I've spent the past month studying the service manual schematics for the VX2000 and PD150 to figure out a way to duplicate what the BBC did. I work on electronics in my day job.... find out more about myself here.

I performed this modification on my Sony DCR-TRVX2000. The built in mic still works when camera is set to AGC. When the camera is set to Manual Gain in the menu, the audio now comes from the RCA jacks on the camera sending high level +4 dBu into the AK4550 Analog-Digital converter... skipping the noisy and filtered mic amp chip in the handle, and on the main VC-242 board I bypass the Voltage Controlled Amp M5222FP that introduces even more noise. I have my mic going into a Sound Devices MixPre that feeds into my modified camera's RCA jacks that normally output sound during Camera operation. I can still monitor sound using the headphone jack (yes, the headphone jack has some hiss but is not recorded on tape after the modification is done.)

I have some data to look at the results. Since I do own an audio analyzer, I ran the well known RightMark test using a Audigy 2 soundcard producing analog test signal into my MixPre then into the camera. Before tests were done going into 1/8" Line-In jack. After modification signal goes into RCA jacks on modified VX2000 in camera mode. Both tests were done using manual gain, levels at -6 dBfs (I had to use these hot levels to make RightMark program happy). Then I recorded the test signals and transfered them into my PC by firewire and saved them as wav files. You can listen to these files: Before modification sound using 1/8" Line-In (5.3 Mbyte) and the After modification sound (5.1 MByte). Note the hiss on the quiet part using headphones and it's absence after the modification. Then I use RightMark to analyize the files to produce these reports found here.

Like I say, since I not using a Terrasonde analyzer but you can get a general idea of the difference in sound quality the modification has made. I really like the fact that I do not have any more of that annoying hiss!

       

This is a picture of my new setup. A modified Oktava MC-012 mics is used.

It seems the best way to FIX the audio is to bypass the electronic gain control on the mainboard and get your mic signals (through a mixer) into the RCA jacks. The RCA jacks and cable are about 1.5" long - plugs right into the mainboard right next where it needs to go before going to the digital world. I used my modified camera last night and after listening to the audio captured, I finally feel my audio sounds professional now. For detailed questions about the modifcation can be found here.

I will offer this modification described above for $300 + all shipping costs to Rochester, NY. THIS MOD IS FOR DSR-PD150 and the DSR-PD170 MODEL. It takes me about 4 hours to do the modification and no visible changes are made to your camera. It is more work to do this bypass as there are 2 AGC units. In the Audio menu when set to AUTO - sound will come from built in XLR jacks just like normal (along with all the hiss and poor freq. response). When set to MANUAL - sound will come in from the built in RCA jacks on your camera. You must use a mixer to convert mic level signals into +4 dBu levels, unbalanced. You DO NOT lose the ability to record sound in when set to VTR. The only thing you lose is the ability to play sound out the RCA when set to VTR. You can still play video and hear sound using the headphone jack, just like the BBC mod. Call or email me to discuss if you are interested. Turn around time depends on my workload, but I won't have you ship it unless I can turn it around within a week.

Technical details on why the audio specs are poor on this professional camera:

First - if you look at the signal path - it has to route itself through the handle and many boards to get to the VC-242... the mainboard inside the camera. Using a unshielded flat cables, no less. So there is lots of opportunity to pick up noise. The PD-150 is somewhat better since it uses slightly hotter levels that get padded back down in a newer version of the VC-242, after the gain control VCA (Voltage Controlled Amplifier).

