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[#26343] Leak Club for Leakies or Leak user    
restoration


heu
個人訊息 正式會員
118.xxx.xxx.28
2012-04-05 21:58
[#26344] Leak Club for Leakies or Leak user    
if i make misstake in restoration part.
pls advice.

heu
個人訊息 正式會員
118.xxx.xxx.28
2012-04-05 22:05
[#26345] Leak Club for Leakies or Leak user    
still have nosie on both amp.
this is 1960 with 3920 main transformer and 3921 output transformer.

heu
個人訊息 正式會員
118.xxx.xxx.28
2012-04-05 22:09
[#26346] Leak Club for Leakies or Leak user    
ready try on octal plug. still have nosie. Its from tweeter speaker.

heu
個人訊息 正式會員
118.xxx.xxx.28
2012-04-05 22:13
[#26347] Leak Club for Leakies or Leak user    
this is 1959 year main transformer 3920R output transformer 3921, other component and board are same.
heu
個人訊息 正式會員
118.xxx.xxx.28
2012-04-05 22:15
[#26348] Leak Club for Leakies or Leak user    
I make appologize.
I had miss overlooked the page 873.
I had try the octal plugs with shunt resistors , noise still there.
I will try on disconnect the earth wire from power to amp later.
hope can solve the noise problem.
heu
個人訊息 正式會員
118.xxx.xxx.28
2012-04-05 22:23
[#26349] Leak Club for Leakies or Leak user    
Try to replace the 0.25 TCC caps with Russian PIO. It wouldn't cost you arm and leg.
rsbn589
個人訊息 正式會員
115.xxx.xxx.157
2012-04-05 22:27
[#26350] Leak Club for Leakies or Leak user    
Try to replace the 0.25 TCC caps with Russian PIO. It wouldn't cost you arm and leg.
---------------------------------------

KY, Heu,

Bad coupling caps would case red hot plates of EL84's. Any such sign?

Russian PIO is not my cup of tea in sonics anyway. :)

If noise is consistent like 50/60Hz hum, it is normally due to smoothing caps instead. If it is sporatic noise heard at times or sometimes, it is somewhere else or something else. Do the right diagnosis and give the right treatment.

Cheers!

最後修改時間: 2012-04-05 22:45:25
rcwy
個人訊息 正式會員
221.xxx.xxx.238
2012-04-05 22:44
[#26351] Leak Club for Leakies or Leak user    
"I had try the octal plugs with shunt resistors , noise still there."


Heu, What values are the shunt resistors?

rcwy
個人訊息 正式會員
221.xxx.xxx.238
2012-04-05 22:55
[#26352] Leak Club for Leakies or Leak user    
"still have nosie. Its from tweeter speaker."

It sounds like "white noise"... likely from very old carbon resistors in the power amp AND in the preamp.

If it is indeed white noise which comes from the pre-amp, too high input sensitivity of the power amp could magnify the noise from the pre-amp making the noise intolerable and is the culprit. So, the value of the shunt resistors may be significant in your case.



最後修改時間: 2012-04-05 23:03:51
rcwy
個人訊息 正式會員
221.xxx.xxx.238
2012-04-05 23:00
[#26353] Leak Club for Leakies or Leak user    
Heu,

Regarding whether you need to change the caps, measure voltage at the grids of EL84's. What are the value in Volt(s) against ground (chasis)?

Normally, grid against ground should measure ZERO volt. If it is +1 or above, the vintage TCC coupling caps are leaky. Replace them with modern PIO's, like those from Jensen, etc. that will not cost an arm and a leg too. ^^





最後修改時間: 2012-04-05 23:20:48
rcwy
個人訊息 正式會員
221.xxx.xxx.238
2012-04-05 23:13
[#26354] Leak Club for Leakies or Leak user    
Had try the russian cap, its not my cup of tea.
I more like the tcc 0.25.
its poison my ear.
heu
個人訊息 正式會員
118.xxx.xxx.28
2012-04-05 23:25
[#26355] Leak Club for Leakies or Leak user    
the shunt resistors value is about 120K and 47K if i not make misstake. the plug ready return back can't measure.
heu
個人訊息 正式會員
118.xxx.xxx.28
2012-04-05 23:29
[#26356] Leak Club for Leakies or Leak user    
leg and arm ready cut lo, total restoration component part and learning cost can purchase another 1 unit leak tl 12 plus.
heu
個人訊息 正式會員
118.xxx.xxx.28
2012-04-05 23:34
[#26357] Leak Club for Leakies or Leak user    
can I know what is the point or pin for the grids i can measure it. i have the 12 plus circuit diagram. can found it from the diagram?
heu
個人訊息 正式會員
118.xxx.xxx.28
2012-04-05 23:36
[#26358] Leak Club for Leakies or Leak user    
i had removed the earth wire from power socket to amp, its a bit nosie reduce, aleast hear and feel more comfortable. will have more testing first to confirm it
heu
個人訊息 正式會員
118.xxx.xxx.28
2012-04-05 23:42
[#26359] Leak Club for Leakies or Leak user    
Its the grids of EL84s pin 7, 9 to output transformer pin 4,6, and 5, 8 ?
I guess it.

Very thanks to KY and Rcwy give a support.
heu
個人訊息 正式會員
118.xxx.xxx.28
2012-04-05 23:47
[#26360] Leak Club for Leakies or Leak user    
the shunt resistors value is about 120K and 47K
---------------------

That combination is OK.
rcwy
個人訊息 正式會員
221.xxx.xxx.238
2012-04-06 00:05
[#26361] Leak Club for Leakies or Leak user    

For EL84, grid is Pin 2; Cathod is Pin 3; and Plate is Pin 7.



rcwy
個人訊息 正式會員
221.xxx.xxx.238
2012-04-06 00:08
[#26362] Leak Club for Leakies or Leak user    
i had removed the earth wire from power socket to amp, its a bit nosie reduce, aleast hear and feel more comfortable.
---------------------------

Did you say noise was audible from the tweeters of your speakers only? This observation is strange, if the noise is indeed hum that you reduced by removing earth wire.

Make sure what nature is the noise?
rcwy
個人訊息 正式會員
221.xxx.xxx.238
2012-04-06 00:15
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