want to build an amp

[binkgle]

i have basically no prior diy experience. i have a soldering iron (though it may be too big cause it's got a huge tank of gas, propane i think, but i'm not sure, about the size of a 1 liter soda bottle on it), and some solder, though i'm not sure what type (i.e. i can't be bothered to go find it and look).

i want to build an amp for the ms-1s that i will soon be getting, and i think an a47 would be the way to go. where would i find highly detailed instructions (with photos/diagrams) and a list of necessary parts? how much should it all cost, and where would i buy the parts from?

is this project too advanced for a total newbie? should i buy two sets of all the parts in case i screw up on the first?

thx,
Jack

edit: my brother, who all the soldering stuff belongs to, says he's also got a jeweler's soldering iron, which is a lot smaller, and i expect would be better for circuitboard work. he says he thinks the solder he has is silver and tin, but can't remember how much of each.

 

[mono]

The smaller iron is a good idea, and might be essential (not knowing exactly what you have). It is easier to start out using a lower melting point solder like 63/37 or 60/40 (good ole lead and tin) instead of silver types.

Most popular A47 page? As for the list of parts, that page should cover it, look at the schematic and start writing down each. How much it costs might depend on whether you had *any* parts at all yet, even things like wire, and if you go for a higher-end OPAMP instead of OPA2132 that will raise the price some too.

Honestly I don't have a grand total but would put it around the $35 mark if you buy all parts from one place and/or locally so shipping or small-order fees don't hurt you.

Radio Shack is the common place to get the board used in above link. Digikey or Mouser will have suitable remaining parts though I don't know if MOuser has BUF634 in the TO-220 form on above link, so I suggest Digikey though they have a low-order fee of $5 for orders under $25(?).

I wouldn't say it's too advanced, but I think soldering on Radio Shack/etc unplated board is harder than on a professional PCB.... but practice makes perfect, you might want to practice soldering with that "new" iron before exposing any delicate parts to it

I wouldn't expect you'd need order duplicates of all parts, as that gets pretty expensive rather quickly unless you had definite (or at least reasonable) expectation to use the leftovers on another project.

Main thing is, there are no stupid questions when you're first starting out... this is a great forum to get help with any unresolved details, though you might try the forum search function first as a lot of people have built A47 and many issues are already covered.

 

[binkgle]

what's different about the radio shack pcb and a professional one?

also, i know i'll need to do some soldering, but what exactly will it be that I'm soldering? what should i do for practice before diving into the real thing?

i've never done any work with electronics, either (i'm taking physics this year in high school, but electicity/electronics will only be covered in the second semester, and i won't learn anywhere near enough to do this project from that). is that a big problem?

are there any videos of people making an amp's circuit board so that I can know what the soldering action is supposed to look like, for instance?

how are the parts on the page you linked quality-wise? are any in outstanding need of an upgrade? if so, to what?

thx,
Jack

 

[ben.phelps]

im also in high school, and my first amp was a CMOY, having no experience in circuits and that sort of theing. I bought 2 of the boards from radio shack, and used one to practice basic soldering on. all of the parts should be fine quality, and there shouldnt be a need to upgrade until you have a bit more knowlodge in the amp building relm. always ask any questions here, everyone always seems happy to help in any way.

have fun.

Ben

 

[mono]

Quote:

Originally Posted by binkgle what's different about the radio shack pcb and a professional one?

The Radio Shack is just a generic board that you have to solder on jumper leads and it's thin unplated copper is harder to solder to. It's not really "hard" at all, but relatively harder than a thicker copper, tinned, plated through-hole board custom designed and manufactured.


Quote:

also, i know i'll need to do some soldering, but what exactly will it be that I'm soldering? what should i do for practice before diving into the real thing?

Soldering all those little parts together. If you were to go into a Radio Shack and see the boards with the holes, and the parts with metal leads, you'd see what to do, that the solder electrically (and mechanically in the case of an A47) holds the entire thing together.

I don't know if you have anything around you could practice soldering on... the inside of an old broken radio (unplugged from AC of course, if that applies) or a spare circuit board from Radio Shack or whatever. You might want to also Google for some basic soldering tutorials. The most common mistake a beginner might make is trying to melt the solder with the iron instead of using the iron to heat the part and having the hot part melt the solder, BUT, you dont' want to overheat the parts, practice quickly but carefully soldering with only the length of time necessary for a good result.

Quote:

i've never done any work with electronics, either (i'm taking physics this year in high school, but electicity/electronics will only be covered in the second semester, and i won't learn anywhere near enough to do this project from that). is that a big problem?

