Topic: Sound Devices USBPre 2

[hammerhorror]

I'm currently using a Tekkeon MP3450 battery to power my Tascam DR-680. http://www.tekkeon.com/downloads/dtasht_MP3450.pdf

The Tekkeon MP3450 has DC output, plus an additional 5V USB power output. I can set the DC output to 12V to power my DR-680, and then use the 5V USB output to power the Sound Devices USBPre2. Both outputs are active at all times.

To me this seems like the easiest/best/all in one powering solution for using the USBPre2 with whatever recorder you are currently using. You can power both devices with one battery!

[kirk97132]

Yeah those Tekkon batteries are badass mofo's for sure.   There is a similar type of set=up being sold on e-bay for around half what they set you back, granted it is a honk kong item.  Since I already owned a stack of dvd batteries I wanted to be able to use them.  Plus I like making my own stuff when I can, My total outlay was small for this.   

I wish these USBPre2's would ship....I'm itching to play with the new toy. 

[sunjan]

Cheap and compact way to power this thing in the field:

http://cgi.ebay.com/4-X-AA-Battery-Holder-Box-1PCS-5V-DC-USB-OUTPUT-NEW-/150509987935?pt=LH_DefaultDomain_0&hash=item230b18285f#ht_2085wt_1139

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=320518833585&ssPageName=STRK:MEWAX:IT#ht_1972wt_976

Neat with right angle, except that the cable should be mini-USB, but I get the point! Any of those available as right angle too?

[SClassical]

It looks like USB type B not the mini one..

[Todd R]

1. I need 12 volts for an Apogee AD-1000.  2. I already own 3 DVD batteries.  So stepping it down from 18 volts ( two dvd batteries in series) is most economical way to go.  In fact I have completed that set up, I'll post pictures.   

I don't think you'll be able to get this to work, but I'm curious if you can.  I don't know anyone who has successfully put 2 DVD batteries in series to get 18v.  Probably possible I'm sure, but not with a simple cable it seems.  Something about the protection circuit used with those li-ion DVD batteries does not allow them to be put in series and work.

[kirk97132]

Todd, I plugged in all in and it is delivering 11.9 volts at the xlr-4 connector.   So it sure appears to be working.  I have not plugged it into the deck yet I'll do that today.

[Todd R]

Thanks for the report back kirk, good to know it's working.  Not sure what you've done though -- I thought you said you were just tying together 2x 9v DVD batteries to get 18v.  As I recall, several people tried that before and couldn't get it to work.

Looking more closely at the pics of your cable though, it looks like you've got a voltage regulator buried in there (to get to 12v I guess).  Maybe it is this configuration that is making it work for you when it failed for others?

BTW, if that is what you've done, and are dropping 18v down to 12v for use with the Apogee, I'd be a bit worried about heat dissipation.  I think the AD1000 draws something like 1.2 Amps, and you're dropping 6v.  That's 7.2 Watts of power that needs to be dissipated as heat.

[rastasean]

this machine provides 80 dB of gain when using mic in!! thats more than the 744 and the mixpre. 

[page]

this machine provides 80 dB of gain when using mic in!! thats more than the 744 and the mixpre. 

and more then the 788 (manual says 76db).

it a typo?

[andromedanwarmachine]

probably not!

That's technology for you!

it's all relative to the noise floor though- at a quoted -127bBu that's some peformance...!

[kirk97132]

Thanks for the report back kirk, good to know it's working.  Not sure what you've done though -- I thought you said you were just tying together 2x 9v DVD batteries to get 18v.  As I recall, several people tried that before and couldn't get it to work.

Looking more closely at the pics of your cable though, it looks like you've got a voltage regulator buried in there (to get to 12v I guess).  Maybe it is this configuration that is making it work for you when it failed for others?

BTW, if that is what you've done, and are dropping 18v down to 12v for use with the Apogee, I'd be a bit worried about heat dissipation.  I think the AD1000 draws something like 1.2 Amps, and you're dropping 6v.  That's 7.2 Watts of power that needs to be dissipated as heat.

True about the voltage regulator and I am using the XLR housing as the heat sink.  The top part of the voltage regulator lays against the housing when assembled.  Or at least that is my plan.  Since that assenbly is seperated from the unit by the break out cable, I think it will work fine.  And the additional xlr4 housing will give even more surface area.  I'll give it a trail run today.  Then a field test at Mule the end of the week. 

Same deal with the USB power setup.  I attached a stack of washers to the dissipate the heat and there is a metal plate that installs fist in the project box before the black lid.  I have the top of the heatsink contacting the metal plate in addition to the washer heat sink to get rid of the heat.  Good catch!  But I did take that into consideration. 

[kirk97132]

AH, Todd you bring up a good point.  I have to use a different VR that supplies 1.5 amps not 1.0 amps.  Otrherwise it's good to go.  I guess having the VR in line makes the difference.

[page]

probably not!

That's technology for you!

it's all relative to the noise floor though- at a quoted -127bBu that's some peformance...!

Well, then tentatively we have a discrepency; If they are the same pre-amps as the early 7 series boxes had, then I don't think you would get 80db (unless something has changed in which case the question turns to what else was affected?). So are they new (a 3rd generation different from the entre 7 series line) or is it a typo?

[vibrato]

He even is passing on our suggestions, one of mine was have the unit able to accept external clocking.

This feature has been included for release. Mostly due to discussions here and some feedback from other users as well.

Here's the updated user guide: http://sounddevices.com/download/guides/USBPre2_en.pdf

Wow, impressive how SD is listening and implementing customer feedback!

Would this have any impact on the ability to use two of these with a Mac?  Specifically would you be able to avoid the Resample function when trying to aggregate them in Core Audio?

[andromedanwarmachine]

(just speccing up my next rig here!)

Could I use an FR2-LE with a USB pre 2 through USB connection?

Using the USB pre 2 as a front end for the Fostex, feeding it through USB...?

Probably more of a Fostex question than a Sound Devices question...