[randy1kenobi]

I have an old 60's Sansui AU-111 tube receiver that needs some work. I
want to replace the leaky oil filled caps and figure the germanium
rectifiers should probably be changed as well. Any suggestions on
which replacement caps would be best to use? Any other tips or tricks
for this amp would be greatly appreciated. Thanks.

-Randy

[tubegarden]

On Feb 5, 1:39?pm, "randy1kenobi" wrote:
I have an old 60's Sansui AU-111 tube receiver that needs some work. I
want to replace the leaky oil filled caps and figure the germanium
rectifiers should probably be changed as well. Any suggestions on
which replacement caps would be best to use? Any other tips or tricks
for this amp would be greatly appreciated. Thanks.

-Randy


Hi RATs!

www.DigiKey.com

Happy Ears!
Al

[[email protected]]

On Feb 5, 3:39 pm, "randy1kenobi" wrote:
I have an old 60's Sansui AU-111 tube receiver that needs some work. I
want to replace the leaky oil filled caps and figure the germanium
rectifiers should probably be changed as well. Any suggestions on
which replacement caps would be best to use? Any other tips or tricks
for this amp would be greatly appreciated. Thanks.

Whoever tells you to replace oil-filled caps and germanium rectifiers
in that amp will probably also be telling you to change the air in
your car tires and the catastrophic converter in the exhaust
system :-).

I'm not denying that your amp might very well need some TLC, but doing
it by buzzwords is not a good approach.

Tim.

[Sander deWaal]

said:


On Feb 5, 3:39 pm, "randy1kenobi" wrote:
I have an old 60's Sansui AU-111 tube receiver that needs some work. I
want to replace the leaky oil filled caps and figure the germanium
rectifiers should probably be changed as well. Any suggestions on
which replacement caps would be best to use? Any other tips or tricks
for this amp would be greatly appreciated. Thanks.


Whoever tells you to replace oil-filled caps and germanium rectifiers
in that amp will probably also be telling you to change the air in
your car tires and the catastrophic converter in the exhaust
system :-).


Those grey '60s Suzuki or Tangamo PIO caps are always suspect.
Germanium rectifiers in general don't need re[;acement, selenium ones
do.

--

- Maggies are an addiction for life. -

[Sander deWaal]

Sander deWaal said:


Those grey '60s Suzuki or Tangamo PIO caps are always suspect.
Germanium rectifiers in general don't need re[;acement, selenium ones
do.


Sangamo and replacement, yes.
Damned keyboard ;-)

--

- Maggies are an addiction for life. -

[randy1kenobi]

I meant Selenium, not Germanium. Thanks for catching that....

How do I know what value diodes to use?


-Randy


On Feb 7, 11:06 am, Sander deWaal wrote:
said:

On Feb 5, 3:39 pm, "randy1kenobi" wrote:
I have an old 60's Sansui AU-111 tube receiver that needs some work. I
want to replace the leaky oil filled caps and figure the germanium
rectifiers should probably be changed as well. Any suggestions on
which replacement caps would be best to use? Any other tips or tricks
for this amp would be greatly appreciated. Thanks.
Whoever tells you to replace oil-filled caps and germanium rectifiers
in that amp will probably also be telling you to change the air in
your car tires and the catastrophic converter in the exhaust
system :-).

Those grey '60s Suzuki or Tangamo PIO caps are always suspect.
Germanium rectifiers in general don't need re[;acement, selenium ones
do.

--

- Maggies are an addiction for life. -

[randy1kenobi]

The caps I am planning to change are the small grey suzuki oil caps.
There are about 2 dozen in there... One of them already went up in
smoke and some others don't look so hot.

-R


On Feb 7, 11:26 am, Sander deWaal wrote:
Sander deWaal said:

Those grey '60s Suzuki or Tangamo PIO caps are always suspect.
Germanium rectifiers in general don't need re[;acement, selenium ones
do.

