Important thought!


The planning and hoped for results with any of our mods will depend, to some degree, on the underlying health of the original amp. Consider these helpful improvements.


Hafler Pro Amplifiers


We have given short shrift to these amps so let us begin to remedy that. The PA-XX series mods will work fine in Pro Series amps such as the P500(not PA-8), P225, P230 and so on. The kit prices are same, but some amps require more labor, i.e. installed prices go up. Other modifications touted for the home versions work quite well. Our instructions are aimed at home versions.


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PA-8 is here!


PA-8, for Hafler DH-200, DH-220, XL-280, is a physically larger PA-7 with directly mounted power mosfets.


PA-8 Features:



PA-8 Eliminates:



PA-8 is installed only for now. PA-8 has 12 new MOSFETS. Elite version is $899.00 installed, Ultra version is $1099 installed. Kit is coming, uh a little slowly.

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New PA-7.3 Hafler Driver Boards


The PA-7.3 is a new version of the PA-7 retaining the heart of the original but with sonic improvements and much simpler to install than the PA-7 V2.  Kit and installed version ready.

Elite and Ultra driver boards are now ready to install into Hafler DH-200/220, XL-280, DH-500 and XL-600 amps. Introductory price: Same As original PA-7 Ultra for now. See prices below.


PA-7.3 - Vision for excellence >Proper image to be added soon!


The Design: Our designer John Hillig has refined the PA-XX series modifications over many years. This research created new circuitry enhancing clarity and transparency without brightness or ‘etching’. You know that ‘forced detail’ sound you probably know too well with ‘high-end’ gear. With a laser focus we fashioned a new path to a new level of excellence.



The PA-7.3 is a tweaked-by-ear amplifier circuit. MOSFETs, the OEM Hafler output devices, are very easy to drive. A traditional higher current, Class-B driver stage, is not required resulting in a simpler Class-A transconductance stage(VAS) which does a great job. We used wideband video transistors for their minimal loading of the input stage. They also need only a minimum of compensation.





The PA-7.3 Sound: This is no mere Hafler. No, we don’t demean this great basic amp design which so many still love. Still the music lover ‘ear’ always wants more. PA-7 V2 is a great amplifier in a Hafler chassis. The word fidelity is big, not just a marketing term. You want to feel a connection to the vocalist and background vocalists too. You want to hear instruments in a striking, natural way. You want true tonal structure and timbral clarity of each instrument. Voices are clear, full-bodied and so intelligible that emotion is conveyed in the performances at a new level. You feel the mood, the intensity of the performer. Many will hear ‘new’ background vocals singing along with the lead vocal or the multi-layered vocals of the performer overdubbing ‘background’ vocals. There is a sense of gut solidity, simple majesty and air-moving power that must be heard. If your speakers play deep you’ll be thrilled. PA-7.3 amps will easily compare to the finest sounding amplifiers available today.



PA-7.3 New Highlights:



NOTE: (PA-7.3 photo to come soon)PA-7 kit shown has the PA-7 Ultra version boards featuring Audio Grade caps, premium resistors, more.  View the PA-7 kit installation instructions.


>>Information for kit builders. All of our front-end boards are fully tested in an actual power amp design. Settings for DC Offset and Bias are roughly dialed-in to test the function of these adjustable settings. <<



Options? Visit these pages - Amp Options  including maintenance suggestions, power supplies PS-200

See our "Connector" page for RCA jacks, binding posts, IEC sockets!




PA-7.3 Modification Range


NEW!  PA-7.3 Elite/Ultra Modification


Elite has great naturalness. The Elite version does a tremendous job. Then the Ultra ups your game with even better imaging, focus and delicacy. Superb sounding caps are used in the and front-end power supply. Feedback loop has Muse Audio-Grade caps on the PA-7 Elite for higher resolution, crystal-clear frequency extension, clarity and just plain naturalness.


Ultra adds near complete premium audio grade resistors array, superb front-end power supply caps.


These kits include: additional installation parts including hookup wire, solder, capacitors, etc.


>>Price Schedule<<


PA-7.3 Elite driver boards:  $529.00 kit, $679.00 installed

PA-7.3 Ultra driver boards: $629.00 kit, $829.00 installed  - Kit or installed includes Premium RCA jacks


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 Budget choices


PA-7 V2 still available - Reduced $100 - Call for availability

PA-7 V2 Elite driver boards: $429.00 kit, $579.00 installed

PA- V2 Ultra driver boards: $529.00 kit, $729.00 installed  - Kit or installed includes Premium RCA jacks


PA-6 Elite Modification Range - Reduced $ from original


  These kits includes additional installation parts including hookup wire, solder, capacitors, etc.


PA-6 Elite driver boards: $249.00 kit, $379.00 installed

PA-6 Ultra driver boards: $349.00 kit, $479.00 installed


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*PLUS UPGRADES FOR ALL PA-XX VERSIONS*


You not only want superior sound but extended reliability and confidence that you’re getting the best from your power amplifier. You want all this at a price that is unmatched considering the top quality of parts and sound. This more complete modification includes:


PA-XX Elite Driver Boards, pre-tested with all kit installation parts


You will receive a PS-220/500 power supply specialized for your amp, please specify your amp model when you order. See more PS-220/500 versions here, some of these items are on Exotic Parts page.


PA-XX Elite Plus for Hafler DH-200/220, XL-280 series amps:   Add $499.00* kit   -   $699.00* installed     

PA-XX Elite Plus for HaflerDH-500/XL-600 series amps:   Add $580.00* kit   -   $780.00* installed


 

OPTIONS FOR ALL PA-XXX VERSIONS


For Hafler DH-200/220, XL-280


PS-220M with 10KuF/80V premium caps, add $100 to either kit or installed price  

PS-200M with 10KuF/80V  great performance caps, Add $120, kit or installed

  

OPTIONS FOR DH-500, XL-600


PS-500M power supply , 8 premium 10KuF caps in CRC connection - add $690 to either kit or installed price above.


*For PA-7.3 Ultra driver boards add $250 to kit and installed pricing above.



Full PA-7.3 Ultra Modification

Our PA-7.3 Ultra mod is truly State of the Art and beyond State of the Art in sound as it is offered by so-called high-end manufacturers. Although we at Musical Concepts have modified many expensive well known amplifiers we've never seen build quality close to the Ultra. The superb resistors are used in nearly all slots for all Ultra driver boards. For all amps the Ultra also includes a new high in-rush current, silver-alloy power switch and a upscale IEC power cord socket with hi-current cord. Just imagine what this incomparable product might sell for if it had some fancy over-hyped manufacturers name on the front panel. This is the finest mod we have to offer.


PA-7.3 Ultra modification includes


Cardas Gold/Rhodium RCA Jacks - jewelry look, smooth, clear, solid sound

Cardas Gold-Rhodium(or Copper) Binding Posts, elegant rock solid connections, liquid sound - choose gold or copper




PA-7.3 Ultra for DH-200/DH-220/XL-280/P225/P230:  $2550 installed only - add $100 labor for “PRO” amps


PA-7.3 Ultra for DH-500/XL-600:   $2895 Installed only - add $100 labor for PRO-500, consult for ‘noisy’ fan solution


>>>>Please Make Your Choice >>>  Keep or remove speaker fuse and output relay for more purity

Hafler Amplifier Modifications