I ask who has been involved in restoring of a 400A his views and opinions on the various brands of electrolytic capacitors used to replace the old ones... Who has used Nichicon, Panasonic, Mallory, Elna and other brands could tell me impressions and opinions?
Then, I also would to know where I can buy some spare parts as the power on-off switch, a fuse cap and fuse holders.
Thanks for help.
Then, I also would to know where I can buy some spare parts as the power on-off switch, a fuse cap and fuse holders.
Thanks for help.
Nino, does the amp work fine?
I ask because if it doesn't, I'd rather fix it before changing caps and other parts just for fun.
If it's working fine, no hum or noise, crackling or sparking, I see no reason to change caps.
If you can't resist the urge, go ahead but I am unable to provide info on Italian suppliers.
/Hugo
I ask because if it doesn't, I'd rather fix it before changing caps and other parts just for fun.
If it's working fine, no hum or noise, crackling or sparking
, I see no reason to change caps.If you can't resist the urge, go ahead but I am unable to provide info on Italian suppliers.
/Hugo
Hi Hugo,
my 400A, as I described in another thread, works, but not fine.
It sounds hard, harsh, dry, woody, above all into mid-high and high frequencies... It's unearable for my tastes. I don't believe this is the real sound of the 400A.
Some mates (and Nelson too) suggested me to replace all the electrolytics, fuse holders and check the bias current...
Anyway I can purchase the caps in an overseas online shop (not necessarily in Italy...) I would only know a good very supplied seller.
Cheers,
Nino
my 400A, as I described in another thread, works, but not fine.
It sounds hard, harsh, dry, woody, above all into mid-high and high frequencies... It's unearable for my tastes. I don't believe this is the real sound of the 400A.
Some mates (and Nelson too) suggested me to replace all the electrolytics, fuse holders and check the bias current...
Anyway I can purchase the caps in an overseas online shop (not necessarily in Italy...) I would only know a good very supplied seller.
Cheers,
Nino
This kind of situation makes me nervous. We're asked to comment on modifications to a circuit that may or may not be working properly.
I see no reason not to replace caps, assuming that you are handy with a soldering iron and have access to decent parts.
From your e-mail:
--I gather that you're unsure about what voltage rating to buy when buying replacement capacitors. The answer is to buy a part that is rated for (at least) the same voltage as the part it is to replace. It should be printed on the part.
--I've got a schematic for this amp, but not it's not immediately accessible. There aren't any modifications I'd suggest under the current circumstances.
--You ask about increasing capacitance. In one place it sounds as though you're talking about the main power supply caps. In another you mention 22uF and 39uF caps, which are most certainly not power supply caps. It's hard to make recommendations without knowing what the capacitors do.
--I have no earthly idea what sort of power switch (or any other part) Nelson used in those days or where to get them...assuming that they're still being manufactured.
Your best bet will be to find someone who is at least somewhat experienced in electronics to help you. If you're determined to go it alone, I'd suggest that you begin by reading the other repair threads here that relate to your amp. Read all of them all the way through before attempting anything on your amp. It's best to go slowly so as not to make mistakes that could make things worse than they already are.
Grey
I see no reason not to replace caps, assuming that you are handy with a soldering iron and have access to decent parts.
From your e-mail:
--I gather that you're unsure about what voltage rating to buy when buying replacement capacitors. The answer is to buy a part that is rated for (at least) the same voltage as the part it is to replace. It should be printed on the part.
--I've got a schematic for this amp, but not it's not immediately accessible. There aren't any modifications I'd suggest under the current circumstances.
--You ask about increasing capacitance. In one place it sounds as though you're talking about the main power supply caps. In another you mention 22uF and 39uF caps, which are most certainly not power supply caps. It's hard to make recommendations without knowing what the capacitors do.
--I have no earthly idea what sort of power switch (or any other part) Nelson used in those days or where to get them...assuming that they're still being manufactured.
Your best bet will be to find someone who is at least somewhat experienced in electronics to help you. If you're determined to go it alone, I'd suggest that you begin by reading the other repair threads here that relate to your amp. Read all of them all the way through before attempting anything on your amp. It's best to go slowly so as not to make mistakes that could make things worse than they already are.
Grey
looking at attached pdf file - you'll see that 400A doesn't have mucho caps ........ but certainly have few worth changing and/or upgrading
if cap on input isn't your fave , change it with some polypropilen thingie ;
also - cap in feedback net (470uF) - put there some Elna Silmic or similar quality one , bypass it with nice little one - 220~410nF , polycarbonat or 'pilen,whatever
two 10uF jobbies ( up and down,,near rails ) - put , if nothing better , two little Wima's of 4u7/63V in parallel ,instead of one 10uF elko .
all other caps - under 100nF - replace them with mica or styroflex
main reservoir caps - have you anyone near you - with ESR meter ?
if you like to play safe - replace them with some computer grade caps, up to 3 times in capacity (maybe you'll need to increase mains fuse afetr that , but just slightly ; think about NTC in line with mains , if that part isn't already there .