This leads to 2nd reason... the VCA in both VX2000 and the PD150, is a cheap part (M5222FP)that has poor specs. I guess it keeps the sound from sounding as good as their higher end cameras! To control the VCA, they use M623676P A/D convertor that sends a voltage to the VCA's. In the PD150 there are 2 different level controls. Sound is better in AUTO matic AGC mode because it bypass both VCA's! My guess is that part of the problem with digital volume controls like this setup; there is noise in the analog control signal that controls gain and this noise gets into the analog signal - creating that HISS that everyone talks about hearing. I think one of the fixes made to the early PD150 is adding an RC filter on the control signal that brought the noise level down... and the level boost/reduction to control noise. But it the hiss is present on all the PD150 models. The PD170 has a -6 dB improvement before modification by changing the VCA. The remainder of the internal audio circuitry remains unchanged. With both cameras the mod will improve the sound by 20 dB S/N ratio and frequency response is flat from 50 Hz to 20 kHz. You can see test results of this mod performed by Jay Rose on this link.

I am offering this modification described above for $200 + all shipping costs to Rochester, NY. THIS MOD IS FOR THE DCR-VX2000 & DCR-VX21000 MODEL. It takes me about 3 hours to do the modification and no visible changes are made to your camera. In the Audio menu when set to AUTO - sound will come from built in mic just like normal (along with all the hiss and poor freq. response). When set to MANUAL - sound will come in from the built in RCA jacks on your camera (see specs on webpage). You must use a mixer to convert mic level signals into +4 dBu levels, unbalanced. You DO NOT lose the ability to record sound in when set to VTR. The RCA jacks will function as inputs only, however, you can still play video and hear sound using the headphone jack, just like the BBC mod. Call or email me to discuss if you are interested. Turn around time depends on my workload, but I won't have you ship it unless I can turn it around within a week.

Technical details on why audio is so poor quality on VX2000: (Only 6 dB S/N improvement in stock VX2100)

First - the siganls form both the 1/8" jack and the built in electret mic goes into this MA-386 board with a custom chip that adds all sorts of controls we don't need. Along with the features are noise and roll-off. Then if you look at the signal path that the camera mic OR line-in (1/8" jack) goes through to get to the VC-242... it goes to all over the place! Using a unshielded flat cable, no less. So there is lots of opportunity to pick up noise.

This leads to 2nd reason... the VCA in the TRV-900, VX2000 and the PD150, is a cheap part (M5222FP)that has poor specs. To control the VCA, they use M623676P A/D convertor that sends a voltage to the VCA's. In the VX2000, there is only one VCA used. My guess is that part of the problem with digital volume controls like this setup; there is noise in the analog control signal that controls gain and this noise gets into the analog signal - creating that HISS that everyone talks about hearing.

I take the signal from RCA jacks and cable that are about 1.5" long; plugs right into the mainboard and route L&R to IC1001 where it needs to go before going to the digital world. This is done by IC1002, the AK4550, which is not a bad A/D and D/A chip. It has decent specs to give you the best possible sound you can get with 16-bits.

The VX2100 is the same design internally in terms of sound circuitry except that Sony changed the M5222FP to a new part made by Maxim-ic that acts as a digital pot. This does improve the S/N ratio by 6 dB in manual gain mode. All other specs remain as a stock VX2000 due to identical components used and layout issues. You may listen to sound files and read a review of the mod by Bryan Beasleigh is here.

A gentleman recently requested that I perform a sound modification on his TRV-900. After studying the schematics of the VI-151 board I figured out a way to do the same mod to this camera as I have been doing to the VX2000/VX2100 and PD150/PD170.

Overall I am pleased with the results. The noise goes down 13 dB and dynamic range goes up 13 dB. The frequency response is ruler flat - even more so than the mod'ed VX2k.

Due to the compactness of the TRV-900 design, I have to take the whole camera apart to get to the VI-151 mainboard (with the exception of the CCD array and optics) so I am offering this modification described above for $300 + all shipping costs to Rochester, NY. THIS MOD IS FOR THE DCR-TRV900. You can find the measurements on this mod here.

Greg is a member of the International Laser Displays Association and is the designated Laser Safety Officer for the laser light and sound show at High Falls Park, Rochester, NY.

This website is a part-time venture putting his creative talents to work for you at a fair price.