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Gear / Technical Help => Battery Boxes, Preamps, Mixers, ADCs, and Processors => Topic started by: johnw on June 24, 2017, 10:02:18 AM

Title: 48V vs 60V version PFA?
Post by: johnw on June 24, 2017, 10:02:18 AM
I apologize as I'm sure there is a thread on here. I tried searching the site and came up with nothing but I admittedly suck at searching here.

Anyway, I have the 48V version of the Naiant PFA. I believe this was replaced by a 60V version. At the time it was introduced, I think Jon explained the difference but I can't remember what it was. I'm trying to put together a more compact setup with the MP6 and was wondering what benefit I'd see by upgrading to the 60V version for both the Nbox cable and KCY I have?
Title: Re: 48V vs 60V version PFA?
Post by: jbell on June 24, 2017, 11:04:44 AM
The older version you have probably doesn't have the low noise feature which is standard in today's PFA's.  The 60v version is longer, but will polarize the caps to 60v.  I have owned both, but currently run the 60v PFA and have been really happy with its performance. 
Title: Re: 48V vs 60V version PFA?
Post by: fanofjam on June 24, 2017, 11:22:11 AM
In practical application, the differences are minimal.  The 60V PFA will give you something like 3 or 4 db additional mic sensitivity which also gives you 3 or 4 db of headroom above the noise floor.  So if your rig runs hot that could work to your disadvantage (see my situation explained below).  On the opposite end, if you record nature sounds and/or very low volume applications, then the additional sensitivity might be worthwhile to you, because that extra headroom above noise floor can be useful.  The 60v PFA draws more current than the 48v version, so if you have issues with the battery setup you currently use, that works against you although I do believe that the power difference isn't so much that it would make a large difference in run-time.  You could figure it out if you needed to...the power specs are published on Jon's website.

Technically speaking, the 60v version shouldn't IMHO be considered an 'upgrade'.  It's just a different option.  There's been alot of discussion about whether running Schoeps capsules at lower voltage (than 60V) should matter.  The bottom line is according to Schoeps is that there's no frequency response impact of running capsules at lower voltage, only sensitivity.  So apply all of this to your own choice and use that to make your decision.

Personally, I record loud music concerts.  The gain structure on my Zoom F8 (with PSP2 as input) has me running way low with my level knobs rotated almost completely counterclockwise.  In extreme case where I'm really close to the stage and the music is also really loud, I've had to use external attenuators because with my level knobs turned all the way down, I was still peaking.  Obviously, since I record loud shows, I don't care about the headroom, so for my recording rig I have no reason whatsoever to change from the 48V to 60V version and, in fact, prefer the 48V version.

Hope this helps.
Title: Re: 48V vs 60V version PFA?
Post by: fanofjam on June 24, 2017, 11:33:33 AM
The older version you have probably doesn't have the low noise feature which is standard in today's PFA's.  The 60v version is longer, but will polarize the caps to 60v.  I have owned both, but currently run the 60v PFA and have been really happy with its performance.

Please explain bolded portion of your response.  I wasn't aware of this.
Title: Re: 48V vs 60V version PFA?
Post by: jbell on June 24, 2017, 11:40:25 AM
The low noise option wasn't available with the original PFA it became an add on eventually.  Now it is standard with all newer PFA's.  I think Jon deleted the thread that talked about the low noise option becoming standard in all PFA's.  I have 2 sets of 60v PFA's one I added the Low Noise option and the other it was standard.  Also I've run 60v PFA's without any problems of them running to hot.  Not even close.
Title: Re: 48V vs 60V version PFA?
Post by: johnw on June 24, 2017, 12:36:16 PM
Thanks guys. I think for now I'll stick with the 48v version. Doesn't seem like the benefits are worth the extra $250ish to get 2 new sets
Title: Re: 48V vs 60V version PFA?
Post by: fanofjam on June 24, 2017, 01:47:45 PM
The low noise option wasn't available with the original PFA it became an add on eventually.  Now it is standard with all newer PFA's.  I think Jon deleted the thread that talked about the low noise option becoming standard in all PFA's.  I have 2 sets of 60v PFA's one I added the Low Noise option and the other it was standard.  Also I've run 60v PFA's without any problems of them running hot.  Not even close.

Thanks for the clarification. 

I expect that most people would be in the same situation as you (never coming close to running hot).  The PSP2 is the only preamp I've ever owned that forces this to be an issue for me because of the gain setting at 35db at its lowest  It's also my favorite sounding preamp of many that I've owned so I suppose it's a good problem to have to deal with.  ;)
Title: Re: 48V vs 60V version PFA?
Post by: hi and lo on June 24, 2017, 03:51:42 PM

Technically speaking, the 60v version shouldn't IMHO be considered an 'upgrade'.

