Building my first "Gainclone"
Hi all,
I've commited to building my first power amp and decided to go with a "Gainclone". I'm sort of a n00b but I know how to use a soldering iron, I've recapped a motherboard and fixed it, recapped my current amp (Cambridge Audio A5.... cheapo I know, shh!), done some volt-mods on a couple of motherboards, fixed more than enough xbox's etc etc. I've been wanting to build an amp for a long time, looking at Rod Elliots stuff, but the parts for most of his stuff seem hard to find / quite expensive over here in the UK.
So anyway, I have bought myself four LM3886T's on FleaBay for £7 (which is what has basically commited me to building it!). I did a day's worth of reading Gainclone stuff yesterday, and think I have it pretty much sorted. I intend to build carlosfm's regulated / snubbed power supply (I don't really understand what a snubber is or why it helps but hey), and also following his schematic for the amp (v4).
I've decided to go with a single transformer and two regulated supplies, one for each channel. From what I have read I should be able to do this. I'm mainly only doing it because it seems (from the spec sheet) the LM338 "only" puts out a guaranteed (constant?) 1A when regulating to 30v. I figured that's not really enough to power two channels all that well.
My current amp has a preout, so I can just use it as a preamp. I will start off by hooking the Gainclone to this and powering the speakers (a lowly pair of Celestion 7's) from the Gainclone. I have a Rane MX23 active crossover sitting here doing nothing, so in the future I intend to go bi-amping or tri-amping, all depending on how well the first Gainclone goes really
I have absolutely no idea how I am going to actually wire it all up. I bought some blank PCB's, but have nothing to actually produce the PCB's at home (intelligent idea I know). I'm not sure a PCB can be produced without all that etching stuff can it? I read someone someone just used a scalpel and did it manually, how would that work? Just scratch away at the copper creating the traces?
At the moment I'm thinking about trying to get it all on prototype board / veroboard / whatever you want to call it. I haven't really seen any Gainclones built like this though, apparently because the LM3886 is awkward to mount on such board. I am not sure I would be happy doing it P2P. I would be constantly worrying about shorts and things!
I couldn't find a 300pF MKT cap for carlosfm's amp schematic. Am I able to leave this out? Or perhaps go with a 1000pF MKT instead? Also finding a 0.1R carbon film is impossible. I'm thinking about going with a 0.22R there and a 2.2uF cap instead.
Think that's all for now. Mainly just posting because, well, I don't really know To let the world know there's someone else attempting a Gainclone and to thank carlosfm for the schematics, and everyone else for all the general info and discussions
Hi all,
I've commited to building my first power amp and decided to go with a "Gainclone". I'm sort of a n00b but I know how to use a soldering iron, I've recapped a motherboard and fixed it, recapped my current amp (Cambridge Audio A5.... cheapo I know, shh!), done some volt-mods on a couple of motherboards, fixed more than enough xbox's etc etc. I've been wanting to build an amp for a long time, looking at Rod Elliots stuff, but the parts for most of his stuff seem hard to find / quite expensive over here in the UK.
So anyway, I have bought myself four LM3886T's on FleaBay for £7 (which is what has basically commited me to building it!). I did a day's worth of reading Gainclone stuff yesterday, and think I have it pretty much sorted. I intend to build carlosfm's regulated / snubbed power supply (I don't really understand what a snubber is or why it helps but hey), and also following his schematic for the amp (v4).
I've decided to go with a single transformer and two regulated supplies, one for each channel. From what I have read I should be able to do this. I'm mainly only doing it because it seems (from the spec sheet) the LM338 "only" puts out a guaranteed (constant?) 1A when regulating to 30v. I figured that's not really enough to power two channels all that well.
My current amp has a preout, so I can just use it as a preamp. I will start off by hooking the Gainclone to this and powering the speakers (a lowly pair of Celestion 7's) from the Gainclone. I have a Rane MX23 active crossover sitting here doing nothing, so in the future I intend to go bi-amping or tri-amping, all depending on how well the first Gainclone goes really
I have absolutely no idea how I am going to actually wire it all up. I bought some blank PCB's, but have nothing to actually produce the PCB's at home (intelligent idea I know). I'm not sure a PCB can be produced without all that etching stuff can it? I read someone someone just used a scalpel and did it manually, how would that work? Just scratch away at the copper creating the traces?
