Zen and the Art Of Microphone Modification

 

 

 

After much standing on the side procrastinating, reading various websites, blogs and how-to guides, I decided to get my hands dirty and take on a microphone modification. I had recently bought an Apex 460 valve mic from the states, and an upgrade kit from the very helpful people at Microphone-parts.com. The kit comprises everything you need to convert the stock Apex 460 into a very nice sounding mic. The stock mic sound is nothing special, but it’s only when I did a comparison with the modified version did I realise how big a difference the mod really makes.

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Basically, the modification involves changing the tube to a better quality, lower noise one, removing the RF filter circuit, swapping critical capacitors, diodes and resistors with higher quality components, and changing the capsule for a better quality version.

I spent the best part of a day doing this, but I was going slowly because it was

a) My first time, particularly doing desoldering work

b) I was ultra paranoid about wrecking the mic

Here’s what I got, where I got it and how much it cost:

– APEX 460 Tube mic from Ebay (MegaToneMusic) Total cost including shipping to UK and customs = £205

– Apex 460 mod kit (The Fox SG version from Microphone-Parts.com), approx £140

– Thermostatically controlled soldering iron and desoldering pump – Ebay – £15.99

– Desoldering Braid – Ebay – £3.49

– Helping Hand crocodile clip and magnifying glass (for holding PCBs whilst soldering) – Ebay – £2.88

– 4% silver solder (1m) for audio connections – Ebay – £1.99

– 99.9% Isopropyl alcohol – Ebay – £3.95

These items I already had lying around:

– A clean toothbrush and some cotton buds

– regular solder for de-soldering

– wire cutters, screwdrivers

– clean containers for storage

So you can see that it’s actually quite cheap (compared to spending several hundreds of pounds on a valve mic). I’m not a particularly experienced solderer, I know how to do it and have done the odd repair job, but nothing major, and I’ve never desoldered and replaced components on a board before. I found the overall process of moderate difficulty, once I got the hang of desoldering it was actually quite quick. The kit recommends using the vacuum pump to desolder, but I also ended up using the braid in some places because it was easier and cleaner.

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The first task is to swap out a pair of diodes in the power supply, this is fairly straightforward and a good way of easing yourself into the job, you have to make sure the power supply has been disconnected from the mains for at least 1 hour so all the caps have fully discharged and you avoid the risk of electric shock. Once this swap is done, fire up the mic and check all is ok, then it’s time to work on the mic itself.

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Opening up the mic, firstly you remove the old tube, which is held in place by a spring loaded pad at the bottom, once done you can unscrew the 2 PCBs from the frame, desolder the capsule wires and open up the 2 PCBs to access the joints on the underside. The very detailed and comprehensive instructions tell you exactly which components to desolder. A useful tip here is to always bring the soldering iron in from the edge of the board, to avoid burning any wires or components on it by accident (as I did!). The “helping Hand” tool was also quite useful here, allowing me to hold the PCBs at the best angles to facilitate access to the joints.

Once the necessary components had been removed, it’s time to repopulate the board with the new components (taking care to observe correct polarity for certain capacitors). The FOX SG kit comes with a bit of 4% silver solder (audiophile grade apparently), however I bought a meter of the stuff off Ebay, probably my soldering but I ran out of the stuff they provided before the last component was done. Once the components are in, time to clean the boards with the alcohol to remove flux and other contaminants (taking care not to get any on the polystyrene capacitors).

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At this stage, they recommend testing the mic, probably wise, so put the new tube in, reconnect the capsule wires and plug in. Providing this goes successfully it is then time to remove the headbasket and swap the capsule. This was the bit I found most fiddly, probably because I was so paranoid of touching or damaging the new diaphragm that I ended up being over cautious. Suffice to say, it was actually quite straightforward in the end, and the new capsule was on in no time at all. The wires onto the PCB need to be trimmed as short as possible to reduce capacitance, but be careful here, I cut mine a little too short and had real trouble accessing the joints to reattach them.After a final clean and inspection it was time to reassemble and test.

Initial results were very encouraging, on vocals the mic sounded big, warm and deep, listening to the pre-mod version it sounded thin and harsh, this new mic is very smooth indeed, looking forward to putting it too work in the coming days. I did a quick comparison with a few other mics to get an idea of how it sounds:

I had been lent a Sontronics Aria for a few days to play with, which was perfect timing as it gave me a high quality reference to compare with. Although the Aria ultimately performs better (slightly quieter and smoother), it is over twice the price and the 460 holds it’s own very well.

