quad 405-2 - diyAudio
Go Back   Home > Forums > Design & Build > Parts

Parts Where to get, and how to make the best bits. PCB's, caps, transformers, etc.

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 6th May 2012, 07:05 AM   #1
diyAudio Member
 
Join Date: Feb 2011
Default quad 405-2

Hi. And thanks for taking the time to read this post.

Can anyone tell me where to purchase a high performance bridge rectifier for my quad 405-2 amplifier. At the moment i have replaced the power modules with 405-3's from net audio and purchased 10,000uf caps for the power supply (not fitted yet), replaced all wiring with silver plated ptfe, high quality phono outs and finally michele speaker posts.

Also are there any instructions for the dual mono power supply.
I did a google search and there are descriptions of caps but not how to wire them up, ie which wires go where, which terminals on the transformer are to be connected to which terminals on the bridge rectifier then the caps.

Many thanks in advance. John.
  Reply With Quote
Old 6th May 2012, 07:13 AM   #2
Mooly is offline Mooly  United Kingdom
diyAudio Moderator
 
Mooly's Avatar
 
Join Date: Sep 2007
You need a bridge with a high current surge ability such as,
GBPC2504 - FAIRCHILD SEMICONDUCTOR - BRIDGE RECTIFIER, 25A, 400V | CPC

It's worth adding a snubber (0.1 uf and 1 ohm in series) across each diode in the bridge to reduce commutation noise.

Wiring is straightforward but it's hard to give specifics without seeing it all.
__________________
-------------------------------------------------------
Installing and using LTspice. From beginner to advanced.
  Reply With Quote
Old 6th May 2012, 07:16 AM   #3
Mooly is offline Mooly  United Kingdom
diyAudio Moderator
 
Mooly's Avatar
 
Join Date: Sep 2007
That one came up as out of stock but there are dozens suitable,
GBPC3504 - FAIRCHILD SEMICONDUCTOR - BRIDGE RECTIFIER, 35A, 400V | CPC
__________________
-------------------------------------------------------
Installing and using LTspice. From beginner to advanced.
  Reply With Quote
Old 8th May 2012, 05:33 AM   #4
diyAudio Member
 
Join Date: Feb 2011
Default quad 405-2

Hi. Thanks for the reply.

So will any rectifier do, with the smoothing capacitors some brands tend to be better thsn others.

I can see the rectifer has two connections on one side which should go the transformer, then the two on the other side should go to the capaitors. Only problem my 405-2 has a fifth wire which comes from the secondary set of windings, bypasses the rectifier and goes straight to the lower capacitor the one nearest the phono inputs and the speaker output connectors.

Many thanks. John.
  Reply With Quote
Old 8th May 2012, 06:41 AM   #5
Mooly is offline Mooly  United Kingdom
diyAudio Moderator
 
Mooly's Avatar
 
Join Date: Sep 2007
Any suitably rated rectifier is OK as long as from a reputable supplier so you can be sure you are getting what is advertised.

When wiring this up you need to be very careful. The AC from the transformer will go to "opposite corners" on the bridge. It should be marked on the device.

Maybe if you could post a detailed clear picture of the transformer and wiring we could identify what goes where but it will be straightforward. The original 405 had multiple secondaries connected in parallel but all very conventional.
Attached Images
File Type: jpg PSU.JPG (71.7 KB, 272 views)
__________________
-------------------------------------------------------
Installing and using LTspice. From beginner to advanced.
  Reply With Quote
Old 11th May 2012, 05:20 AM   #6
diyAudio Member
 
