LXII modifications for Hafler DH-101, DH-110

A very complete Line stage/Power Supply mod or a full modification including your phono stage is now available for your Hafler DH-101 or DH-110. We are introducing the first model revision in many years. The old version was good enough to have a long run but now we have a real treat for Hafler owners. We have parlayed some of our experience in optimizing our Chameleon tube preamp into useful techniques to enhance the Hafler solid-state preamps. Transform your Hafler into a musically compelling, natural sound quality with a sweeter fatigue quality.

The phono stage receives a thorough refreshing with new film input coupling cap, new RIAA caps and resistors, much lower frequency roll-off point via much larger DC restoring cap in feedback loop. Optionally we can give you higher gain up to a point.

Your line stage is now DC coupled with added phase integrity. Typically there is a capacitor at the input and output which corrupts the signal! An RFI input filter to reduce the wideband noise, more and more a part of our modern environment, yields  quite striking improvements in sweetness and a sense of ease to the music at all frequencies and levels. Larger time constants via FB loop modifications are engineered into the design to give a more spacious stage with better instrument location clues, and an authoritative natural quality.

Power supply is enlarged with superior sounding capacitors, better reference voltage section/stabilization and high frequency bypassing producing better stability and noise performance. This is an important new design feature.

LXII Elite modification utilizes superb quality Nichicon Muse capacitors, superior film caps, Schottky power rectifiers, additional superb sounding resistors in strategic locations and all the great high-quality parts/procedures from the standard modifications. Elite has a more majestic sweep of power and emotion. It gets the musical timbres more correct and complex at the same time. Instruments have a more pinpoint location within the image. At the same time it’s even more relaxed and timbre/tempo accurate. Superb!

Standard Level Modifications for Hafler DH-101, DH-110

LXII Preamp Mod

Line Stage Only Modifications: $319/installed only in line stage. #


LXII Full Preamp Modification(RIAA Phono + Line Stage): $399 installed(full mod) # Full mod includes power supply, phono,line stages.

Update mods for earlier versions(original buyer, 5 yrs old or newer) of our Musical Concepts standard modification: $229 installed only  #

>>Update Mods<< This is for earlier versions(original buyer, 3 yrs old or newer) of our Musical Concepts modifications: $219 installed only for Line Stage version, for ‘complete’ mod $299 installed  #

Elite Level Modifications for Hafler DH-101, DH-110


Line Stage Only Modification:  $399 installed only in line stage. #

LXII Full Elite Preamp Modification(RIAA Phono + Line Stage): $499 installed(full mod) # Full mod includes power supply, phono, line stages.

>>Update Mods<< This is for earlier versions(original buyer, 3 yrs old or newer) of our Musical Concepts modifications: $299 installed only for Line Stage mod, $399 installed only for Complete Mod  #

#Due to the construction techniques used in the DH-101 and DH-110 they are subject to noise and loss of channel issues which are strictly mechanical. Correcting these issues in the right way is time consuming. Extra charges may apply to preamps that are not clear of these issues when they are received for service.

MC-3 Preamp Circuit Board Modification

Phono, line stage and four individual power supplies are on board. Make no mistake! This is a "State of the Art" sound. Preamps with the MC-3 board are often accused of sounding tube-like, vividly three dimensional and very dynamic while retaining a solid bass authority. We plead guilty. The MC-3 fits HAFLER DH-101 - kit available. Factory installation available for the HAFLER DH-101, HAFLER DH-100, DH-110. <<<<<<CUSTOM INSTALLATIONS are available. We have installed this board in many other preamps including the Dynaco PAT-4 / PAT-5, Mod Squad Line Drive, Spectral and even a tube preamp.>>>>>> The OPS-8 listed below is always recommended, and sometimes required. HAFLER DH-100 and DH-110 preamps require the OPS-8 when used with the MC-3

MC-3 circuit card: $549 installed only for DH-101. #599 for DH-110 *Volume control not included with Hafler DH-100/110. Important Note: tone controls/filters are eliminated, those functions are not built in to the the MC-3. On the DH-101 the bass and treble controls are replaced with short bolts for remounting the knobs so that your preamp looks like any other DH-101. With a DH-110/SE-100 the MC-3 in installed like a daughter board. This requires clearing an area of parts on the main board no larger than a resistor to get the board into the low profile of these preamps. Then the MC-3 is wired into the switching/control system of the main board. An outboard power supply must be used in these since the power transformer must be removed or is inadequate for fitting/operating the MC-3.

>>>>For Elite versions, add $100 for Line Stage/Power Supply ( includes outboard power supply mods ), $75 extra for Phono stage.

Update Versions: If you have an older MC-1/2/3 and want to update the unit either ship it in for a quote or snap some pictures and email them to us with any comments on operating issues.  

Hafler Preamp Model 915

Similar in concept to our well respected Hafler DH-101 mod, here we have many mods to line stage, coupling caps, feedback circuit and internal regulated power supply. The quality of the sound is enhanced with wide dynamics, sweet tonal quality and more precise soundstage. An already good product, becomes a finer more sophisticated instrument. Recommended - OPS-4B Outboard Power Supply, described below.

915 mod: $299.00 installed. Elite version is $449.00 installed

Preamplifier Options

OPS-4B outboard power supply is for Hafler DH-101, DH-110, 915 and 945. It has one +30VDC and one -30VDC output. OPS-8 has dual + 30VDC outputs, i.e. dual-mono required for MC-3 circuit board. They are equipped with a quiet toroid transformer and high-quality capacitors. OPS-8 is dual-mono configuration for MC-3 preamp board. 

Expect excellent dynamics, low noise, tonal purity, maintenance of distinct instrumental clarity at even high volumes.

We do a lot of custom power supplies from the basic to the exotic. Call with your ideas.

OPS-4B: $Call(built and tested) with shielded output cable. Installation $75.00

OPS-8: $Call kit (built and tested) with shielded output cable. Installation:$75.00

Hafler Preamplifier Modifications