Cavendish Mod

Earlier this year, I got myself a little post-Christmas present in the form of a complete GSSL kit from PCBgrinder. For those uninitiated, the GSSL is a DIY clone of the famous SSL 4000 bus compressor.

2017-01-13 23.14.36
GSSL PCB with a few resistors

Building the clone itself was no problem at all, but now I’m trying to implement the Cavendish all discreet signal path upgrade. And it’s been a bit of a shaky journey so far.

2017-01-30 19.53.53
Fully functioning GSSL living in my hand made studio desk

I’ve probably had the Cavendish board since March of this year, building it very slowly over time. As you can see from the featured picture, it’s finally complete, now I just have to get it to play nice with the GSSL board.

2017-02-15 20.40.08
Cavendish Board, mostly unpopulated.

Unfortunately, the documentation for this mod is out of date by one revision. That might not seem like a big deal, but there’s really no way for me to know for sure what changes were made with the new revision board that I own as compared to the original. For example, the original board requires certain pins of the NE5532 IC chips to be transposed when jumping them to the cavendish board (that’s what those grey ribbon cables are for). Does this new revision board still need those transpositions? One GroupDIY user has said so, so I currently have it wired up with them in place. I hope it’s correct, because soldering onto those tiny little dip8 headers is a huge pain.

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As seen here, featuring some pretty ugly soldering.

I would know, as I’ve already had to re-orient my cables on them once. I was doing an initial test on just one channel while I waited for the parts to com in to finish the last Discreet Op-Amp.

2017-09-08 21.46.21
A Discreet Operational Amplifier (or DOA) in case you were wondering what I was talking about.

Because it’s been so long since I put the headers on the Cavendish board, I was starting to second guess myself about the orientation of the pins. For some reason, I decided that I had soldered the headers on upside-down. Bad idea. Powered the unit on and smoked a 10 Ohm resistor in the power section of the main board. My first burnt component, I guess it’s kind of a rite of passage. Anyway, now I have to wait for a desoldering iron and some fresh resistors to come in the mail before I can try for take two. Hopefully sometime this weekend I’ll be able to update the blog with my results.

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