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Gear / Technical Help => Battery Boxes, Preamps, Mixers, ADCs, and Processors => Topic started by: gorlando on October 18, 2012, 12:42:57 PM
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After a few years I was happily using my Microtrack 2496, I was bitten by the "change bug" (also due to the enthusiastic posts here on Taperssection...) and bought a Sony PCM-M10. At first I connected my DPA's 4060 via Plug-In Power (as I was doing with the MT) but soon realized the voltage was not enough.
I have then revived the battery box I built long ago (with two 6.15 KOhm resistors and no capacitors) and changed the connections to the recorder. I like stable connections, having a mini-jack free to rotate in its plug does not seem ok to me, so with some patience I have built the custom connector you can see in the pictures. Now the connection is rock solid!
I have tested my new rig last week and it works very well. So I post this in case others need something similar.
Giovanni
PS: I am very happy of my new gear, the M10 mic-in is really low-noise and the quality in 24/48 is very good (I tape classical music concerts in "stealth" mode), not to talk of the battery life, after years with auxiliary battery packs to support the anemic battery of the MT.
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Nice work. I have been struggling with the best way to deal with the mic plug on the m10 myself. I've been thinking of using a rubber band, but I like your design better! How did you make the plug? Did you mold it yourself?
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Cool. So is the line-in plug a dummy while the mic-in plug works, or visa versa?
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That's so cool :) Well done. I'm always worried by the free rotating plug as well, but wouldn't have thought of that excellent way to solve it. Might try something similar for my Roland!
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My M10's line in mini jack rotates all the time when im positioning the M10 in my bag once the show starts. And [knock on wood], has never been audible YET ;) :)
Nice work tho and happy taping with the M10. I love my 2 M10s :)
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Nice work. I have been struggling with the best way to deal with the mic plug on the m10 myself. I've been thinking of using a rubber band, but I like your design better! How did you make the plug? Did you mold it yourself?
I did mold it myself, it is not too difficult, I used a small piece of fiberglass PCB (printed circuit board), drilling two holes at the right distance, one for the "active" pin (the mic-in), one for the "dummy" one (the line-in). Some patience to file the holes to fit the plugs and to trim the PCB outer edge is then needed.
I have used a straight 3.5mm stereo Neutrik plug for the mic-in and a cheap 3.5mm plug as the dummy one.
The mold cover is from any suitable plastic shape. I used a Gillette shaving blades dispenser.... You can use anything you like, really.
The two plugs have to be installed in the PCB holes and fixed to it with low profile nuts, I used the plastic cover of the cheap 3.5mm plug and sawed two slices out of it, which were used as nuts.
Then I connected the cable to the active plug (and tested it, it is difficult to undo the mold...).
To ensure the plugs geometry is correct, I have actually plugged this assembly in the M10 and then tightened the plastic nuts (not too much, the plastic slices from the cheap connector are not strong - If you have access to proper metal nuts, the result would be stronger, but it is not really necessary, after the mold the assembly is strong enough anyway) before pouring the fused plastic glue.
Please note that the M-10 must be protected to avoid any fused plastic to reach it. I have used a paper sheet with scotch tape to do so.
At this point, using the fusible glue gun, I poured carefully the glue around the connectors and the cable and made a small mound. I then put on top the plastic cover and filled the remaining gaps with the glue gun as much as possible.
Then a bit of patience to wait for the mold to solidify (10 min, half an hour is better, make sure the glue is solid). The connector can now be extracted, the paper protection removed from the M-10 and, voila'... it's done!!!
This is not too difficult, with some patience and DIY skill.
The result is a stable and reassuring connector, which plugs in the M-10 without straining the sockets and ensures a proper connection for hopefully a long time.
Hope this is of help.
Giovanni
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If you could find a way to mass produce that, I bet you could sell quite a few.
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Nice work Giovanni :clapping:
It looks like the spacing is about the same as an airline adapter. If it is exact match maybe modding one of those with a 3 conductor 3.5mm plug for the M10 mic input and replacing the jack on the adapter with a hard wired cable could be workable too. Assuming the spacing is the same and the given airline adapter doesn't have a molded assembly.
(http://ecx.images-amazon.com/images/I/415kdb9hNVL._SL500_AA300_.jpg) (http://www.bose.com/assets/images/shop_online/qc3_airlineadapter_acc/qc3_airlineadapter_acc_bl_lg.jpg)
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Nice work Giovanni :clapping:
It looks like the spacing is about the same as an airline adapter. If it is exact match maybe modding one of those with a 3 conductor 3.5mm plug for the M10 mic input and replacing the jack on the adapter with a hard wired cable could be workable too. Assuming the spacing is the same and the given airline adapter doesn't have a molded assembly.
