Does have anybody schematic af BBC fix?
I like to evaluate actual modification and cause of hiss problem.

Do a search on the Audio forum at DV.com. There you will find answers to all your "BBC fix" questions. The BBC VX2000 audio fix was a hot topic for a long time. Also you can contact the BBC. Again, check that forum for contacts. The only contact I know of is:

www.global-dvc.org

and I've posted this a few times here at dvinfo.

What Hiss problem? vx 2k user.

They basically change the RCA out on the VX2K and make it into a RCA in. This reduces the noise because RCA is line Level. Then they use the Glensound XLR preamp to power the mic, this basically bypasses Sony's built-in AMP. You can probably do the RCA yourself, but schematics for the Glensound would be copyrighted at the very least and Patented at the most. The Glensound box is about $200. The BBC fix will cost about $350 sans the shipping back and forth, so it will be worth it to have them do it.

Charles,

When both the PD150 and VX2000 first came out, there was a Hiss problem when using Manual gain on the microphones. Sony fixed it with later released PD-150s but Sony, stated that the VX2K is a consumer product and refused to fix it claiming that for its intended use the audio levels are "adequate" and they recommend using AGC.

If you really like to hear it, take an external mic, shotgun, and connect it to the mic out on the camera. Change the audio settings to manual and monitor the sound. The hiss is very prominent when the levels are abovce 40%. Albeit, not that noticeable on tape, it is unfortunately still present. Three solutions. (?)
1. Use AGC.
2. Get a Studio One XLR box with two ground settings, the Beachtek does not eliminate the hiss.
3.Get the BBC fix.

Oh lastly, get a PD 150 ;P. That's what I did.

BBC modifications for VX2000

BBC SOUND MODIFICATION FOR SONY VX2000 At our Global-DVC Center many DVC-members are using the Sony VX2000 and PD150 for TV productionwork. For better sound with the VX2000 we always adviced the StudioPro1 mixer box underneath the camera for XLR and or MiniJack use. BUT it is good to see what the high-tech department of BBC has figured out to obtain higher sound-quality for the Sony VX2000: Notes for Sony VX 2000 Audio Mod. The modification is designed to reduce audio hiss by 12dB. * Phono audio o/p's on camera are converted to audio i/p's - they no longer work as audio o/p's. * To use phono's for audio i/p menu item TAPE SET - MIC LEVEL has to be set to MANUAL. * The mod is designed to be used with a GlenSound GSTN1 mic amp with phono connectors and peak o/p level of approx -30dBu. * For audio o/p the headphone socket or i.Link (FireWire) connector has to be used. NOTE - the level from the headphone socket is controlled by the volume buttons on the flip-out LCD screen. (peak level approx -12dBu) * Dummy plug in the EXT MIC socket is supplied to disable wind filter (low cut). * To use on the board microphone - remove the dummy plug and set MIC LEVEL menu to AUTO. * To use external mic (without using GlenSound box) connect to EXT MIC socket and set MIC LEVEL to AUTO. With the BBC audio mod the VX2000 may well be better than the PD150. It will also cost about the same. PD150 DVCAM has locked audio, which is of little or no practical advantage in the NLE world, and setable time code and user bits, which can be employed as a way of avoiding recapture errors, identifying what camera was used for a given shot, etc., all of which are useful but not indispensable.

Glensound will give you superior sound Quality - better than the PD150 or even more expensive camera's - checkout the GSTN1 box at www.glensound.com A new version of the GSTN1 is now available designed to be compatible with the VX2000. When used in conjunction with a modification to the VX2000 (undertaken for a fee by a department of the BBC (contact details on request)) this new GSTN1 offers a superior sound than Sony's professional DVCs. Please quote GSTN1 (VX2000) when ordering.

..and what Frank said, yeah. Wow Frank I'm dumbfounded. Seriously, since the Glensound is superior to the PD's amp, would it be possible to use this box on the PD, sinc eI sold my VX2000?

dang, that was some kind of explanation! I don't know sh#t from shinola. But I do know anything will make weird noises if you crank it up enough.

The Glenbox XLR adaptor is not unlike others, such as the Beachtek units, except that, I think, it's the best one made (my opinion). To answer your question, the BBC fix is only for the VX2000. The PD150 already is XLR capable. I don't think there is a after market audio fix for the PD150---the best solution is to use a good mic and keep the gain low.

Thanks all of you for very clear explanation of this issue.
Finally I understand what's going on. Actually we have to disable entire Sony Internal MIC preamplifier and replace it with some Generic made by Glenbox, but not by SONY.
Technically if I do so (disable internal preamplifier), than I really can use any good quality preamplifier with XLR inputs.
The most difficult part is modification of VX2000 (internal).
One what I'm not sure about is, if RCA output has been converted to RCA input because is radiating noise or just for reason to create line input in to camcorder. I think it has been done for reason of noise, because as I can see in schematic of audio section of VX2000, there is switch to change MIC input to Line Input what can be used to feed high level audio from Glenbox or other Preamplifier.
Also I did not learn from this thread if Glenbox adaptor is passive or active. It must be active, because is preamplifier. Question is: from where is taking power to operate?
I designed my own passive XLR box and I like to share this design with all of you, but I'm not permitted to have any attachments to this post. If anybody wish to see this design, I do have it in PDF format. I will more than happy to send by e-mail to anybody who will ask for it.
Thanks all of you again.

I think I read somewhere that the Glenbox uses a 9Volt or may a couple of LR6's (AA)...

The Glensound box gets it's power from the Lanc socket on the camera.

John.

Thanks all of you for final explanation hove BBC actually works.
Final resolution of this thread:
BBC Fix is very complex modification of VX2000/PD150.
Require additional hardware (preamplifier) and connection thru two cables and one dummy connector. Giving away audio line out (RCA) connection and around $500.
From my perspective, this fix has to be very considered for most of VX2000 and PD150 users if hiss issue is worth to go thru this pain and wallet suffering.
As Sony wrote in their bulletin, just keep AGC enabled and use manual control only in very loud environment to decrees sensitivity of microphone. In case of recording extremely quiet or low level sounds, than inexpensive audio preamplifier with adjustable sensitivity (trim) will do work.
As I understand the problem: Low level audio captured with microphone is processed in preamplifier and than with higher amplitude if feed to microphone input. In camcorders menu set turn off AGC and set gain to less than 40%. All necessary gain adjustment should be done in preamplifier with sensitivity, gain or trim adjustment. Do not forget about impedance matching.
I'm sure this will replace BBC fix without modifying camcorder and costly "choce of one" preamplifier.
I like to ours moderators or professionals read this post and evaluate my conclusion.

Peter, the BBC fix is only for the VX2000, and it's not complex. This fix is the best way to improve the VX2000's audio. A few years back, I was thinking of buying a VX2000 and sending it for this fix. However, Although I like the VX2000, I don't like it that much: it was a costly cam in Canada a few years ago, and I found it too heavy for hand-held shooting. I still recommend it though, and the BBC fix.