Saffron Squeeze/Ross Compressor question

Started by soggybag, December 30, 2009, 12:57:07 PM

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soggybag

I'm building a Saffron Squeeze/Ross Compressor. I have a question about caps. I'm using MarkM's layout. Here's a link to the schematic:
http://aronnelson.com/gallery/main.php/v/SteveC/saffron2.jpg.html?g2_imageViewsIndex=1

There are a few caps listed as 33uf. These all look to me to be power filter type caps. I'm assuming I can swap these with 47uf?

There is a 41.2k resistor, which is a size I don't happen to have on hand. It looks like this feeds into the sustain pot. So I figure this value can't be as critical as it appears. Looks like Mark says he used 39k for this.

The transistors are listed MPSA18. The Ross uses 2N3904. Which looks like a big change. I don't have any MPSA18 on hand. What would be a good sub for this? I do have a few MPSA13 on hand

MikeH

Quote from: soggybag on December 30, 2009, 12:57:07 PM
I'm building a Saffron Squeeze/Ross Compressor. I have a question about caps. I'm using MarkM's layout. Here's a link to the schematic:
http://aronnelson.com/gallery/main.php/v/SteveC/saffron2.jpg.html?g2_imageViewsIndex=1

There are a few caps listed as 33uf. These all look to me to be power filter type caps. I'm assuming I can swap these with 47uf?

There is a 41.2k resistor, which is a size I don't happen to have on hand. It looks like this feeds into the sustain pot. So I figure this value can't be as critical as it appears. Looks like Mark says he used 39k for this.

The transistors are listed MPSA18. The Ross uses 2N3904. Which looks like a big change. I don't have any MPSA18 on hand. What would be a good sub for this? I do have a few MPSA13 on hand

47uf and 39k would be fine.  An MPSA13 is a darlington tranny and is not a plug in substitute for an MPSA18, IIRC.
"Sounds like a Fab Metal to me." -DougH

soggybag

Thanks for the reply. I was thinking the MPSA18 was a darlington, which was an error on my part. Looks like it could be replaced with 2N5089 or other typical NPN.