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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...

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.