[tangent]

Quote:

I didn't want to assume that the cable came on the "brick" and that it would magically fit in any the jack that i buy for it, since i'm pretty sure there is more than one type of jack that you can buy, but i guess everything will work out.

You misunderstand what I am telling you. I am recommending a specific wall wart, the Elpac WM080, and a specific jack, which I gave details for in my previous post. These will work together, no magic required.

Now if you go and get a different power supply, obviously you have no guarantee any more. I gave you a combination that will work; that is not the only combination that will work, but I have no interest in coming up with new combinations for you. If you want a different wall wart, you'll have to find the matching jack yourself. You'll even have to do the research to find out if it comes with a cord -- I can't tell you that all wall warts come with cords, because I suppose the world has enough variety in it that there are wall warts that come without cords.

Quote:

when you say jumper c1, do you mean just leave it unpopulated?

I mean to jumper the cap position. Then you have no RC filter, and thus no worries about corner frequencies or phase shifts. You also have no DC offset protection. These issues are discussed in the docs.

[size=xx-small]I'm starting to sound like a broken record....[/size]

Quote:

So i use the same diode that i would have used in D1.

No, not at all. You can use a 1N400x in D1, but usually you want a much larger diode there because D1 sees a heavier load in many conditions. D2 has a much easier load, so it can use a small diode like one of the 1N400x series.

Quote:

Edit: ok, this has become too expensive, i'm going with a panasonic EVJ-C20 pot, my question is, what volume know will fit this. There are some listed in the parts list, but i'm not sure if they all fit the panasonic pot. One is ALUMINUM .61"D and the other from digikey says .75" but i can't find any measurement like this for the panasonic pot except for 12 mm. any ideas.

0.61 and 0.75 are outside diameters of the knob. What you care about is the shaft hole diameter. The shaft on the Panasonic pot is 6mm. Ideally, you should find a knob for 6mm shafts. If you can't find one in a style you like, you can go with an 0.25" shaft knob, which is 6.35mm. This will result in a bit of wobble as you turn the knob, unless you pad the shaft out to 6.35mm. This can be done with a layer or two of Scotch tape, but you have to cinch the knob mounting screw down tight so that the knob doesn't slip on the padded shaft.

 

[Kal525]

Quote:

Originally posted by tangent You misunderstand what I am telling you. I am recommending a specific wall wart, the Elpac WM080, and a specific jack, which I gave details for in my previous post. These will work together, no magic required.

You recommended the wall wart to me, ok, that's fine i will go with that and i don't think it's an absurd question to ask if it comes with power cord, forgive me. But the "specific" jack you recommended to me was in no way specific. There is more than one 5.5mm/2.5mm DC jack listed for "similar unit by DGS" listed on mouser's webpage: http://www.mouser.com/index.cfm?hand...12&pdffile=412

Also, you said:
"Use Radio Shack's heavy duty 5.5mm/2.5mm DC power jack, or the similar unit by DGS, available from Mouser. I should put this in the docs, but I haven't yet."

But, there is in fact a recommendation for a DC power jack in your documents. So i am i supposed to presume the part numbers for the power jack you have listed on your site are correct, even though you say you have not put it on your site?


Quote:

Originally posted by tangent Now if you go and get a different power supply, obviously you have no guarantee any more. I gave you a combination that will work; that is not the only combination that will work, but I have no interest in coming up with new combinations for you. If you want a different wall wart, you'll have to find the matching jack yourself. You'll even have to do the research to find out if it comes with a cord -- I can't tell you that all wall warts come with cords, because I suppose the world has enough variety in it that there are wall warts that come without cords.[/B]

I NEVER asked you to come up with a new combination for me, nor did i say i wanted a different wall wart, so there is no need for the condescending attitude. I'm simply trying to get as much information as i can before i order everything and realize there exist incompatabilities with what i have ordered. I don't think this warrants you coming down so hard on me for a simple question. I think i've done more than my share of research, do you expect me to be able to replicate your design after two weeks of working with it? This has been quite a difficult hurdle to overcome and i appreciate your help, but the one thing i can't stand is when people dispense thier advice with a hint of godlike stature, congradulations on your design and that you know so much about this stuff, but I do not, and if your job is in fact to communicate with the outside world and help answer any questions about your design, please do so without considering the rest of the world sheep and you the wolf. You may think my questions are stupid, but to me they matter.

