BARACUDA-Legend-1

[6666]

AP
just for interest would you mind telling me the exact part number on U2 and U4
that you used in your Bara please

thanks

[plumabob]

Thanks, Maikl! Now i got it!

Bob

[maikl]

PLEASE can somebody show me which 2 fets should be matched???? I don't want to cook my one and only board.

Thanks

Bob

There is talk of Q3 and Q4.

[plumabob]

PLEASE can somebody show me which 2 fets should be matched???? I don't want to cook my one and only board.

Thanks

Bob

[Alexismex]

Thanks Apberg for this real discover ...if i remember many years ago Eric Foster tell that he match the fets in their circuit ...but nobody react in the forum ... and now it is a good notice for us ....
For the 4066 i have many times compared with the single fet in particular the J113 and for my appreciation it is much better the fet configuration J113
Thanks again

[habitbraker]

The analog switch should operate with both polarities. What is the funny?

oh yes of course - you always can connect negative supply to VSS and 0V to VDD.
Why funny?

[Vortxrex]

Should add FET Sockets

Should add some simple 3 pin sockets in place of the FETS so you can experiment with FETs to find a good match.

Dave Frank

[mikebg]

...But then sample pulse pulse polarity must be changed

The analog switch should operate with both polarities. What is the funny?

[habitbraker]

...But then sample pulse pulse polarity must be changed

[mikebg]

Thanks for trying to help me. Still don't understand it. Like I said this is greek to me, if someone could just point out which 2 fets should be the same I would appreciate it.
Bob

Bob, I agree with DIRCEU that you can use 4066 because Q3 and Q4 operate as analog switches. In this case the most important parameter is Rds_on.
The parameter can be measured with an ohmmeter as shown below.

[DIRCEU]

Hi! All


If you use 4066 instead the fets, like Surfmaster, then...

Dirceu

[plumabob]

Thanks for trying to help me. Still don't understand it. Like I said this is greek to me, if someone could just point out which 2 fets should be the same I would appreciate it.

Bob

[TH Jim]

BTW:

Great job ApBerg!! Good work, as always from you!

As you know I thought it was strange to have 2 different FET's, now we can guess why - it doesn't matter as long as they are matched!

Regards, Jim.

[TH Jim]

We are talking about the 2 FET's that are used to gate the output of the NE5534 into the LF412.

[plumabob]

I'm not getting this. What FETs are being changed to get the depth increase? Some sort on diagram would be helpful. My understanding of these components is limited but I'm great at looking at pictures...LOL

Thanks