PreSonus 96 USB

[ef37a]

Does anyone have hands on experience of this AI please?

The unit seems very good value for 'name' with 2 in, 2 out and MIDI with the very capable Studio One software. The fly in the ointment however seems to be the mic pre's gain specc' at just 35dB. That seems very low and really not fit for the almost inevitable coupling of a budget AI and a dynamic microphone?

PreSonus have a reputation for excellent mic preamps in the rest of their range and I have never read of a 'gain shy' product. Could this be a typo?

Dave.

[Forum Admin]

Does sound low, if you are referring to their old AudioBox USB range.

Better bet would be their Studio 26 AI - see https://www.presonus.com/products/Studio-26

It offers 70dB gain range on mic, line and instrument inputs for around £156 quid.

It's a newer model and thus will have better converters than the old AudioBox models.

[Hugh Robjohns]

Pretty sure it's a typo.

The front panel gain knobs are marked as INST -10 to +30 and MIC 0 to +60

Also, page 3 of the manual states:

Input Gain/Trim Control.
These knobs provide the following gain structure:
• Microphone: 60 dB of variable gain (0 to +60 dB)
• Instrument: 40 dB of variable gain (-10 dB to +30 dB)

https://www-media-presonus.netdna-ssl.com/downloads/products/pdf/AudioBoxUSB96_OwnersManual_EN_25052017.pdf

H

[ef37a]

Ah! Thanks Hugh. I went straight to "specifications" so, must be a typo.

While I am here? Very few if any AI manufacturers give a figure for phantom power CURRENT delivery, it is also very often missing from mic speccs. I mention this because I have read of a few instances now of newbs having problems with budget AIs and capacitor mics and AIs that are USB bus powered are often limited in the current the XLRs can deliver.

It is easy for 'us' to check this with a meter and couple of resistors, not so for the newb who often has the AI, mic and no clue!

Dave.

[Hugh Robjohns]

Very few if any AI manufacturers give a figure for phantom power CURRENT delivery, it is also very often missing from mic specs.

It is.... but probably because there is an assumption (often misplaced) that everyone conforms with the international standard.

This has changed slightly over the years. Originally it allowed for 2mA, then in 1976 it was updated to 7mA, and then in 1979 to 10mA per channel, which is where we should be today. (the maximum current under short-circuit conditions is 14mA, but then there would be no voltage...)

There's a good article on Phantom Power -- and a simple method to check whether a phantom supply meets the standards -- here:

http://microphone-data.com/media/filest ... om-10_.pdf

I mention this because I have read of a few instances now of newbs having problems with budget AIs and capacitor mics and AIs that are USB bus powered are often limited in the current the XLRs can deliver.

Well, there's only so much power available over USB2. I know some interfaces will only enable phantom power when powered from a wall-wart. The other issue is that different mics have very different phantom current requirements. Although this is a gross generalisaton, the better designed (and thus more expensive) mics tend to have lower current demands (ie 2-4mA) compared to cheaper mics which often need 5-10mA.

Schoeps makes a plug-in phantom tester that won't light up unless it can draw at least 4mA of current:

http://www.schoeps.de/en/products/phs48

And for those who won't kill themselves with a soldering, there's a DIY phantom checker here that does much the same -- I use it all the time!

https://ips.org.uk/wp-content/uploads/2 ... hecker.pdf

H

[Mike Stranks]

... and I haven't checked recently, but some of the 'shallow-end' preamps and AIs didn't supply standard 48-volts either! Not so bad if manufacturers/suppliers state this explicitly, but some didn't - either just stating that phantom was available - or worse, saying it was 48-volts when it wasn't.

Our friends, the wall-warts, were involved again!

[Hugh Robjohns]

Yes, I expect that is more of a problem than a limited current capability. Some mics will work on any phantom supply between 9-52V , but most need the full nominal 44-52V. As you say, some budget preamps, active speakers and interfaces provide only 24, 15, or even 12V 'phantom' supplies.

The DIY tester mentioned above won't light up for anything less than 44V!

H

[Mike Stranks]

... some budget preamps, active speakers and interfaces provide only 24, 15, or even 12V 'phantom' supplies.

H

I was 'caught' with an unstated 36-volt supply... I was suspicious, measured it, then sent it back with a snotagram!