This guy gets it.
Title: Re: 48V vs 60V version PFA?
Post by: drewloo on June 25, 2017, 03:01:39 PM
Thanks guys. I think for now I'll stick with the 48v version. Doesn't seem like the benefits are worth the extra $250ish to get 2 new sets

I don't think you need to order 2 sets.  When you specify KCY it doubles the number of PFA/XLRs by default, so one pair should only run about $130.

Personally I'm in the exact same boat as $5bill in that on my F8 I often have to run attenuators if I'm close to the sound source and think it's kind of silly to get the extra gain from the 60V PFAs and then have to reduce gain so I don't overload the F8.

Can one get the low noise option on the 48V PFAs?
Title: Re: 48V vs 60V version PFA?
Post by: jbell on June 25, 2017, 04:17:26 PM
As I understand it all new PFA's come as a low noise version!  It isn't an option anymore it comes standard.   

Thanks guys. I think for now I'll stick with the 48v version. Doesn't seem like the benefits are worth the extra $250ish to get 2 new sets

I don't think you need to order 2 sets.  When you specify KCY it doubles the number of PFA/XLRs by default, so one pair should only run about $130.

Personally I'm in the exact same boat as $5bill in that on my F8 I often have to run attenuators if I'm close to the sound source and think it's kind of silly to get the extra gain from the 60V PFAs and then have to reduce gain so I don't overload the F8.

Can one get the low noise option on the 48V PFAs?
Title: Re: 48V vs 60V version PFA?
Post by: it-goes-to-eleven on June 29, 2017, 08:31:58 AM
This is straying off topic, but it is worth it to cite what I think is the best reference on psp2 gain.

Note that the unbalanced output levels will be different.

The gain ranges I estimated were pretty close.

I set up my computer to generate a steady tone, then from my DAC (Headamp Pico), I fed an unbalanced signal to my V3, and then SPDIF out to my PMD-661. I adjusted the signal to a specific level on the meter using the gain and the trim on the V3. Then I placed the PSP-2 between the DAC and V3 and measured the signal increase. I used the balanced outs on the PSP-2.

Mic sens "-35": gain of +28 (ie., the meter increased from -40 dB to -12)
Gain switches +6 and +12 add +6 dB and +12 dB respectively.

Mic sens "-55": gain of +48 (the meter increased from -60 to -12)
Gain switches +6 and +12 add +6 dB and +12 dB respectively.

Mic sens "-70": gain of >+60 (the meter increased from -60 to "over"; I adjusted the trim on the V3 downwards by 4 dB, and it was right around 0, so I estimate that it adds about +65 dB)

That's the best I can do with my equipment I have on hand.

So the revised gain range for the PSP-2 is:

+28 (Mic sens: "-35"; Gain "0")
+34 (Mic sens: "-35"; Gain "+6")
+40 (Mic sens: "-35"; Gain "+12")
+48 (Mic sens: "-55"; Gain "0")
+54 (Mic sens: "-55"; Gain "+6")
+60 (Mic sens: "-55"; Gain "+12")
+65 (Mic sens: "-70"; Gain "0")
+71 (Mic sens: "-70"; Gain "+6")
+77 (Mic sens: "-70"; Gain "+12")

So there probably is a pretty big margin of error and it would be nice to get an actual number for the peak value instead of estimating it by eye. I would say +/- 5 dB. I tried feeding the signal to another computer but couldn't really get the digital in or line in to work.

Title: Re: 48V vs 60V version PFA?
Post by: DSatz on July 15, 2017, 10:55:23 PM
I'm not familiar with the hardware that you're discussing and don't even know what PFA stands for (pantom fower adapter?), but the difference between 60 V polarization and 48 V polarization is 1.94 dB. The higher voltage brings a corresponding increase in capsule sensitivity (i.e. voltage output for a given sound pressure level). That probably won't affect the signal-to-noise ratio of your recording at all, depending on what the main source of audible noise is in your recordings. The increase in sensitivity would at best help you only very slightly, but could hurt you more if the preamp is subject to overload at the highest peak levels that you record.

--best regards
Title: Re: 48V vs 60V version PFA?
Post by: pohaku on July 16, 2017, 12:29:44 AM
I'm not familiar with the hardware that you're discussing and don't even know what PFA stands for (pantom fower adapter?), but the difference between 60 V polarization and 48 V polarization is 1.94 dB. The higher voltage brings a corresponding increase in capsule sensitivity (i.e. voltage output for a given sound pressure level). That probably won't affect the signal-to-noise ratio of your recording at all, depending on what the main source of audible noise is in your recordings. The increase in sensitivity would at best help you only very slightly, but could hurt you more if the preamp is subject to overload at the highest peak levels that you record.

--best regards

It is indeed a phantom power adapter manufactured by Naiant.  Many of us use them to run active remote capsule rigs such as Schoeps KCY and AKG active rigs.

http://naiant.com/studio-electronics-products/inline-devices/pfa-phantom-power-adaptor/