Hafler dh-200 switch - diyAudio
Go Back   Home > Forums > Amplifiers > Solid State

Solid State Talk all about solid state amplification.

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 15th March 2006, 05:33 PM   #1
diyAudio Member
 
Join Date: Mar 2006
Location: La
Question Hafler dh-200 switch

Hi all. Newbe here. First I want to thank all who are helping me in another thread here.

I was just given a Dh-200 with a bad on\off switch. I went to radio shack and bought another 3 prong switch. Replaced the switch the excact same way the bad switch was. Plugged the amp in and blow the main fuse. The switch I bought is a 3 prong switch similar to the original, different look but same 3 prong. I'm lost as to what went wrong.

I did a search on this amp here and WOW, there are threads that last forever. But I patiently read through all of them and came up empty handed.

I also plan on bridging this amp for a sub amp. Is this a good idea? Does Hafler still make the bidgeing kit? Also, is there a way to bridge it without the kit?

I know i have alot of questions and I appreciate everyone's patients. Any help would be appreciated.
  Reply With Quote
Old 15th March 2006, 05:50 PM   #2
anatech is offline anatech  Canada
diyAudio Moderator
 
anatech's Avatar
 
Join Date: Jun 2004
Location: Georgetown, On
Hi jakelm3075,
You may have damaged the new switch now.

There is a feed contact, a contact to the transformer and another that goes to the other side of the line (for the light). There is no standard way to hook them up. You need to look at the diagram for the new switch and change the wiring.

The DH 200 is a nice sounding amp, it should be "gone over". I am not a fan of bridging amplifiers. Do you have two subs or just one? Use one channel if you have only one.

You are lucky to have been given one of these. It's a nice classic.

-Chris
  Reply With Quote
Old 15th March 2006, 06:18 PM   #3
diyAudio Member
 
Join Date: Mar 2006
Location: La
I have one 12" MTX powered sub 4ohms with 100w plate amp. I'm rebuilding the box and changing the tuning FR. I was going to use the plate amp it came with, but not if the Hafler will do a better job at driving it. I read alot about bridgeing this amp with the kit. But it does seem like a big project, becides the fact that you have to spend more money on the big kit. But at 100w @ 8ohms in one channel. A 4ohm load on just one channel wont hurt it?. I would like to use all avaliable wattage the amp could provide, but like I said, it seems like a big project, unless I could bridge it out without buying a kit?

But first I need to fix that darn power switch.
  Reply With Quote
Old 15th March 2006, 06:51 PM   #4
diyAudio Member
 
BobEllis's Avatar
 
Join Date: Sep 2003
Location: Upstate NY
there may be a reason that the switch went bad - you might want to run it up on a variac or with a light bulb in series with the amp next time you turn it on. Hopefully nothing in the amp is blown.

for bridging see http://sound.westhost.com/project20.htm It's not the best way to bridge an amp, but suitable for subwoofer use.

WARNING! your four ohm sub will be seen by a bridged amp as a two ohm load. It probably won't like it much. You're better off using just one channel and/or adding another sub
  Reply With Quote
Old 15th March 2006, 06:58 PM   #5
diyAudio Member
 
Join Date: Mar 2006
Location: La
Thanks Bob. So it would be better to just run the 4ohm sub off of one channel? Also, will I have a gain issue? Since I will be using my sub preout to the amp. Will I need an additional preamp to adjust sub volume?
  Reply With Quote
Old 15th March 2006, 06:58 PM   #6
anatech is offline anatech  Canada
diyAudio Moderator
 
anatech's Avatar
 
Join Date: Jun 2004
Location: Georgetown, On
Hi jakelm3075,
See Bob's post above. If you want to use all the power, do get another speaker or just use one channel.

Other things happen when bridging, such as losing 1/2 of the damping factor. That and there is only 3dB difference (just audible) so why bother? With another speaker you will reduce the average voice coil temperature (you may then have the same power and more headroom) and also the excursson for each driver. SOunds like a win-win to me.

-Chris
  Reply With Quote
Old 15th March 2006, 07:12 PM   #7
diyAudio Member
 
Join Date: Mar 2006
Location: La
Like I said I'm rebuilding the MTX sub system. I do have a PSW10 Polk Audio 10" powered sub that I can bypass the built in amp on there and run both subs. But I would rather run 4ohms into each channel then 8 ohm bridged. The reason for 8ohms bridged is because I will hook them up in series so I dont drop down to 2 ohms. I think 2ohms would cause alittle instability in the amp and have the amp run alittle too hot.
  Reply With Quote
Old 15th March 2006, 07:30 PM   #8
diyAudio Member
 
Join Date: Mar 2006
Location: La
Quote:
Originally posted by anatech
There is no standard way to hook them up. You need to look at the diagram for the new switch and change the wiring.


-Chris

But Chris, excuse the ignorence. But isnt all 3 prong switches the same? I just disconnected one wire at a time and put it in the same place on the other switch. That should have worked right? Also, what is that little round resistor that connects the middle prong to the bottom prong? Could that have been damaged and cause the short?
  Reply With Quote
Old 15th March 2006, 07:31 PM   #9
diyAudio Member
 
BobEllis's Avatar
 
Join Date: Sep 2003
Location: Upstate NY
With solid state amps you do not select the 8 ohm or 4 ohm tap, you just hook up hte load and it is what it is.

With a single 4 ohm speaker as a load, use only one channel.

With 2 four ohm speakers, use each channel individually. Especially if they are not identical.

A bridged amp will see the load you connect as half of what it is. Because a bridged amp swings twice the voltage, the load draws twice the current. So an amp rated for a 4 ohm load should handle an 8 ohm load bridged. But it would not necessarily handle a 4 ohm load bridged, since the amp has to deliver current like the load was 2 ohms.

That round thing probably has a number like .005 on it and is a capacitor to limit the arcing that occurs when turning the amp off. That should not cause your problem
  Reply With Quote
Old 15th March 2006, 07:40 PM   #10
diyAudio Member
 
Join Date: Mar 2006
Location: La
Quote:
That round thing probably has a number like .005 on it and is a capacitor to limit the arcing that occurs when turning the amp off. That should not cause your problem
So I could accually remove that capacitor? I didnt knwo if it was to ajdust the voltage going to the light or what. Thanks for the input.

Back to the gain (volume) subject. Do any of you forsee a problem with this being I'm going straight from sub preout on receiver to amp?
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Hafler 9500 Power Switch partialresponse Solid State 1 22nd October 2009 07:12 PM
Hafler XL280 Thermal/Heat Switch? RnR Solid State 3 16th July 2009 04:33 PM
switch-on, switch-off sequence for preamp/amp cbutterworth Tubes / Valves 1 2nd March 2007 12:41 PM
Never try to switch 450V DC at 3A with a conventional mains switch... Eva Power Supplies 28 1st November 2006 09:24 AM
Using a momentary switch for main power switch? FullThrottleRic Parts 9 25th June 2002 08:23 PM


New To Site? Need Help?

All times are GMT. The time now is 12:08 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2