re-capping Pass Aelph 2's

[davidismynaim]

I have just become the proud owner of Pass Aleph 2's, plus preamp p and phone ono.

I don't think any work has been done on these amps, so I am assuming the power caps with need to be replaced after all this time?

Can anyone recommend a drop in replacement power cap make and model? are they soldered or bolted to the circuit board?

Any other work that might need to be considered?

I am in the UK, is this work something someone can do if they are ok at soldering? or is there anyone in the UK with good experience with these amps?

Thanks for help.

David

 

[Zen Mod]

pics please

that's for starters

 

[davidismynaim]

I don't have the amps in hand yet, but they are original Nelson Pass amps, so should have what ever he used in his designs. Thought someone on here might now this. If not, once I have them, I can post photos of the current caps.

 

[Gyuri]

A little help:

 

[davidismynaim]

Thanks, I already have the service manual, but limited info re the actual capacitor size and design. Unless I have missed it. 4 x 22,000 (I think they are 40V, too) but would like to confirm their physical aspects too, Height, dia, mounting.

 

[Gyuri]

I guess these are at least 50VDC caps, something computer grade ones with screw terminals, will be good.
We are waiting for pictures.

 

[davidismynaim]

when i get them, i will post.

 

[Dane]

I found these web images...

An externally hosted image should be here but it was not working when we last tested it.

An externally hosted image should be here but it was not working when we last tested it.

Could be CGS313U050W4C
Diameter: 63.5 mm (2.5 in)
Length: 105 mm (4.125 in)

 

[Zen Mod]

if you search , I bet you can find few threads with same theme , no more old than few years

everything written and shown there applicable for your amp

main problem is finding computer grade caps of proper voltage , same or bigger capacity and exact dimensions , so not being forced to change anything in their mounting , meaning both on clamps and exact dimension between screw posts (pcb clamped to their terminals !)
so , better wait to measure all in vivo

rest of caps ....... not critical (Elna Silmic , Panasonic , practically any of known old brands )...... Elna Silmic being Papa's fave for signal positions
all in all - 3pcs per channel - all of them 220uF/35V (or more volts)

you can bypass C5 and C10 with 1uF solid cap of your choice ........ or not,whatever suits you

also , thorough inspection of all solder joints , especially ones in mains paths ...... and there especially NTC position ; solder joints there tend to age , due to prolonged heating

if thermal goo around IRFs is not dry , leave it ; same for all positions where you see white thermal goo

be sure to check all bolts on IRF outputs ; nice and tight.

OK , that's for starters ...... and just to remind you of rulezzzzz here - no porn , no help



edit : oh , yeah ....... nice small solid cap of 1uF or so , across 9V1 zenner (Z5) will kill any possible noise there

good to read Aleph reloaded thread ..... Papa summarized few things

 

[hm4nine]

Re-capping Pass Aleph2's

For substituting big elcaps I would suggest you to go for TDK/EPCOS-caps like this one from Mouser (part number):

871-B41550E8229Q000

Don't be annoyed that they have "only" 22.000uF which agrees with schematics. Look on its specs and compare them with those from your orignal caps.

I once had to service an Aleph 2 and replaced its caps with these TDK/EPCOS. Soundwise they are true killer caps!

 

[Zen Mod]

if dimens. are OK, these are extremely good