bypass main reservoir caps with 1uF / whatever
edit:
I forgot to attach file
author of scan - look at file properties
if cap on input isn't your fave , change it with some polypropilen thingie ;
also - cap in feedback net (470uF) - put there some Elna Silmic or similar quality one , bypass it with nice little one - 220~410nF , polycarbonat or 'pilen,whatever
two 10uF jobbies ( up and down,,near rails ) - put , if nothing better , two little Wima's of 4u7/63V in parallel ,instead of one 10uF elko .
all other caps - under 100nF - replace them with mica or styroflex
main reservoir caps - have you anyone near you - with ESR meter ?
if you like to play safe - replace them with some computer grade caps, up to 3 times in capacity (maybe you'll need to increase mains fuse afetr that , but just slightly ; think about NTC in line with mains , if that part isn't already there .
bypass main reservoir caps with 1uF / whatever
edit:
I forgot to attach file
author of scan - look at file properties
Thanks for inputs guys.
Grey,
So I had write 22,000 and 39,000. Pardon, was been my fault...
Another thing:
do you think is it a good choise re-wiring some old inside cables or is at lost time?
Nino
Grey,
Sorry for trouble, I wrote 22.000 and 39.000: here in Italy and continental Europe . is for your , into numbers.GRollins said:
So I had write 22,000 and 39,000. Pardon, was been my fault...
Another thing:
do you think is it a good choise re-wiring some old inside cables or is at lost time?
Nino
Attachments
Mywing said:
you know what ?
I decided to help you with that bad amp - just send it to me , and I'll do proper disposal ........ it's old and even when new it wasn't great amp .......
if you see that insulation look old and brittle , and - if you see excessive oxidation on bare ends of cables - then replace them - with proper ( or audiofool type) ones .....
I forgot to tell you - regarding power switch - I can't really help you with that ....... I'm living in Serbia ........
You're so witty, ChockyZen Mod said:
you know what ?
I decided to help you with that bad amp - just send it to me , and I'll do proper disposal ........ it's old and even when new it wasn't great amp .......
The two PSU caps are screwmounted, I think would not be difficult replace them. Only two small electrolitycs must be soldered, maybe I'll succeed to do
I must only find an online seller with a good choice of electrolitycs... any suggestion?
About power switch I had already contacted Jon...
If there will be difficulties with what I need, I'll send to you a whistle...
Thanks for help,
Nino
I come back on this thread for a small inconvenience in searching for caps.
I decided to replace the old electrolitycs with Elna Silmic II because I have already installed them on my SL10 preamp and I am very happy with them. But unfortunately the values my 400A needs are not available in any of the best-known dealers. It looks like 47uF/50V and 470uF/16V were replaced with the 47uF/100V and 470uF/35V.
Can I also use the 100V and 35V, or is it better to search the exact values among other brands of capacitors?
Thanks for suggestions
I decided to replace the old electrolitycs with Elna Silmic II because I have already installed them on my SL10 preamp and I am very happy with them. But unfortunately the values my 400A needs are not available in any of the best-known dealers. It looks like 47uF/50V and 470uF/16V were replaced with the 47uF/100V and 470uF/35V.
Can I also use the 100V and 35V, or is it better to search the exact values among other brands of capacitors?
Thanks for suggestions
My 400A refreshing operations proceed.
As Psu caps I've bought two Epcos 22,000uF/100v, now following the suggestion of many guys (also Choky) I will buy two filmcaps about 1.5-2 uF for bypass the Psus. I thought that the correct voltage for these caps was 100 V (as the Psu), but among the Mundorfs
( http://www.partsconnexion.com/catalog/CapacitorsFilm.html )
that I have chosen to purchase, I find some very superior voltages to the 100. Which could a good filmcap to choose for my purpose?
Thanks
As Psu caps I've bought two Epcos 22,000uF/100v, now following the suggestion of many guys (also Choky) I will buy two filmcaps about 1.5-2 uF for bypass the Psus. I thought that the correct voltage for these caps was 100 V (as the Psu), but among the Mundorfs
( http://www.partsconnexion.com/catalog/CapacitorsFilm.html )
that I have chosen to purchase, I find some very superior voltages to the 100. Which could a good filmcap to choose for my purpose?
Thanks
Well,
now I've all parts here. And now I must bypass big can electrolytics with the filmcaps: it means I'll connect in parallel the small with the big? And how to join the film's rheophores to the big cans screw terminal?
Maybe a picture could be the best explanation for me...
I continue to thank for helping...
now I've all parts here. And now I must bypass big can electrolytics with the filmcaps: it means I'll connect in parallel the small with the big? And how to join the film's rheophores to the big cans screw terminal?
Maybe a picture could be the best explanation for me...
I continue to thank for helping...
Mywing said:Well,
now I've all parts here. And now I must bypass big can electrolytics with the filmcaps: it means I'll connect in parallel the small with the big? And how to join the film's rheophores to the big cans screw terminal?
Maybe a picture could be the best explanation for me...
I continue to thank for helping...
if that's proper word - eyelets ;
piece of tin , with two holes in it - one big ( for screw) and one small - for soldering anything you want
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.