Quad 306 recap

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10-Jan-2018 03:05 PM

LOWTHERMAN62

LOWTHERMAN62

Posts: 28

I have recently completed the 306 dada revision in full with the exception of the main power supply capacitors. I plan to use 6800Uf 63V and would like you recommendations on the best caps for this purpose. Do you recommend by passing these with small film caps and if so what type and value would be suitable.

 Regards Stewart

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11-Jan-2018 12:49 AM

EJP

EJP

Posts: 1525

Opinions vary but I use Kemet BHC. I think the 306 has snap-ins, so RS part #434-0778 would be suitable.
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11-Jan-2018 01:50 AM

LOWTHERMAN62

LOWTHERMAN62

Posts: 28

Thanks for the information. On the subject of bypassing these with small fim caps, do you recommend and if so what type and value. Do you stock these caps in the DaDa web shop?


Regards Stewart

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11-Jan-2018 03:49 AM

EJP

EJP

Posts: 1525

Bypassing with say 1uF was practised a decade or two ago, but capacitors have improved so much with rising CPU bandwidths that it's pretty obsolete. If you want to try it there are film capacitors in the Webshop here.
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14-Feb-2018 12:56 PM

FBatista

FBatista

Posts: 119

Hey Lowtherman62,

did you, by any chance implemented the bypass caps to the filter caps in your 306?

If so, what were the results? And what caps did you put in?

Best,

Fbatista

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14-Feb-2018 05:37 PM

LOWTHERMAN62

LOWTHERMAN62

Posts: 28

Hello. I just replaced the main caps with kemet 6800uf 63v. On advise from the forum and EJP  I did not bypass. However subjectively the sound seems  tighter and especially the low end. I also had a little noise which has dissappeared with just black sound between music tracks. Full Da Da revision  now complete. I now love my 306 over and above my 405-2 and 606 which have both been fully revised. This is one nice sounding little amplifer which i use with Dynaudio speakers. 

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16-Feb-2018 12:16 AM

FBatista

FBatista

Posts: 119

Hi,

thank you for your feedback.

I was hoping you'd test with and without the 0,1uF bypass caps. The 306 has great access to the PCB, though eventualy, dificult to fit 4 polipropylene underneath the pcb due to narrow space.

Interesting you mention your 306 playing better than your 606, since their circuit is very similar.

I did this mod to my 606 (with DADA kit and 4 new BHC ALP22 dated 2012 filter caps), it requires completely removing the transformer and power supply pcb to get to the 4 filter caps terminals, so it's a bit time consuming. But the result paid off.

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16-Feb-2018 10:12 AM

LOWTHERMAN62

LOWTHERMAN62

Posts: 28

Hello. I did purchase 4  High quality polyprop caps to do this but as you said these are too big to fit between the back of the board and the chassis. No doubt I will find a use for these down the line. 

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16-Feb-2018 04:35 PM

FBatista

FBatista

Posts: 119

Hi,

Thanks for the info!

Well, should you ever try to apply them to your 606, I'd really like to know your impression on that.

I am yet to do this to my 405-1 - also revised and with 4x new 10.000uF Panasonic filter caps - The "Dual Mono power supply", I bought from DADA, some 8 years ago.

Best,

Francisco


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