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Messages - troublerat

I may well have an canditate for a soul transplant. I have a crate dx212, was a great amp with nice models,a really nice amp and what makes this worse is getting another one like this is out of the question. Getting someone around here to work on it is almost impossible. I have a local tech and the only guy I know that is capable of fixing it  likes to take amps apart, put them in a back room and think about them for a longgggggg time, two years its been there.This is whats sitting there in pieces with other amps sitting on top of it,  at the very minimum I have a solid case, speakers, knobs,and transformer although I"ll miss those other goodies. But hey I think I can do something with it now.
Amplifier Discussion / Re: LM3886AMPBUILDCOMPLETED
September 29, 2009, 08:36:19 PM
the pins that were not used I clipped them off,and the holes that the pins did not want to line up with I drilled out larger. The am fm radio cd player that the heatsink belonged to accomadated stereo amps but I just centrally located the amp and drilled a new hole for it.I used the 3886 with black plastic so insulating it from the chassis was not an issue.By the way I dragged the chassis[bottom with heatsink, fuse,and transformer out of the trash.The transformer secondaries had aprox.24.76 volts which after the rect. and smoothing ended up with nearly a healthy 36 volts pos and neg.Thanks to reading this group along with RG at arons I acquired the necessary tidbits. The heatsink doesnt even begin to get warm. I admit working with mains voltage had me psyched out but  absorbing a little learning curve demystified it somewhat.I used one of those radio shack boards meant for ics, this bring the connections out front. I have to get my man cave up and running as my son and his wife are moving out  ;D and I have to pinch myself to make sure this is for real because he was forewarned that I wouldnt lightly come off of it again. Then I can get to some recording.
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 / Re: have chosen my pre-amp
July 29, 2009, 08:33:51 PM
I"m sure glad you dont have to be an electronics genius to have good ears, I knew I had something and I think I"ll stay with it. This thing in stereo with a tasty small amount of od in front[ maybe spike it with some compression and you truly would have a rug scorcher.I used opa 134 for the op-amps. dont have a way to post any sound samples yet and one more word on this build just about the only other thing I am going to do with this amp is put an effects loop in[the one mentioned in teemuks book]
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.
Preamps and Effects / Re: How do I test my Pre-Amp?
June 28, 2009, 10:53:43 AM
Not that I can add a lot to what has been said, but I have built that pre-amp and am very pleased with the sound. I used R G method of getting 9+ 9- out of  9volts supply. Use a 1044 charge pump. I like the way elliot makes the tone shaping elements so you can totally cut a particular band.
#8  I understand now what RDV was speaking about in some post I"ve read on shorting out the chip. If you go to this site and read the pdf file on the practise amp utilizing the tda2030. It describes using the metalic back of the chip as an direct connection to -ve and should be isolated from everything else. Also it describes that thermal grease may not be needed. This sounds to me that its an recipe for disaster. Especially someone like myself  being [just a little ignorant of the facts] maybe. Iwant to do this right the first time. I am going to assume that this a top order build [all though its not] but pretending that it is hopefully that being a deterent to future mistakes...... Now on the note of connecting -ve via the back of the tda 2030 what theyre doing is using that back instead of the -ve pin on the chip which would be the safer route. Am I close to being correct? I mean if you use the pin for -ve and  utilize thermal grease and mica on thr back of the chip then your fairly well protected.
   Hey I get it, I have a history of making fairly simple or unkown things very difficult to understand.  I went around the mountain several times  when I went on the " lets understand these transformer kick. And then the light turns on and all of a sudden " ok that was fairly simple after all. This is a part time hobby for me after all, it all started when I realized that very soon that I would not be able to buy any more gear and if I wanted anything then I better learn how to make some of this stuff. Heres a sad story, at one time I had no less than three amps, four guitars, pedals out the ying yang, effects processors [ three of them]  hell man I couldnt even make up my mind which one to turn on. This is my story I was an gearoholic. Long after the fall I find myself plugging in to an 1.75 realistic 12 watt power amp and one of the few things I kept,an 4/10 univox cab. One day I was looking at the tiny hacked up power amp and telling myself this cant be that hard to make. But its all good now. By the way everything that was said made good sence and thanks for the help..........stripped stereos   :)Hey thats where I have been acquing parts and storing them until I found out what to do with them. LM 3886 tf I think thats the one I ordered.
I have been reading up on heat sinks at Elliot sound products and have a little better understanding. The chip needs thermal grease/ the smoother the finish on the flat side of the alum. the better mating of the two. I also have been looking back at some post at diy stompboxes. R G writes that an  lm3886 will work on an unregulated power supply. So I have an trans. with 24 -0 - 24 secondaries and I"m going to use an 25a bridge rect. with some largish caps [between2000 and 4000 uf] with those snubberizer caps. I"m not too interested in getting max vol. or even gigging with it. Forgive me for being a little thick on this thermal grease /heat sink thing. What we want is to pass the heat from chip to the heat sink but not the electrical characteristics of the chip itself. With an + - power supply. The pos volt connected to the pos. pin the neg. volt connected to the neg pin. The surface of the chip and heat sink are the grnd ?
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.
This circuita has on board compander chip NE 572. I guess my ignorance is showing but I suppose this is what controls the low rolloff.
The chip is a dual channel 22watt, by looking at the data sheet c2 controls the low rolloff.
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.