Feeler: Quad 8 444 EQ with M/S extension in 51x format.

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Yes it is... I changed jobs and moved into a new house last year... and till last week my lab was still packaged.

It will happen! I just need to move my ass and route the second version of the board
 
Hello! Is it absolutely necessary to use shorting (MBB) switches for the frequency selection? I guess that the gain controls will pop with a non-shorting (BBM) switch, but I'm unsure about the frequency selection ones.

Thanks in advance!
 
dmnieto said:
Yes it is... I changed jobs and moved into a new house last year... and till last week my lab was still packaged.

It will happen! I just need to move my ass and route the second version of the board

Any update on this project? If it's still happening I'm in for two kits!
 
Since this thread has been long abandoned. I am willing to try and get this project restarted. I stumbled upon the Gerber files for the main PCB, and the 990 opamp while deep down an electronics nerd rabbit hole. They are untested/unverified at this point. And they are quite pricey little suckers! (The layout does seem quite full, plus the card edge connectors, and transformer cut outs)

When I get the extra R&D funds, I will get a batch made up and build one for testing. It seems like it would be a fantastic EQ!
 
Since this thread has been long abandoned. I am willing to try and get this project restarted. I stumbled upon the Gerber files for the main PCB, and the 990 opamp while deep down an electronics nerd rabbit hole. They are untested/unverified at this point. And they are quite pricey little suckers! (The layout does seem quite full, plus the card edge connectors, and transformer cut outs)

When I get the extra R&D funds, I will get a batch made up and build one for testing. It seems like it would be a fantastic EQ!
To be clear... You have the Gerber files for the project described in the first post? The 500 series version? Or another version?
 
To be clear... You have the Gerber files for the project described in the first post? The 500 series version? Or another version?
Yes, it has the 51x logo in the screen print layer just like the one in the first post. And the SMA version of the 990 op amp that is pictured as well. If i did a medium run of the main boards they would be about $30ish ea. shipped to your door. Still need a full BOM however!
 
Yes, it does. Wow! I was really excited about this project and disappointed when it faded away. I hope you can revive it.

Dare I ask the difficult questions about the source of the files, and contact with dmnieto?
 
They seem to have been made public domain, creative commons in 2017. I have not been in contact with dmnieto, I would love to however!
 
Looks like the same board to me!
Disclaimer: I have not seen the original thread. That being said, I'm wondering how it happens that the "input" transformer has the same footprint as the "output" transformer. An output type transformer (QEE parts were typically bifilar-wound with no Faraday shield and designed for low-Z drive and loads) and an input type (with Faraday shield for CMRR and designed for hi-Z loads). Their similarity pretty much begins and ends with passing a signal ... they're not interchangeable!
 
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