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Post by aamicrophones on Nov 16, 2017 2:59:46 GMT -6
The filament in a tube will ramp up naturally. When the voltage is put across a filament it has a high resistance as current starts to flow, the resistance of the "tungsten" filament starts to decrease as it warms up. No current can flow through the tube until the filament heats up the cathode enough for it to emit electrons that can now flow from the negative cathode to the postive plate. The signal grid is like a tap that control how much current flows through the tube. Cheers, Dave aamicrophones.com Yes, I know all that, I spent decades as an amp tech. However you still haven't answered my question. I'm assuming you know who Klaus and David are? Hi John, sorry there was a birthday party starting up around me as I was writing that and I got distracted!!! I also got the facts reversed, the filament resistance starts low and increase as it heats up. The 5654W for example draws 200ma at 6.3v and would have a resistance of 31.5 ohms fully lit but when its cold it measures 5.3 ohms. This still creates a ramp up affect. I know who Klaus and Dave are. I think they are referring to new supplies that have a high current filament supply with a separate low current plate supply. If your U47 supply fails you can't just re-wire it to the new more common low plate current power supplies. 1) Neumann series the filament supply of the U47 with the plate supply and it will draw 4 times more current than the plate current alone. 2) The filter capacitors must also be larger because the total current draw will be much higher than a plate current only supply. For, example our power supply can be set for 105 volts to run a U47 but all the resistors have to be lower in value and the capacitor values increased to supply the extra current required for the filament. Also, I believe Klaus and Dave might be referring to the unregulated power supply dropping its voltage with extreme current draws. Because the filtering in the U47 supply is a network of resistors and capacitors then the voltage drop across these resistors will increase as the current draw from the tube increases. So, as you push the level through the tube the plate supply can drop slightly reducing the output level but I think this effect would be ultra subtle in a single tube circuit with only a 10ma draw? The power supply was designed to deliver 50ma and I don't think varying just the plate supply a few milliamps would not change the supply voltage significantly to be audible? Its also a trade-off, the U47 supply voltage will vary with any variation in the A/C voltage supply from the wall plug. A regulated supply can hold the voltage consistent and is less suseptible to A/C input variations. So, the regulated supply will provide a more consistent sound in studios suceptible to brown-outs. I believe the un-regulated to regulated power supply considerations has less consequence in a low current single plate circuit than other components in the microphone build. For, example to get the low frequency response to match you must use a .5ufd coupling capacitor so there is an early LF roll-off and a slight resonance created by the .5ufd and the inductance of the BV8. Paying strict attention to the response of each capsule is also very important. The capsule needs to measure between 78pf and 83pf according to the schematic. The other consideration is that the back-plate voltage and the rear diaphragm voltage are exactly the same in cardiod. If there is 60v on the rear diaphragm then there should be 60v on the backplate. If the rear diaphragm polarization voltage is lower than the back-plate then the pattern will be wider Cardiod. If the rear diaphragm polarization voltage is higher than the back-plate voltage then the pattern will be a tighter cardiod. The U47 has passive polarization so that the rear diaphragm connection is left hanging in Cardiod and is not energized. In our CM48T tube microphone we combine the Fig8/Cardiod of the U48 and the OMNI/Cardiod of the U47 and keep the passive polarization method of both the U48 and U47. However, I also love the extra feature that our 9 pattern supplies provide just like the WA47 does but its imperative that the rear diaphragm and back-plate are at the same potential for true cardiod. Cheers, Dave
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Post by aamicrophones on Nov 15, 2017 17:07:03 GMT -6
The filament in a tube will ramp up naturally. When the voltage is put across a filament it has a high resistance as current starts to flow, the resistance of the "tungsten" filament starts to decrease as it warms up.
No current can flow through the tube until the filament heats up the cathode enough for it to emit electrons that can now flow from the negative cathode to the postive plate. The signal grid is like a tap that control how much current flows through the tube.