At the moment I'm thinking about trying to get it all on prototype board / veroboard / whatever you want to call it. I haven't really seen any Gainclones built like this though, apparently because the LM3886 is awkward to mount on such board. I am not sure I would be happy doing it P2P. I would be constantly worrying about shorts and things!
I couldn't find a 300pF MKT cap for carlosfm's amp schematic. Am I able to leave this out? Or perhaps go with a 1000pF MKT instead? Also finding a 0.1R carbon film is impossible. I'm thinking about going with a 0.22R there and a 2.2uF cap instead.
Think that's all for now. Mainly just posting because, well, I don't really know
To let the world know there's someone else attempting a Gainclone and to thank carlosfm for the schematics, and everyone else for all the general info and discussions 
It honestly isn't difficult to build a GC using P2P!Take your time and do one componets at a time and you shouldn't go wrong.
May I suggest you have a read through this before you start as it should give you some good guidelines and answer at least some of your questions.
A system using an active crossover and GC amps will sound pretty good but start simple and get two channels working OK first!
May I suggest you have a read through this before you start as it should give you some good guidelines and answer at least some of your questions.
A system using an active crossover and GC amps will sound pretty good but start simple and get two channels working OK first!
Re: Building my first "Gainclone"
Else you will need 'that etching stuff'. I assume you've seen the PCB's available. I believe they are what Carlos uses as a basis and mods it to implement his design
http://www.diyaudio.com/forums/showthread.php?s=&threadid=88644
A good DMM to check the connections and patience is all you need. Probably wise not attempting it for a first effort though.
Yup, I guess you could draw the design on the copper and then just scalpel it away but that's bordering on insanitymarkiemrboo said:
Else you will need 'that etching stuff'. I assume you've seen the PCB's available. I believe they are what Carlos uses as a basis and mods it to implement his design It's not too difficult.markiemrboo said:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=88644
A good DMM to check the connections and patience is all you need. Probably wise not attempting it for a first effort though.
Nick
Not often I the surf chip room I was a little confused, but I think Nordic is refering to your diagram showing 47uF input cap not 4.7uF
http://myweb.tiscali.co.uk/nuukspot/decdun/gainclonecircuits.html
A simple error in the vast Decibel Dungeon
Not often I the surf chip room I was a little confused, but I think Nordic is refering to your diagram showing 47uF input cap not 4.7uF
http://myweb.tiscali.co.uk/nuukspot/decdun/gainclonecircuits.html
A simple error in the vast Decibel Dungeon
Looks fine to me
but folks often just look for pictures and diagrams by searching the image function of search engines the pictures show without the parent page they reside in that's when mistakes happen 
That single page on building a basic IGC is not a too difficult read is it.
easier than "the little red lorry books"
Re: Re: Building my first "Gainclone"
Aaah, you are the owner of DD? Seems a good site! I got the schematics from there. Came across it several times on my google searching I'll give it another & more thorough read though tomorrow I reckon.
I will be starting with just two channels first, that's my plan Besides I think using this active crossover may require some DIY speakers. My speakers are two-way, and the crossover is 4-way (3-way stereo only + a 'sub' output). I do really want to experiment with an active system though, and look forward to getting to that point.
lol nothing wrong with a bit of insanity here and there. I think P2P is probably actually the easiest route. I tend to find prototype board a bit hard to lay things out. I'll see what happens when I have all the components I suppose
The GC in that link looks pretty neat actually! I quite like it.
I have a DMM "borrowed" from my Dad, and would check the connections and everything. It's not my first first first ever go at copying a schematic to a board, and I do like a bit of a challenge It keeps me busy! I'm looking forward to building it, and hopefully I will learn alot from it / get caught by the tweaking bug
I will, of course, be posting pictures and a few thoughts once it's done, or near done. I'm still not sure about casing yet, I've not really got the resources / tools available to make me a case really. Seen something on Maplin which looks like it might work, just about. I will have to build the thing and see what kind of size case I need first
I feel like I've got quite alot of it planned out so far, which probably means in reality it's not going to go to plan at all
Off to sleep now anyway! Night folks!
