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-   -   BBC mod and Glensound (https://www.dvinfo.net/forum/all-things-audio/46302-bbc-mod-glensound.html)

Lizi Hesling June 15th, 2005 10:54 PM

BBC mod and Glensound
Hi guys,
I use a Sony VX 2000 - I'm planning to get it modified by the BBC next month. This means I'll have to buy a Glensound mixer. The problem with this mixer is that it doesn't provide phantom (and it's also rather pricey). I asked the BBC if I could use a different mixer that does provide phantom (like the Shure FP24 or a Beachtek), but they said their mod was specifically designed for the Glensound box, and doing it differently would be far too complicated.

What do you think? Am I limiting myself too much by getting a mixer that doesn't provide phantom? (I wanted to buy a Sennheiser MKH 416, but without phantom, I'm going to have to settle for the ME66 with a battery pack.)
Also, is the modifcation really necessary? What if I just attached my own choice of mixer without bothering with the mod?

Any advice appreciated!

Nate Ford June 16th, 2005 12:00 PM

"Also, is the modifcation really necessary? What if I just attached my own choice of mixer without bothering with the mod?"

that's what i'd do. i don't know what the mod is that the beeb is doing for you, but i have a vx2000 and i get good sound with it all the time.

here's the thing: the mic preamps built into the vx2000 are crap (as they are on most prosumer camcorders.) but the nice thing about the 2000 is that it can take a line level input (the little switch next to the mic input.) changing the input to "line" lets you bypass sony's crappy mic preamplification section altogether.

the sound devices mixpre is a fabulous little field mixer for the money. (it's 2 input, though they make 3 and 4 input models too.) the mixpre has great preamps and a limiter that doesn't sound bad like limiters sometimes do. the mixpre will give you a tape/line level output on a 1/8" mini jack, just like the input on the sony wants. so you just get a 4' cable that has stereo male mini plugs on either end. (if you want to get fancy, use the right-angle plugs, which will sit better on the camera end.)

the mixpre provides phantom and is great all around. by the way, the fp24 is the mixpre, re-branded. anf it costs more at b&h.

so my best advice is get the mixpre, don't do the mod.

Glenn Chan June 16th, 2005 02:34 PM

If you're in the States, Greg Winter does a similar mod. I think with his mod you could add a Beachtek with phantom power? Other folks would know more about this than I do. You could try the dv.com forums or search this forum.

I believe Jay Rose (CAS) took measurements of the mod. The before result may also possibly be good enough for you.

Lizi Hesling June 17th, 2005 01:10 AM

Thanks for your replies.
I live in China and will be going to the UK this summer. I know about the Greg Winter modification - but it would be impractical for me.

What I really want to know is exactly what the Greg Winter and the BBC mods actually do - in other words - do they make any REAL difference?

This is what the BBC have said to me in email communication:

About the Glensound box: "The modification is designed to work with the Glensound GSTN-1 audio interface box. It's not really possible for us to modify the camera to work with other mixers. The only way this could be done for a reasonable price would be to change the connectors on the mixer to RCA Phono connectors. The mixer would probably have to be modified to make it's output level match the camera. Without a circuit diagram for the mixer this would be a very time consuming to work out which components we would have to change."

About the modification itself: "Our modification reconfigures the output RCA Phono connectors of the camera to be inputs. It improves the signal to noise ratio of the camera by 12dB when using external microphones. We attach a dummy plug to the camera which can be used to switch off the camera's wind filter. Apart from the improvement in S/N, the performance of the camera is not changed."

About the BBC's camera of choice: "The BBC still uses quite a lot of VX2000s. The usual microphone of choice is a Sennheiser ME66, which is powered by an internal AA battery. The camera doesn't generate phantom power so you wouldn't be able to use the 416. Currently the preferred camera is a DSR-PD170P it's the DV cam version of the DCR-VX2100E which superseded the VX2000. There's little to choose between the sound on the PD170 and the VX2000 with the GSTN-1 box, the latter is probably slightly superior. The PD170 has in built XLR connectors and generates phantom power. Generally the VX2000 is preferred by the operators as the GSTN-1 has level controls on the back and LED's to indicate when the level is peaking correctly. The soft limiter in it means that extra high peak levels aren't too objectionable."

I'm not very technically minded, so there's quite a lot in this that I don't understand.
Can anyone enlighten me?
Thanks - Lizi

PS As for the MixPre/Shure FP24, sure, they're cool - but they're not very practical because of problems attaching them to the camera. How to the Beachtek mixers compare?

