Dirtbag BBD bypass

[Chi_Boy]

I'm currently debugging a Dirtbag with MN3005's that isn't getting enough delay time.  I'm only getting 250ms right now.

I would like to be able to run 1 chip at a time to help determine if I have a single bad chip, or 2 fakes.

Can I remove one of the delay chips and jumper from Pin 7 to Pin 3?  Or maybe the jumper should be a 1uF cap?  If I was to jumper IC5, would I want to change the balance at all?  Or would jumpering screw something up?

Also, I hear signal on Pin 3 of both chips when biasing.  Does that mean that both are delaying, or could 1 be delaying 250ms and the other nothing?

[Loztboy]

If you only get 250ms I think both your chips are relabeled 3008's. I get 510ms with two genuine mn3005's. Did you measure the 5k6 resistor, the  240pf cap and the delay pot?

[mysticwhiskey]

Apart from fake (relabelled MN3008) BBD chips, the only other thing that I can think of that would give half the delay time is either C41 (240pF) or the delay pot being half of their specified values.  Check that you didn't accidentally swap C31 (120pF) with C41 (240pF).

[Scruffie]

Apart from fake (relabelled MN3008) BBD chips, the only other thing that I can think of that would give half the delay time is either C41 (240pF) or the delay pot being half of their specified values.  Check that you didn't accidentally swap C31 (120pF) with C41 (240pF).

Prettyy much.

I'm gunna guess you got faked.

Try and get your money back, i'd be interested in taking them off your hands though if the price is right, 3008s are still good!

[gtr2]

I'd agree on the fakes buy just an FYI.  You can use always use an audio probe to check after the first bbd.

Josh

[Chi_Boy]

Yes, the more I look, the closer I get to the conclusion that these are fake.   I'll have to post some pictures, because if these are fake, someone put a lot of effort into them.

Any thoughts on the bypass question?  Might be good information regardless of wether or not these are fake.