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Modding Hafler Amps?

Hi all. I've been away from the boards here for about a year, but I've got the audio bug...again.

The power switch on my Hafler DH-500 broke last month, giving me the lame excuse I needed to fork out the bucks to have it modded. An internet search found not only John Hillig (Musical Concepts), who I already knew about, but also Van Alstine. Has anyone compared the mods to recommend which company I should use to mod the amp? I'm not looking for all the exotic stuff- I just want the most bang for my buck.

Then the next problem: I also have a McCormack .5 amp (Rev A) that I love with my McCormack RLD-1. I could do a number of things - bi amp using both amps (Hafler for bass and McCormack for mid/high), toss the .5 (which I'd hate to do) and use either the Hafler by itself or purchase another used Hafler 500 and have it modded as well for biamping.

I can't really assess power needs right now, as I won't upgrade to speakers that really need the Hafler's power for another year, and I have no idea what speakers I'll buy. I'm thinking if I have more power than I need, no problem. Some day I'll probably want/need all that power, even if not in the near future.

Sorry this is so long, but thanks in advance for your advice!

aggielaw

Showing 2 responses by sean

sean
6,231 posts
 
Van Alstine probably has a greater degree of design experience although he is just learning about the differences in passive parts ( caps, resistors, etc... ). Hillig has probably modified WAY more gear but has more experience with the various sonic attributes of the passive parts that one would normally work with when modding gear. Only thing is, John may not have the technical design prowess that Frank has. So long as one is simply doing direct parts substitutions i.e. upgrading caps, etc.. Hillig may be the way to go. Then again and in your specific case, Van Alstine used to work directly with David Hafler ( if i remember correctly ) and may have greater insight into the actual design of these amps. Obviously, these are just my personal thoughts and ramblings, so take them for what they are worth. Sean
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sean
6,231 posts
 
I guess i was "thinking inside the box" on that one. I agree with the others. That is, there are GOBS of info available about modifying these amps. Much of what either of these guys would do and charge a high hourly labor rate, you can do yourself. That is, it is simply a matter of unsoldering one part and replacing and resoldering with another higher grade part. That part could be capacitors, resistors, wiring, etc... There's nothing hard about doing something like this, but it can seem VERY scary at first. Just take your time and make notes along the way. Having a schematic and then looking at how the schematic equates to the actual parts layout on the board can help you with signal flow and what parts play key roles. Sean
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