 

[Kal525]

Anyone know what the PRV (V) rating is necessary for the 1N400x diode for D2. They basically go from 50 to 1000. I'm thinking this number has to do with the power supply, which in my case is 24v. Here is a link for the different ones.

http://www.mouser.com/index.cfm?hand...set&pdffile=74

thanks

 

[tangent]

Quote:

But, there is in fact a recommendation for a DC power jack in your documents. So i am i supposed to presume the part numbers for the power jack you have listed on your site are correct, even though you say you have not put it on your site?

The power jack in the docs is a different style. That's why I made a point of telling you that the one I was talking about isn't in the docs. It would work, but the one I tried to guide you to is better for your situation.

What I hoped you would do is find the heavy duty power jack either in a Radio Shack store or at radioshack.com and then find the similar-looking one at Mouser. The Mouser part number is 163-1825. So yes, I was being purposefully lazy -- I could have looked that number up for you and saved you the effort of chasing the part number down. I hope you see the inequity in our situation here.

Quote:

there is no need for the condescending attitude

I'm being short with you because you keep asking questions that are answered in the documentation I spent a few weeks writing, or in various places around the Internet that you could find with a simple Google or Head-Fi archive search. I realize that one of my options in reacting to this imposition on my time is to ignore you, but as one of the META42's representatives I don't feel comfortable with that. So instead, I tried to drop the hint that you can often get answers easier and quicker by looking at the relevant resources before asking questions.

When you've exhausted all other avenues, by all means, post a question here. I think I've proven myself more than willing to answer questions. But I reserve the right to be testy when answering questions that you could have answered easily for yourself with a little bit of effort.

It's more than that, actually. It's this idea that it's possible to make the best possible amplifier your first time out, with no mistakes in the component list. If you're afraid of making mistakes, you will not learn. I am not telling you to be reckless in choosing components. It is admirable to check things in advance. But at some point, you just have to break down and place an order. It's not the end of the world if everything's not perfect the first time out. You'll learn from it. You don't learn much with me telling you what parts to buy.

 

[Kal525]

I agree with everything you have said, but please, next time you become annoyed with my questions just don't answer them, or tell me to look elsewhere before posting them. I am trying my best here. Throwing it in my face condescendingly isn't exactly encouraging while i'm sorting through 60 pages of your printed documents, which i am very greatful for. I have about 30 different parts going through my mind as i try to connect everything together and fully understand this thing. And believe me, i have tried my best not to ask questions for which the answer is already posted in your documents, but some stuff is not in your documents and i have been asking mainly those parts, such as what DC jack to use with the wallwart and if the wallwart you recommended comes with a cable. Instead of "reserving the right to be testy when answering my questions" that could have easily been answered elsewhere, please keep in mind that i am not purposely trying to do this. A better alternative is to tell me to look elsewhere or just flat out ignore me, i would prefer that than the whole "you're such a newbie" mentality, it's more professional, and you seem to be a very professional type of person with your work.

Yes it is true, of course i am affraid to make a mistake, as i am sure you were the first time you set out to do something like this. If this was over $60, ok, i wouldn't ask so many questions, but i am spending nearly $200 on this amp due to the praise it has received across these forums and i just want to make sure that it works, i'm sure you understand. And to say that i'm not putting any effort into this is completely untrue, as i have said, i constantly read and reread your documents making sure that i have not missed anything, they are a very valuable resource and i thank you for writing them.

I am now at the point where i will probably submit the order tomorrow, as i have had my shopping cart populated for a few days now. The reason i created this thread is for feedback to see what you thought and to get help with the questions i still had. You have been a great help to me, you and others, and i thank you for answering my questions and appologize if any of them have annoyed you, that was not at all my intention.

Again, thank you for answering my questions, and i apologize for asking so many of them.

 

[slindeman]

Quote:

If this was over $60, ok, i wouldn't ask so many questions, but i am spending nearly $200 on this amp due to the praise it has received across these forums and i just want to make sure that it works

It's just my opinion but I think you're crazy to spend $200 on your first DIY project. I know you don't want to hear this, but I would advise starting slowly.

Quote:

thanks for the input, and trust me, it's not that i don't like the choices, it's just that i want to make sure i'm getting what will sound best and not something that will totally screw it up.

Even you yourself seem to be arguing that you don't have enough experience to choose the right parts. I would suggest building one or two $50 projects first, doing an extensive read of the Headwize and Head-fi DIY archives, and ordering a bunch of parts catalogs. Most manufacturers also have detailed drawings of their parts on their website. Be sure to download documentation for all of the opamps/buffers also.

These are just some friendly suggestions from one DIY'er to another...