(http://ecx.images-amazon.com/images/I/415kdb9hNVL._SL500_AA300_.jpg) (http://www.bose.com/assets/images/shop_online/qc3_airlineadapter_acc/qc3_airlineadapter_acc_bl_lg.jpg)
Well spotted DigiGal!! It is exactly the same pitch! I happen to have one which can be opened by a screwdriver and has one of the 2 pins, one of which is stereo. I could have saved some work and modify it. I will keep my adapter, it has a nice Neutrik connector and is done, but this could help other TS readers, it should be easy to get one airline adapter and the rest is simple.
I post some photos of my airline adapter to clarify the idea.
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Awesome thread Giovanni. Thanks for getting it going. I was coming back for ideas on making the dual connector and see the airplane adapter idea which never even occurred to me. Thanks DigiGal.
I've been considering adding a second recorder as a backup and to run two rigs at times for comparison and have been considering stepping up to higher end recorders but this M10 is just such a good option for the money. Little things like this make me that much more confident in it as you get some of the benefit of a locking type connector, ie more security. Feeling like I should stock up on M10's!
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Awesome thread Giovanni. Thanks for getting it going. I was coming back for ideas on making the dual connector and see the airplane adapter idea which never even occurred to me. Thanks DigiGal.
I've been considering adding a second recorder as a backup and to run two rigs at times for comparison and have been considering stepping up to higher end recorders but this M10 is just such a good option for the money. Little things like this make me that much more confident in it as you get some of the benefit of a locking type connector, ie more security. Feeling like I should stock up on M10's!
I ahve owned everything from microcassette recorder>cassette recorder>DAT recorder>Nomad JB3>SD 722>M120, and I like the M10 the BEST! The SD 722 was the nicest piece of gear I ever owned, but its own preamps just werent as good as a preamp>722. So I sold my 722 and bought 2 x M10s and havent looked back. I will probably ALWAYS have an M10 in my recording bag, even after the next big thing comes out. Its ADC>Recorder was essentially just as good/better than the 722s was, so why keep the 722 just to use as an ADC/Recorder ??? Im quite content with my M10, and you know its a good recorder when all of us Schoeps/Phish guys sell their high end recorders and buy M10s ;) ;D 8)
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After a few years I was happily using my Microtrack 2496, I was bitten by the "change bug" (also due to the enthusiastic posts here on Taperssection...) and bought a Sony PCM-M10. At first I connected my DPA's 4060 via Plug-In Power (as I was doing with the MT) but soon realized the voltage was not enough.
I have then revived the battery box I built long ago (with two 6.15 KOhm resistors and no capacitors) and changed the connections to the recorder. I like stable connections, having a mini-jack free to rotate in its plug does not seem ok to me, so with some patience I have built the custom connector you can see in the pictures. Now the connection is rock solid!
I have tested my new rig last week and it works very well. So I post this in case others need something similar.
Giovanni
PS: I am very happy of my new gear, the M10 mic-in is really low-noise and the quality in 24/48 is very good (I tape classical music concerts in "stealth" mode), not to talk of the battery life, after years with auxiliary battery packs to support the anemic battery of the MT.
No capacitors? Not a good idea. You will want caps inside your battery box. I use 10uf. I would install a switch so you can toggle from mic input to line input :) Since you are using both I assume? That would be very cool. You would need to double up on the cable or use Star quad cable to do that. And a DPDT switch. And throw in a few more caps and another DPDT switch to use for a HPF.
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Chris,
I decided not to put capacitors based on the following considerations:
- The M-10 can provide PIP, so there is already a capacitor on the mic preamp input. This capacitor should be good quality, possibly plastic film non-polarized type, so should be able to withstand 9V easily;
- I use 6.15 KOhm resistors in the battery box. With a current of 1 mA absorbed by the mic FET, the voltage drop across this resistor is 6V, so about 3V are applied to the mic and to the preamp input.
Therefore, in operation, only about 3V DC are applied to the mic-in of the preamp, which has anyway a capacitor to prevent DC from entering the preamp. This capacitor (being a good quality film type) should be robust enough to cope also with the full 9V of the battery box in case the BB is connected to the preamp without any mic connected to it.
Is there any flaw in the above way of thinking? I don't like capacitors on the signal lines, if I can avoid them.
Moreover, I want to keep things simple, so no switches or double cables. I only enter mic-in in the M-10. If I want to enter Line-in, I will do another battery box....
I have taped a couple of concerts already with this BB, without any problem.
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Chris,
I decided not to put capacitors based on the following considerations:
- The M-10 can provide PIP, so there is already a capacitor on the mic preamp input. This capacitor should be good quality, possibly plastic film non-polarized type, so should be able to withstand 9V easily;
- I use 6.15 KOhm resistors in the battery box. With a current of 1 mA absorbed by the mic FET, the voltage drop across this resistor is 6V, so about 3V are applied to the mic and to the preamp input.
