but switchable -20dBm/+4dBm inputs and outputs on an old Roland RSP-550 So, the traditional way to convert an unbalanced signal to a balanced signal is to run it into a D.I. box. We're all familiar with those little boxes that cover many a studio and stage floor, right? They work just great but while they balance the signal, they also knock down the level of the signal to a few millivolts which means that you have no option other than to run the other end into a mic. pre-amp, either as a separate unit or built into a desk. That's not always convenient and it seems stupid attenuating a signal, only to amplify it again, anyway! Have you noticed another downside to trying to use a D.I. box to solve this problem, yet? Earlier I gave the example of the Roland RSP-550. It's an effects unit. It has +4dBu inputs! So you ain't easily gonna be able to send signal from your desk to it via a D.I. box! The inputs on the RSP-550 are looking for either -20dBV or +4dBu. The microphone level output from a D.I. box just won't be enough to drive the unit. On top of that, the D.I. box output is balanced. The inputs on the RSP-550 are unbalanced. That's actually two downsides. 🙁 To convert an unbalanced signal to a balanced signal and maintain the level of the original signal was a problem I decided to solve once and for all, many years ago. I developed the transformer coupled interface (TCI). It's not rocket science (as they say) but boy, do these things come in handy. The TCI is a non-powered device (like a passive D.I. box) which basically comprises a single transformer on each channel. I designed the transformer myself as not only did I want the best linearity I could get over the entire audio spectrum but I also wanted minimum phase distortion, especially down the bottom end, something that cheaper transformers tend to generate. Anyway, I managed to get a bunch of these things made here in the UK and the TCI was born. Similar to a passive D.I. box, one hidden benefit to using the TCI, is that it offers something called 'galvanic' isolation which means that the signal path between your source and destination equipment is 'broken'. With the ability to easily lift the earth on the output (balanced side) of the TCI, these things are just great for getting rid of ground loop problems! IMPEDANCE All equipment has what’s called an input impedance and an output impedance. Impedance, like resistance and is measured in Ohms but differs in that it's frequency dependant. The impedance varies depending on the frequencies in the signal. Taking a guitar signal as an example, the input impedance of an amp let's say, will be different at 500Hz than it will at 5kHz. Having said that, due to the nature of things, a common resistor is often used on for example, the output of an electronic circuit to provide the output impedance of a device. Most guitarists will be quite aware that everything to do with guitar electronics is high impedance and that the first thing you plug your guitar into should have a very high input impedance. This reduces the ‘loading’ on the guitar pick-ups and allows for a good frequency response further on down the chain. Unbalanced outputs like those found on a lot of consumer electronics such as hi-fi gear, have a high impedance, perhaps in the order of thousands of Ohms. Balanced outputs in contrast, are always low impedance; just a couple of hundred Ohms. Again, I won't go into the physics suffice to say that this is why amongst other things, low impedance outputs allow for long cable runs. There are exception; unbalanced outputs on a lot of ‘studio’ gear can be low impedance. This makes life a lot easier! The TCI has a low input impedance and while it will technically work on something with a high output impedance, you might notice some high-end roll-off. Basically, you’ll need to check the output impedance of your gear before considering a solution like the transformer coupled interface. That’s why D.I. boxes are so popular. D.I. boxes have a high input impedance which means you can plug in just about anything. Like my transformer coupled interface, passive D.I. boxes also have a transformer to convert the input to a balanced line. The turns ratio of the transformer however, is such that while presenting a high impedance at the input and low impedance at the output, the signal voltage is greatly attenuated. Hence, the output of D.I boxes is mic. level....

MARSHALL JMP-1 SERVICE

February 13, 2020Here’s a Marshall JMP-1 MIDI valve pre-amp that I’ve just serviced. I’ve changed the valves and power supply capacitors, cleaned up the metal work and implemented my ‘Live-for-Ever’ battery mod’. The battery is bang in the middle of the board so you really don't want this to leak. The serial number indicates that it was built in early 1992 which not only makes it twenty-eight years old but one of the first JMP-1s off the Marshall production line. An early MIDI valve pre-amp, the Marshall JMP-1 has always been a really under rated bit of kit, despite the fact that named artists such as Billy Gibbons (ZZ Top), Phil Collen (Def Leppard), Iron Maiden, Megadeth and many more, still use them even today. In production for well over ten years, also says something about this little gem. The JMP-1 is not a modeler like modern stuff; it’s the real thing, just with MIDI. Run into a valve power amp (or two), it just sounds amazing and the quality of the speaker emulated outputs is definitely good enough to go straight into the board or your DAW. With most of the distortion being generated in the semi-conductor domain (some of which is highlighted in the image below), many purists might shy away from this beast. On the other hand, classic Marshalls such as the legendary Silver Jubilee series and the monstrous JCM900 Dual Reverb, also use semiconductors to produce some of their distortion tones. And then there's the clean channel of the JMP-1 which is based on the classic Fender design... with a few tweaks, of course. Anyway, at the end of the day, it's the sound that counts and as I've said, these things have still got it, even today. RATTLE A' HUM If there's one annoying characteristic of an ageing Marshall JMP-1, then it's got to be the humming transformer. Anyone in the know, might think it strange that this box which resides in a 1U rack enclosure doesn't have a toroidal transformer. The thing is, the JMP-1 transformer chucks out several voltages including those required for the two valves and it's quite challenging to build all that into a toroidal design. So after a few years, the laminates inside the conventional transformer can become lose and start oscillating. The mechanical vibration can be annoying but does not appear on the audio signal. If you're heavily in love with your humming JMP-1 and want to do something about it, then give me shout! Marshall JMP-1s now go for between £400 and £700 (yes, £700). If you can pick one up nearer £400, then I personally think you've got yourself a bargin and a seriously good bit of gear. If you want to find out more about the JMP-1, then there's loads of resources on-line and of course the Marshyall JMP-1 forum on Facebook: https://www.facebook.com/MarshallJmp1/ If you have a JMP-1 and it's in need of a little TLC, then don't hesitate to contact me. MARSHALL JMP-1 FACTORY RESET WARNING: Implementing this procedure will permanently delete all user-made changes to any patches. Switch off JMP-1 via the power button on the far right. Hold down the OD1 button and the CLEAN 1 button. While holding down these buttons, switch on the JMP-1. Wait a few seconds while the display flashes and then release the OD1 and CLEAN 1 buttons. ...