Cheers, Dave aamicrophones.com
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Post by aamicrophones on Nov 15, 2017 16:56:15 GMT -6
That would definitely be a problem with an original U47 but today we have solid state regulation and the power supplies we use have zener regulation on the plate supply and a 6v regulator on the filament. The modern power supplies that we use and Bryce would be using are fully regulated so the filament is up to temperature within a minute and the regulator holds it within + and - 2%. The last U47 I restored took 50 minutes before the filament and plate supply came up to 105V. With regulation you can hot swap the microphones as the supplies voltage don't vary under different loads (mike connected/no mike connected). Cheers, Dave The regulated power supplies will provide more consistentcy between microphones, it is not unusual for a vintage tube supply to vary plus or minus 10%. The U47 schematic calls for 105v but the last U47 I serviced has a voltage up at 117v after warm up and I had increase the resistor values slightly in the supply to bring it down to 105v. This is not a tube guitar amplifier or power amp or even a tube compressor. Its just a single tube which with a maximum current draw of about 3ma. The U47 circuit is unique to itself with the filament supply and tube plate supply sharing the same supply voltage and path to ground. The U47 actually draws around 42ma give or take the tolerances. 40ma is need to supply the filament current. In the Warm 47 it will have a separate 6v dc filament supply like our microphone circuits and the plate supply will be upwards of 125v. The U47 circuit was designed to ramp up extremely slowly to protect the filament. Today we run the 6v filaments from a solid state regulator which is separate from the plate (audio) supply. So, power supply upgrades, swaps and mods could affect the U47 depending on where the voltage sits after the large wire wound resistor in the U47 heats up. How does the modern power supply affect the sound of the mic? If I'm not mistaken, either Klaus or Dave Bock said on another forum that power supply mods, swaps, or upgrades will affect the sound of vintage mics like the Neumann U47s
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Post by aamicrophones on Nov 14, 2017 20:20:10 GMT -6
What were you recording? I've never had that issue with any of their mics. In fact the output isn't even as hot as my U87ai. Bass drum, 1 foot away You would definitely have to PAD a CM47 in front of the kick drum. That's a lot of level. Unfortunately, when you pad preamp at the input side then you reduce some of the transformer sound. This does not happen with transformerless circuit but you need a really good transformerless circuit to handle those kinds of transients. Our MT8016 transformer coupled preamp can handle the CM47 kick level without padding before the transformer. Like the Neve 1073 we pad after the transformer, keeping all the transformer sound but dropping the level so the first stage is not overloaded. Our MT8016 also has two gain stage like the 1073 that are brought up in two tandem 30db stages. The input transformer has 16db of voltage gain. Cheers, Dave aamicrophones.com
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Post by aamicrophones on Nov 14, 2017 20:04:59 GMT -6
This mic isn't about having a 47. Its about looking like you have a 47. I already figured this out a while ago. Hello, you are right!!! Classical recordists love our CM49, CM47ve and CM67se microphones big studios would love to replace their vintage microphones with ours but they keep telling me I need to make them look more like the original but they never have a problem with the sound. When you a scoring a film and have 40 musicians and multiple tube microphones up it only takes one failing vintage microphone to really mess up the budget. Our good friend Joseph Magee tells me it costs $50 a minute when he is recording on a scoring session. If you lose even a 10 minute scene because of a failing microphone it cost you $500 and 10 minutes less time to get a take. Also, Joe Carrell told me at Summer Namm that folks our often underwelmed when they finally get to use a U47. They expect it somehow to deliver a finished vocal, processing and all? The reason that its impossible to "clone" exactly a U47 is that no two U47's sound the same. The might have back in 1958 if they were selected at purchase but you are dealing with old school electronics. There were two different types of capsules and the K47 went through at least 3 different versions. There was also at least 3 different types of BV8 transformer versions used over the years. There was also a later version of U47's that used a 6CW4 Nuvistor tube. Even though folks tell me the don't sound the same I heard one on Harry Connick jr that sounded pretty amazing. Resistors that have at best 10% tolerances where today we use 1% resistors. Capacitors had 20% tolerances while today the we use 1% polystyrene capacitors between the capsule and tube. U47 Power supplies can easily vary plus or minus 10% from each other. Capsules could only be made within plus or minus 2db of each other if you were lucky. M7 capsules start to age the moment the PVC is poured and the PVC gets more brittle over time increasing the highs and tightening the low frequencies. The advantage of the WA47 is that it will be reliable, all WA47 microphones will be more consistent in sound from each other than the vintage U47's. The microphone will be quieter and have a few db more headroom plus the tube is much less costly when it needs to be replaced. The 7 pin gold pinned Neutriks connectors is much better in my experience than the older Tuchel. I couldn't build a Long Body U47, with a 5654W traditional circuit, large frame BV8 (T47) transformer and our AK47, put the microphone in the wooden box with HD shock-mount and vintage supply and sell it for $899 and I have very low overhead. So I have to tip my hat to Bryce bringing a microphone with these features to market at this price point. Cheers, Dave Thomas aamicrophones.com