I can't reallyp put myself in your place and "know" what it is that you do and don't know, so that's hard to answer. Since you seem to already have an inclination towards electronics you might check out some books at the library before starting, basics about electricity and get a solid foundation in that before worrying about audio-specific topics. It could be that you're not ready to build such an amp yet, but then again you have to start somewhere... just keep away from AC power for the time being. Edit: Actually I meant high-voltage, AC household power merely being one of the most common HV a beginning DIYer might encounter.

Quote:

are there any videos of people making an amp's circuit board so that I can know what the soldering action is supposed to look like, for instance?

I don't know where, but there are probably some very short videos of certain soldering techniques. Briefly you want to touch a large contact point on the iron tip (if space allows to do it) to heat the part and melt the solder onto that part, not touching the unmelted solder to the iron itself. Even some old copper wire is a start for practicing soldering... just look around and see what you can come up with.

Quote:

how are the parts on the page you linked quality-wise? are any in outstanding need of an upgrade? if so, to what?

For your first amp and skill level, I recommend just building it "by the book", then later you'll understand better that the overall amp design itself will matter more than individual choices on a very basic amp. Having written that much, I'd go with larger and better quality capacitors like 470-680uF 25V Panasonic FM from Digikey, though there are a lot of other suitable alternatives too. Mainly, recognize that "most" of the stuff sold at Radio Shack is junk.

 

[binkgle]

using an old radio, huh? well, i'm sure i can come up with a ton of old electronics at home to steal the circuit boards from.

so i should heat the part (let's say, one of the metal wires coming out of a capacitator), put it where it should be on the board, then touch the solder to it, melting the solder where it needs to be, not dripping molten metal all over the circuit board?

will using the silver/tin solder be a problem? is it electrically inferior to the lead/tin solders, or is it just harder to melt, and therefore impractical, especially for a newbie's purposes?

is the radio shack board going to make the amp work any better or worse than a pro board? how much does the radio shack board cost? a pro board?

edit: just did a google search on soldering, and found that i should be using an electric soldering iron, one with a pointy tip. i now have a gas powered iron which probably uses either butance or propane. is this a problem? i can turn doown the flame quite low, but i don't want to melt my amp/heat and burn parts i'm not supposed to............

edit 2: when people say they are going to "etch" a board, what are they talking about? also, would a professional pcb make building the amp significantly easier (i need this to be really easy)? what are the other differences/advantages between pro and radio shack boards?

 

[binkgle]

to tell you guys the truth, i'm starting to have serious doubts about this diy amp thing. i just read "getting started in diy" article on tangentsoft, and the starter kit for doing diy work is $120. i can't afford that, and the actual putting together of the amp doesn't exactly look easy, either.

seeing as my soldering iron uses an open flame, and i apparently have the wrong solder, meaning i have to buy all the tools as well as all the amp parts, is it safe to say i am in no way ready for this?

who on head-fi are known to be good amp builders who i could request an a47 from, and what should i expect to pay them?

thx,
jack

 

[diredesire]

Quote:

Originally Posted by binkgle to tell you guys the truth, i'm starting to have serious doubts about this diy amp thing. i just read "getting started in diy" article on tangentsoft, and the starter kit for doing diy work is $120. i can't afford that, and the actual putting together of the amp doesn't exactly look easy, either. seeing as my soldering iron uses an open flame, and i apparently have the wrong solder, meaning i have to buy all the tools as well as all the amp parts, is it safe to say i am in no way ready for this? who on head-fi are known to be good amp builders who i could request an a47 from, and what should i expect to pay them? thx, jack

bare minimum i suppose would be a soldering iron and some solder. You can find soldering irons under $10, the radioshack one(s) are about ~$8. If you're REALLY on a budget, you can find a 99 cent special at some electronics shop. My first iron was $1 from fry's in a grab bin. Solder costs ~$2 for normal 60/40, and it'll serve you fine.

As far as building amps, i'm sure there are plenty of people on the board that have built A47s, i would, but i don't have any Buf634Ts available. Labor varies per seller. I would expect to pay 50-60 at least for an a47

 

[binkgle]

for about $60, how does a pa2v2 stack up against an a47 for ms-1s, which need more current than voltage?

 

[skyskraper]

for $60 surely you can find a mint?

 

[mono]

Quote:

Originally Posted by binkgle using an old radio, huh? well, i'm sure i can come up with a ton of old electronics at home to steal the circuit boards from. so i should heat the part (let's say, one of the metal wires coming out of a capacitator), put it where it should be on the board, then touch the solder to it, melting the solder where it needs to be, not dripping molten metal all over the circuit board?

Mount the part where it belongs on the board, THEN heat quickly, melting the solder onto the junction between the parts (or part and circuit board).

Quote:

will using the silver/tin solder be a problem? is it electrically inferior to the lead/tin solders, or is it just harder to melt, and therefore impractical, especially for a newbie's purposes?

