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About JFtaper

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    field recording guy

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  1. you might want to try measuring voltage under load. official DPA accessories like d:vice and the DAD6001 phantom>microdot adapter only give ~2.6V when loaded with an MMP-G. running it with a consumer sony handheld that provides 2.4V under load, sound is good, and noise is very very low, around -90 dB down
  2. right.. dynamic range is not the same as max SPL crudely dynamic range would be equal to Max SPL minus self noise
  3. not sure where that 122dB max spl came from, i dont see a max spl listed for MMP-G perhaps that was a typo as 122 dB is the dynamic range spec.... or maybe they used to publish the spec and updated it max SPL would be dependent on capsule but preamp also plays a role. For example a MMC4011 cap clips at 159 dB on an A preamp, 152 dB on a C preamp, and 144 dB on an E preamp. the G is probably closer to the E although it has a lower dynamic range (122 for the G vs 131 for the E). just a guess comparing these that a MMC4011 on an MMP-G would clip in the upper 130s
  4. Larry what is the available current on the dedicated 5V pin? with a 2 mA (1mA x 2 mics) load it dropped to 4V (slightly less than 4V on one channel) also can you clarify which DPA you are talking about? i think you mean 406x but this thread is about the MMP-G thanks
  5. also worth noting that not all packs put out the full 5V the DPA requires. for example servo input on the lectrosonics SPDR can put out 0, 2V or 4V on a 2-wire bias power, which is lower than spec for the 5V DPA microdot-powered mics require (why many people favor 3V 4063s with the lectros). i have tested myself that 4061s had about 6dB less headroom (due to higher noise floor) when powered by servo input at 4V vs 5V the lectrosonics dedicated 5V rail (used for the 3rd wire in a CMR) puts out only 3.95-4.05V under load, at least on the SPDR i tested (they say servo input is identical between all units but the SPDR has 2 channels pulling 1mA each so maybe the voltage sag is greater?). This 4V power is running the CMR at its absolute minimum spec (lowest headroom), but it should be within the spec, im guessing that powering at 4V corresponds to the specified "0.6 normal senstivity of CMC6 amplifier" (4.5 dB confirmed by new cmr specs listed here:https://schoeps.de/en/products/colette/microphone-amplifiers/cmr.html and also this handy mv to dbV calculator here: http://www.sengpielaudio.com/calculator-db-volt.htm . Also looking at that new schoeps link they offer different mV/dbV output based on input impedance of your transmitter, they run 4dB hotter into 20kohm vs 2kohm impedance. For this reason when i used the CMR with lectrosonics i went into the line-in circuit, which has higher impedance. the gain stage inside the pack is probably the same regardless of mic or line in, and with the line in you are getting a hotter signal from the CMR and applying less of a gain stage (even though your gain setting is set physically higher on the unit) so its difficult to compare dpa vs schoeps specs on an apples-to-apples basis because its not measured with *your* particular equipment and its voltage and impedance. We know CMR headroom can be improved by running it at 10V with a separate power supply (simple 9V battery box). I'm not as clear on how much can be gained by stepping up DPAs from 5V to 9V or so. ive read with the 4060 series that they gain nothing over 7V, the new MMP-G series has not been tested in this manner as far as im aware. i am getting some MMP-G next week and will compare them with the other solutions. I have an MMP-E preamp that apparently has the same sensitivity as the A and C preamps (10 mV/Pa, which you'll notice is right between the MK4 on a CMR and CMC6). However, this is *nominal* sensitivity, and dependent on the capsule. I have 2 MMC4011 caps from 2017, one is 8 mV/Pa, the other is over 11 mV/Pa, both are within spec, that is from the factory calibration certificates. so right there is 3 dB different between them in output, despite the certs listing identical noise floors of 19 dBA
  6. fortunately there is no shortage of affordable multitrack recorders these days
  7. sensitivity is 60%, not dynamic range they are 4 dB less sensitive than a CMC-powered cap due to slightly reduced polarization voltage (ive been told 40V, but ive also been told by schoeps that output level varies with input voltage, presuambly this might affect polarization voltage). Ive always run mine from 7-10V just in case.
  8. yes i try not to speak out of turn, ive never used timecode only wordclock in with multiple audio devices.
