Quad 303 IEC power socket upgrade

martin5 · 31st July 2011, 09:11 PM

I'm working on my old Quad 303. It deserves a little attention.

One problem is that awkward power connector - mine had a broken pin and soldered power leads. I've made a template for replacing it with an IEC connector. Worked really well.

Here are some pictures.

I've drawn up the panel, if anybody needs the file drop me a note.

Tajzmaj · 1st August 2011, 12:54 AM

Hi
303 is nice vintage amp. I have one.
Bulgin PX0429 3 Pin Male Socket, Quad 303, Racal 1772 | eBay
Quad303 Quad 303 pcb set for renovation/cloning V.4 | eBay
2x BULGIN 3 PIN MAINS CONNECTORS FOR QUAD 33, 303, FM3 | eBay
But of course it will be good ide to replace input connector too......
Best regards, Taj

llwhtt · 1st August 2011, 02:39 AM

Looks like you could use some new filter capacitors too!

Craig

Tajzmaj · 1st August 2011, 02:05 PM

When I restore mine 303 I find some nice caps from epcos......with bolt on terminals.....
Regards

robmil · 2nd August 2011, 10:31 AM

Those filter caps have had it

Better change them REALLY soon (like yesterday) as they are leaking electrolyte.

rob

Tajzmaj · 2nd August 2011, 02:08 PM

At the moment I'm on vacation but can check which caps I used.....but I buy everything from farnell......
Best regards, Taj

ms08 · 18th September 2011, 06:17 AM

I have three 303's two have recently bee re-built to varying degrees using DADA supplies.

john_ellis · 24th September 2011, 08:16 PM

I've bult several 303 clones but with some mods. The best was to use new epi 3055's and most of the HF roll-off capacitors could be halved. Performance improved from the standard 35 kHz with original capacitor values and RCA original transistors to over 70kHz, using ST 3055's (but I suspect ON semi would be similar) and (at least I thought so) sounded better for it.

John

alfian · 12:21 AM

I did a true esoteric renewal of 303, upgrading all except the original casing and transformer. Epcos, Elna, Wima, RIFA & SMica Caps, Bourns trim, Kiwame, Mills & Takman resistors, ON Semi 15030/31 + 15003/4, J507/510, Van Den Hul cs18/16 wiring... But, the new metric screws are not matching to the old ones!!!
Does anyone know where I can find new screws for 303 (4BA thread)?

Branko, Serbia

31st July 2011, 09:11 PM	#1
martin5 diyAudio Member Join Date: Jul 2011	Quad 303 IEC power socket upgrade I'm working on my old Quad 303. It deserves a little attention. One problem is that awkward power connector - mine had a broken pin and soldered power leads. I've made a template for replacing it with an IEC connector. Worked really well. Here are some pictures. I've drawn up the panel, if anybody needs the file drop me a note.

23rd January 2012, 12:06 AM	#9
alfian diyAudio Member Join Date: May 2010 Location: Belgrade	I did a true esoteric renewal of 303, upgrading all except the original casing and transformer. Epcos, Elna, Wima, RIFA & SMica Caps, Bourns trim, Kiwame, Mills & Takman resistors, ON Semi 15030/31 + 15003/4, J507/510, Van Den Hul cs18/16 wiring... But, the new metric screws are not matching to the old ones!!! Does anyone know where I can find new screws for 303 (4BA thread)? Branko, Serbia Last edited by alfian; 23rd January 2012 at 12:21 AM.

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1st August 2011, 12:54 AM	#2
Tajzmaj diyAudio Member Join Date: Mar 2011 Location: Ljubljana	Hi 303 is nice vintage amp. I have one. Bulgin PX0429 3 Pin Male Socket, Quad 303, Racal 1772 \| eBay Quad303 Quad 303 pcb set for renovation/cloning V.4 \| eBay 2x BULGIN 3 PIN MAINS CONNECTORS FOR QUAD 33, 303, FM3 \| eBay But of course it will be good ide to replace input connector too...... Best regards, Taj

1st August 2011, 02:39 AM	#3
llwhtt diyAudio Member Join Date: Jun 2008	Looks like you could use some new filter capacitors too! Craig

1st August 2011, 02:05 PM	#4
Tajzmaj diyAudio Member Join Date: Mar 2011 Location: Ljubljana	When I restore mine 303 I find some nice caps from epcos......with bolt on terminals..... Regards

2nd August 2011, 10:31 AM	#5
robmil diyAudio Member Join Date: Jun 2004 Location: London	Those filter caps have had it Better change them REALLY soon (like yesterday) as they are leaking electrolyte. rob

2nd August 2011, 02:08 PM	#6
Tajzmaj diyAudio Member Join Date: Mar 2011 Location: Ljubljana	At the moment I'm on vacation but can check which caps I used.....but I buy everything from farnell...... Best regards, Taj

24th September 2011, 08:16 PM	#8
john_ellis diyAudio Member Join Date: Sep 2006	I've bult several 303 clones but with some mods. The best was to use new epi 3055's and most of the HF roll-off capacitors could be halved. Performance improved from the standard 35 kHz with original capacitor values and RCA original transistors to over 70kHz, using ST 3055's (but I suspect ON semi would be similar) and (at least I thought so) sounded better for it. John

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