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Old 10th November 2004, 05:13 AM   #11
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Quote:
Originally posted by EC8010
A leaky coupling capacitor could destroy a perfectly good EL84.
And/Or an Output or power tranny!
Watch out for red plates.
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Old 10th November 2004, 09:00 AM   #12
GeirW is offline GeirW  Norway
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Gday.

Yes. the 84`s are telefunk to, i have searched here in norway
for someone that have original telefunken left ,
but no luck. Does anyone of you a clue where i can obtain some,
or are they gone.?
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Old 10th November 2004, 11:55 AM   #13
mcs is offline mcs  Denmark
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They are very hard to get and very expensive. But if you have the old tubes, why do you want replacements? The ECC83 is fine - the TFK ECC83 tubes last nearly forever. The EL84 tubes may be worn, but not nescesarily. Try getting some Russian EL84 tubes (cheap) and compare.

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Old 10th November 2004, 02:24 PM   #14
GeirW is offline GeirW  Norway
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Gday.

here: http://www.demostenes.no/2.0/nor.htm
they got sovtek el84 for 8$. a tube.
For not so long ago they offered matching pair svetlana
for ca. 20$.
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Old 10th November 2004, 03:16 PM   #15
GeirW is offline GeirW  Norway
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Gday.

Quote:
Originally posted by SY
Replace any selenium rectifiers, then see how it all works.
yes.. but there is a slight problem, the rectifier here, is a
siemens aleminium cased one.
pic. of the type here:
http://home.arcor.de/w.zucker/elektr...ichrichter.jpg
type:
SSF
B 250v 100C
Kc 0.6b 22/8
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Old 10th November 2004, 03:29 PM   #16
mcs is offline mcs  Denmark
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Just replace the rectifier with a W04G or similar standard rectifier bridge. You may need to increase the filter resistors in the powersupply to get back to the original voltages. I'll have a look at the schematic.

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Old 10th November 2004, 04:45 PM   #17
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This may be a real newbie question, but why would you want to replace the -working- resistors? I was just looking at some really old radios if I could use the resistors for my amp..
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Old 10th November 2004, 04:50 PM   #18
mcs is offline mcs  Denmark
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Quote:
Originally posted by Miniwatt
why would you want to replace the -working- resistors?
Because a selenium rectifier has a higher voltage drop than a silicon rectifier. So the output voltages would be too high with the original resistors.

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Old 10th November 2004, 06:25 PM   #19
SY is offline SY  United States
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Geir, I was imprecise in my language. By "replace" I did indeed mean with modern silicon rectifiers. Whether or not you'll need to change power supply resistors depends on what the circuit looks like, but yes, that may also be necessary.
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Old 10th November 2004, 07:45 PM   #20
GeirW is offline GeirW  Norway
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Gday.

I have tried earlier to attach the shematic,
but the image size is to big.
Am attach it as a zip. for those who are interested.
(never mind the radio part, am going to make a replica
with only the ps/powerstage.)
Attached Files
File Type: zip tan-ss-75-20png.zip (68.3 KB, 40 views)
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