It has a higher melting point and thus you need a hotter iron and to heat parts more. While you're getting started and getting a feel for soldering, it would be best to use the easiest solder. I don't know what this jeweler's iron you mentioned is like though, if it's meant for soldering silver to large metal jewelry it might run a little hotter than optimal for building an A47- it'd probably work, but again isn't as easy to learn with, and that much quicker you could potentially overheat a part like the opamp or buffer, etc.

Quote:

is the radio shack board going to make the amp work any better or worse than a pro board? how much does the radio shack board cost? a pro board?

I don't even know if there is a pro A47 board, I was speaking relatively, since you are a (Not even yet) beginning solderer for this purpose. A Pro board "should" make it sturdier, easier to solder, layout is easy (you just stuff parts in the right holes as there are few unused holes) and the parts locations may even be marked for you. Pro boards would tend to be more expensive but since i know of no pro A47 board I can't directly compare. A Radio Shack board just like Ben Feist used (Linked previously) is about $2-3, if I remember correctly.

Quote:

edit: just did a google search on soldering, and found that i should be using an electric soldering iron, one with a pointy tip. i now have a gas powered iron which probably uses either butance or propane. is this a problem? i can turn doown the flame quite low, but i don't want to melt my amp/heat and burn parts i'm not supposed to............

What type of gas iron, exactly? There are some tiny gas irons that are meant to be a portable (cordless) replacement for a standard corded iron, though the adjustment on temperature may not be easy to figure out. They're still not quite suiable for amp building in my opinion because one usually is more up close and detail oriented building an amp, unless you have one of those giant swing-arm lamps with a magnifying lens so you can solder from further away. Otherwise you have additional heat coming off the iron, rising up... the tinier gas irons would work with some practice, once you're used to them but they're still not ideal.

You can find a cheap iron and tube of solder for under $10 at many places like Radio Shack, a hobby store, online... it's not a great iron for < $10 but certainly sufficient for building an A47 if it's the typical pencil type, not a gun type, with somewhere in a 20-30W range and a reasonably small tip.. There is no need to buy expensive tools up front, but those when the time comes and you then know, from personal experience, that you need something.

Quote:

edit 2: when people say they are going to "etch" a board, what are they talking about? also, would a professional pcb make building the amp significantly easier (i need this to be really easy)? what are the other differences/advantages between pro and radio shack boards?

Etch means use ETCHant. A Chemical that dissolves away copper, so you start out with a circuit board that is 100% covered with copper and remove the parts you dont' want, leaving behind the thin electrical connections between each point, the traces, or larger areas sometimes. There are multiple ways to control (limit) what copper gets removed and what stays, but basically it involves covering some copper so the etchant can't get to it.

TO start out right now I suggest either that A47 built just like it was shown on the link I provided previously, or a CMOY (is even easier and cheaper).

 

[Pars]

Quote:

Originally Posted by mono I don't even know if there is a pro A47 board, I was speaking relatively, since you are a (Not even yet) beginning solderer for this purpose. A Pro board "should" make it sturdier, easier to solder, layout is easy (you just stuff parts in the right holes as there are few unused holes) and the parts locations may even be marked for you. Pro boards would tend to be more expensive but since i know of no pro A47 board I can't directly compare. A Radio Shack board just like Ben Feist used (Linked previously) is about $2-3, if I remember correctly.

There is, from Jason Hanjk (sp?) at sgheadphones.net (a Singapore I believe site similar to head-fi... Jason is also a member here). Link is here. This is a reworked A47-based design which uses a driven ground channel ala Pimeta. etc. If you build the A47 on RatShack board, you can do it easier than the one shown on the feistworks link, and omit the BUF634. Basically you can just take Tangent's CMoy layout and:

1) Replace the voltage divider virtual ground with a TLE2426
2) Use the 1st opamp as the L-R amplifying opamp and add a second socket directly below it on the layout for the buffer L-R opamp. (I usually move the initial socket up one or two rows on the perfboard)
3) Four 47 ohm resistors (in addition to the normal CMoy parts) and the TLE and that's that (with the appropriate wiring for the buffer opamp... sorry, I never drew up a layout and/or wiring diagram).

I have built several A47s using this method and it works fine (sounds better than a CMoy IMHO).

Chris

 

[binkgle]

the gas iron is small and i believe it uses propane and an open flame, so i can see why it's less than ideal. i dunno whether i'm ready for a diy project yet, though. i think i'll wait until the christmas vacation to try (school is starting up and i need to concentrate on schoolwork now

)

should i get an a47 from a head-fi builder (is there anyone who is well known for their high quality amps?) or evilfire.com? or should i get a pa2v2?