AUDIO TRIGGERED MAINS SWITCH

February 11, 2020Over the past couple of weeks, I’ve been designing a gadget to switch on a power amp when an audio signal is detected and to wait a few minutes to switch off the power amp when no signal is present on the input. The audio signal comes straight from the sub bass output of an A/V amp and is therefore about -10dBV (approximately 310 mV) unbalanced. So apart from auto switch-on / switch-off, the circuit also amplifies the input signal to +4dBu (about 1.25 V) balanced so as to properly drive the power amp. After testing a prototype for several months, this evening I ordered the PCB (the design of which is pictured above) for the final version. SO WHAT'S THIS ACTUALLY USED FOR? Well, the power amp in question, drives a sub-bass system on a home cinema. It's a big, professional amp and definitely wouldn't come with auto power-on / power-off which of course, the main (consumer) A/V amp does have and which 99.9% of consumer sub-bass units have built-in. The idea is that when the home cinema system is switched on, the power amp comes on when it detects a signal. When the system is switched off, the power amp switches off a few minutes later... PERFECT! CREDITS I don't see the point of reinventing the wheel, especially if someone has already designed something really good that works. Hence, the switching circuitry of this gadget is based on a design by Rod Elliot of Elliot Sound Products (see project 38). Rod puts up some fantastic, in-depth explanation into how the circuit works and how it can be tweaked to your specific requirements. UPDATE - 18th February 2020 This morning, my PCBs arrived. I couldn't wait and quickly got down to populating one of them ready to test later in the afternoon. Well, I'm pleased to report that all worked well. With a 1kHz sine wave, the sensitivity of the circuit is about 4.5mV and the delay to switch-off time is about ten minutes. Unfortunately, the case I'll be using for this, is currently out of stock 'till 17th March, so it looks like this is going to sit on the shelf for a few weeks 🙁 UPDATE - 18th March 2020 Today I went over to RS Components in Watford to collect the enclosure that I'd planned to use for this project and the dimensions of which were part of the design of the PCB. Well, I couldn't believe what I was told; the boxes remain on back-order 'till, wait for it... 31st July. Seriously?!?!? I checked last night and there was no change in status. What the hell are you playing at?...

ROLAND VK-7 – POWER SUPPLY REBUILD

December 4, 2019This Roland VK-7 belongs to my mate, Alex Richards. The transformer is mounted upside-down on the inside of the top chassis. Guess what? It fell off! The machine was plugged in at the time so the accident caused considerable damage. To avoid this happening again, I mounted this heavy little component to the bottom (steel) chassis and laid new connections to the power supply board. Twenty years old, has taken quite a few knocks, it plays and sounds great....

NEKTAR IMPACT – BEST TECH SUPPORT EVER

December 4, 2019Customers’ units come first so when my own stuff needs repairing, it kind of gets put to the back of the que, especially if it’s not a critical system. Anyway, a few weeks ago, the attack slider on my Nektar Impact LX61+ MIDI keyboard started playing up. I tried to do a quick fix but the potentiometer was definitely duff. I fired up a support ticket and received the most amazing response from Nektar. The company basically just sent me a whole new PCB! All I really wanted was the slider pot’. Cost-effective, versatile and easy to program, the Nektar Imact range of MIDI controllers seem perfect for any project studio set-up. Now that I’ve experienced the company’s support first-had, I really can’t recommend them enough. Mine’s a 61-note which means it’s only got USB out. With a USB switch though, I can run it into my DAW or to a USB MIDI host which allows me to drive my MIDI synths....