  9. interesting. i know guys that do multitrack audio with multiple recorders and claim they get audible phasing in short order. a quote from a friend from another board I generally allow +/- 20 ms max error, which would be +/- 960 samples at 48kHz. Some purists will say that they can hear 10ms smear but I don't find it much of a problem for rock & roll. Sony, Tascam, Roland (Edirol)... none of these machines have tightly matched clocks between machines. After an hour, you can hear a "Flam" on almost any two recorders. Use my spreadsheet if you would like to fiddle with some examples. You can download it if you prefer. https://docs.google.com/spreadsheets/d/1pQGfYwPgBFFzcY5m6aRj-Zbu9HsRumLy-tJB1d8Eufg/edit#gid=583050244
  10. i hope firmware would fix some shortcomings, its a well built unit with good sound on the analog in. Support wasnt very useful in regard to unit function, just first level support i had high hopes but ended up returning the one i purchased. I was hoping for a low-pro unit that could power my Schoeps CMRs (and occasionaly DPA 4061s) without an additional box, as well as capture digital signal from my portable Benchmark ADC. It did power the CMRs but barely. the dedicated 5V rail (CMR is a 3-wire mic) dropped to 4V and below (slight difference between channels) with even the minimal 1mA load of the CMRs applied. They are designed to run from 4-10V input, but powering with lower voltages impact headroom on a setup already limited in headroom relative to CMC6. I was willing to drop from the performance of my normal (not much larger than a 9V) battery box that puts out a solid 9-10V with NIMH, to the claimed 5V of the SPDR, but when i saw under 4V under load i wasnt as convinced that it was a good option. My DPA 4061s (2-wire bias power) were noticeably noiser with the 4V servo bias relative to the 5V device i normally use them with. Would require 4063s and i wasnt up for buying new mics as my 4061s are a year old. Both Lectrosonics and DPA are cautionary about running the 5V 4060/4061/4071 with Lectro gear, with a generic answer of 'it works for some people at reduced performance', upon testing it was about a 6dB hit on noise floor (the little DPAs are already somewhat limited in headroom). As i mentioned, i didnt buy it primarily for the 4061s but it would be nice if that worked. Heck if the dedicated 5V pin was actually 5V it could be done from there with a simple circuit inside the TA5F cable adapter housing, but alas, not an option. The fact that it cant write digital data correctly sealed the deal. too many prosumer handhelds out there at 1/3 of the price that can do that, and as for the mics ill just deal with having the extra tiny battery box. I think the timecode is what makes it so expensive, and its something i would never need. Im not exactly sure (please educate me im not an ENG/broadcast guy), but isnt 'Time Code Jam' just a reference marker? Multiple devices would still run off their own clocks once disconnected so im not even sure you could say this has 'real' timecode/word clock. even the best clocks out there will drift apart due to crystal variation as well as thermal factors. maybe not a factor with short take ENG stuff, but i want to record several hours of audio at a time, which requires post-processing to sync multiple sources a summary of my thoughts pros: -rugged -relatively compact -good battery life -easy interface -reasonably foolproof recording -low noise floor on analog input -has decent plug-in-power and 3rd wire mic power (decent say relative to say zaxcom) cons: -three to six times the cost of other handhelds of similar function. Has some unique features but perhaps not enough to justify cost (YMMV if you need TC) -resamples digital input -no way to turn off low cut filter -no way to turn off limiter -non-standard inputs require custom cabling -fair amount of metal for those concerned about that (some would like lighter weight or metal-free for other reasons) -anemic headphone output -doesnt show actual recording time, just displays TC since the device was powered on or TCJammed -difficult to judge what the signal path actually looks like, seems like a lot of unnecessary DSP applied -like most handhelds, mic power voltage is low. cannot power mics requiring 5V to full spec. dedicated 5V rail drops to 4V and below with even a small load.
  11. while using wrong impedance cable can cause jitter and dropouts, it wouldnt cause digital gain and signal processing. some hardware is pickier than others but usually if it locks right away an doesnt drop out it will pass the digital data adequately digital cable isnt typically twisted pair its almost always coaxial (or balanced + shield in the case of AES). in my tests above i hacked up a canare 110 ohm AEScable originally equipped with 3-pin XLRs , as i had to make the requisite 5-pin TA5F termination on the end
  12. Thats because the SPDR is not a bit-accurate device, it resamples all digital inputs (among other digital processing). It does not write raw data like bit-accurate digital recorders I noticed this behavior when feeding it AES from my benchmark ADC, which has very accurate meters with peak hold. With the benchmark peaking at -1 dBFS the SPDR was clipping past FSD so i knew something was wrong right away, upon further investigation (comparing signal from same ADC captured by a known bit-accurate device with that recorded by SPDR), it is distinctly different. The fact that it resamples all inputs should be obvious though because the SPDR will accept any input from 44.1 to 192 kHz and reclock it all to either 48 K or 96K. When matching sample rates from source device it still reclocks and processes. Its obviously more designed as a catch-all backup if you have an AES signal available, but if youre looking to capture accurate data from a dedicated ADC its the wrong tool for the job. There are prosumer larger handhelds like sony and tascam that can do this (the midgrade ones with XLRS and phnatom that start at $400 and up usually offer this). The extra gain and other digital processing involved in the SPDR adds insult to injury nfortuantely I know lecrosonics prides itself on accurate clocks but its a pretty basic feature on every digital recorder out there to slave lock to a source clock feeding the device. Processing AES or S/PDIF to I2S and buffering it to disk is the simplest task in the world so im wondering why they chose to intentionally process all digital input. Perhaps to make it more universal so it would work reliably under all conditions. But dumbing it down like that is a mentality more commonly seen with consumer gear.
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