User’s Manual for models PS34, P4, JR4 & JR2/2 ____________________________________________________ www.puebloaudio.com vox/txt: 626.755.
The Microphone Preamplifier System (Models: PS34, P4, JR4, and JR2/2) meets the Class B specification limits defined by Code of Federal Regulations Title 47, Part 15. WARNINGS CAUTION: To reduce the risk of electrical shock, do not remove the cover. No user serviceable parts inside; refer servicing to qualified personnel. WARNING: To reduce the risk of fire or electrical shock, do not expose this equipment to rain or moisture.
PS34 • Central Power Supply Unit INTRODUCTION: The Pueblo Audio PS34 power supply provides 160 watts of linearly regulated DC power. It can power from one to four Pueblo Audio products (16 channels max.). It will operate reliably under significant ac service voltage sag due to brown outs. LOCATION: The PS34 is an external, centralized power source. This beneficial arrangement allows heat, vibration, and residual emi of the power supply to be placed at a distance from sensitive audio circuits.
FUSES: Two 20x5mm, 1Amp slo-blo fuses (T 1A L 250V) on front panel. CAUTION: for continuos protection against fire, replace with same type and rating fuse. P+ fuse for the independent precision phantom network supply. V± fuse for the independent bipolar amplifier supply. GROUND LIFT: A toggle switch on the front panel connects/disconnects the DC common/signal ground from the PS34’s AC Safety Ground. This may alleviate ground ‘loop’ problems under certain interconnect configurations.
P4 • Quad Precision Phantom Network INTRODUCTION: The 4 channel Precision Phantom Network™ renders power for unimpaired microphone operation. Each channel of the P4 has a stable, high current, independently regulated supply. This eliminates signal cross-coupling, improving channel isolation and imaging. Precision matched componentry maintains tight impedance balance for greatest signal yield and lowest noise. The P4 is the perfect companion product to our JR4 dc-coupled mic preamp.
JR4 • Quad Microphone Preamplifier INTRODUCTION: Four DC-Coupled, transformerless preamplifiers. Ideal for ribbon, dynamic and tube microphones. Also useful as DI preamp, Passive EQ/Compressor gain make-up, etc. Outstanding imaging and ambiance retrieval. Ultra-Low noise. Virtually overload proof. All unnecessary features and components omitted for signal path purity. DC POWER INPUT: A single 5-pin male XLR connector is located on the rear panel.
GAIN: 24-Position rotary switch (2.5dB per step) for exact, resettable gain. • Minimum Gain: +7.5dB (6 o’clock position) • Maximum Gain: +65dB • Gain Settings: +7.5, 10, 12.5, 15, 17.5, 20, 22.5, 25, 27.5, 30, 37.5, 40, 42.5, 45, 47.5, 50, 52.5, 55, 57.5, 60, 62.5, 65dB. • Interchannel Matching: ±0.1dB (any channel, any box, any gain setting) CMRR @ 50Hz: 110dB [gain = +60dB] CMRR @ 10kHz: 100dB [gain = +60dB] Maximum Input: +21dBu [gain = +7.5dB] Max. Output into 10kΩ: +29dBu [ ≤ 0.004% thd] Max.
JR2/2 • Two Channel Phantom/Preamp Combo INTRODUCTION: Two DC-Coupled, transformerless preamplifiers wtih two Precision Phantom Networks in one package. All the proporties described earlier in this manual regarding JR4 & P4 apply to the JR2/2. The quality and performance are the same. For utmost purity and flexibility the phantom and preamp channels remain indepenent. Short xlr interconnects are required to connect to a preamplifier channel.
FAQ's (frequently asked questions) Q: What does "DC-Coupled" mean? A: DC is an abbreviation for Direct Current. DC is an electric current which flows in a single direction, as from a battery. In contrast, audio signals are AC or Alternating Current. Typically, capacitors and transformers are used to form AC-Coupled circuits which allow AC signals to pass while blocking DC. Most commercial preamps are ACCoupled. But caps and transformers are reactive components which produce frequency dependent phase shifts.
Q: So then why use an XLR cable to patch the Phantom channel to the Preamp? Why not just use a switch or relay? A: After extensive auditions it was found that very few switches or relays sounded more transparent than an XLR. Those that did were so expensive it would have pushed final product pricing out of reach. Further, the XLR configuration offered the absolute minimal number of connections in the signal path.
LIMITED WARRANTY Subject to the conditions set forth below, for three years after the original purchase date of the product, Pueblo Audio, Inc. will repair the product free of charge in the United States & Canada in the event of a defect in materials or workmanship. Pueblo Audio, Inc. may exchange new or rebuilt parts for defective parts. This warranty is extended only to an original purchaser of the product from Pueblo Audio, Inc., or an authorized reseller of Pueblo Audio, Inc.