Hafler DH-200/220 Mods - Page 114 - 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 31st March 2013, 04:00 AM   #1131
Rick G is offline Rick G  United States
diyAudio Member
 
Join Date: Feb 2013
Location: Eminence,MO
Hello all, newbie here. I recently bought a DH-200 on Ebay. It does work, but upon inspection, R39 on Both Chl's is blown. Can any one tell me what is the function of R39 on PC-6. It is supposed to be R2.2 1/2 watt.

I have been reading thru this thread and plan on making most if not all of your collective mods.
Thanks,
Rick
  Reply With Quote
Old 31st March 2013, 06:37 AM   #1132
diyAudio Member
 
Stormrider's Avatar
 
Join Date: Apr 2006
Location: Connecticut
Blog Entries: 2
Send a message via AIM to Stormrider Send a message via MSN to Stormrider
Quote:
Originally Posted by ouimetnick View Post
Guys, I'm sad to report, but diyAudio member Dick West (Richard Westenskow) has passed away at 82.

diyAudio - View Profile: Dick West

He will be missed by the community and I will miss him deeply. He knew everything that there is to know about Hafler amps. I learned a great deal from him! He also was the guy to go to if you needed your MOSFETs tested and matched. He had a rare Hafler MOSFET Checker/Matcher. He was a very kind person.

Rest in peace.


Rockford Register Star

Obituary Notices: Week of Feb. 27-March 5, 2013 | The Rock River Times
This is sad news indeed. I purchased three Haflers from Dick, as well as learned a great deal about Haflers, amp design, and troubleshooting in general from him. I can say that he alone got me into the hobby, as well as helped propel me towards a career that I now enjoy in Electrical Engineering.

Good bye friend, you will be missed.
__________________
AJ
  Reply With Quote
Old 16th April 2013, 11:01 PM   #1133
diyAudio Member
 
Stormrider's Avatar
 
Join Date: Apr 2006
Location: Connecticut
Blog Entries: 2
Send a message via AIM to Stormrider Send a message via MSN to Stormrider
I finally posted the second part of my blog on the repair I did on a DH200 if anyone is interested. Please point out any errors you notice.

diyAudio - Stormrider

Not much modifying went on, it's basically the same as the way it would have left the factory... But some may find it interesting.
__________________
AJ
  Reply With Quote
Old 16th April 2013, 11:50 PM   #1134
humble is offline humble  United Kingdom
diyAudio Member
 
Join Date: May 2007
Hiya Rick G please look at Page 40 and post number398 this resistor R39 simply joins the input earth to the output earth, it has varied in value i think from 0.5 ohms to the later 2.2 ohms, it has a nasty habit of burning out as the amplifier can go unstable which increases circulating currents at high frequency around the earth paths, best way if you can follow the advice given in previous posts about isolating the I/P earth and the O/P by taking wires separately back to the main earth star between the main reservoirs, the whole explanation is in those earlier posts, if you feel unable to cope
just increase this 2.2 ohm resistor power rating but don't use any inductive types
wirewound etc you can use two 4.7 ohm in parallel of the 0.6 watt variety which will survive somewhat better best wishes Humble
  Reply With Quote
Old 17th April 2013, 04:14 PM   #1135
Rick G is offline Rick G  United States
diyAudio Member
 
Join Date: Feb 2013
Location: Eminence,MO
Humble,
Thanks for the insight. i have made all the gnd corrections on my dh200 as well as most of the other mods as far as caps & wiring go, and it sounds 100% better to my ears. I think i will use this Ebay amp to try some of the more to me anyway 'advanced' mods. Also as you have said, i adj my bias with meter leads and sure enough, that board is not working now.! will use the blown fuse with resistor from now on. Guess i was lucky first 2 times i did it that way. Now have to figure what all got blown.

Regards
Rick
  Reply With Quote
Old 6th May 2013, 05:59 PM   #1136
diyAudio Member
 
Join Date: May 2013
Does anyone know what the circuit board inductor is?
  Reply With Quote
Old 6th May 2013, 06:37 PM   #1137
diyAudio Member
 
Join Date: May 2011
Location: Beverly, Massachusetts, USA
Send a message via AIM to ouimetnick Send a message via Skype™ to ouimetnick
The inductor is 1.4 H
  Reply With Quote
Old 7th May 2013, 03:30 PM   #1138
diyAudio Member
 
Join Date: May 2013
Quote:
Originally Posted by ouimetnick View Post
The inductor is 1.4 H
Thanks!
  Reply With Quote
Old 8th May 2013, 10:05 PM   #1139
stenks is offline stenks  Serbia
diyAudio Member
 
stenks's Avatar
 
Join Date: Aug 2011
Location: Serbia,Belgrade
Quote:
Originally Posted by Stormrider View Post
I finally posted the second part of my blog on the repair I did on a DH200 if anyone is interested. Please point out any errors you notice.

diyAudio - Stormrider

Not much modifying went on, it's basically the same as the way it would have left the factory... But some may find it interesting.
Very nice ..
  Reply With Quote
Old 8th May 2013, 10:17 PM   #1140
stenks is offline stenks  Serbia
diyAudio Member
 
stenks's Avatar
 
Join Date: Aug 2011
Location: Serbia,Belgrade
Smile Power supply BUS wire correction

I finally found some time to correct the problem with the power supply, also bought a VDH CS 12 wire has cost me a small fortune.

Click the image to open in full size.


Click the image to open in full size.

Last edited by stenks; 8th May 2013 at 10:20 PM.
  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 dh110 mods anyone? amp_guy Solid State 5 30th January 2011 01:57 AM
Hafler xl-280 mods Audionirvana Solid State 5 11th November 2010 05:25 AM
Hafler DH 101 preamp mods Zen Mod Solid State 6 3rd May 2004 01:24 AM


New To Site? Need Help?

All times are GMT. The time now is 11:52 AM.


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