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Post by aamicrophones on Nov 14, 2017 19:25:23 GMT -6
It will be a popular product is my guess. Capsule looks like its is from 3u audio. It will be interesting to find out how they have implemented the 5751 which is a lower gain 12AX7. The AMI transformer looks like a custom job for warm audio. Hi Guys, that would be my guess that the capsule is sourced through 3U audio. As, a design engineer the only way to use the 5751 successfully would be to use it in the CCDA platform which is my favourite microphone circuit but its more "HiFi" than the original U47 circuit. The 5751 has a plate resistance of 58,000 ohms even if you parallel them like the STAM circuit you only have 29,000 ohms while configuring the 5751 as a CCDA circuit will yield an output impedance which will be closer to 600 ohms. The VF14m was a single pentode wired as a triode and had a resultant plate resistance of around 5000 ohms which is similar to our CM48T circuit using the GE/JAN5654W. However, the 5751 configured as a CCDA will nicely drive the T47 transformer and it will subtley have a better transient response than the U47 circuit and a smoother low end response. The CCDA circuit will deliver nearly 4db more headroom than the U47 circuit. When the T47 or BV08 is driven from 5000 ohms then there tends to be a bit more harmonics generated in the lower midrange to upper bass frequencies. The K47 in the original U47's a M49's had a brass surround and not the nylon. I have a sample of what looks like a 3U 6 micron skinned capsule here and it seems to have about 2db more lift in the high end and a little less low end than our AK47 in tests I did here. It did not sound bad and was quite pleasant sounding but was just a bit brighter than our AK47. Cheers, Dave aamicrophones.com
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Post by aamicrophones on Nov 14, 2017 19:06:48 GMT -6
Notice how he turned on psu without the mike attached and hot swapped it: doubt the cap likes that ? Also, wouldn’t you want to let the tube warm up and blow off some electrons to have a better sense of what the mike really sounds like ? That would definitely be a problem with an original U47 but today we have solid state regulation and the power supplies we use have zener regulation on the plate supply and a 6v regulator on the filament. The modern power supplies that we use and Bryce would be using are fully regulated so the filament is up to temperature within a minute and the regulator holds it within + and - 2%. The last U47 I restored took 50 minutes before the filament and plate supply came up to 105V. With regulation you can hot swap the microphones as the supplies voltage don't vary under different loads (mike connected/no mike connected). Cheers, Dave
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Post by aamicrophones on Nov 14, 2017 18:46:07 GMT -6
The WA-47 FET Jr. looks exactly like Advanced Audio's CM48. I'm curious about o hear how these sound. I haven't thought the clips of the WA-87 sounded like a real U87, but for a lot of people these will be great options for beginner mics. Hi Vincent, the CM48 has a class "A" transformer coupled discrete circuit like the original u47fet microphone with our AK47 capsule, which is true to the original K47 pictured on the left from a 1958 U47. The WA-47jr has a "K47" type capsule with 6 micron skinned diaphragms but it has a transformerless circuit. The original K47 capsules has a brass surround not the later nylon surrounds. However, the body is exactly the same as our CM48 fet microphone which is $100 more than the WA47jr or $50 more for Real Gear On-Line members. Cheers, Dave
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Post by aamicrophones on Nov 14, 2017 18:43:33 GMT -6
The WA-47 FET Jr. looks exactly like Advanced Audio's CM48. I'm curious about o hear how these sound. I haven't thought the clips of the WA-87 sounded like a real U87, but for a lot of people these will be great options for beginner mics. Hi Vincent, the CM48 has a class "A" transformer coupled discrete circuit like the original u47fet microphone with our AK47 capsule, which is true to the original K47 pictured on the left from a 1958 U47. The WA-47jr has a "K47" type capsule with 6 micron skinned diaphragms but it has a transformerless circuit. The original K47 capsules has a brass surround not the later nylon surrounds. However, the body is exactly the same as our CM48 fet microphone which is $100 more than the WA47jr or $50 more for Real Gear On-Line members. Cheers, Dave Attachments:
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Post by aamicrophones on Nov 1, 2017 16:44:57 GMT -6
I have finally used my CM47 on kick drum, one feet away, dead center. Instant "finished" sound! I'm even willing to live with the (great sounding) leakage. It sounds like an actual kick drum, instead of my usual "sounds like a mic stuck in the hole of a kick drum". Did you use the CM47 or our CM47FET? The FET can handle more level but the CM47 tube microphone can also handle a lot of level without a PAD. I really like our CM47fet in front of the kick and in front of the bass amp. Here is a live in the studio shot of a very famous vocalist singing into our CM47ve in Nashville a few weeks ago. I have been listening to John's voice since the early 70's. I was stoked to get this picture sent to me by my good friend Joe Carrell. I have a sample body and T49 transformer arriving next week so I will be able to build up the CM49LE prototype. I have the circuit boards and tubes on hand. I hope to have the circuit and body logistics worked out before I head for Mexico on December 9th and then its 8-10 weeks before we have bodies finished with circuit boards and transformer mounted. So, we are looking at an early Spring soft release of the CM49LE and then release it for review for Summer Namm 2018. Our goal is to sell it for around $1495 depending on our final cost. Cheers, Dave