As a final mod, I decided to remove 2 of the 3 layers in the headbasket, this took a bit of patience and fiddling with a pair of pliers to get them both out, I found using a sharp pointed object to prise up some of the mesh before getting stuck in with the pliers worked best.

So there you have it, if you are thinking about doing this and are reasonably handy with a soldering iron then I would thoroughly recommend it, the mic is quite easy to work with and the upgrade kit is great, well documented and the choice of components really makes a massive difference. I’ll be doing this again I think!

 

 

 

 

 

 

 

 

 

 

 

A location recording case study – The Duval Project

Here’s the first of 2 videos from this superb Bristol-based Nu soul / R&B outfit. Location recorded and mixed by Wij Productions.

This was an intense job, we had a small time window to make use of the venue during the day, 5 hours in all to get in, get setup (audio and video) and capture 2 tunes plus some string section overdubs.

Upon arrival, first thing to do was to assess the space and work out the best location for recording. As this was a simultaneous video shoot, the choice of location would have to be some compromise between the best visuals and sound.  The venue is a long vault, the acoustics could have been awful but there was enough treatment and choice of position to work with. We opted for the wooden floor in front of the stage, with the band arranged in a semi circle. The video guys set up a track to allow them to slide 1 stand mounted camera back and forth into the middle of the semicircle, with another hand held camera for alternative shots. In this kind of setup, there will always be a compromise between the best setup for acoustics and separation, and the best setup for visuals.

The band line up included keys, bass, drums, flugelhorn, 2nd keys, vocal and 3 string players (cello and 2 violins). I used a Universal Audio Apollo Duo and an MOTU 828 mk3 (as an ADAT slave to the Apollo) to capture the full set up, with Universal Audio Solo 610 external preamp to give me another mic channel. The band was mainly electric so I didnt need that many mic channels, just for the flugel horn (with an EV RE20), the drum kit (Audix overheads, RE20 on the kick, Audix D5 on snare, AKG 414 on the high hat) and the voice (Oktavamod Rode NT1a running through the UA 610 preamp). I put a couple of mics on the string trio but we decided to overdub them for the final audio as there was too much spill from the band. Everyone played live through their amps, and a foldback monitor was used for the vocalist. In the end we decided to overdub the vocal as there was a bit too much spill. Part way through the recordings I noticed someone had put the ventilation on, always one of the little things you have to look out for on location recordings in these kinds of places, only becomes apparent when you have a very quiet section (as 1 of the tunes here did).

The band we’re a joy to work with, slick, tight and super well rehearsed, they banged out 5 or 6 takes of each tune just like that, which is exactly what you want when time is tight. Once the video guys were happy that they had enough footage to work with, we quickly set up the mics for a more intimate recording of the strings. Acoustically they sounded absolutely gorgeous, the space served the sound very well. I used 4 mics, two Oktavamod NT1a’s as overheads, another facing the cello from behind and to the right, and a TBone ribbon mic in front of the cello. Some may argue that that is a slightly odd setup, but it gave me good results in the mix, I had been reading about how different acoustic instruments project different frequency ranges in different directions and I wanted to explore this.

Again, the string trio being seasoned pro’s laid down a few alternative takes of their parts and then we were done and dusted, just half an hour over schedule which was fine as it turns out.

The first thing to do when I’m back in the studio is back up the session, you never know! The vocalist came by another day and recorded a couple of perfect takes for each track (I say perfect as they synced up with the original vocal track word for word), then the mix began.

I used mainly Universal Audio plugins on this, the concept was to keep it warm and acoustic. Close micing and direct sound from the electric instruments gave me good control over the overall acoustic, I had to do some careful reverb and subtle edit tricks on the overdub vocal as there was some spill from the original vocal on the drum and trumpet mics, it worked out well though. I used a bit of SPL Transient Designer on the drums to help control the ambiance and shape the individual tones.  I was really pleased with the way the strings came out to, bussed them through the Fairchild compressor plugin to smooth them out and add some of that fabled valve and transformer warmth.

The final mix was mastered by Richie Blake (the bass player in the band) before being sent to the video guy for final integration into the finished product.