Best luck

 

[pearle]

I'm about to dive into the DIY arena with zero experience with electronics and soldering. I will definitely be starting small as I know I will make mistakes and waste materials. The thought of frying $100 worth of components on my first project gives me the willies

- Peter

 

[Kal525]

It is true, i don't have enough experience to know all the proper parts to choose, but i know how to solder very well, since i took a class that was based entirely on soldering. I don't see a reason for building something that i won't be happy with, when i can invest the time to make sure i have all the right parts the first time around and stick with it for a while to come. I appreciate your advice though.

 

[puppyslugg]

Quote:

Originally posted by Kal525 It is true, i don't have enough experience to know all the proper parts to choose, but i know how to solder very well, since i took a class that was based entirely on soldering.

I assume you can also follow a schematic? If that's the case....., GO FOR IT!

I don't see much difference, in difficulty, from a cmoy/cha47 to a meta42.

Good luck.

 

[slindeman]

Quote:

I don't see a reason for building something that i won't be happy with, when i can invest the time to make sure i have all the right parts the first time around and stick with it for a while to come.

A well-though out parts list isn't some magical thing that will produce a headphone amp you will cherish forever. To get to that point often involves wasting a large amount of money on parts (or complete projects) that end up unused, discarded, or damaged.

The thing is, without enough experience you won't really know if what you've built is something you will be happy with forever. How many other headphone amps have you heard? How many opamps? If all you're after is something that sounds better than a soundcard, then your parts list hardly matters as much as you think it does. Even the most basic META42 in stock configuration blows a soundcard away.

Based on everything you've written it seems like a complete kit (such as the Corda HA-1 kit) would be better suited to what you are after. Or perhaps just buying a commercial amp. Anybody can learn to solder and read a schematic, but those are the least difficult parts of building a satisfying DIY amp. Its the listening and comparing, the trying different circuits and different parts, the tweaking -- those are the time consuming and rewarding aspects of DIY IMO.

 

[Kal525]

haha, thanks for the vote of confidence puppyslugg, i can definitely read a schematic, i spent half of last year soldering a robot made up of 30 pages of them. Most of the cost comes from a few parts anyway. The wallwart alone is $30, and the solder i'm getting is $20-$40, so that's $50 alone without even adding any parts. In actuality it will probably cost around $150 total, the main pain in the ass being that i have to order from multiple places and many charge a "handling" fee for orders under $25, so that's why it adds up.

 

[Kal525]

slindeman, when i set out on this project, my main goal, was as you said, to get something that sounded better than my soundcard. My only options in terms of what i could purchase, was an airhead, or totalairhead, due to the high price of the better amps. From what i have been reading the meta42 competes with amps many times its price, and i'm sure it will beat an airhead. When it comes down to how much i will notice from tweaking this amp, i will probalby not notice much right away. As i gain experience through listening to it and then picking certain aspects that i want to change, then perhaps i will tweak it further. All i have set out to accomplish is to gather parts to construct an amp that have been recommended, used, and tested. If it doesn't sound as good as it possibly can with my setup, that's just fine, i'm sure it will sound better than what i'm using now, and i'll have fun building it. I have already learned a great deal about how it works, and i'm glad i took the time to do so, because this seems like a very interesting, rewarding.......expensive, hobby

 

[Voodoochile]

Have you considered banging out a cmoy first? I'm thinking you could get a feel for tinkering with gain (though not multiloop) and listen to a few sample op-amps before you embark on the META journey.

Just a thought

 

[Kal525]

heh, i would love to, but i don't have the time, i've already invested so much time into the meta42, and i definitely think it is doable. If i'm not satisfied with the gain or anything else, i can always change it later, constructing it is not the hard part at all, it's understanding everything and knowing how to tweak it, as many of you have mentioned, resistors are dirt cheap anyway and i plan to use IC sockets so i should be ok in case i am not happy with anything. I know a friend who has an entire metal workshop at home so he'll be doing most of the casework for me which is what i was most affraid of. damn, you guys are starting to scare me here, this is no kevin gilmore DIY amp, right?

I just bit the bullet though and placed my first order with tangent for $45. Next comes my mouser order. Common guys, have faith, it can't be THAT hard

 

[puppyslugg]

Quote:

Originally posted by Kal525 damn, you guys are starting to scare me here, this is no kevin gilmore DIY amp, right?

No, it's not a Gilmore. If it was, I'd be afraid!

Quote:

Common guys, have faith, it can't be THAT hard [/B]

Famous last words! But I like your attitude, kid!

If it don't work....don't post! I don't wanna hear the 'I told you so....'