Built this for my son for Xmas and sounds awesome. My clear lacquer spraying wasn't so hot but still. https://www.flickr.com/photos/197214338@N03/52579663089/in/dateposted-public/
There are a few mismatched component values compared to the schematic: the 1k resistor from P2-S2 should by 4k7, the cap connecting lugs 1&2 of the Bass pot (F2-H2) should be 100n, and the 1k resistor coming off IC3 pin 1 (Y17-AB17) should be 2k2. Other than that, this is definitely verified, and sounds great. It really has that Ampeg snarl, with lots of top-end bite available—perfect for gnarly post-punk sounds à la Birthday Party or the Stranglers.
I found (as some noted at FSB) that it overdrives really quickly, from anywhere above 9 o'clock on the Gain pot. To help tame it, I suggest omitting the clipping diodes (D1&D2) and using a log taper pot for the Gain. This gives a much more useful range of drive.
Power inductors! With such low currents, there's not really much point in RF inductors in pedals. Better to handle noise through power filtering, wire dressing, and (salute to Fuzzhead) clever layouts. These 10mH inductors are the little black cylindrical ones you can get from Mouser, eBay, etc.
To be clear, I made it WITH the inductors. I was just remarking that the kind of inductor used in this pedal is a power inductor, as opposed to an RF inductor (which handles frequencies/noise well outside the range & voltage of an effect pedal).
Looking at Bajaman's schematic, I'm sure you could chop out the whole mid control (where the inductors are) and it would work fine. But, for me, the active mid control is part of the signature Ampeg sound.
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ReplyDeleteBuilt this for my son for Xmas and sounds awesome. My clear lacquer spraying wasn't so hot but still. https://www.flickr.com/photos/197214338@N03/52579663089/in/dateposted-public/
ReplyDeleteVery cool!
DeleteWould love to hear how it sounds...
Tagged.
There are a few mismatched component values compared to the schematic: the 1k resistor from P2-S2 should by 4k7, the cap connecting lugs 1&2 of the Bass pot (F2-H2) should be 100n, and the 1k resistor coming off IC3 pin 1 (Y17-AB17) should be 2k2. Other than that, this is definitely verified, and sounds great. It really has that Ampeg snarl, with lots of top-end bite available—perfect for gnarly post-punk sounds à la Birthday Party or the Stranglers.
ReplyDeleteI found (as some noted at FSB) that it overdrives really quickly, from anywhere above 9 o'clock on the Gain pot. To help tame it, I suggest omitting the clipping diodes (D1&D2) and using a log taper pot for the Gain. This gives a much more useful range of drive.
Cool!
DeleteThanks for the report!
Layout is updated.
sounds killer
ReplyDeletemade clipping switchable, 3mm red LED are way better imo
also 100kA for Gain is the difference!
I have a beginner question, are these power or RF inductors or others?
ReplyDeletePower inductors! With such low currents, there's not really much point in RF inductors in pedals. Better to handle noise through power filtering, wire dressing, and (salute to Fuzzhead) clever layouts. These 10mH inductors are the little black cylindrical ones you can get from Mouser, eBay, etc.
DeleteHow does it sound without the inductors?
DeleteTo be clear, I made it WITH the inductors. I was just remarking that the kind of inductor used in this pedal is a power inductor, as opposed to an RF inductor (which handles frequencies/noise well outside the range & voltage of an effect pedal).
DeleteLooking at Bajaman's schematic, I'm sure you could chop out the whole mid control (where the inductors are) and it would work fine. But, for me, the active mid control is part of the signature Ampeg sound.
Thanks for the reply!
DeleteI've built a lot of pedals, but until now I've never used inductors.
I’ll have to listen for that the next time I fire mine up.
ReplyDelete