Sangamo and replacement, yes.
Damned keyboard ;-)

--

- Maggies are an addiction for life. -

[randy1kenobi]

I'm not chaning stuff just for the sake of changing them. I've had two
of the small grey suzuki oil caps fail already and some others look
questionable. Also had a selenium (not germanium as I said earlier)
rectifier fail, so figured i'd change them too. I think there are only
three. Anything other common weak points on these amps that I should
check out?
-Randy


On Feb 7, 10:50 am, wrote:
On Feb 5, 3:39 pm, "randy1kenobi" wrote:

I have an old 60's Sansui AU-111 tube receiver that needs some work. I
want to replace the leaky oil filled caps and figure the germanium
rectifiers should probably be changed as well. Any suggestions on
which replacement caps would be best to use? Any other tips or tricks
for this amp would be greatly appreciated. Thanks.

Whoever tells you to replace oil-filled caps and germanium rectifiers
in that amp will probably also be telling you to change the air in
your car tires and the catastrophic converter in the exhaust
system :-).

I'm not denying that your amp might very well need some TLC, but doing
it by buzzwords is not a good approach.

Tim.

[randy1kenobi]

Hi Al,

I'm familar with Digi-key. I just am curious which brand/type of caps
would be best for this amp? Would the Mallory 150's be a good
candidate? That sorta what i was leaning toward since they are fairly
cheap.

-Randy


On Feb 6, 6:07 am, "tubegarden" wrote:
On Feb 5, 1:39?pm, "randy1kenobi" wrote:

I have an old 60's Sansui AU-111 tube receiver that needs some work. I
want to replace the leaky oil filled caps and figure the germanium
rectifiers should probably be changed as well. Any suggestions on
which replacement caps would be best to use? Any other tips or tricks
for this amp would be greatly appreciated. Thanks.

-Randy

Hi RATs!

www.DigiKey.com

Happy Ears!
Al

[Sander deWaal]

"randy1kenobi" said:

I meant Selenium, not Germanium. Thanks for catching that....

How do I know what value diodes to use?


Take a 1N4007 with a 1 kohm 1 watt resistor in series.
Remember that bias voltage is negative wrt. ground, so be sure to
place the diode in the right direction!

The Suzuki caps can be replaced by e.g. Wima, or, if you want fancy
names, Audyn or Auricap.

The Wimas will do fine, though.
Be sure to use at least 400V and preferably 630V types.

Also, replacing the power supply electrolytics might be a good thing.

--

- Maggies are an addiction for life. -

[randy1kenobi]

Sander,

Thanks for all your help so far. Just curious, what does the 1kohm
resistor do? Also there are .005 uf caps in parallel with the
rectifier diodes currently. Should I leave those? If so, where do the
resistors fit in with those? Should they be in series with the cap as
well? What side of the diode would the resistor go?

If you are interested in seeing the schem, i have it posted he

http://panic.rutgers.edu/~rnewman/Ma..._au-111pg1.jpg
http://panic.rutgers.edu/~rnewman/Ma..._au-111pg2.jpg

I also was digging through my parts bin last night and realized I
already have most of the values of caps I need in Mallory 150's from
my guitar amp repair parts. Are these OK to use? How do they sound
compared to the Wilmas? Where do you get Wilma caps. I'm not familar
with them.

Thanks and sorry about all the questions.

-Randy





On Feb 9, 10:05 am, Sander deWaal wrote:
"randy1kenobi" said:

I meant Selenium, not Germanium. Thanks for catching that....
How do I know what value diodes to use?

Take a 1N4007 with a 1 kohm 1 watt resistor in series.
Remember that bias voltage is negative wrt. ground, so be sure to
place the diode in the right direction!

The Suzuki caps can be replaced by e.g. Wima, or, if you want fancy
names, Audyn or Auricap.

The Wimas will do fine, though.
Be sure to use at least 400V and preferably 630V types.

Also, replacing the power supply electrolytics might be a good thing.

--

- Maggies are an addiction for life. -

[Sander deWaal]

"randy1kenobi" said:


Sander,

Thanks for all your help so far. Just curious, what does the 1kohm
resistor do? Also there are .005 uf caps in parallel with the
rectifier diodes currently. Should I leave those? If so, where do the
resistors fit in with those? Should they be in series with the cap as
well? What side of the diode would the resistor go?