MARSHALL MONDAYS

October 7, 2019Of course I don't just do Marshall repairs on Mondays but what a great way to start the week; a gorgeous 4502 JCM900 50W Dual Channel Reverb on the bench. There's nothing too wrong with this amp. It just came in for a re-valve and a tune-up (bias check) after the customer complained that it sounded a bit dull and lifeless. In my humble opinion, the JCM900 Dual Channel Reverb was the last 'proper' Marshall. Personally I'm a 100W head freak but the 50W heads and combos do sound sweeter. Put a 50W through a 4 x 12 and you get a whole lotta' beef underneath that sweetness. HEAR AND FEEL THE DIFFERENCE I ALWAYS USE PREMIUM MATCHED VALVES AND I ALWAYS RE-BIAS CONTACT ME I get a lot of people ask me about impedance matching valve amps and speaker cabs so sometime over the next couple of weeks, I'll be posting some bumf on how it all works and best practices. Stay tuned!...

COOL STUFF – THE YAMAHA GPI

October 5, 2019General Purpose Interface under the User Defined Keys section on a Yamaha DM2000 Virtually all high-end Yamaha mixing desks such as the DM series, PM5D, LS9 and CL / QL series to name but a few, are equipped with the Yamaha General Purpose Interface or GPI. The picture above shows the GPI buttons under the 'User Defined Keys' section on a Yamaha DM2000. It's a great idea and can be so incredibly useful in so many situations. Unfortunately, very few people know what GPI is all about and Yamaha only offer limited implementation options. Often used to interface a desk with video equipment, the Yamaha GPI standard can also be used to switch on and switch off other equipment such as amplifiers, computers and outboard gear which might be located some distance from the mixing desk. For recording and live applications, this facility could be so incredibly useful. To take advantage of the Yamaha general purpose interface, I build a distribution box and various gadgets which will allow the GPI on your Yamaha mixing desk, to do just that. Pictured below is a 3-channel mains power switcher in a solid steel case, capable of switching three loads totalling 10 amps. This particular interface switches three power amps located in another room in a recording studio. Also pictured, is the breakout box which splits the GPI from the desk to eight individual lines. Channels 7 and 8 of this particular switch for example, are used to switch on two computers, also directly from the desk. Do magic things with GPI switching and breakout systems at Plasma Music If you have a Yamaha mixing desk equipped with GPI and want to remotely switch gear on and off from it, then don't hesitate to get in touch....

RME FIREFACE 800 REPAIR

October 4, 2019On the bench today; a RME Fireface 800 repair Many will know that I'm a mega-big RME fan. Stylish, reliable, oozing sonic excellence in abundance and very easy to use, RME interfaces like the Fireface 800 are sonically very transparent. When it comes to drivers and firmware, RME is constantly on the ball and software issues with their products simply don't exist. A bold statement I know but in my experience, it's true! Anyway, every six or seven years the power supplies on these systems pack up. Delivering a reliable but significant output, they do get hot and despite the use of high-temperature tolerant components, time takes its toll. Symptoms range from flashing lights on the front panel, to the unit not powering up at all. So, if you're in need of a RME Fireface 800 repair, then I'll be more than happy to help you out. It's well worth it. These interfaces are just great. Just contact me. Click here for more information on RME interfaces. In the meantime, here's the spec': Input AD: 8 x 1/4" TRS, 4 x XLR Mic, 4 x 1/4" TRS Line, all servo-balanced. 1 x 1/4" TS unbalanced Output DA: 8 x 1/4" TRS, servo-balanced, DC-coupled signal path. 1 x 1/4" TRS unbalanced Input Digital: 2 x ADAT optical or SPDIF optical, SPDIF coaxial (AES/EBU compatible) Output Digital: 2 x ADAT optical or SPDIF optical, SPDIF coaxial (AES/EBU compatible) MIDI: 1 x MIDI I/O via 5-pin DIN jacks, for 16 channels low jitter hi-speed MIDI Dynamic range AD: 109 dB RMS unweighted, 112 dBA THD AD: < -110 dB (< 0.00032 %) THD+N AD: < -104 dB (< 0.00063 %) Crosstalk AD: > 110 dB Dynamic range DA: 116 dB RMS unweighted, 119 dBA (unmuted) THD DA: < -103 dB (< 0.0007 %) THD+N DA: < -100 dB (< 0.001 %) Crosstalk DA: > 110 dB Input/Output level for 0 dBFS @ Hi Gain: +19 dBu Input/Output level for 0 dBFS @ +4 dBu: +13 dBu Input/Output level for 0 dBFS @ -10 dBV: +2 dBV Sample rate internally: 32, 44.1, 48, 64, 88.2 kHz, 96 kHz, 128, 176.4, 192 kHz Sample rate externally: 28 kHz - 200 kHz Frequency response AD/DA: -0.1 dB: 5 Hz - 21.5 kHz (sf 48 kHz) Frequency response AD/DA: -0.5 dB: < 5 Hz - 43.5 kHz (sf 96 kHz) Frequency response AD/DA: -1 dB: < 5 Hz - 70 kHz (sf 192 kHz) ...