β22 gallery - Page 2
tedro's β22Tedro's 3-channel active-ground β22 and σ22 PSU are housed in a striking home-made clear acrylic enclosure. Even the volume knob and feet are clear acrylic. This β22 features Nichicon Muse electrolytic capacitors, all matched transistors, Alps RK27 volume potentiometer, and Neutrik locking headphone jack. The σ22 is powered by a 80VA toroidal transformer. Internal wiring is silver-plated copper. Despite the lack of EMI/EFI shielding from the case, Tedro says that the β22 is silent with any headphones he uses.       
β22 by ferrariFerrari built his elegant β22 amplifier and σ22 power supply in ATI 737U and HiFi-2000 Galaxy Max 283 (with 10mm faceplate) cases, respectively. The 50mm volume control knob is from DACT. Amphenol circular connectors are used for the power umbilical.The β22 is in 3-channel active-ground configuration on an ε22 backplane board. All electrolytic capacitors used on the amplifier boards are Black Gate Std. and the small values capacitors are MKT, MKP and polystyrene. Manganin 1% resistors (type PBH) are used at the output while Vishay-Dale RN55D resistors are used on the remaining part of the amp. All BJTs are matched within 5% . The volume control is an Alps RK40 "black beauty". The switch on the front of the amp is prepaired for use as an on/off switch, which will be implemented later. The σ22 includes an AC line filter module rated at 6A and a 120VA toroidal power transformer from Sedlbauer AG. The electrolytic capacitors used on the PSU are Panasonic TS-HA and Nichicon Muse KZ. Small values capacitors are MKC and MKP. The output voltage of the PSU is set to ±30V. All heatsinks used are 2" tall.        
n_maher's β22This one-box β22 and σ22, built by n_maher, is housed in a Par-Metal 20-series enclosure with clear anodized face plate and custom hammered-black painted body and rear panel. A custom "Nugget Audio Beta22" badge, made by Front Panel Express, is backlit by two blue LEDs. The power switch is a NKK LB illuminated pushbutton, custom modified to use a diffused lens. The volume control is an Alps RK40 "black beauty". On the rear panel, there are two switched RCA input pairs (via toggle switch) using Cardas GRFA jacks. Speaker output binding posts from Parts Express are also present for small bookshelf speakers and AKG K1000 headphones. The β22 amplifier boards are in 3-channel active-ground configuration, mounted on an ε22 backplane board. Belden silver plated copper wiring is used throughout the internals.For the σ22 power supply, an Avel-Lindberg 80VA 30V+30V toroidal transformer is employed. A Hammond steel box (painted hammered black) encloses the transformer, and a total thickness of 0.1" of High Saturation Magnetic Alloy (from lessemf.com) between the transformer and signal wires on the ε22 backplane along with another 0.04" on the top of the transformer to shield against magnetic interference. This was needed to make the amplifier hum-free with highly-sensitive headphones like the Etymotic ER4P. is a look at the inside of the transformer box.        
β22 by rjkdivinThis 3-channel active-ground β22 employs a single ATI 645T chassis for the amp and σ22 PSU. The case is a tight fit front-to-back for the amplifier boards (mounted on a ε22 backplane board) and PSU. There is a aluminum divider wall between the amplifier and PSU sections, with grounded copper foil on one side and mu-metal on the other. Originally an Alps RK40 pot was planned but it wouldn't fit in the confines, so an RK27 pot was used instead. Screened cutouts were added to the case-top cover to improve ventilation.All parts selection are as recommended in the parts list, with a voltage gain of 8. Rjkdivin describes the sound quality as "amazing", "featuring an absolutely black background and full spectrum but non-fatiguing listening." Rjkdivin is now building a 4-channel balanced β22 to complement this one, using full-size offboard heatsinks and dual σ22 PSUs.        
Balanced β22 by cotdt and pageman99This 4-channel balanced β22 was built by cotdt for his buddy, pageman99. A vintage Kenwood integrated amplifier case was used to house the amplifier. Pageman99 fabricated a custom aluminum front panel with laser-etched labels. The four β22 boards fit perfectly inside, and the σ22 PSU was mounted outboard in a cookie jar. Superbright blue LEDs light up the interior of the amp to let you know it's on.Even though each amplifier board is configured for the default 8x gain (for an effective 16x), a gain switch allows pre-attenution of 0dB, -10dB or -30dB. This allows the amp to be used with a very wide range of headphones of differing impedance and sensitivity. A Goldpoint 25K quad stepped attenuator is used for the volume control. For the input, the user may select (via a switch) from one balanced XLR pair or two RCA unbalanced pairs. There is one balanced XLR headphone output pair, two unbalanced TRS headphone jacks, and one set of speaker outputs. A Mute switch to disable the headphones and enable the rear mounted speaker outputs. Switchcraft XLR jacks are used throughout for balanced interconnection. Black Gate electrolytic capacitors are used in the power rails, and silver mica capacitors are used for HF compensation. The PSU features a 100VA Avel-Lindberg toroidal transformer. All internal wiring are teflon-coated silver.        
Two β22s by MazukiTwo β22 amplifiers built by Mazuki are featured here. Both are 3-channel active ground configurations in a single chassis solution.The first one, shown in the first 6 photos, was built for ast. It is housed in a Par-Metal 20 series enclosure with black cover and panels. The three β22 boards are mounted on an ε22 backplane board. The σ22 PSU is fed by an Avel-Lindberg toroidal transformer, which is mounted inside an internal box. The illuminated power switch on the front was sourced from ebay. The stepped attenuator is a DIY kit from diyfidelity.com.au. There are two sets of inputs on the back (selectable by a DPDT switch), as well as a set of speaker binding posts. Two headphone jacks are located on the front. All other parts are as recommended on the parts list. The second one, shown in the subsequent 6 photos, was built for budburma. It is housed in a similar but lower-profile black Par-Metal 20 series enclosure with an internal divider. Shielding material from lessemf.com was taped to the divider. Some notable features are the use of an extender shaft to keep the Alps RK27 volume pot in the back near the input jacks. There are two switch-selectable RCA input jacks, one set is controlled by the volume pot while the other set is unattenuated to be use with a dedicated pre-amp. All wiring is done using teflon coated silver plate copper. Some of the electrolytic capacitors used are Nichicon Muse KZ series. The toroidal transformer is a 80VA Avel-Linderg unit.            
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