Nate Ford June 17th, 2005 07:29 AM

i took a look at glensound's site and i must admit it's something of a quandary. their box (with the modification,) seems really good. it looks like it is better than the beachtek boxes in that it bypasses much of the bad input circuitry in the vx2000. i also think it's great that it draws its power from the camera, as opposed to using another battery. however, for me, i couldn't use it because it doesn't provide phantom power. most of the better shotgun/short shotgun mics require phantom power. in my opinion, the me66 is not a great mic. so if you really need the device to mount onto the camera (which the mixpre/fp24 won't,) you're sort of forced to choose between better mic box and mediocre mic, or slightly inferior box and better mics. personally, i'd choose the latter. actually, i do- when i need a camera mounted box i use the beachtek dxa-8. the short shotgun i use with it is an audio-technica at-4073, which is a much better mic than the me-66. i feel like the mic is the most important part in the signal path. and though the beachtek box does connect through the vx2000's (bad) mic input, it puts out a loud enough signal that the crap sony circuitry doesn't need to do too much work.

i guess you're not working with a soundperson, huh? are you absolutely sure you need a box that connects to the camera? mounting your mic on the camera isn't usually the best place to put it. but if you really must, then i personally would recommend a better mic (the a.t. mic above is the best around for the money,) and the beachtek dxa-8 box. that's just one man's opinion, though.

Nate Ford June 18th, 2005 11:35 AM

one last update-
i checked out greg winter's site and sent him an email.
he does a mod much like the bbc's, and it'll work with any any number of mixer.

better yet, he will also modify a sound devices mixpre to mount to the bottom of your vx2000. i was really interested to learn this, and i'm strongly considering doing it with mine.

if you can figure out shipping your camera and a mixpre to him, it seems like this is without question the best way to go. you end up with the camera-mounted mixer, improved sound on the sony, and the bext mixer around for the money, which will let you use any mic you want. having worked with the mixpre and the beachtek boxes, i can definitely say that there is a marked difference in audio quality between the two, not to mention all of the added functionality of the mixpre (phantom, level meters, limiters, etc.)

Lizi Hesling June 18th, 2005 02:36 PM

Yeah - but I'm still unclear about the BBC and the Greg Winter modifications. Are they worth it? What difference do they make? And is having a mod any different from just attaching a good mixer?


Richard Maloney June 18th, 2005 11:35 PM

I have Greg's mod done with the mounted mixPre and the sound is super great. As stated by BBC, this modification, increases s/n ration by at least 12db, and its very clear.
I would recommend the mixPre, even if BBC does the mod- I believe its the same mod-, because the mixPre is quality> oh yeah! Save and wait if you have to, this thing is built like a tank and has all the things you need for such a setup like source or camera audio monitoring. When the vx2000 goes to the dinosaurs you will still have the mixPre, a professional 2 channel mixer/preamp.
Mounting it to the camera? Thats a tough call. I wish I had another mixPre that wasn't attached to the camera! Greg makes a bracket for the mixPre (to be mounted on the cam), which would be the best solution. Unfortunately, hes only made a few prototypes and I'm sure they are great but heavy. If hes building them lighter thats what I would do. Or beg or bribe him to make a lighter version :).
Is it worth it? That depends on a number of factors. On the high end there is the Sound devices 722 but that isn't on camera. Then there is the sell the vx2000 get a Z1 option. The mixPre is the thing you can't go wrong with. All the best with your decision.

Spike Spiegel July 2nd, 2005 01:51 AM

how much does the greg winters mod cost?

Lizi Hesling July 2nd, 2005 07:29 PM

how to carry the MixPre?
About the MixPre - if you don't have it attached to the camera, how are you supposed to carry it? Doesn't it get in the way when you're shooting? If you're carrying in on a shoulder strap, won't you be touching the wires all the time? And don't longer wires lessen the quality of the audio input?

Simon P Lowe July 4th, 2005 02:19 PM

Hello ,
The modification to the vx2000 is very simple really.Basically the hisssey opamp Ic1007 is bypassed and line in feed straight to IC 1001 .As Richard say it increases s/n by 12db and it also extends the frequency response at both ends of the spectrum .The difference is like night and day, well worth having it done.

I have the glensound GSTN1 - no phantom power but it does have high quality limiters ( 2x analog devises ssm2166 chip) ,works very well with ME 66 / k6 and Rode NT3.
I have pictures of the GSTN1 , vx2000 schematics here :-

The TRV900 can be modified in a similar way , see here :-

Lizi Hesling July 4th, 2005 07:53 PM

Thanks Simon for your reply. It's great to find someone who's actually had the BBC modification done and uses the Glensound.
But do you think I'd be able to use another mixer like the MixPre?

Nate Ford July 5th, 2005 11:10 AM

if the bbc mod is indeed giving you a line level input (like greg's,) then yes, the mixpre will work.

Dave Largent July 6th, 2005 04:38 AM

I wonder if Greg does a mod where you can
have the Mixpre on the bottom of the VX and then
have a tripod screw into the bottom of the Mixpre,
so that the whole setup can be tripod mounted?

Nate Ford July 6th, 2005 08:30 AM

i emailed greg about the mod and he told me he does do it with a 1/4" 20 threaded tripod mount. unlike the box mod, which lets you remove the mixpre easily, this one is a bit more permanent. you can take off the mixpre, but only by taking it apart first. but if you're going to be using the mixpre exclusively with that camera, it makes sense, and it's lighter weight than the removable box mod. he describes it here in this faq: (it's the last "q" at the bottom of the page.)

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