Join Date: Feb 2011
Default quad 405-2

Hi. Thank you for the reply.
Many apologies Unfortunately I have stripped down the quad 405-2 so am unable to take a photo. However I have uploaded a photo which shows a quad 405-2 with an identical transformer to mine so some similarities can be drawn.
With my transformer the wires on the right hand side are identical to the wires on the right hand side of the uploaded photo.
On the left hand side of my amplifierís transformer there are the same 8 terminals as the photo. The first one (highest one up) is connected to the bridge rectifier as per the photo and also is connected to the eighth terminal (lowest one down) by a piece of yellow wire.
The second and third terminals are bridged together as per the photo, but there is a green wire which also connects them both to the sixth and seventh terminal. The sixth and seventh terminals are also bridged together as per the photo.
The fourth terminal is connected to the bride rectifier as per the photo but there is a yellow wire which also connects it to the fifth terminal.
Finally as mentioned earlier the sixth and seventh terminal are connected together but there is also a wire connecting the seventh terminal to the positive terminal of the lower smoothing capacitor, the one nearest the phono input sockets and speaker output binding posts. There are only two smoothing capacitors in this case.
The uploaded photo has the dual mono supply fully installed what I am struggling to see and is not clear, is which wire goes where or how it all connects up to the bridge rectifier and capacitors.

Many thanks.
Attached Images
File Type: jpg quad 405.jpg (439.5 KB, 247 views)
  Reply With Quote
Old 11th May 2012, 07:31 AM   #7
Mooly is offline Mooly  United Kingdom
diyAudio Moderator
 
Mooly's Avatar
 
Join Date: Sep 2007
Your description of the wiring shows it to be as in the picture I posted above.

It's just the windings connected in parallel to double the current capability. Look at my picture. It's similar to having two physically separate transformers and connecting all the wires in parallel to double it up.

So in your picture they have been separated and each set of windings (each group of four tags) powers one amplifier via its own bridge and caps.

So for each you keep the middle tags joined as shown and that is the ground (just as before). The yellow wires are the AC and go to the bridge. It doesn't matter which way round they go as long as they go to the two AC terminals on the bridge.

The caps are wired as per the originals (in my picture). They are in series so the positive of one of them does indeed go to ground (C14 in my picture).

Does that make sense ? All you are doing is separating the windings and duplicating another bridge and set of caps. If your not sure on all this then you risk damaging the amp.

Where it gets more difficult is grounding it all correctly for no hum etc. Without first hand experience of the Quad and it's wiring scheme I wouldn't like to say on that.
__________________
-------------------------------------------------------
Installing and using LTspice. From beginner to advanced.
  Reply With Quote
Old 13th May 2012, 05:58 AM   #8
diyAudio Member
 
Join Date: Feb 2011
Default quad 405-2

Hi. Thanks very much for the reply.

I am going to dash off now and pick up the rectifier and caps.

Wish me luck, it's my first time, erm first project i mean.
  Reply With Quote
Old 13th May 2012, 06:13 AM   #9
Mooly is offline Mooly  United Kingdom
diyAudio Moderator
 
Mooly's Avatar
 
Join Date: Sep 2007
Just take your time with the wiring. If you are unsure then it might be a good idea to use a bulb tester for initial powering up.
__________________
-------------------------------------------------------
Installing and using LTspice. From beginner to advanced.
  Reply With Quote
Old 5th September 2012, 05:33 AM   #10
diyAudio Member
 
Join Date: Feb 2011
Default quad 405-2

Hi. Sorry to reawaken this thread from the dead.

I emailed net audio who suggested wiring the powersupply to the chassis, here is the exact reply got no idea what it means. Can anyone please explain. What does ov mean.


" Simply connect the LH speaker return to the center (0V) part of the twin caps nearest the caps for that channel and same for the right channel. Connect the same center by an individual wire to the chassis. Think of it as an H with the tall sides of the H is one channel 0V and the same for the other. The center of the H is two separate wires to the chassis. The speaker return goes to the T junction part of the H for each channel.

Best Regards

David Pritchard



  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
quad 405 luigicosta Solid State 4 20th April 2012 11:37 AM
Quad 405 Piersma Swap Meet 8 25th October 2011 03:23 PM
quad 405-2 goodguys Solid State 3 14th March 2011 09:35 AM
Something comparable to a Quad 405? PoorSound Solid State 0 23rd January 2006 03:19 PM
quad 405 hazenhoe Solid State 2 27th December 2003 01:32 AM


New To Site? Need Help?

All times are GMT. The time now is 08:35 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