Nuuk said:It honestly isn't difficult to build a GC using P2P!Take your time and do one componets at a time and you shouldn't go wrong.
May I suggest you have a read through this before you start as it should give you some good guidelines and answer at least some of your questions.
A system using an active crossover and GC amps will sound pretty good but start simple and get two channels working OK first!
Aaah, you are the owner of DD? Seems a good site! I got the schematics from there. Came across it several times on my google searching
I'll give it another & more thorough read though tomorrow I reckon.I will be starting with just two channels first, that's my plan
Besides I think using this active crossover may require some DIY speakers. My speakers are two-way, and the crossover is 4-way (3-way stereo only + a 'sub' output). I do really want to experiment with an active system though, and look forward to getting to that point.Vikash said:
Yup, I guess you could draw the design on the copper and then just scalpel it away but that's bordering on insanity
It's not too difficult.
http://www.diyaudio.com/forums/showthread.php?s=&threadid=88644
A good DMM to check the connections and patience is all you need. Probably wise not attempting it for a first effort though.
lol nothing wrong with a bit of insanity here and there. I think P2P is probably actually the easiest route. I tend to find prototype board a bit hard to lay things out. I'll see what happens when I have all the components I suppose
The GC in that link looks pretty neat actually! I quite like it.
I have a DMM "borrowed" from my Dad, and would check the connections and everything. It's not my first first first ever go at copying a schematic to a board, and I do like a bit of a challenge
It keeps me busy! I'm looking forward to building it, and hopefully I will learn alot from it / get caught by the tweaking bug I will, of course, be posting pictures and a few thoughts once it's done, or near done. I'm still not sure about casing yet, I've not really got the resources / tools available to make me a case really. Seen something on Maplin which looks like it might work, just about. I will have to build the thing and see what kind of size case I need first
I feel like I've got quite alot of it planned out so far, which probably means in reality it's not going to go to plan at all
Off to sleep now anyway! Night folks!
a Sharpy, a piece of blank pcb, and some ferric cholride should cost bout the same as a piece of veroboard/protoboard...
I agree with Nuuk, that it won't "break" anything... but when I was an absolute beginner, I found that value strange.. compared to all the other circuits I saw... and then I learned about highpass filter and found it even stranger... It was my first chipamp... apart from the single component it was the best tutorial out there.
I agree with Nuuk, that it won't "break" anything... but when I was an absolute beginner, I found that value strange.. compared to all the other circuits I saw... and then I learned about highpass filter and found it even stranger... It was my first chipamp... apart from the single component it was the best tutorial out there.
Nordic said:
Hmm, dunno about that. I can get four sheets of prototype and four sheets of blank PCB for the same price, so the PCB is definately gonna cost more.
What's a Sharpy? Would I be able to get away with one of those "PCB pens"? I don't know of anywhere with a photocopier around here, and I am not quite lucky enough to have a laser printer / big UV setup
Nuuk said:
You can still use your active crossover for a two-way speaker. You use the low-pass and high-pass sections and ignore the band-pass and sub sections.
I thought about this, but the LP on it "only" goes up to 1KHz. I don't know if my tweeter would "go that low" very well. Worth a try I suppose.
Nuuk said:
No, that's too low for a tweeter really. Don't despair though, you can always built some active crossovers on stripboard.
Heh, I was thinking about doing that a long time ago too, when I was looking at Rod Elliots projects. I think if I eventually manage to get three stereo GC's built (one at a time of course) I will probably end up buying a couple of mid range drivers and having a three-way system.
Anyhow, I have a question!
http://myweb.tiscali.co.uk/nuukspot/decdun/gcg/gccfm4l.JPG
The board in that picture, each hole just has a small separated copper pad on the back, not in rows like Veroboard. What might this board be called? It seems like that might be nicer to work with than Veroboard, unless it IS Veroboard, but someone had the patience to cut up the tracks in to individual pads?
Nordic said:
hmm, good logic but you have no idea how much I paid for the board. It was £3 for four boards of 160mm x 120mm. Far cheaper than I could find at RS/Farnell/Maplin, which seem to be about £3 for a single board of that size? Unless I am looking at the wrong thing. I can get two boards of Veroboard, double sided, a few mm smaller for the same price.
Never mind. I'll just get both and when the time comes I'll see which I decide to use!
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