Wooops..........my mistake, I thought of a selenium rectifier for the
bias voltage only.
All 3 original diodes seem to be silicon types, if they measure good
they won't need replacement.
In case you still want to replace them, something a bit more beefy
than a 1N4007 is required, due to the voltage doubler.
I'd recommend the 1N5408 for all 3 diodes, they're still cheap as the
proverbial........silicon ;-)

No resistors should be added in this case.
This is only necessary when a selenium rectifier is replaced with a
silicon type diode, due to the larger voltage drop of the selenium
rect.
The resistor compensates somewhat for that.

The 0.005 uF caps should stay, they're snubbers to dampen the
switching pulses from the rectifiers.


If you are interested in seeing the schem, i have it posted he

http://panic.rutgers.edu/~rnewman/Ma..._au-111pg1.jpg
http://panic.rutgers.edu/~rnewman/Ma..._au-111pg2.jpg


I also was digging through my parts bin last night and realized I
already have most of the values of caps I need in Mallory 150's from
my guitar amp repair parts. Are these OK to use? How do they sound
compared to the Wilmas? Where do you get Wilma caps. I'm not familar
with them.


I don't know the Mallories since I'm on the other side of a shirtload
of water from you.
I'd guess your Mallory is our Wima, just decent caps.
In case the 150 number is the voltage rating, they're not suitable of
course.

I'm not really a capacitor sound man, at least not when global
feedback is used as is done in your amp.
And even then, most stories about capacitor "sound" are IMO a bit
hyperboled, to say the least.

OK, I used Mundorfs in my amps, just because I had them lying around
and I like the sight of them sitting in my amps. ;-)

Other people may chime in about specific cap sound characteristics,
though.


Thanks and sorry about all the questions.


Nothing to be sorry about, if it wasn't for your questions, this group
would be almost empty ;-)

--

- Maggies are an addiction for life. -

[randy1kenobi]

Great,

Thanks so much. i just assumed those would be selenium rectifiers
since they seem to be original from the early 60's but i'll check them
and if they are OK i'll leave them. As for the Mallory 150's, the 150
is the series #. They are rated at 630v. I guess i'll try them in
there and see how they sound. I'm not really in the mood to spend $14
per cap on those fancy caps I see advertized on many of the hi-fi
parts sites.

-R

On Feb 9, 1:28 pm, Sander deWaal wrote:
"randy1kenobi" said:

Sander,
Thanks for all your help so far. Just curious, what does the 1kohm
resistor do? Also there are .005 uf caps in parallel with the
rectifier diodes currently. Should I leave those? If so, where do the
resistors fit in with those? Should they be in series with the cap as
well? What side of the diode would the resistor go?

Wooops..........my mistake, I thought of a selenium rectifier for the
bias voltage only.
All 3 original diodes seem to be silicon types, if they measure good
they won't need replacement.
In case you still want to replace them, something a bit more beefy
than a 1N4007 is required, due to the voltage doubler.
I'd recommend the 1N5408 for all 3 diodes, they're still cheap as the
proverbial........silicon ;-)

No resistors should be added in this case.
This is only necessary when a selenium rectifier is replaced with a
silicon type diode, due to the larger voltage drop of the selenium
rect.
The resistor compensates somewhat for that.

The 0.005 uF caps should stay, they're snubbers to dampen the
switching pulses from the rectifiers.

If you are interested in seeing the schem, i have it posted he
http://panic.rutgers.edu/~rnewman/Ma...nsui_au-111pg1...
http://panic.rutgers.edu/~rnewman/Ma...nsui_au-111pg2...
I also was digging through my parts bin last night and realized I
already have most of the values of caps I need in Mallory 150's from
my guitar amp repair parts. Are these OK to use? How do they sound
compared to the Wilmas? Where do you get Wilma caps. I'm not familar
with them.

I don't know the Mallories since I'm on the other side of a shirtload
of water from you.
I'd guess your Mallory is our Wima, just decent caps.
In case the 150 number is the voltage rating, they're not suitable of
course.

I'm not really a capacitor sound man, at least not when global
feedback is used as is done in your amp.
And even then, most stories about capacitor "sound" are IMO a bit
hyperboled, to say the least.

OK, I used Mundorfs in my amps, just because I had them lying around
and I like the sight of them sitting in my amps. ;-)

Other people may chime in about specific cap sound characteristics,
though.

Thanks and sorry about all the questions.

Nothing to be sorry about, if it wasn't for your questions, this group
would be almost empty ;-)

--

- Maggies are an addiction for life. -