Aleph 1 7 preamplifier design

December 20, First Watt's Aleph J amplifier This blog is meant to be a relatively step-by-step guide for relatively inexperienced hobbyists "noobs" interested in successfully building an Aleph J stereo audio amplifier. The project and this blog is possible only thanks to the contributions of talented and generous folks who hang out at the DIYAudio forums. In fact, before this journey is over, you'll likely have become very, very familiar with DIYAudio , especially the Pass Labs sub-forum and the many threads devoted to the Aleph J. What is an Aleph J amplifier? Good question!

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Content:

• pink fish media
• Laminate Flooring Edition 1 ALEPH
• Nelson Pass
• Pass Labs HPA-1 Class A Headphone Amplifier Now Available
• DIY Aleph J: A Build Guide
• Aleph P lass A SE MOSFET pre-amp PCB one channel
• Pass Labs Aleph P Preamplifiers
• Pass Labs Aleph 3 Circuit - High Power Duel Mono 30W Pure Class A Power Amplifier
• Aleph l schematic

WATCH RELATED VIDEO: Class A Amplifier Project Aleph 5 First Tests

pink fish media

The Pass Aleph P design philosophy can be summed up in one word: simplicity. Its exterior styling is positively austere. The rotary selector on the left side has just four dots to delineate each of the four possible input selections. The master gain control knob on the right has only a slit for a setting mark.

The front-panel center is populated by a glowing blue light and a pair of knobs to control the gain of each channel. A bale of hay has more visual interest. To choose single-ended inputs, you insert a gold U-shaped shorting plug into the corresponding XLR input. There are two RCA outputs, one with fixed gain for supplying a tape deck and one with variable gain to connect to an amplifier. Two XLR outputs provide the same functions for balanced devices.

The final item on the rear panel is an EIC connector for the power cord. To eliminate nasty feedback howls, input 4 is intended to be used as a tape input, so a relay shuts off the tape outputs on the back of the preamplifier when it is engaged. Safety is a wonderful thing. The test sample was a manual unit, sans remote control. The Aleph circuit is as simple as its exterior. Upon entering the Aleph P.

Only the source selector relays, one ohm resistor to prevent parasitic oscillations , and one metalized film capacitor to block DC are in the path in front of the MOSFET. The resistance between these two sources helps to set the intrinsic gain of the circuit.

This is the patented differential error correction. A further bit of cleverness is that differential distortion-cancellation occurs whether you use a balanced or a single-ended input or output. The master volume control for the four outputs one positive-polarity and one negative-polarity per channel is clone via four-pole double-throw relays controlling precision Dale metal-film resistors placed just before the output.

Let me emphasize that the audio signal is not transposed into the digital domain. With anything other than a digital controller, the preamplifiers CMRR common mode rejection ratio would be far less than optimal. Through careful matching of resistor values, this master volume arrangement makes it possible to achieve CMRR of at least 60dB.

This unregulated power is then filtered before it reaches active discrete regulator circuits, which employ both passive and active systems. The regulated power is then sent to each channel through a double set of passive filters. Using one active and six passive filters reduces power-supply noise to a level of about 5mV. Tonearms mounted on the table were the Graham 1. Is it perfect? Is it the fabled Holy Grail of a straight wire with gain? Who do you think Nelson Pass is— God?

Without any preamplifier, the delineation between the presence and absence of music was more distinct, so sound faded away in a more natural and realistic way. Cymbals have an airiness that evaporates through the Pass. Microdynamics were also ever so slightly compressed by the Aleph, resulting in a loss of vibrancy and rhythm.

The Aleph P is the least colored of the bunch. Even through a Dixie cup and a string you could hear the differences between these two records. The Classic Records reissue has far greater low bass information, with more distinct timpani and double-bass parts. The Classic reissue also has a plethora of top-end air—lacking on the original—on flutes, violins, and triangle.

Inner detail and low-level information are superior on the reissue; you can even hear Maestro Reiner stamping during a few passages on side one.

While the original gives you a wonderful feeling of the whole orchestra as a unit on stage, the reissue separates the orchestra into its individual parts. This effect reminds me of the difference between the sound of my Gibson Southern Jumbo and a Gibson Advanced Jumbo. The guitar sounds tighter, with a clearer, more distinct differentiation between the strings, but is less harmonically cohesive.

The Classic Records re-release is just like this. Too little center-fill on the reissue could be the problem. Reflected sound from the rear walls is lost, while reflected sound from the side-wall seems exaggerated. This increase in sidewall reflection also makes the stage seem wider, but not as deep as on the original.

