Quad 405 Upgrade and Revision Kit Problems!

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11-Nov-2011 07:53 PM

macakinho

macakinho

Posts: 7

Whilst I didn't get an answer I continued the process according to the instructions and ha a few more questions.

"Hi Stefaan!

I have now completed everything apart from the PCBs which I still need your help with!

I have come across a few more questions I have to ask you!

Hope you're available to answer all my questions as I really want to get this project finished asap in order to get back to work at the studio!

So here it goes:

When removing the old speaker connectors, this board was attached to the terminals on the inside:

http://imgur.com/CWhAE

Is it not gonna be needed? Can I just remove it for good?

- - - - - - - - - - - -

On this website: http://www.quadmodsusa.com/405upgrades.html there is a description of this upgrade performed by you. In this particular picture there can be seen what appear to be two condensers connected to the transformer terminals.

Am I supposed to do anything like it? if so, are the condensers provided in the kit?

Here is another picture where these components can be seen.

"

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11-Nov-2011 07:55 PM

macakinho

macakinho

Posts: 7


Sorry about the long post but I think it might be useful for someone else in the future!


So, can anyone else help me with these questions?

Also, any pictures of a finished unit would be great as I would love to compare the wiring I did to a finished one!

Will post pictures of mine once I get it done!


Thank you! 

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11-Nov-2011 09:59 PM

Stefaan

Stefaan

Posts: 601

Hello,

We give 7/7 technical support via e-mail but that does not mean 24/24 ;-) Specially on a national Holiday like today. In Belgium we are celebrating the end of the first World War and all bsinesses are closed.

To answer the questions in the same order:

- The manual does not say to replace the zeners with a capacitor but to solder a capacitor in parallel with the zeners (220µF in parallel with D1 & 100nF in parallel with D2). The zener-diodes themselves are replaced with 15V 1,3 Watt types to provide enough power for the new Opamps.

- About C2: the voltage of a capacitor is the maximum DC voltage it can handle. 100µF 10V is perfect for 100µF 6,3V.

- In some versions of the kit there are 100nF Ceramic (brown) capacitors instead of Film (white or yellow) capacitors for decoupling D2. This does not matter.

- In the 405 Mk1 the clamp-circuit (and C17) are on a small circuit-board soldered to the LS-terminals. (see next question)

- The small PCB soldered to the LS-connectors is the Clamp-circuit that should protect the loudspeakers agains DC-voltage on the output when one of the power-transistors is broken. It should be kept (and it can be soldered to the new LS-connectors) or, even better, it can be replaced by 2x http://www.dadaelectronics.eu/shop/dada-high-end-boards/dada-electronics-loudspeaker-protection-delay that will protect the speakers against DC with relays and at the same time eliminate all start-up or shut-down "plop" or "krr" noises by switching the amplifier on after a few seconds.

Stefaan

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11-Nov-2011 11:05 PM

macakinho

macakinho

Posts: 7

I was not aware that today was bank holiday in Belgium! Sorry about that!

Thank you and have a nice weekend!

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12-Nov-2011 02:51 AM

macakinho

macakinho

Posts: 7


Have just finished upgrading my 405 and I must say, it is sounding WAY better!

Thank you so much Dada for the kit!

here are a few pictures of the finished boards in case someone might find it handy!

these are the 405-1 version!

back of the board: http://i.imgur.com/EAvCZ.jpg

boards side by side: http://i.imgur.com/SkD7u.jpg

boards top view: http://i.imgur.com/C30Eb.jpg

The kit is not that complicated to install but, for someone like me with little experience in electronics, a guidebook with a lot more pictures of each step and a revised text (some steps are phrased in a confusing way) would have been perfect!

Thanks again for all your help!

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12-Nov-2011 01:19 PM

Glitterbug

Glitterbug

Posts: 73

Thank you so much for your post! I am about to enter the same endeavor, and actually, some pictures of the boards before and after the revision would be great! Could you maybe send me some? My Email address is glitter@glitterbug.de

Another issue is that there has been some work put into my specific amp, and it will be a little challenging to revise it since many parts have been exchanged. Having a picture of what they are supposed to look like will make it much easier for me.

Looking forward to throw it back into my chain after I am done... I order the parts today. Happy listening!


www.glitterbug.de
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13-Nov-2011 11:42 AM

macakinho

macakinho

Posts: 7


Sure!  I have a few more pictures and I can open the amp up if you want any specific parts!


Will post the pictures here later when I'm back at my computer!

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15-Nov-2011 06:18 PM

macakinho

macakinho

Posts: 7


Hey Glitterbug, here are all the pictures I took whilst I was working on it!

http://imgur.com/a/UeopL#0

Hope these may help you!



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15-Nov-2011 07:21 PM

Stefaan

Stefaan

Posts: 601

And there are lots of 405 revision pictures in the Blog archives of course...

Stefaan
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23-Jul-2019 12:38 PM

Pholipe

Pholipe

Posts: 11

Hello,

I firstly apologize about my english. I am blocked at Step 3: Upgrading circuit boards; and I started to found the components on them.

I have to remove the C17 but I cannot found it anywhere; not on the circuit board except if it could be a little capa (1 n) on the back of the board without any other identification ?

The documentation says that C17 could be on the clamp circuit but on my Quad 405, there is no identification of the components on this little board soldered on the entries of the LS, only "M12400 ISS2".  Can I send you pictures  ?

Many thanks because I am blocked .

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23-Jul-2019 01:00 PM

EJP

EJP

Posts: 1638

Don't hijack threads. Nobody will see it. Start your own thread.
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