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Post by aamicrophones on Sept 26, 2017 14:16:38 GMT -6
Hi Guys, really proud of the way the CM49 stands up. With Vincent's amazing vocals it sound like a Class Act. Just turned 70 last week and it was a great birthday present to get this file from Vincent. I have a new CM49LE on the drawing board and we are just pricing it out. We have found a larger body the same size as the M49 and we can fit a larger frame BV11 transformer with the exact same windings and inductance as the original in the M49. We believe this will give us a little more "warmth" in the low midrange. We will use the same circuit as our CM48T with the GE/JAN 5654w configured as a triode with cathode bias like the M49C. However, the circuit will have the remote 9 pattern switching option. I just ordered a large frame BV11 transformer that we can try with the circuit. So, its still just on the drawing board at the moment but we have two major studios that are very interested in the build. Thanks for all your support which gives me the inspiration to carry on. Cheers, Dave
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Post by aamicrophones on Sept 12, 2017 18:08:58 GMT -6
Sept 12, 2017 5:08:31 GMT -7 kcatthedog said: ok no offense, in this comment butam I missing something, for example, the radar 24 is quite an old design, including the conversion, is it really better than say the new apogee symphony or are we just splitting sonic hairs and actually talking about workflow preference ? I to sure what happened with this post I wrote. The first time I posted it only the picture attachments appeared??? So, I had to edit and re-type my observations of RADAR. I have been using RADAR Systems since 1995. The RADAR Classic converters no matter how old will have better resolution than most modern converters unless you are running yours from a Big Ben or other high resolution clocking system. The RADAR NYQUIST converters which sample at 192/24bit are in a league of their own. Barry and the guys are RADAR spent a lot of time designing the analogue front end & output stage of the converters. The analogue sections run on + & -18 volts while most converters runs on + &- 15 volts. So, right out of the gate the input to the RADAR converters can handle 2db more level before clipping and can output 2db more before clipping. The RADAR has a internal clock with very, very low jitter. In my experience the RADAR running at 48khz/24 bit sounds every bit as good as other converters running at 96khz 24/bit. Someone twisted my arm a few weeks ago to come in the studio and cut a vocal on one of our microphones. They brought in their LOGIC system with a Focusrite converter. It took them 20 minutes to get analogue audio out of the Focusrite and then another 15 minutes for it to accept the analogue output from the Radar. The producer kept blaming my analogue set-up, yet we could hear the microphone and vocalist and see the level on the RADAR. I patch the output of my microphone preamps whether our MT8016, LA610, 1073 Clone or Sony MXP3036 preamps directly into the analogue line inputs of the RADAR converters. The output of the RADAR converters come back up on Channels 1-24 on the Sony MXP3036 console. When any track on the RADAR is selected for Record and Input is also selected the audio runs through the RADAR converters with no latency. Like the old tape machines the analogue input is switched to the analogue outputs via a relay. Once we got the Logic/Focurite to send and receive analogue audio then I noticed that the clip light was coming on the Focusrite but the RADAR still seemed to have lots of headroom. The audio quality through the RADAR was definitely fuller, punchier and cleaner sounding than the Logic/Focusrite audio. I have two RADAR units in the Advanced Audio (Two Cats by the Lake) Studios. One is a Classic 24 that I bought used over 6 years ago for $5K CAD with controller. I sent it down to Barry at IZ Technologies about 4 year ago and had a new motherboard fitted that supports USB back-up plus I had a removeable solid state drive installed. This unit also has Tascam I/O's. The folks at IZ ran a frequency response on the converter and replace two faulty caps that were cause the low end to roll out early. I have seen RADAR 24 Classic units sell for as low as $2500 CAD with controller. That's pretty amazing for 24 channels of high end conversion. I bought a 2nd one 3 years ago for $3K CAD and sent it down to Barry at IZ and they upgraded it to the RADAR STUDIO with solid state drive for $4K CAD. So, I have 48 converters that go 96khz between the two RADAR units. The 2nd RADAR Studio also has 24 light pipe I/O's Now, the older RADAR 24 will only run with the RADAR operating system and only allows you to record 24 tracks for every project. However, for example if you want to re-do the drum tracks and keep everything else you can hit the COPY project button and everything is instantly copied over to a new project and then you just put the drum tracks into record and have the drummer play along. With the new RADAR STUDIO even operating in RADAR mode, you can have 8 takes for every track without having to create a new project. Radar does all these operations from a single keystroke on the controller. Now, the RADAR STUDIO can be booted up in PC mode and run any DAW software and the advantage is you can now access