Recommended caps for Quad 405-2

[gilwe]

I was testing the caps in my 405-2, and most just seem dead! (i.e no capacitance, or very low capacitance...). What caps would you recommend to recap with?

Referring to the small electrolytes, not the big cans.

Thanks!

 

[JonSnell Electronic]

I was testing the caps in my 405-2, and most just seem dead! (i.e no capacitance, or very low capacitance...). What caps would you recommend to recap with?

Referring to the small electrolytes, not the big cans.

Thanks!

Replace the electrolytics with the same voltage and capacitance value. Make; I would use any reasonable capacitor manufacturer, Panasonic, Rubycon, Vishay, Werth etc are all good and trusted makes.

 

[Mooly]

If the amp is working OK then I'd firstly be suspecting your measurement methods... if they were all bad then the amp would have obvious issues.

What to replace with... good quality commercial grade parts would be my recommend. Go for 105C rated parts rather than the more common older 85C. Make sure the parts will fit, and if any of the originals are 'axials' (wires coming out from each end) then you will be limited unless you fit suitably sized 'radials' (both legs at the same end) and carefully bend them to suit.

Buy top brand names from authorised suppliers such as RS, Farnell, Digikey and so on. Don't by from auction sites.

 

[gilwe]

Definitely read them correctly, as other new caps do show their correct values.

I wonder which exact type of manufacturer and model I should order, for the 100uf/47uf/10uf caps. There are not many, only two of each.

 

[sgrossklass]

Replace the electrolytics with the same voltage and capacitance value.

Actually, I'd generally recommend a voltage rating one step higher, maybe two - caps have gotten smaller due to tighter tolerances. All within reason, of course - there is little point in having a 63 V cap on a 15 V supply, usually a factor of 3 is ample, so 35 V would be easily justified. See what's the same size as the old one and whether that makes any kind of sense.

There appears to be a single bipolar cap, C17; look at e.g. the Nichicon UES series for replacement.

Study this page with mods and notes. He notes, in particular:

The 405-2 PCB pictured above is one of the worst builds of the product range ~ Although the circuit had been improved and hence the title "405–2" the use of cheap resistors and a small ceramic capacitor for C8 which often "broke down" and under rated electroytics which "dry out" was not a good move ~ but keeping the RCA transistors was

EDIT:

I wonder which exact type of manufacturer and model I should order, for the 100uf/47uf/10uf caps. There are not many, only two of each.

Nobody ever got fired for buying Panasonic FCs. Or any other comparable Nichicon / Elna / whatever.

 

[Mooly]

Definitely read them correctly, as other new caps do show their correct values.

I wonder which exact type of manufacturer and model I should order, for the 100uf/47uf/10uf caps. There are not many, only two of each.

You should normally check them out of circuit in order to get accurate results.

Jon listed four well known and recognized manufacturers and I'd go along with that recommend.

 

[gilwe]

Tested out of circuit, all dead. Placed cheap Jamicons instead, as this is what I had available... Still a tremendous change in sound!!

 

[Mooly]

Pleased to hear its made a big improvement. The caps have an easy life in the Quad electrically although if they run near hot components I would recommend 105C parts, however the Jamicons are probably as good or better than what was used back in the day the Quad was manufactured.