Author Topic: OC44 values/measurements  (Read 407 times)

rangermaster

OC44 values/measurements
« on: January 25, 2021, 02:34:39 AM »
Hi there.

I've got some old NOS original OC44 and OC71 transistors at home that i want to use to build some Rangemaster clones.

However.. i want to test them to check if they are still ok. I'm not really familiar with how to do this and what should be the right value/measurements.

Can someone please help me how to do this ?

Thanks!

cab42

Re: OC44 values/measurements
« Reply #1 on: January 25, 2021, 03:25:42 AM »
As always, check geofex  :)

http://www.geofex.com/article_folders/ffselect.htm

I used this method for my germaniums (CV7112)

Edit: You can also just plug them in and try them. If they sound good, they are good! I don't have any idea of the gain of the tranny in my RM, but it sounds great. I built it before I tested my germaniums. I just tried a few and picked the one I liked best.

« Last Edit: January 25, 2021, 03:57:34 AM by cab42 »
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rangermaster

Re: OC44 values/measurements
« Reply #2 on: January 25, 2021, 07:04:03 AM »
Thanks for the link. Did not found that already.

Do you also know if there are sound differences between the new and old OC44's ?

I have a couple of old OC44 here and got some new 'OC44K Tung' in order.

garcho

Re: OC44 values/measurements
« Reply #3 on: January 25, 2021, 09:25:11 AM »
Transistors dont have a sound, circuits do. Old Ge transistors have attributes that are difficult to nail down by model number. Thats why people have come up with tests, like RG at Geofex. Two transistors of the exact same model might end up making two very different sounding pedals. Id worry more about who/where Im buying germanium devices and less about specific models. Reputable sellers will sell you something useful, eBay pirates will sell you anything labeled Ge, regardless of usefulness relevant to pedal building, just to cash in on germanium mania.
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rangermaster

Re: OC44 values/measurements
« Reply #4 on: January 25, 2021, 10:34:54 AM »
Ok thanks. That clears thi gs up.

Normally u don't buy new 'old' transistors. I buy old old radio's and get them from there. That way you have the old germanium transistors.

garcho

Re: OC44 values/measurements
« Reply #5 on: January 25, 2021, 11:52:17 AM »
Quote
That way you have the old germanium transistors.

You are safe to assume, in guitar pedal audio world, there are only old germanium transistors.
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rangermaster

Re: OC44 values/measurements
« Reply #6 on: January 28, 2021, 12:32:27 PM »
Ok little confusing. Because i got some newer metal can's oc44 here.

See pics:
https://www.dropbox.com/s/i5mxfjqfxc6qly5/20210128_173736.jpg?dl=0

https://www.dropbox.com/s/q619uxlw9jzkzlz/20210128_173532.jpg?dl=0


So there should not be a difference in Black glass vs Metal can ?

garcho

Re: OC44 values/measurements
« Reply #7 on: January 28, 2021, 01:05:07 PM »
Ah, I get it now, by "new" you mean from the `60s? Could it be more glass = military spec, can = hope for the best? Sorry, I thought you meant new production, my bad, sorry to derail.
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Big Monk

Re: OC44 values/measurements
« Reply #8 on: January 29, 2021, 09:23:38 PM »
Ah, I get it now, by "new" you mean from the `60s? Could it be more glass = military spec, can = hope for the best? Sorry, I thought you meant new production, my bad, sorry to derail.

 ;D
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