plug-ins and mix in the box. In the RADAR STUDIO mode you can mix in the box with your favourite DAW software, fix pitch and auto-time tracks. You don't need to bring the 24 analogue outputs up through an analogue mixer. Now, I started recording professionally in 1971 to tape and I have used analogue mixers all my life and it feels foreign to me to mix in the box, although I have done it on the rare occasion. With RADAR Studio you have the best of both worlds. There is something about cutting tracks on the RADAR that is very organic, very fast and very user friendly. The older Radar 24 does have a noiser power supply fan and the older hard drives were noisy. However, my RADAR 24 is in a storage room behind the control room and I just have the controller and monitor in the control room. The only time I have to access the main frame is to plug in the back-up drive. The Radar Studio is lighter and quieter. I take the RADAR Studio out for live recordings and I have run it in the control room and the noise is not bothersome. The Radar Studio backed-up a 2 hour/12 track recording to a USB drive in less than 3 minutes via the USB port. The older Radar Classic 24 only had VGA monitoring but the RADAR STUDIO will support DVI, VGA and HDMI. There are good reasons why folks like Daniel Lanois are using the RADAR system. I still like to mix via the console with real faders but I now have the option to use plug-ins like the lovely EMI reverb plate in the mix. However, I can take the RADAR studio to a remote location, record in RADAR MODE. Then boot the RADAR up in DAW mode and do a quick mix in the box right there at the live venue. The RADAR is an incredibly rugged system. I can only remember having to re-boot it during a session on one or two occasions and these were both sessions were the hard drive was nearly full. I have had to re-boot it on a couple of other occasions over its 6 years in the studio just when I was backing up tracks and it couldn't recognize the back-up Hard Drive. The Radar Studio seems to have no problem recognizing the USB hard drive and it was the older unit that has a problem on occasion. Cheers, Dave Thomas aamicrophones.com Attachments:
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Post by aamicrophones on Sept 11, 2017 20:14:19 GMT -6
Dave, Congrats on the nominations! I'm rooting for you! Thanks, everyone!!! Still waiting for Joe to give us some clips from Oceanway but he's incredibly busy and we feel privileged to call him our friend. Our other good Nashville friend Joe Carrell has been using our CM12se and CM28 combination on session guitar players in Nashville and getting an amazing sound. Here is a picture of John Oates singing into our CM47 at Joes Studio last Friday...we are stoked!!! This was a real recording session not a photo-op shot. John was so gracious to let Joe take this picture. Abandoned Lunchonette was one of my favourite albums from the early 70 and Bernard Purdie played drums on it. He can't say yet what they were recording the vocals for.
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Post by aamicrophones on Aug 18, 2017 14:49:17 GMT -6
Hi Guys, our good friend Joseph Magee has been scoring at Oceanway in Nashville. He has been shooting out some our microphones against the classics there. He just sent this picture today and we will post results, clips and we hope video once he is finished as he is working around his scoring schedule. It also looks like our CM48T tube microphones has been nominated for a NAMM Tech Award as well as our MT8016 preamp. Megatrax studios in LA just bought our CM49, CM12se, CM47ve and CM47fet for film scoring. Here our CM47ve among two classics at Oceanway in Nashville.
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Post by aamicrophones on Aug 5, 2017 10:12:54 GMT -6
Hello, the TLM107 and TLM170 both have edge fed capsules and a transformerless IC output stage. The Neumann edge fed capsule has a 4db rise up past 10khz but no rise in the midrange in Cardiod. According to the Neumann curve they even dip a little in the presence area. While and original U47 or a microphone with a traditional K47 capsule like our CM48fet or CM48T have 2-3db lift in the presence range. This is what our ears often hear as the "47" sound. Here is Kyle Cook from Matchbox 20 on the CM48T.. The CM48T is a true tube microphone with our AK47 capsule and BV8 output transformer. It sells for $595 but RGO members get a 10% discount using the code "RGO" on the payment page. www.facebook.com/fluidrev/videos/1636600256382625/
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Post by aamicrophones on Aug 4, 2017 15:12:06 GMT -6
Hi Guys, I have had the privilege of working with a couple of Masters. One being the late Bill Porter. What I learned from Bill can be paraphrased as follows, " There is not a microphone, FX device or piece of gear that makes the difference between a song being a hit or not".
Here is a quote from Tom Dowd,
"The most important thing is that you must have a good song. You must have a good song. You have got to have a song that is so good that if the kid delivering coffee walked through the door, he could sing the song and you would have a hit. That’s how strong the song has to be. It’s as simple as that. Now if you have a song that is that strong you are half way home. That comes from the monetary, from the recording point of view that if you have a hit song that is all you need. A hit song and get out of my way, I am home free. You have to have your hand on the pulse of the audience. You must know what they like, what they are sensitive to, and what they are ready for. Unfortunately in the last ten years we have gone through such wacky permutations in the industry. This is a time where TV is selling records based on what people see rather than what they hear."
