Quad 606 modifications - 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 12th February 2005, 06:16 PM   #1
aarsoe is offline aarsoe  Denmark
diyAudio Member
 
Join Date: Jun 2004
Location: Copenhagen
Default Quad 606 modifications

Hi

Does anyone have experience in modding the Quad 606 power amp? I am especially looking for one thing to achieve.
Namely - lower input sensitivity. As it is original, a 0.5V signal will give full power, and I really would like to increase this to at least 2.0V

Should you have other ideas, then please feel free to add..

PS: Schematics can be found here: http://iquebec.ifrance.com/quadfranc...s/schemas.html
  Reply With Quote
Old 12th February 2005, 09:51 PM   #2
diyAudio Member
 
Graham Maynard's Avatar
 
Join Date: Dec 2003
Location: UK
Hi Aarsoe,

I would not change anything within this amplifier as Quad have gone to a lot of trouble to optimise it.

Why not make up an external fixed potentiometer using resistors ?

Cheers ........ Graham.
  Reply With Quote
Old 12th February 2005, 10:00 PM   #3
diyAudio Moderator
 
pinkmouse's Avatar
 
Join Date: Apr 2002
Location: Chatham, England
I agree with Graham, a simple two resistor voltage divider in the input lead seems the way to go to me.
__________________
Rick: Oh Cliff / Sometimes it must be difficult not to feel as if / You really are a cliff / when fascists keep trying to push you over it! / Are they the lemmings / Or are you, Cliff? / Or are you Cliff?
  Reply With Quote
Old 13th February 2005, 07:07 AM   #4
aarsoe is offline aarsoe  Denmark
diyAudio Member
 
Join Date: Jun 2004
Location: Copenhagen
Thanks - I was also under the impression that the easiest way was to use resistors - that is until I saw someone reducing the gain on a 405 by chanching the input module. so why not do the same on the 606 - anyway any other people have ideas?
  Reply With Quote
Old 13th February 2005, 08:12 AM   #5
diyAudio Member
 
analog_sa's Avatar
 
Join Date: Aug 2002
Location: Sofia
Ehm, what exactly do you call an input module? It's very simple - you can either reduce the gain before the amp or you can change the feedback to suit you. The fb route seems extremely inappropriate with the Quads but may well work.
  Reply With Quote
Old 13th February 2005, 09:11 AM   #6
Zombie is offline Zombie  Sweden
diyAudio Member
 
Join Date: Feb 2003
Location: At home
The 405 and 306/606 have different input stages....
  Reply With Quote
Old 13th February 2005, 09:19 AM   #7
aarsoe is offline aarsoe  Denmark
diyAudio Member
 
Join Date: Jun 2004
Location: Copenhagen
Well - what can I say but bummer...
I really love my 606, but using it with my Krell KRC-3 that can gives an output of max 9V makes it somewhat difficult. Guess I will have to try the resister solution... Thanks..
  Reply With Quote
Old 13th February 2005, 09:27 AM   #8
diyAudio Member
 
Phasenoise's Avatar
 
Join Date: Nov 2004
Location: London
Well here is my first post.

The 606 is a fine amp, I wouldn't mess about with the input stage or the feedback as the current dumping is from what I remember part of the feedback loop. (Probably wrong, it's been a long time.)

I would use external resistors.

All that needs changing really is some nice cable from the phono plugs to the boards as they used nasty generic cable and not of equal length, and some nice speaker cable from the boards to the outputs.

When I had the 606 MK1 I used Van Den Hul Thunder line to the amp modules and Van Den Hul The Wind for the outputs. I also changed the binding posts as the counter sunk ones tend to melt when trying to solder anything but the nasty string cable they used.

The 606 as I said is a fine amp and doesn't relly need any more re working, Good solid clean design and well implemented.

Hope this helps

Phasenoise
  Reply With Quote
Old 13th February 2005, 10:14 AM   #9
aarsoe is offline aarsoe  Denmark
diyAudio Member
 
Join Date: Jun 2004
Location: Copenhagen
Phasenoise

The speaker post are already changed. They are typical of the time when the amp was built, pretty cheap stuff (even though you can still see something like that being used today). Was pretty easy. All it took was a nice sharp drill to enlarge the holes to the new speaker post's.
Have also changed the rca plugs, as they are also pretty bad. On the cable side, I am waiting for some cable I have ordered to do so.
Have also done some changes to the cabinet, as it have a tendency to ring if you knock on it. So some dampening have been applied.
Finnally I have exchanged a few capacitors to black gate types, but as the amp is still running in, it is to early to judge the end results. Have alwayes found that black gates, and in fact most caps, sound awfull for the first 100 hours before they start to open up.
So the input sensitivity was really just the final icing on the cake I was looking for when I was due to change the cables anyway..
  Reply With Quote
Old 13th February 2005, 12:14 PM   #10
Zombie is offline Zombie  Sweden
diyAudio Member
 
Join Date: Feb 2003
Location: At home
Or why not go the other way around...damp the Krell...I know that Quad does this on the 34, just change som resistors at the output...
  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
NHT 3.3 Modifications SY Multi-Way 22 22nd June 2008 05:12 AM
DAC-in-the-Box modifications. Again. Aleksunder Digital Source 1 19th July 2007 03:10 AM
DAC modifications elaar Parts 5 29th May 2006 01:11 PM
Zen V4 modifications pro Pass Labs 2 31st August 2004 05:19 PM
Results of Modifications. pixie Solid State 0 2nd February 2001 04:31 PM


New To Site? Need Help?

All times are GMT. The time now is 03:17 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