| | |
| | |
|
Moving Coil Phono Step-Up Kit 
The problem of getting enough gain to use a moving coil phono cartridge with a preamplifier designed for moving magnet cartridge use without lots of noise is easily solved using a Lundahl LL9206 or LL1678 transformer. These transformers are used by several high-end audio manufacturers for this same purpose. This kit provides two channels of transformer-based MC Step-Up. The kit includes connectors, transformers, PC boards, wire, hardware, and enclosure. The enclosure is a black powder coated diecast aluminum case that provides exceptional RF shielding. The wire used in the kit is the excellent AG23 silver wire made by DH Labs. The RCA connectors are rhodium plated Cardas units. You can set this unit up for 14, 20 or 26 dB of gain. The kit can also be supplied with the LL1678 transformer for 18, 24, or 30dB of gain. The K&K Audio MC Phono Step-Up Kit is not really "newbie" kit, but can be constructed successfully by anyone with good mechanical skills and some soldering experience who can follow instructions. Included with the kit is a step-by-step instruction manual. K&K Audio stands behind you as you build with telephone/e-mail support, however if you feel that this kit is beyond your skills/inclination, we offer it assembled to your specifications, as well. Moving Coil Step-Up Kit: $290
Single-Ended Triode Phono Preamplifier Kit 
The family of K&K Audio Phono Preamp Kits accommodate just about all of the LP playing needs that anyone could have at price levels that accommodate a range of users. The kit is equipped to handle moving magnet or moving iron cartridges and, for moving coil cartridges, an input transformer can be added to step-up the lower cartridge output voltage. The circuit was developed to combine the best qualities of tubes and semiconductors and achieve a better result than could be had with either technology alone. The first stage for a moving magnet cartridge consists of a very high transconductance JFET / triode (6N23P/6DJ8/6922/7308) cascode amplifier. This stage is capable of very high gain (about 50dB) with very low noise. An all tube cascode could have been used, but without the simplicity and noise performance of the hybrid approach. The hybrid cascode drives a precision passive RIAA network. This feeds a constant current source loaded triode that is transformer coupled to the outside world using the parallel feed configuration. The lack of DC in the output transformer primary allows the use of a very high quality cobalt amorphous core transformer made by Lundahl Transformers, or, for economy’s sake, an excellent high nickel core Lundahl transformer. Because the output is transformer coupled, both balanced (XLR) and unbalanced (RCA) connections can be used, achieving the same excellent sound. The power supply is a robust choke-loaded design and the kit builder is given the option of using either solid state (FRED) or vacuum tube rectification, based on sonic taste. 
There are two levels of Phono Preamp Kits: Basic and "Maxxed-Out". The Basic kit uses high quality parts such as Kimber and Nichicon Muse capacitors, and Mills, Holco and PRP resistors to achieve the best sound in its price class. The Maxxed-Out Kit uses Cardas, Black Gate and Mundorf caps, and Caddock, Mills, Holco, and PRP resistors for the best sound, period! The circuit topologies (and the PC boards) of the two levels are the same, so it is possible to upgrade the Basic Kit to the Maxxed-Out Kit, as resources allow. The K&K Audio Phono Preamp Kits are not "newbie" kits, but can be constructed successfully by anyone with good mechanical skills and some soldering experience who can tell the difference between a resistor, a diode, and a capacitor, and can follow instructions. Included with the kit is a 20+ page instruction manual and a CD-ROM with pictures illustrating various steps in the process. K&K Audio stands behind you as you build with telephone/e-mail support, and, if necessary, will finish/troubleshoot a complete kit for a modest time-based fee. You have the option of purchasing either Main Board Kits to which you must add power supply magnetics, switches, connectors, and an enclosure; or Complete Kits, which include all of the parts necessary for a complete phono preamplifier, except the solder, tools, and the time to assemble it. Furthermore, you can add options to either kit to enhance its usefulness in your music system. Mono/Stereo switching and stereo Volume controls are available as options on both versions. The specifications for the two levels are:
See the K&K Audio Phono Preamp Kit schematic here. Basic Kits The Basic Kits are currently in the instruction-writing phase and more details will be available soon. We are targeting a Basic Complete MM Phono Kit for well less than $1000. Selected upgrades will also be offered to reduce the sonic gap between the Basic Kit and the Maxxed-Out Kit. Maxxed-Out Kits Main Board Kit 
All of the parts (except power supply magnetics, switches, connectors, MC input components, and an enclosure) are included, as well as detailed assembly instructions and a CD full of assembly pictures, to build a 37/43dB gain moving magnet phono preamplifier circuit. Maxxed-Out Main Board Kit: $799 Complete Kit The Complete Kit contains every part for building a high-end phono preamplifier comparable to the best on the market. In addition to the features mentioned above, the Maxxed-Out Complete Kit includes:
Maxxed-Out Complete Kit: $1899 
There are several options for the Maxxed-Out Complete Kit that can be easily installed at the time of building the unit. For you mono Beatles LP fanatics, we offer a front panel Stereo/Mono switch. We use a very high quality Seiden switch (as we do for the Polarity/Mute switch) to combine the left and right channels to derive a mono signal from a stereo cartridge output. The output impedance of the K&K Audio SE Phono Preamplifier is low enough to drive a volume control directly, thereby facilitating phono-only systems without the need for a line stage preamp. This is a shunt-type volume control that puts two fixed, low value Caddock resistors in the signal path, preserving the balanced/unbalanced output versatility. The variable shunt element is custom constructed from a 23 position Seiden switch and discrete Holco/PRP audio-grade metal film resistors. Only one resistor is present as a shunt element at each volume control setting in each channel. Lastly, my personal favorite among the parafeed coupling capacitors I’ve auditioned to date is the Cardas 4.7mF 600v capacitor. These are not used as a standard part in the kit due to the significant added cost and the close performance of the less expensive Mundorf Silver/Gold capacitor. But if you must... Stereo/Mono Switch Option: add $100
Original SE Phono Preamplifier Upgrade Kits Every audio product can be improved. Since the original version of the SE Phono Preamp was developed I have auditioned modifications, some of which actually improved the sound. However, none of these changes really offered the sonic value that the price of the modifications would have suggested. These modifications do. They consist of parts manufacturer changes and parts value changes. These modifications have already been incorporated into the Basic and Maxxed-Out Kits described above, so are only applicable to older, "original" kits. If you bought an assembled K&K Audio Phono Preamplifier Kit on the used market, call and we can tell you how to determine the upgrade status of your unit. Original SE Phono Preamplifier Capacitor Upgrade Kit The Cardas capacitors supplied with this kit are the most reasonably priced, transparent capacitors that I have listened through. They are excellent. The value of the interstage coupling cap has been reduced substantially. This helps mitigate the effects of poor cartridge/tonearm matching that can result in large subsonic resonances. Even in the absence of resonances, the bass is rendered more harmonically correct with this change. Original SE Phono Preamplifier Capacitor Upgrade Kit: $85 Original SE Phono Preamplifier Input Stage Upgrade Kit Transparency, bass extension, and naturalness can be improved by reducing local feedback in the input stage and operating the input stage at a higher bias current. Replacement JFETs, new source resistors, and Black Gate source resistor bypass capacitors comprise this simple, but sonically profound upgrade. Original SE Phono Preamplifier Input Stage Upgrade Kit: $40 |
1004 Olive Chapel Rd.
Apex, NC 27502 USA (919) 387-0911 Mon-Fri 8 a.m. - 5 p.m. EST
E-mail