Therefore, in operation, only about 3V DC are applied to the mic-in of the preamp, which has anyway a capacitor to prevent DC from entering the preamp. This capacitor (being a good quality film type) should be robust enough to cope also with the full 9V of the battery box in case the BB is connected to the preamp without any mic connected to it.
Is there any flaw in the above way of thinking? I don't like capacitors on the signal lines, if I can avoid them.
Moreover, I want to keep things simple, so no switches or double cables. I only enter mic-in in the M-10. If I want to enter Line-in, I will do another battery box....
I have taped a couple of concerts already with this BB, without any problem.
Yeah the cap on the input has a lower voltage rating then 9v I bet because the plug in power voltage is only 3v :) Second you are feeding the bias supply on the Sony voltage from your battery box!! because there are no caps in the circuit. So yeah I would think there is a possibility you can blow up your Sony :) So I would suggest installing caps.. They are cheap and there for a reason.
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Measuring the voltage at the BB after having connected the 4060, I found 2.79V and 2.53V on the 2 channels.
The BB resistors (metal 1%) measure 6.15 KOhm and 6.19 KOhm.
I guess the voltage difference (coming the power from the same 9V battery) is due to the tolerances of the BB resistors and of the mics FET. The current absorbed by the 2 mics is anyway 1 mA to 1.05 mA, which should be ok.
Anyway, the voltage seen by the M-10 is less than 3V, similar to PIP given by the same M-10.
Being careful to connect the mics to the BB before connecting the BB to the M-10 (which is what I normally do in the connecting sequence of my "stealth" rig, the BB is in a pocket already connected to the mics, then I connect the BB to the M-10 in my jacket...) should be ok, I think.
I'll get low voltage, plastic film 10 micro Farad caps and test them anyway, to see their effect, but with no hurry...
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Measuring the voltage at the BB after having connected the 4060, I found 2.79V and 2.53V on the 2 channels.
The BB resistors (metal 1%) measure 6.15 KOhm and 6.19 KOhm.
I guess the voltage difference (coming the power from the same 9V battery) is due to the tolerances of the BB resistors and of the mics FET. The current absorbed by the 2 mics is anyway 1 mA to 1.05 mA, which should be ok.
Anyway, the voltage seen by the M-10 is less than 3V, similar to PIP given by the same M-10.
Being careful to connect the mics to the BB before connecting the BB to the M-10 (which is what I normally do in the connecting sequence of my "stealth" rig, the BB is in a pocket already connected to the mics, then I connect the BB to the M-10 in my jacket...) should be ok, I think.
I'll get low voltage, plastic film 10 micro Farad caps and test them anyway, to see their effect, but with no hurry...
Put caps in the circuit before you blow up your bias supply or worse on your Sony. There will be little to no effect if you use a 10uf cap. Also use metal film resistors not carbon. 1% Tolerance or .1% Also Use 4.7k or 10k for your DPA mics. Both values work fine. You must use caps for your battery box. You can use a larger value then 10uf if you want. I use tantalum caps they work fine for this application Poly also work well. Look at digikey.
Use surface mount parts if you want to keep it small. That's what I use on my battery boxes.
My battery box uses 10uf Tantalum + 10k or 4.7k resistors. Never had an issue with sound quality or noise.
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Chris,
NO tantalum caps EVER in audio circuits for coupling. Using them in this application means trouble, and I mean TROUBLE. I prefer low ESR high temperature electrolytics for audio, for example Panasonic FC, if I need 10uF or more. For lower values, I prefer WIMA MKS2 metallized Polyester film caps, since they are available up to 10uF in a compact package.
BTW I see no risk in gorlandos application. The voltage difference is low, and the currents can not reach dangerous values (there are also resistors in the Sony mic input for PIP (6k8 in most cases). He also states that he uses 1% metal film resistors.
Greetings,
Rainer
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Chris,
NO tantalum caps EVER in audio circuits for coupling. Using them in this application means trouble, and I mean TROUBLE. I prefer low ESR high temperature electrolytics for audio, for example Panasonic FC, if I need 10uF or more. For lower values, I prefer WIMA MKS2 metallized Polyester film caps, since they are available up to 10uF in a compact package.
BTW I see no risk in gorlandos application. The voltage difference is low, and the currents can not reach dangerous values (there are also resistors in the Sony mic input for PIP (6k8 in most cases). He also states that he uses 1% metal film resistors.
Greetings,
Rainer
strange some of the best mic preamps in the world use tantalum caps as audio coupling caps. you better tell them to stop. Including Neve, Midas,SSL and many signal processors.. Everyone had an opinion. I know what I see when I work on large consoles I see all kinds of caps it depends on the designer. and oh yeah I see them in Large format condenser mics made in Germany :)