So, I ebayed this Hafler DH-110 preamp...

Bogie · 19th December 2004, 05:11 PM

...and when it arrived, I plugged everything in...

(normal system has been a Marantz 2230 for the pre, a DH-200, and a pair of Maggie MMGs)

Anywho, something didn't sound right. Got up, walked up to the speaks, and started listening... Ohmigawd! The left speak sounded like something was flapping on the low end... Bad distortion.

Whew. Pulled the DH-110, and plugged the Marantz back in, and the noises went away...

So, is there an "easy" way to troubleshoot this, maybe for what might be a simple fix? Or does this sound like it could be gnarsty?

Thanks!

Zen Mod · 19th December 2004, 06:40 PM

even if basic electronic layout is good ,after all this yrs all that mumbo jumbo patch field (push button fields) is nothing more than PITA. read between the lines

- when you have 5 or more ooooold switches in line with your poor signal .......
I solved this in mine DH110 puttin' several takamisawa mini relays ditto in between rca connectors ,and patch field is now just for relay controling .
thats another story

now I have decent preamp with multi switching for use near my 'puter.
if ya want scan of poodgin' DH just send me a mail.

nuvistor · 19th December 2004, 07:48 PM

I have a $5 DH-110 that worked fine except for the front panel pushbutton switches. Toggling the tone control switch sent large transients on the output. Removing and bypassing the switch fixed the problem.

You may have a similar problem, or perhaps a different problem, like leaky output coupling capacitors or a bad power supply section. In any case some troubleshooting will be needed, using at least a voltmeter and schematic.

A manual including schematic is available here

jackinnj · 19th December 2004, 11:45 PM

at the time this preamp was introduced it received rave reviews -- I still have one built from a kit (bought at the same time with a '220) -- there is a lot of space for mods -- be patient, get the schematic and tinker.

there was also a moving coil preamp sold with the unit (or it could be purchased at a later date -- this is from the era in which CD's were just being introduced).

19th December 2004, 05:11 PM	#1
Bogie diyAudio Member Join Date: Dec 2004 Location: St. Louis	So, I ebayed this Hafler DH-110 preamp... ...and when it arrived, I plugged everything in... (normal system has been a Marantz 2230 for the pre, a DH-200, and a pair of Maggie MMGs) Anywho, something didn't sound right. Got up, walked up to the speaks, and started listening... Ohmigawd! The left speak sounded like something was flapping on the low end... Bad distortion. Whew. Pulled the DH-110, and plugged the Marantz back in, and the noises went away... So, is there an "easy" way to troubleshoot this, maybe for what might be a simple fix? Or does this sound like it could be gnarsty? Thanks!

19th December 2004, 06:40 PM	#2
Zen Mod diyAudio Member Join Date: Jan 2003 Location: ancient Batsch , behind Iron Curtain	even if basic electronic layout is good ,after all this yrs all that mumbo jumbo patch field (push button fields) is nothing more than PITA. read between the lines - when you have 5 or more ooooold switches in line with your poor signal ....... I solved this in mine DH110 puttin' several takamisawa mini relays ditto in between rca connectors ,and patch field is now just for relay controling . thats another story now I have decent preamp with multi switching for use near my 'puter. if ya want scan of poodgin' DH just send me a mail. __________________ my Papa is smarter than your Nelson ! tnx to clean thread ; Cook Book ; PSM LS Cook Book ; Baby Diyaudio FORUM ; Mighty ZM's Bloggg;I'm dumb

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19th December 2004, 07:48 PM	#3
nuvistor diyAudio Member Join Date: Jun 2004 Location: Richmond CA	I have a $5 DH-110 that worked fine except for the front panel pushbutton switches. Toggling the tone control switch sent large transients on the output. Removing and bypassing the switch fixed the problem. You may have a similar problem, or perhaps a different problem, like leaky output coupling capacitors or a bad power supply section. In any case some troubleshooting will be needed, using at least a voltmeter and schematic. A manual including schematic is available here

19th December 2004, 11:45 PM	#4
jackinnj diyAudio Member Join Date: Apr 2002 Location: Llanddewi Brefi, NJ	at the time this preamp was introduced it received rave reviews -- I still have one built from a kit (bought at the same time with a '220) -- there is a lot of space for mods -- be patient, get the schematic and tinker. there was also a moving coil preamp sold with the unit (or it could be purchased at a later date -- this is from the era in which CD's were just being introduced).