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Well, another day of tinkering later and I'm sorta getting a hold on it. It sounds digital, all right, but spring sounds springy, so it's not bad, it's just different. I suspect some may like it. I've put in a master, which I intended to do anyway, and am working a way through getting everything to not interact. I'm going to actually draw a schematic of this next change, so I'll post it in a bit as I'm finally rounding the corner on this.
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Success, mostly, but not quite what I intended. My objective had been to replace the tube, transformer and tank and try to leave everything close to stock. This was hissy and had overload issues, and I needed the space I had dedicated to the knobs you could fiddle with and make it work for the master volume. The final, mostly successful try is as follows, horridly hand-drawn.
the top yellow 470k is the new mixer, and the 10k pot is the the load/input trimmer for the recovery stage, those are the only "not a fender" part besides the location. I bet if one were to, say, place that circuit after the 3.3m in a normal fender, and replace that with 2.2m, they'd be able to drop this in, using the 470k (or better, 1m) for a mixer. They may get caps in parallel i've gotta listen more. I'm using it with an ev12l now so everythings "bright enough" so far. The controls don't interact with each other at all (I don't think) and it's all good but one, little issue.
It works very well allowing you to dial in any tone you want. The two pots by the brick are mounted on the same thing as the brick, so it's all tidy. The 10k is now redundant as well, but since I've made other changes in the amp, the dwell pot is now back to duty keeping the diodes from clipping. I presume I just have to work out the right vd/pot combination for my input range. This is WAY better than 24 hours ago.
Incidentally, if you whack the front end of it with enough signal, diode clamp or not, it will oscillate, and it's not pretty. It could wreck some speakers or reputations. I'm hoping once I figure out the above it'll not do that... again....Comment
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Hey all,
How are things coming along with the Belton reverb brick? I'm stalking this post, along with a similar one at ax84. Tuna, are you planning to power the chip from the wall wart, or are you going to eventually power it from the amp's power supply. I know that a few folks are working on running it off of the 6.3V filament supply, then regulating it to 5V. Have you found a good way to do it?
Thanks!
JoelComment
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It's working great! I doesn't have a whole lot of swing, and no gain, so you have to place it accordingly, but thats a matter of application.
I thought of a few different ways to get the thing powered, but again, it's different in every application. However, the way I did it is so freakishly easy and cheap, it's worth thinking about it. I've heard about issues powering audio devices off the heater filament, noise and such. I've never tried, but I can understand why you'd want to, it's easy for some relays or vactrols or such. But...
The belton pulls 100ma, and it makes significant noise at power down. It also pulls a power up spike of 500ma. I also have about 100ma of other 5v tasks to take care of in the amp. I don't have that much comfortable headroom on my heater tap, and the unused rec fil tap would need a voltage doubler, actually afaik a tripler, then a bridge rec and it's filter to make the 8v dc that a 7805 needs to be really stable. And then a filter. Granted, those parts are a buck or two, and a board to put em on, etc. But, for a buck or two at the salvage, on amazon, ebay, wherever, you can buy a USB or cell phone psu that puts out 500-1000ma.
Thats what I did, heated it open with the heatgun, took the guts out and stuck em' in a little aluminum box, mounted on the back; ran 120 to it off the mains. It's internally fused. I put a 22uf parallel with a .1 at the b+ of the brick. Not particularly "home made" but it took less than 10 min. and makes no noise whatsoever.
ack I have to go cook dinner! Good luck!Comment
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Digiverb
Hey Tuna,
That's a great idea! I had a psu sitting around here that puts out 9V. I bet it will be fine. I had been banging my head against the wall with the reverb circuit. For whatever reason, I tried several different designs, and my rectifier diodes kept going up in smoke. It's probably a fairly obvious solution, but it eluded me. I think this will help.
Is the hand drawn circuit from your earlier post just a part of the drive/recovery circuit? Being a bit limited with my ability to cobble circuits together from scratch, can you suggest any schematics of a solid state driver/recovery circuit that would work well with the Belton digiverb?
Thanks,
JoelComment
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I don't know if you have the datasheet, so here's a link:
http://www.smallbearelec.com/Projects/BTDR-1H.pdf
It has a max of 5.5v listed, and I wouldn't push it. That said you could use the 9v to supply the 7805 (small bear has super tiny ones, btw)
also, from small bear, a pedal schematic which might be more appropriate to your application:
http://www.smallbearelec.com/Project...lSchematic.pdf
small bear is a great resource, by the by. Also, i've made a few tweaks to that circuit since i posted that, namely more recovery gain.Comment
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