Stub Mandrel Posted January 4, 2022 Share Posted January 4, 2022 I made this a long time ago. I mentioned it once or twice and someone asked for a picture/details, but it was locked deep in a storage container at the time. It was meant as an attempt at building a practice amp but also to see how 'pro' I could make it look. This is with the grille (made from an old fireguard) removed. I have some proper grille cloth on order to replace that on an old guitar combo and when that arrives I'll use the offcut to sort this one as well. The drivers are 4" 8R units rated 5 watts each (10W max) that were (IIRC) intended as woofers in two-way hifi units my brother built, then moved on from. I think I got some vague guidance on enclosure volume, which I possibly ignored. A few years ago I dug it out and greatly improved the bottom end by removing the huge amount of wadding stuffed inside, then further improved it by cutting a fairly random 65 mm hole in the back. This made the open E sound louder when not covered up. I finally dug it out again a few days ago, and added a 60mm long tube to the port. An A/B experiment showed that it made the bottom end better so I didn't bother with any further experimentation - it's hardly a stage amp! The amp is an own design preamp (pretty clean CMOS op-amp based I think...) and very good bipolar transistor power amp design from Michael Tooley. I added my own three-stage LED monitors - on, medium and high, set subjectively. It has a very clean sound without much colour and could probably be improved by a better designed preamp with some built in overdrive or using it with a DI pedal or emulator. The only thing bass specific about it is the EQ which is (IIRC) I slightly shifted to suit bass guitar. There is a tiny but audible bit of mains hum (despite a transformer with integral shielding in the bottom of the cab, well away from the inputs), so I think the PSU smoothing caps need to be replaced or improved. Not sure of the power, but volume-wise it's similar to my Crush 20. Sound wise it's nothing special at all but it might be fun to bring it to a bass bash and see if we can blow it up. 2 Quote Link to comment Share on other sites More sharing options...
Jus Lukin Posted January 4, 2022 Share Posted January 4, 2022 (edited) - Edited March 16, 2022 by Jus Lukin 1 Quote Link to comment Share on other sites More sharing options...
FirstBass Posted January 5, 2022 Share Posted January 5, 2022 it might be fun to bring it to a bass bash and see if we can blow it up. I like your style..... 😁 1 Quote Link to comment Share on other sites More sharing options...
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