It sounds as if some giant grabbed the soundstage and pulled on either side, stretching it like Silly Putty from a ball into an egg shape. Through the Pass, both the top-end air and low bass energy were slightly truncated. Obvious differences still exist between the two Mahler releases, but resolution was reduced so that low-frequency information like the foot-stomping on Side One was less obvious. Something more was added between the listener and the music.

Compared to the remarkable Carver Research Lightstar Direct preamplifier used in its passive balanced-output mode see review elsewhere in this issue , the Pass Aleph ran a very close second. Preventing emotional singers from putting some body English into their work is impossible.

With the crossed-figure-8 mike arrangement used on this disc every move seems like a hike across town. On the plus side, the Pass is was silent as the Carver, and added only the very slightest amount of grain to the sound. The neat rimshots sounded more like real rimshots through the Calver. With the Pass they were duller with an excess of thud and less leading edge twack.

The dense guitar textures created by Patti and her producer, guitarist-extraordinaire Jon Leventhal came through the passive Carver with less homogenization. Again, the difference in low-level detail between the passive Carver and the active Pass made the music easier to decipher through the Carver.

At last, a fair fight. The Pass also did a better job of preserving the three-dimensionality of the recording. This added dimensional fidelity is especially noticeable on percussion instruments. The natural acoustics of St. The Threshold and Pass have very similar harmonic signatures except for the slightly brighter upper midrange and warmer upper bass on the Threshold. Low-level detail was also better through the Pass, with more precise individualization of each instrument.

Even when everybody is really wailing during the last verse, each part could be followed through the Pass with greater ease than with the Threshold. In my renew of the Threshold T-2 last July Vol. The Pass is even quieter. The balanced output impedance of the Pass Aleph P at its line output measured ohms slightly less in the left channel ; the unbalanced output impedance measured ohms. Both measurements were at the maximum setting of the main, left, and right level controls; as the main level control was reduced, the output impedance also decreased significantly to ohms at , ohms at unity gain—about —and However, the relatively high gain of the Aleph O The output impedance at the tape output balanced was The preamp is noninverting from its inputs to its main outputs, and in the balanced mode pin 2 is positive, pin 3 negative.

Note that as the level control is reduced, the small rolloff at the high end flattens out. As is typical, capacitive coupling between channels causes the crosstalk to increase at higher frequencies. Distortion is very low across the full range, even with the commonly encountered slight rise at higher frequencies.

The test frequency was 1kHz. The rise at lower output levels is due, as usual, to noise. Finally, the distortion spectrum of a 50Hz input at a high output level of 5V is shown in fig. The third harmonic predominates, but at dB about 0. At a more typical output of 1. With the exception of the moderately high output impedance at maximum settings of the level controls, the measured performance of the Aleph P is first-class. Even its deepest interior recesses show pride of workmanship and attention to detail.

Ergonomically, the Pass Aleph is simple yet quite functional. It is an exercise in minimalism: How much can be eliminated to ensure maximum fidelity? Anything less than absolute and utter sonic neutrality is a reduction in fidelity, and ultimate fidelity is what the High End is all about. Complete transparency must be the ultimate goal of any piece of high-fidelity equipment, especially a preamplifier.

For many audiophiles, using a passive balanced preamplifier or no preamplifier at all is impossible. This is unfortunate. For everyone who must use an active line-level preamplifier with 20dB of gain, the Pass Aleph P is a great way to go. The Aleph P is an exceptional-sounding unit.

It is quiet as death, with only a bit of subtractive coloration separating it from absolute neutrality. I believe the P to be sonically competitive with any active preamplifier on the market, regardless of price.

Need I say more? How gratifying. Nelson Pass, never content to sit on, stand on, or do whatever he does with his laurels, has produced a preamplifier to go along with his Aleph series of amplifiers. This component shares more than just the name Aleph with its beefier brethren; it even uses the same output devices.

What is black, has four knobs, and could be dropped off a second-storey window without sustaining any major damage?