The Tom Dowd documentary, "The Language of Love" is a much watch for any recording engineer. You can watch him mix parts of Layla and how much of a musician he really is. He sits down at the piano and plays the bridge of Layla which was played originally by Jim Gordon the drummer.
One of my favourite mixers is Elliot Scheiner and he mixed Walter Beckers Circus Money which is one of the reference CD's I used for judging monitors. It is a sonlcally honest, transparent and ulta HiFi mix. Elliot is also one of the masters.
I had the privilege of speaking briefly with Al Schmitt when the MIX WITH THE MASTER booth was across from ours at an LA AES show. We talked about him working with my late friend and Midi developer Ralph Dyck who programmed all the sequencing on Toto's Africa plus his work with Diana Krall who I got to record for a radio show in the early 80's. The Mix Master folks pulled him away once they discovered I was probably not interested in spending $20K to go to France and participate in Mix with the Masters.
Rather than pay to participate in Mix with the Masters I would be more likely to hire Elliot, Al or Jaquire to mix a song that I cut tracks for. It would be interesting to take your best song and hire one of these guys to mix it and hang out watching the process.
I think that would be a better learning experience than paying $20K plus flights to the south of France.
i was talking with our good friend Joe Carrell at the NAMM show and just remembered this conversation. Joe has an original U47 at his facility in Nashville and he is often surprised how underwhelmed folks are when they hear their vocals through the microphone.
They somehow expect it to produce a finished HIT vocal sound. Its job is basically to capture a musical performance as musically as possible. I think working on the songwriting, arranging and getting a great sound in tracking is much more important than buying the latest plug-in or trying to fix in the mix.
Cheers, Dave
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Post by aamicrophones on Aug 2, 2017 19:01:39 GMT -6
Hey Dave, long its been a long time since we chatted. Question for ya, with the emitter circuit you are talking about is the capacitor in the audio path? I am assuming it must be some sort of coupling cap? BTW, I am mixing a record next for a client that was tracked with all of your mics plus a SM7. I listened to the tracks already and they sound really good. They used one of your 87 style mics on the vocals and they sound really great. Hi Dan, just found this post. I probably missed it as we were at my grandson's graduation from his avionics course in the Canadian Airforce and assignment to the 424 Search and Rescue squadron. When we returned we were busy on finishing up our CM800T prototype and getting organized for the Summer Namm show. We had a great show and was busy on our return filling orders. Here is the KM84 schematic with the high gain 2N3819. So, there are 4 capacitors in the audio chain. C3 is used to trim the gain of the fet by about 4db. if it is removed there is 4db less headroom. C1 couples the capsules voltage change into the fet so it can be amplified. The 4.7ufd across the 3.9k resistor will also change the gain and LF response. I have repaired several Neumann's with failed 4.7ufd tantalum capacitors but the ESR of a tantalum is twice as good as a electrolytic. C2 couples the audio output of the fet into the 7:1 ratio output transformer and blocks dc from magnetizing the transformer. C4 is also a tantalum and can also fail in older KM84 microphones. With the original C414/C451 emitter follower circuit there is a capacitor between the FET and the output transistor and we use three switchable capacitors to give us a variable HP filter. Notice no small feedback capacitor is required to trim the gain as we have 12db less gain in the first stage from the medium gain 2SK170. We also bypass the R9 with a 22 ufd to ground which optimizes the gain and LF response. The output transformer is coupled from the emitter of the transistor through C4 to the output transformer which has a 2:1 ratio. The CM1084 has one more coupling capacitor in the audio chain but does not need the 4pf negative feedback gain trim capacitor. I am not sure how you could implement the output circuit without a capacitor driving the transformer. If you let DC get to the transformer you will magnetize it in one direction. The only circuit I have seen without a coupling capacitor is the Schoep transformerless circuit. I suppose a Shoep circuit might drive a 1:1 ratio transformer and give you better common mode rejection. Cheers, Dave
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Post by aamicrophones on Aug 2, 2017 17:46:38 GMT -6
Those head grilles got me intrigued. Will they work for the CM54's? I have a pair of those. Hello, sorry for the delayed response. We have been busy since returning from NAMM filling orders and getting our CM800T into production. We will have the bodies in 4-6 weeks. The new pencil microphone vocal head grills and our cardiod headgrill with the KM84 type screening will fit the CM54. The shipment is scheduled to arrive in Vancouver tomorrow so we should have the vocal headgrill in hand by late next week along with more CM48T bodies and more of our CM87 microphones. The CM54 has a really good Schoep transformerless circuut but with the CM1084, I was able to design a KM84 front end with a emitter follower output stage and a lower ratio output transformer giving us 14db more headroom than the KM84. I like to be able to use the CM1084 on the snare and Hi Hat. We also use the same capsule in our CM28 tube pencil microphone. Here is a picture of our CM12se and CM28 tube microphones on session player Dave Cleveland at a recent recording session at Sony's Tree Studios in Nashville. Cheers, Dave ms. Attachment Deleted
