Bringing Marantz PM55 up to SE spec

Just got a PM55 for peanuts (£4), suposedly working, still hasn't arrived so haven't fired it up yet.
I was kind of wanting an SE but couldn't say no for the money.
So, is there much difference between the standard and SE version? Either way, can I bring the standard up to spec with upgrading? I'm imagining box bracing, new caps, PSU upgrades maybe?
Thanks

 

I don't know about SE ...but there are a number of generic mods easily accomplished....

If I was doing this I think I'd work in this order ...listening at ech stage.
swap the opamps and fit good sockets and decouple the power rails to them.
[Assuming opamps as I've not the schems for the pm55]
replace decoupling caps[dc blockers with the very best you can get]
fit a better vol pot
fit better input socketry if possible
recap all psu resovoir caps
then work on the psu ...diodes rectifiers etc.

I would have a listen at each stage ...it may be that its really not worth the effort against cost ..as the out lay will be around £50 minimum for parts..you need to decide if that £50 plus could be better spent.

 

excuse the basic question, but what sockets do you mean here?

How do I identify these?

Although you may be right and not be worth the cost. If I'm cunning about things though I was hoping I'd get some improvements. Is there anything chepaer than a blue alps pot, or should I try this? Would bracing the box be pointless then?
thanks

 

hum......

ok the sockets fit the holes left by the old opamps ...it allows you to swap opamps without the need to desolder each time..

thats a little more tricky as you need the schematics ..basically these caps sit in the signal path between the input section and the pre amp then between preamp and power amp sections...

if they are poor ...they will be emasculating the music as it passes through them. I've used ex soviet military surplus ones [off fleabay] these sound much better than even blackgates or the big mkt film caps. the down side is size as these can be the size of a stack of four jacobs cream crackers....but if I can get two into a quad 77 pre case you should have no probs with an amp !

the alps blue is about the lowest quality unit I'd use ...if you hunt on ebay hong kong site you should be able to get one of £10

 

great thanks zanesh, as always invaluable help. Although just one more thing I forgot to ask, what power rails do I decouple to the opamps? What do these power rails do?
thanks
Harry

 

From the main psu the dc will pass along the power rails one positve and one negative...these may be combined or individual.

to decouple you need 2x 10 uf tant cap of double the voltage on the rail this is placed close to the opamp ...on the positive rail connect + and the - of the cap to ground. on the neg rail conect + to the ground [as its more positive than the neg rail] and - to the neg rail ... do this even if the opamps have film cap decoupling.

 

right, got it. Thanks a lot. Also, what's the best way to discharge all the caps, keep driving the amp after turning the power off?

 

yes ...that will do it

 

Those paper in oil caps really do sound sweet, in my case undertaking DC blocking duties in my CD player.
They are huge though. You really need to plan a space for them before fitting.
I used blu tac to stick them to the chassis so they don't move, but silicone sealant's probably a better bet.

 

ok, i'm sold. Which ones are they (as in item name)? Also, why fleabay, why not ebay? I've never been able to find anything related to what I want on fleabay, am I missing a trick?

 

fleabay ...is ebay its like a flea market ..

I used these

http://cgi.ebay.co.uk/10-uF-160-V-P...96719875QQihZ007QQcategoryZ4662QQcmdZViewItem

http://cgi.ebay.co.uk/2-2-uF-400-V-...04346665QQihZ007QQcategoryZ4662QQcmdZViewItem

and the green ones sound very good to for the cost ...

obviously you can then swap them for Audio note silver in oil at a latter stage if you like what these do.

don't worry that the ones fitted may be 100uf ...its normally because there plentyful as much as the filtering effect.

Its normally recomended to use at least 10uf ...but even swapping for 2uf green pio's the plusses out weigh the cons.
Though theres no reason why you can parallel them up if you have space [to increase the capacitance].