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- From: gfl@herahera.cc.bellcore.com (lenahan,grant f)
- Newsgroups: rec.audio.high-end
- Subject: Re: Bridged Amps and Hafler DH120 Mods
- Date: Tue, 26 Jan 93 14:19:00 GMT
- Organization: Bellcore, Livingston, NJ
- Lines: 45
- Approved: tjk@csd4.csd.uwm.edu
- (5.65c/IDA-1.4.4 for rec-audio-high-end@uunet.uu.net); Tue, 26 Jan 1993 09:19:04 -0500
- Message-ID: <1k63mnINN4gf@uwm.edu>
- References: <1k3fsaINNkjs@uwm.edu>
- NNTP-Posting-Host: 129.89.7.4
- Originator: tjk@csd4.csd.uwm.edu
-
- (Chris Mouzouris) writes:
- > Hi,
- > I have a pair of Hafler DH120's power amps which I run in bridged mode.
- > I have read that bridged amplifiers can suffer from 'load sensitivity'
- > and am wondering -
- >
- > 1) If this is true?
-
- It can be.
-
- > 2) If so, why?
-
- Because bridged amps run their outputs in serial, thus
- the output impedance is 2X unbridged.
- The Hafler has sufficiently low output Z to be OK bridged,
- but its power supply will current limit sooner than
- really big amps.
-
- > 3) Can this be corrected?
-
- Not practically.
- Keep in mind that alll Krell MDA-series amps run this way,
- so its not really a problem.
- >
- > I am also after any recommendations/information regarding relatively simple
- > upgrades that can be made to these amplifiers. I have already made the
- > following modifications -
- >
- > 1) Replaced the input RCA's (the standard ones are rubbish)
- > 2) Added an IEC mains socket (much more convenient)
- > 3) Replaced speaker cable binding posts
- >
- Dunno about the newer Hafler stuff, but the old (DH200/220) had
- poor sounding bridgeing circuitry. An external "balancing
- module" that does the same thing is available from Sonogy
- , but its kinda costly in comparison to the Hafler equipment.
- Very good, though.
-
- The Haflers also benefit from capacitor upgrades in the
- signal path - many are poor (sonic) quality electrolytics and
- ceramic discs. Film type parallels help significantly.
-
- Grant
-
-
-