DAC25.2

DAC25.2 The Music Hall DAC25.2 is a very nice tube DAC that has a USB input as well as both RCA & balanced outputs. It also has a good headphone amp.

The stock DAC has a very good design architecture but is a little on the soft side when run thru the tube RCA output stage. This is fine if listening to Internet radio but not what we want for quality high definition music systems. In addition, the DAC also has a fully balanced side that is only run solid state. We have designed a comprehensive set of mods that makes this DAC superb. The mods were designed by Chris Johnson, the founder and former president of Sonic frontiers.

There is a clock mod as well as both Level-1 and Level-2 mods for both the RCA tube output stage as well as the XLR balanced solid state output stage. We also have a basic $250 mod to upgrade the headphone amp.

The following details the mods:
Clock mod [$799 + frt. preinstalled, $350 + frt. retro-fit]: We add an upgraded Burson Audio clock to the basic DAC. This improves the bass performance, imaging and midrange performance of the basic unit.
At $799 for a new DAC with the $350 clock mod, the clock-modified DAC25.2 is a very good sub $1000 DAC and considerably better than the stock DAC in both RCA tube and XLR solid state output versions.

Level-1 RCA tube mod [$1.390 + frt. preinstalled, $990 + frt. retrofit, $200 for clock mod if ordered at the same time]:

  • 3 x dual Analog Devices AD8620 SMT op amps mounted on custom DIP adaptors
  • 2 x Mundorf M-Cap metalized polypropylene output coupling caps; 2 x MultiCap RTX tin foil, polystyrene film bypass caps
  • 1 x Russian mil-spec 6h23p-eb “ultra low noise” 6922-type tube to replace the stock tube 
  • 1 x Teflon composite silver-plated tube socket
  • 2 feet of DH LABS 23 awg pure 99.99% pure silver, solid-core hook-up wire, with foamed teflon, tape wrap dielectric
  • 2 x high curren” ultra low impedance, Linear Technology adjustable power supply regulators/ LT1033 & 1085
  • 8 x MUR860 ultra fast, soft recover Hexfred style rectifying diodes 
  • 5 Nichicon bi-polar ES non-polar electrolytic power supply caps 
  • 18 x Takman & Riken Japanese-made audio-grade carbon film 1% signal resistors to replace the cheap stock resistors.
  • 1 6”x12” Soundcoat sheet damps chassis resonances.
  • 4 x small EAR compliant sorbothane isolation feet.
  • 7.5 hours of installation labor

The Level-2 RCA tube mod is all of the above with the addition of [$1.790 + frt. preinstalled, $1.390 + frt. retrofit, $200 for clock mod if ordered at the same time]:

  • 3 x dual Burson Audio discrete op amp modules on custom circuit board assemblies, terminated with DIP spaced flying leads. These parts each contain over 68 parts per module. They are considered the best opamps made and are effectively all discrete parts
  • 9 hours total labor 

The final modified RCA tube DAC is superb. It has just enough tube liquidity to add warmth to many system. It outperforms the Parts Connexion modified Benchmark by a good bit.

XLR Solid State Level-1 mod [$1.190 + frt. preinstalled, $790 + frt. retrofit, $200 for clock mod if ordered at the same time]:

  • 1 x pair of dual Analog Devices AD8620 SMT op amps mounted on custom DIP adaptors
  • 2 x high current ultra low impedance Linear Technology adjustable power supply regulators/LT1033 & 1085
  • 8 x MUR860 ultra fast, soft recover Hexfred style rectifying diodes
  • 16 x Takman Japanese-made audio-grade carbon film 1% resistors
  • 1 6”x12” Soundcoat sheet, for damping chassis resonances
  • 4 x small EAR compliant sorbothane isolation feet
  • 1 x German made HiFi Tuning“Classic pure silver element/end-cap fuse, which uses a ceramic body and is internally damped and cryo-treated
  • 6 hours of installation labor

XLR Solid State Level-2 mod [$1.490 + frt. preinstalled, $990 + frt. retrofit, $200 for clock mod if ordered at the same time]:

  • One matched pair of “dual” BURSON AUDIO “discrete” op amp modules, on custom circuit board assemblies, terminated with DIP spaced flying leads. Over 68 parts per module.
  • Over 7.5 hours labor


Headphone Output Option [$750 + frt. preinstalled, $290 + frt. retrofit]:

  • 1 x Analog Devices AD8620 driver/buffer op amp (mounted on DIP adapter) 
  • 4 x polystyrene filter-network capacitors
  • 4 x Takman Japanese-made audio-grade carbon film 1% resistors
  • 4 x Black-Gate C-series audio coupling capacitors
  • 1.5 feet of Connex BL-Ag pure 99.9% silver, Teflon insulated, shielded interconnect cable 
  • 2 hours labor 

The modified DACs are exceptional performers and the RCA tube mods are a great way to add a little tube warmth to systems in need of some tube liquidity. The Level-2 RCA & XLR solid state mods with the Bursons are truly exceptional.

We accept Visa, MasterCard & money orders. Read our over 10,000 points of AudiogoN #1 rated feedback and then call 770-667-5633 with questions or to order one of these exceptional DAC's.
GA residents add 7% sales tax.

Details of this machine:

  • Electro-Harmonix 6922 tube single-ended (rca) output
  • Solid-state differential balanced output
  • Burr Brown TI PCM 1796 24bit/192kHz DAC
  • TI SRC 4192 asynchronous sample rate converter
  • High precision active crystal oscillator master clock
  • User selectable 96kHz or 192kHz upsampling
  • Asynchronous reclocking and anti jitter control system
  • 8 x oversampling digital filter
  • 4 digital inputs: Coaxial, Optical, XLR(AES/EBU), USB
  • 2 gold plated outputs; single ended (RCA), balanced (XLR)
  • Headphone output with adjustable analog volume control
  • Large high current oversize R-core power transformer
  • Thick brushed aluminum fascia and solid chassis
  • 110v/220v voltage selectable transformer
  • detachable power cord
Music Hall