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Topics - troublerat

Amplifier Discussion / LM3886AMPBUILDCOMPLETED
September 28, 2009, 08:49:11 PM The top TWO photos are my finished work. You can see the three sided wrapper [.090 alum] the face plate is mirror, and I chose not to leave anything out when it came to the effects loop, this is right out of teemuks book. send and return vol. controls with blender option. If I hadnt of done that I would have been wondering.The preamp is elliot soundproducts mark2 amp project mentioned in another post... Sound wise I couldnt be more pleased, lots of clean boost, no unwanted dist. noises or hiss and as a matter of fact you can have this thing almost dimed and not even tell its turned on if wasnt for my guitar causing feedback through my cab. I did say there was no dist. but actually when my guitar is turned up [I have active circuitry emg 85 and 81 with midboost ....that may overdrive my preamp if I let it. It is a very loud amp in good way. I have been playing with my new delay through the loop a rocktron shortimer.
Preamps and Effects / have chosen my pre-amp
July 28, 2009, 10:22:30 PM  This has been mentioned before but now that my power amp is finished, I have been reviewing pre-amps. I have several boxes that I have been toying with but for some reason have put this one off until the last. I have had it built [circuit unboxed] and playing through this makeshift power amp [low watt ] thing I had laying around. The schematic calls for 15+15- but all I had available at the time was  9+ 9-. I am thinking about rebuilding it and trying it with the 18+ 18- I have available. To get to the sound, when elliot says it has ample gain available hes not kidding. The tone is sparkling, and it really kicks this lm3886 way up a notch. Compared to some of my typical stompbox circuits they cant really hold a candle to it. At max vol. it has a small amount of breakup [I mean small]. Very loud and clean and you can tell it was designed for a guitar amp. Loud and clean is usually where I practise at anyway. If you build it I would advice against the clipping diodes at the end as they seem almost an after thought in the design process. But everything else is full steam ahead. I may add an od circuit on an dpdt if I cant fig. out a good way to add some overdrive to this one....or I may leave well enough alone......................One more point at total maxed out vol. guitar pre-amp and power amp [well above bedroom level unless your deaf] noise really isnt a problem. It seem I filtered my power amp well and fairly pleased with it]
Preamps and Effects / pre-amp suggestions
June 28, 2009, 12:55:55 PM
This is one thing that I may be able to give some suggestions on. If you need 9+9- go to the circuit sweeping section and look for 9+9- from an 9 volt supply. Go to and use the jiggle side for an clean to overdriven fenderish type sound. Then theres my favorite  the mosboost can be built from radio shack parts and gives an excellent fat clean boost [ you can use bs170, irf511, 2n7000]  Heres one chain to try it involves an boss comp. cs-3 with wampcats mods   guitar/cs-3/mosboost/chip amp. I am probably going with the mosboost[one knob booster] [and the rog double d , just the jiggle side.and put the mos on an dpdt to switch it in and out in front of the jiggle. I am seriously pondering on the classic fuzz face circuit, I built one from the schem. at geofex with no variance from the schematic was very pleased with sound. Go to geofex at the top of the page "The tech of series".  Theres just to many good workable circuits  to bang my head and try to reinvent the wheel. All the above work well. I have use them in front of several amps. The hardest thing you have to do is deciding what kind of tone you want. I prefer the one or to knob types and try to keep the face of the amp from getting to cluttered with knobs.
I have read the posts on RDV lm3886 amp. I want to see if I"m understanding this properly as I am about to build one myself. The chip needs thermal grease to be properly coupled to the heatsink. The heatsink needs to be properly isolated from any other metal parts [case]. The heatsink needs to be properly sized for the chip. Now what I am not clear about is the mica and other substances mentioned. Are they to be used with the thermal grease or an alternative . The heatsink should not come in contact with other pieces on the circuit board. Any help would be appreciated.
I have acquired an altec lansing subwoofer for computers. The speaker [at least one of them] as it has a tweeter or probably an small midrange built into the subwoofer is probably blown. It has a rattling sound. I got this thing for the sole intention of roguing  it for the torroid for another project. The torroid has 120 prim.with dual secondaries ac out 14.77 volts into the two rectifiers out of the rect. dc I get 19.95 volts. The power chip used is KIA6210Ah  dual 22 watts. I could extract the torroid and be good to go for my next project.But what I was thinking was if I could change some components on the board modifying it for guitar use. I know its rolling off treble so I would have to undo that but I can extract everything from the case easy enough. It has one lm 324 and one ne 572n[?] I am in the mood to tinker and this is the perfect project for it. I think I have some good building blocks. Thoughts comments suggestions from the experts.
Just finished the 1517 board and installed it in my ESP clean pre-amp. Very happy with it :) This is the loudest freaking 6watts I have ever heard. Now I can go forward with this design/effect loops etc.