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Check your Germanium diodes!

Posted: Nov 29th, '14, 15:55
by ikke
Measure them before you start.
From the six 1N60 diodes, one came broken out of the bag...
:evil:

Re: Check your Germanium diodes!

Posted: Dec 5th, '14, 14:32
by ikke
I ordered some new diodes but when i got them they were 1N60-p diodes instead of the ones supplied in the kit.
(They look like regular 1N4148's but a tiny bit bigger.)
So the question is if this would make a difference when i put them in the Tom section?

Re: Check your Germanium diodes!

Posted: Dec 5th, '14, 19:35
by jeroenbvo
Hi,

The major difference I see is the I FSM, ie the forward surge current on the P version is higher, which should be no issue I think.
Also the junction Capacitance is different, don't know what that will do to the sound..

http://tydiodes.com/manage/product/pic/ ... 233549.pdf
http://www.allaboutcircuits.com/vol_3/chpt_3/3.html

Edit: Seems like the 1s188fm originals in the 808 are more towards the 1n60p than the 1n60 regarding Ifsm and jC. Hard to find a datasheet for those.

Re: Check your Germanium diodes!

Posted: Dec 9th, '14, 14:04
by ikke
Hey Jeroen,
thank you for your response.
I'll just give them a go and see/hear what happens.
I've been looking for those original diodes (1S188FM) but the only thing i found
was a site that stated to have an equivalent namely the NTE109 at the cost of 1.70$ a piece
and'/or the OA70 at 1.64$... on another site they said the AA119 would a good substitute at the price of 0.71 Eurocent.
I guess i'll have to dig into the data sheets to find the perfect substitute if the ones i have don't work properly.

http://www.weisd.com/test/GenericParts_ ... d1=1S188FM

http://www.weisd.com/test/GenericParts_ ... itid1=OA70

http://de-onlineshop.nl/index.php?route ... uct_id=559

http://www.banzaimusic.com/AA119.html

Re: Check your Germanium diodes!

Posted: Dec 10th, '14, 13:59
by jeroenbvo
Hi ikke,

Yes, I saw that. That NTE109 has about the same specs as the 1N60p's. So I think it shouldn't be a big issue and probably you won't hear a difference.

Re: Check your Germanium diodes!

Posted: Dec 11th, '14, 11:22
by ikke
Thanks a lot for thinking along Jeroen!

Re: Check your Germanium diodes!

Posted: Feb 9th, '15, 21:28
by stevesavage
I have just had the same issue.

1 out of the 6 Germanium diodes were bad, luckily I had read this post before starting the build and it must of stuck in my mind ;)
So checked all the diodes before soldering and found the bad one.
Again as luck would have it , I had a few kicking around in my parts bin :)

Steve

Re: Check your Germanium diodes!

Posted: Feb 13th, '15, 15:18
by arnarmarol
I measured mine and the values were:

.296
.293
.327
1.640
.691
.644

Isn't around 0.3 normal? Whats up with the 1.640 one?

Re: Check your Germanium diodes!

Posted: Feb 14th, '15, 21:12
by jeroenbvo
What unit are these measures. Or what/how did you measure? Is this resistance or voltage drop Vf?

Re: Check your Germanium diodes!

Posted: Feb 14th, '15, 21:16
by arnarmarol
This is forward voltage drop in V.