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E.A.A. PSP-2 Preamplifier Thread - Specifications / Photos / Powering

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I was searching the site for a dedicated PSP-2 thread and found a number of really informative posts placed all around. Since there doesn't appear to be a central thread I have compiled relevant info here.

Preamp Specifications (see Information Sheet links below for additional detailed specs):
 - XLR in/out
 - 1/8-inch (3.55mm) stereo in/out
 - 12V, 24V (internal switching), and 48V phantom powering
 - Mic/Line input
 - 5-9 (max) VDC powered by external battery
 - 6xAA batteries internal power
 - Approximate runtime (with 48V phantom power):  10 hours
 - Gain range: see tedyun's post below
 - Dimensions: 3.4 x 1.4 x 5.6 inches (85 x 35 x 147 mm)


Internal Photos:
Imgur link:


Link to Manual:


Information Sheet:
Imgur link:
Page 1:
Page 2:


Gain Ranges:

--- Quote from: tedyun on July 31, 2011, 01:35:39 AM ---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.

--- End quote ---


Powering / Battery Sleds
Powering via 5V USB rechargeable battery:

Powering via internal NiMH batteries:

Replacement battery sled:


Bench Tests and Repairs
Bench tests performed by Vark:

Information regarding repairs:


Potential Source of Audio Transformers
Palmer Germany (currently under the Adam Hall Group) was the original manufacturer of the transformers. The PMT05 or PMT09 models located on page 92 of PDF linked below may be suitable replacements, although I am not certain of this.

As someone who has used a PSP2 for over 20 years, thanks for starting a thread.

I loved mine wish so still had it. But I moved to an Oade m148 so hard to complain. 😀

Bump for internal photos link in the top post.

Second photo, on the left, the red/blue switch is one of two (the other is out of view below).  These are for switching between 24 and 48 volts phantom powering.

In the top left of the board, what are those trimpots for?  Would these be for input (or output) finer gain adjustments?

It's truly amazing how compact and tightly put together this preamp is.  I would have taken a picture of the other side, but it's basically just a metal wall that extends beyond the battery compartment.  It appears there are three total boards, all facing in towards one another in a sandwich.   

Thanks for starting thread and posting pics. Anyone running there's on a 5v usb battery? When I set mine up that way with fresh charge, low level battery light flashes  as soon as you power the unit on. Haven't run any tests this way. Any thoughts? The usb battery can do 5-12v but it senses voltage automatically, no way to set voltage you want. Weirdness


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