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Post by aamicrophones on Jul 20, 2017 15:58:29 GMT -6
Very cool stuff, Dave! Yeah, I didn't make it back to the booth as I was a little geeked out myself. lol. Hope to meet up with you soon, again! We got to spend some time at Ocean Way with our good friend, client and film music mixer Joseph Magee. How do big studios stay in business...by being smart!!! Ocean Way was built by Allan Sides and Gary Belz and sold to Belmont University in 2001. Allan and Gary probably realized that sustaining a large State of the Art Studio was becoming arduous as good sounding home studios become more prevelant and record budgets fell. Belmont still runs Ocean Way as a fully professional and fully maintained facility but its a tax write-off because Belmont students can apprentice there. So, Ocean Way does not need to make a profit to survive and keep all the gear in tip top shape. The maintenance staff is shared between the University next door and the studio complex. The best of the students get to intern at Ocean Way and Ocean Way always has good candidates to choose from for assistant engineering positions. Joseph was thrilled with his assistant who he nicknamed "Mr Diddles" because of his ability to program a computer and run Pro Tool at a blazing pace. Joseph really likes the big room at Ocean Way for tracking Orchestral ensembles. We hope to get our CM800T up against the Sony C800G then next time Joseph returns. Joseph is in Vancouver this week dubbing the music mixes to film for Lions Gate Pictures. However, he now lives in Nashville and cannot say enough about the level of musicianship that he got from the session players at Ocean Way for the film score. Cheers, Dave
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Post by aamicrophones on Jul 17, 2017 14:51:55 GMT -6
Got to hear the AA mics and was struck by the $350 47CE (I believe that's right.) Really thought it held up well with me screeching like a three footed hyena in it...I can usually make capsules pinch, but this held up like a champ. Not bright at all...I liked. Thought his 67 sounded good and was surprised that the 251 wasn't very bright. That one sounded really nice. Didn't get to sing into the Roswell mics, but they had a video set up with headphones...band was only using the Roswell mics - and it sounded really great. I'm interested in that Delphos. Matt said the top was purposely rolled off...which I like. Hi John, thanks for dropping by. Sorry, we did not get to talk for very long. I wanted to take you for a drink and thank you for keeping RGO "real". The CM47fet/CE has a class "A" circuit like the original 414eb plus our very accurate AK47(K47) reproduction. So, it has 14db more headroom than a U87 circuit. That's why it can handle the "Screech". It also has a U87 type de-emphasis circuit which will pull back any excessive HF "peaks". We tried to make it over to the tracking room but it was songwriter night at the Broken Spoke and I promised some clients we would drop by. Several performers got up and played plus a band. Everyone were such good guitar players singers and writers. You pay $100 easy a couple to go see one performer that good where I live and all I had to do was buy our team drinks at the Broken Spoke. Also, by Saturday I was pretty well "geeked out" from talking tech for three full days and just wanted a drink, relax and to listen to some music. WE LOVED NASHVILLE. The highlight for me was when Bernard Purdie the famous studio drummer came by with his studio builder to talk about microphones. The Purdie Shuffle video on the making of AJA by Steely Dan is very famous. What a lovely guy as was everyone that came by to see us. Everyone in Nashville were so gracious and made us feel at home. Chuck Ainlay was leading a seminar about recording female vocals and mentioned our CM67se as one of his favourite vocal microphones. He came by to give us his take on the original Neumann tube microphones as he is explaining in this picture, " I am done with the old Neumann's...they will sound good but often after an hour into the session they can start crackling or failing in some way" Joseph Magee who is scoring a movie at Ocean Way also took four of our tube microphones back there after the end of the show. He said, they have lovely microphones at Ocean Way that are well maintained but they are getting long in the tooth and he told me with 40 players it costing $50 a minute and if just one microphone starts failing it can cost a lot of money. Joseph just moved to Nashville from LA and he can not believe how great the players are in Nashville and how willing they are to give him exactly what he wants for the musical score. Film mixer Joseph Magee and the AA gang Me and Bernard Chuck Ainlay and the AA gang Thanks to Strat Boy and John plus others from RGO who dropped by to check out our creations. It was a very positive show for us great vibes and it is so great to talk to folks who use our microphones and are also part of the AA family. Cheers, Dave
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Post by aamicrophones on Jul 8, 2017 14:25:53 GMT -6
I think that's really smart.
