Nelson Pass First Watt F4 25W Class A Amplifier, built inside NAD 208 case. Smooth detailed sound not for low efficiency speakers. Like everything else from First Watt the F4 is a unique amplifier. It has no feedback and no voltage gain, only current gain, it will deliver up to 25 watts into 8 ohms and 50 watts into 4 ohms. It is built as dual-mono circuit boards, powered by a 500w toroidal transformer and filtered with 86000uf per channel. It has a soft starter with thermal protection, speaker protection, rhodium plated RCA and banana sockets, input and output wires are silver plated OFC. The combination of a simple Class A circuit operated without feedback and the good objective performance gives us a superb sounding amplifier. The low distortion, bandwidth extension, and high damping results in midrange clarity, treble detail, and control on the bottom end. While these are available from most good solid state amplifiers, the F4 also brings depth, imaging, midrange warmth and top-end sweetness.

Nelson Pass Designed Amp Camp Amp Mono-blocks. Up for sale a lovely pair of Nelson Pass designed amp camp amp mono blocks. They are pure class A outputting 15 watts per channel. They can also be used in stereo ( 12 watts p/ch ).They are in perfect condition and working order. They are really impressive sounding and a great way to get into the Nelson Pass sound. Any Questions please ask and I will get back to you as soon as possible.See my other listings for my Pre amp used with these mono blocks.

Nelson Pass Class A Complementary Power Amp/Buffer with unity gain.This is a cost effective version of the stock BA complementary power amp which I made myself. It uses the Nelson Pass/DIYAudioStore circuit design with high quality components throughout. Compared with the stock amp it uses a slightly smaller case (340 x 320 x 150mm/3U x 300), runs at slightly lower bias (1.2A), has a slightly lower Class A envelope and slightly lower dissipation. It uses the standard +/-24V power supply voltages so will deliver the same power output into 8 ohms (nominal 25 wpc). It incorporates a Soft Start, a DC blocker, a Ground Loop Breaker, has a 300VA transformer, a 248,000uF capacitor bank and Vishay Siliconix output mosfets.Class A amps run warm so it must have plenty of space for cooling, it should not be boxed in or have other equipment stacked directly on top of it. Nelson Pass generously makes these excellent circuits available to the DIY Audio community as long as they are not for commercial use. I originally built this for my own use and it is intentionally listed at less than the cost of the components, you get the NP circuit design for free :) This is a unity gain power amp, it has very good sound quality but requires a preamp with sufficient voltage gain and output. If you have high sensitivity speakers then a normal high quality preamp may work fine. If you have average sensitivity speakers then you will probably need to drive it with a high gain high output preamp such as the DIYAudioStore BA-1/2 or BA-3 preamps. I have a suitable cost effective preamp ideal for driving this amp on my other listing in case you are not up for making your own. The power cord with Neutrik Powercon connector is included in the listing but the interconnects and speaker cables/plugs are for illustration only and are not included.Speaker connection is via Neutrik Speakon connectors but there are also 4mm sockets if required. Speakon plugs are widely available, easy to fit and accommodate most cables. I appreciate you will want to hear what it sounds like in your own system so I will accept a return and issue a prompt refund if you are not happy with it for any reason up to 14 days as long as it is returned in its original condition. Any questions please ask. Collection only from Halifax area, West Yorkshire.

A Nelson Pass 4 stage mosfet output ampliefier . The Adcom GFA-5300 2 Channel 80w/ch@8ohm. But in actually testing just over 100w /ch at 8 ohms. This was display model in 90sat a Brooklyn electron8c store . And was put in storage until I got it. Few weeks ago. And powered up for the 1st time for testing and setting voltages. (Offset and bias are set to exact spec. Dc Offset -0mv Bias - 20mV. ). Both channels are exact.) This Amp 100% working perfect. There are few scratches on top. Im which I touched up. Im aware of the hazards of shipping and will pack accordingly. .

Used, some scratches and dings on sides. Purely cosmetic. US version

Superb Nelson Pass design based upon his Stasis amplifier design exemplified by Threshold Corporation. This is the PA5 rated at 100 watt per channel which is enough STASIS watts to drive any speaker, these even drive the Martin Logan ReQuest electrostatics that dip to just over 1 ohm, with no problems whatever. The sound is crystal clear and ethereal and has a very good bass rythm and drive. I am happy to demonstrate the amplifier driving Sonus Faber speakers. Any questions or queries pop me a question via the ebay messages- more pictures to follow

NELSON PASS FIRST WATT F4POWER AMPLIFIER The First Watt F4 is a classic Nelson Pass/First Watt design with JFET inputs and MOS-FET outputs. However, as with the other FW amps there is a twist here, namely that the F4 has no voltage gain. That means it’s essentially a buffer than can provide a full 25W class A output. its low or no gain so needs a preamp with a decent output Track Page Views WithAuctivas Counter

Used, some scratches and dings on sides. Purely cosmetic. US version

Nelson Pass designed Amp Camp Amp Audio Class A, 2 Channel Amplifier. This class A amplifier is newly built by myself and has an output of 8 watts per channel (2 channels). I am an experienced electronics builder and the amplifier works perfectly. It will move your woofers on shutoff, that’s inherent in this simple design. It’s a great way to inexpensively get an Nelson Pass designed amplifier. Beautiful clean and warm class A sound. You will need reasonably efficient speakers and a preamp to use it. My speakers have a sensitivity of 89db at 1 watt at one meter and they work great. Comes with external 24v power supply. Please ask any questions and I will get back to you right away. I will ship same day if I can. You can read the full specs of the amplifier at https://diyaudiostore.com/products/amp-camp-amp-kit?variant=39678364024905

Nelson Pass First Watt F5 Power Amplifier.. 2nd owner, comes in good condition.

Excellent multi-input MC step up or head amp with the dedicated power supply. The PSU has two outputs, just in case you have another Threshold M series component. The PSU is 220V so its good throughout Europe and other civilised nations. However the step up itself runs on 20V so it will work with any suitable Threshold component. Theyre both in excellent working order. No LEDs or switches or anything - these are purist devices, leave them connected. If there’s no Buy It Now price displayed, there’s no Buy It Now price Unless stated, I ship overseas. If the price isn’t shown, please ask If its not shown or mentioned, its not included Please look at my other items _gsrx_vers_1516 (GS 9.3 (1516))

This is a custom built Pass B1 buffer preamp that I DIYd over a year ago.I built this for my lab as a reference preamp and its served well but its time to let it go as Ive found a better preamp for my needs. I built this using the PCB + four JFET package available as PASSDIY.com. The potentiometer is a genuine Alps Blue, and the case is of chinsese origin. The power supply is a Meanwell 18v PSU. The wire used is silver plated teflon. This is a fantastic preamp for someone needing a simple, transparent, and clean buffer between their source component and preamp for optimum signal transfer. If you have a dac with lots of voltage on tap, this is perfect to interface it with a matching amp. Heres an opportunity to own a fantastic preamp at a fraction of the price of the Firstwatt model, despite them being identical. I will not ship this item outside of the United States unless the buyer uses the Ebay International Shipping Program, otherwise the order will be cancelled.

Used, some scratches and dings on sides. Purely cosmetic. US version