Author Topic: Fake MN3007 are really MN3207???  (Read 274 times)

Prive

Fake MN3007 are really MN3207???
« on: June 28, 2022, 02:50:23 AM »
Some people say fake MN3007 are really MN3207 with wrong label, sadly i have a bunch of these fake MN3007 from a China dealer and i'd like to make the experiment of test it, i've tried in my small clone circuit inverting pins 1 and 5 and nothing, my question is: maybe the clock driver must be different? I usually see 3007/3101 and 3207/3102 combos, my small clone uses a 4047 as a driver. Any help will be welcome, thanks!!!!!

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Chillums

Re: Fake MN3007 are really MN3207???
« Reply #1 on: June 28, 2022, 05:22:40 AM »
Yes this does happen.  I sent some of mine to a guy in Germany and when he opened them up they were all MN3207. 
https://www.richis-lab.de/bbd05.htm
Also here is a link to the thread here with a couple more chips I sent him.
https://www.diystompboxes.com/smfforum/index.php?topic=127053.msg1224982#msg1224982

Kevin Mitchell

Re: Fake MN3007 are really MN3207???
« Reply #2 on: June 28, 2022, 08:05:58 AM »
In your case, if the ICs are getting hot when installed then you're right to be suspicious. But in many cases, you'll get a totally bunk IC rather than a BBD of a different sort. However, I have personally gotten MN3005 chips that were obviously fake and had all of the impressions of a V3205, though they were totally DOA anyhow.

I take it you had missed my BBD tester thread? I can easily come up with a circuit for basic testing. The most simple design is an LED indicator proving if a BBD is passing signal.

You can use a 3102 driver to drive a 3007 with little drawback. You have to lift the VGG pin to provide 14/15th of the BBD's supply. 3007 is opposite polarity of a 3207. I simply use a 3.3K and 47K resistor divider.
To function in an audio circuit you will also have to make another adjustment or two to accommodate. There's plenty of projects that allow the use of both and further explain these details.
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ElectricDruid

Re: Fake MN3007 are really MN3207???
« Reply #3 on: June 28, 2022, 10:08:05 AM »
i've tried in my small clone circuit inverting pins 1 and 5 and nothing, my question is: maybe the clock driver must be different? I usually see 3007/3101 and 3207/3102 combos, my small clone uses a 4047 as a driver.

You can drive either 3007 or 3207 from the 4047. As long as the 4047 has the same supply voltages as the BBD, it's fine.

There can be problems driving longer delay lines or driving BBDs using very high clock frequencies. This happens because the BBD clock pins have a certain capacitance which tends to round off the clock pulses. Longer BBDs have more capacitance, so cause worse problems, and higher clock frequencies get rounded more, so also cause worse problems.

But with 1024-stage devices like you're talking about and "normal" clock rates of a few hundred KHz, the clock at least should be fine.


« Last Edit: June 28, 2022, 03:55:18 PM by ElectricDruid »
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Prive

Re: Fake MN3007 are really MN3207???
« Reply #4 on: June 28, 2022, 03:07:25 PM »
Thanks everyone for your answers
Fuzz boxes don't need on/off switch!!!!!!!!