I think that's how a lot of original recording were done in the 60's and 70's and as consoles, EQ's and processing gear became more sophisticated the mixing process became more compicated and time consuming.
There is a story I heard about Bob Clearmountain mixing a Mick Jagger solo project. He typically would solo all the tracks and EQ each one to sound good but his typical mixing method didn't seem to be be working with these tracks that came from Mick.
So, Bob calls up Steve Lillywhite who had previously recorded and mixed some Stones records. Bob asked Steve if he has any ideas on working with the tracks that Bob had been sent to mix.
Steve tells him, take all the EQ out, set all the faders at O and then just pan the tracks appropriately and hit play. WHAMO, Bob say's it sounds like the Rolling Stones. The Jagger tracks has lots of leakage and sounds that already had effects and the levels were mix ready.
I find if you think a track needs a bit of EQ then EQ in the Mix not in solo.
I worked with an artist and producer back in the 80's who had some huge hit records. He would set up the mix as he went along and would not record a new track until he had a mix balance of the previously recorded tracks.
He had me write all the settings down so we could duplicate the mix balance everytime he came back in to overdub.
One of my favourite songs is "She's Not There" by the Zombies recorded about 1964 to 4-track at Decca records in the UK.
Here's some history about that recording, " Having formed in St Albans in 1962, the Zombies were signed to Decca Records in ’64 and immediately struck gold with their first single, the haunting R&B of ‘She’s Not There’, when it hit number 12 in the UK and, more impressively, number one in the States. Recorded at Decca’s studio in West Hampstead, north London, it was produced by Ken Jones and was quite a progressive recording for the time, particularly with Hugh Grundy’s overdubbing of a second drum part live as the track was being mixed down to its mono master.
In fact, as a result, hearing subsequent stereo mixes of ‘She’s Not There’ on the radio these days tends to infuriate Rod Argent. “Almost every time you hear it, it’s not the original record,” he says. “As it went down to the one-track in mono in 1964, we put on a separate drum part. Now of course that only ever exists on the mix, so when people try and mix it in stereo, there’s a bit missing from the original single that was a hit. I know at least one of the stereo mixes that’s often used was just done by a novice trainee and it doesn’t have the drum part on it. That drives me crazy but there’s nothing I can do about it.”
So, in an attempt to make a stereo mix of the song the original artist's vision was violated. So, I think its important to focus of the artist's vision for the song and not so much on new technology available.
Cheers, Dave
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Post by aamicrophones on Jul 8, 2017 12:14:24 GMT -6
Hi Guys, been busy getting ready for Namm and ended up getting 4 gigs this week playing percussion. When it rains it pours!!!
We arrive on Tuesday July 11th in Nashville and leave July 16th. Our booth is #331 and we will be showing our new CM800T (Sony 800G) offering which will sell for $795.
We will also have 4 of our MT8016 preamps running and we will also be showing our new vocal head grill for our CM1084 pencil microphone.
Hope to see some of you in Nashville at our booth or at some of the Nashville events.
Cheers, Dave
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Post by aamicrophones on Jul 8, 2017 12:05:15 GMT -6
We are at booth #331 at Summer Namm. We are just a few booths away from Matt at Roswell Pro Audio. Love to get together with RGO members for a drink.
Cheers, Dave
Advanced Audio Microphones
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Post by aamicrophones on Jun 23, 2017 13:37:01 GMT -6
Hi Vincent, the proximity effect increases as you move from Cardiod thru super-cardiod 1 and super cardiod 2.
The midrange 3-5khz area tend to rise very slightly as you go thru the Cardiod to Fig 8 settings and the HF response will come down slightly. We are talking a <2db difference max between Card and FIG 8 but its noticeable.
However, the proximity effect is more prominent in my experience than slight change in midrange and HF response. I have the curves for our CM251 in all 9 patterns but not the CM49 at this time.
Been busy, just finished organizing all our products going down to Nashville for Summer Namm. We will have a bit of AA swag to give away at the booth which is #331.
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Post by aamicrophones on Jun 23, 2017 0:20:41 GMT -6
Old or new RADAR with a digital card! I have two RADAR's one is a Classic and has 24 analogue I/O's and 24 digital Tascam I/O's. The 2nd Radar I had upgraded to a Radar Studio and it will run any PC based DAW software. It has 24 analogue I/O's and 24 light pipe digital I/O's.
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