Laminate Flooring Edition 1 ALEPH

This set of circuit boards will make the Aleph J amplifier of Nelson Pass. This amplifier is a direct descendant of the legendary Pass Labs Aleph 3, the amplifier that turned the audio press upon it's ear, brought single-ended amps to many people, and catapulted Pass Labs into the forefront of specialist audio engineering and construction, where it still resides today. Populate these boards with your components, then add your own power supply, chassis and heat sinks to complete the amplifier. It utilizes the Nelson Pass 'Aleph Current Source' to greatly increase the overall efficiency of the output stage, with the benefits of more linearity, a higher damping factor, and greater stability into tough speaker loads, doing all this with less negative feedback than it's predecessors. The Aleph J is a regular kind of amp - a voltage source amplifier, requiring nothing out of the ordinary from the preamp or the speakers. See the build guide for details. The 4U 'Jack of all Chassis' is ideal for this amplifier.

Nelson Pass

Parador laminate flooring Edition takes individual flooring design to a completely new level: with twelve international top designers, who give their creative side free reign exclusively for Parador. Remarkably beautiful: floors in art print quality with. Stylepark-ID: Remarkably beautiful: floors in art print quality with ultimate colour brilliance and intensity. Material laminat Colors shades of blue. In the interview with Uta Abendroth he explains, in which way designers, architects and manufacturers can advance the design of floorings by thinking outside the box and new material compositions. There was a time when floor coverings were called carpets, parquet or tiles. We visited the Domotex fair and now know and what takes off when it gets floored.

Pass Labs HPA-1 Class A Headphone Amplifier Now Available

This privacy statement describes how PassDIY collects and uses the personal information you provide on our Web site: passdiy. It also describes the choices available…. For over ten years, the Aleph series of single-ended Class A amplifi ers have received praise for their outstanding sonic defi nition, warmth, and smoothness; and have often been compared favorably with the very best tube amplifi ers. The Aleph topology achieves state-of-the-art performance with a very simple linear design, and is additionally one of the most stable and reliable audio amplifi ers in existence. A considerable number of audiophiles have found themselves bi-amping their loudspeakers, putting Pass X amplifi ers on the bottom for power and control, conjoined with Alephs on the top for that smooth warm midrange and top end.

DIY Aleph J: A Build Guide

The Pass Aleph P design philosophy can be summed up in one word: simplicity. Its exterior styling is positively austere. The rotary selector on the left side has just four dots to delineate each of the four possible input selections. The master gain control knob on the right has only a slit for a setting mark. The front-panel center is populated by a glowing blue light and a pair of knobs to control the gain of each channel.

Aleph P lass A SE MOSFET pre-amp PCB one channel

Nelson Pass is certainly one of the major technical figures in the international Hi-Fi community. He owns a large number of international patents like, for instance, the dynamic Class A. During the seventies and eighties, he had people dreaming of his spectacular products, such as the Threshold: I still remember the Threshold preamplifier that was my dream for years, and it still is now, maybe unconsciously, my favorite model, thanks to its design simplicity and its very accurate board's aesthetic design. Nowadays, Pass has created his own company, namely Pass Labs, that is producing his designs; it sports two series of products, a budget oriented one in a manner of speaking Unfortunately, Pass gave up the Aleph range at the beginning of - yet Aleph components obviously can be found in the second-hand market at decisely attractive prices. OTOH, although I already knew their production had ceased, when I was told I would probably be given this stuff to test, I didn't think, even for a minute, that I would refuse

Pass Labs Aleph P Preamplifiers

Pass Labs Aleph 1. I am selling a complete set of Pass Labs electronics including an Aleph Ono phono pre-amp, an Aleph P remote pre-amp and a pair of Aleph 1. I purchased the amps new in and purcha. My Pass Labs Aleph P which has given me years of aural pleasure.

Pass Labs Aleph 3 Circuit - High Power Duel Mono 30W Pure Class A Power Amplifier

Preamp design Aleph P 1. Hello to all Well - excuse me in case if this post is totally dumb, but I had a question - maybe someone coud help me. I just started building a pair of aleph's 2 well - ok - ordered the parts for the first stage and I am thinking about suitable preamp too. My problem is that I want to create a sort of modular preamp - since if my aleph's will be successfull I plan later to expand to a nice cinema sound canton speakers.

Aleph l schematic

What Hi-Fi? For OTA circuits that use negative feedback,. A shunt regulator option is available. The AMP contains four 20W linear, transconductance amplifiers for driving brushless motors with sinusoidal commutation. An op-amp with negative feedback is a perfect candidate for such a task: Another name for this circuit is transconductance amplifier. Figure 4.

Shortly after I have decided to build the Aleph JX power amplifier, I came to the conclusion to build a whole system with the Aleph philosophy. I started to build the Aleph P Ver. I choose the Aleph P in the 1. The preamplifier circuit and the analog power supply is taken from the original schematics with nearly no changes.