[BenW]

My roommate is a computer engineering major and he has a class project involving fabrication/design. We thought designing an amp would be a good idea to complete the project and get an amp out of it at the same time! However, we don't know which one we should build. Perhaps you can help... here is what we would like to have:

- good power for Sennheiser HD600 (me) and Sennheiser 497 (him)
- small enough to fit into Altoids or Penguin container (seen this before, we both love the concept)
- powered by a wall-wart and/or battery
- crossfeed optional
- project requires (2) IC's

Which DIY amp would fit us best? After reading some stuff on this forum a lot of folks say that using good components makes the unit sound better, but my roommate, who is going to be assembling it, says that the components are all the same and it will be just as good to go to Radio Shack. Whats the best solution?

Thanks in advance,
ben

 

[myself, aka me]

While i've read you can make a decent sounding amp with radioshack capacitors, it definately makes a difference with a good quality opamp over the radioshack TL072

.

Mint tins.. how about a MINT? By IC, I assume you mean integrated circuit. The MINT has three, at least.

 

[BenW]

thanks. I feel like an idiot for reading about people saying "I love my Mint" and I didnt make the connection.

And by ICs you are correct.

 

[morsel]

Radio Shack does not sell audio quality opamps. You will have to order parts from Digikey or Mouser.

 

[BenW]

thanks Morsel. I guess you are one of the godfathers of the Meta42? Thats pretty cool

I will talk to my roommate and we probably have time to order some opamps as you suggest. Project isnt due until the end of this semester (Dec. 15).

thanks for the advice, keep it coming!!

 

[eric343]

Well, that's why he's a computer engineering major and not an EE... though he should know that kind of stuff regardless. It's rather sad; at my summer job I was talking to the graduate student in charge of the project we were working on, and he had mentioned that stuff like the differences between capacitor types wasn't really taught to them, it was something you "picked up by experience" or looking at the textbook (which was Art of Electronics, btw). Maybe that's why they were using a bipolar electrolytic cap in the feedback loop of an active low-pass filter...

 

[eric343]

Whoa... did anyone else get a message saying JMT had just replied to this thread?

Spoooky...

 

[morsel]

Ben, that's godmother, not godfather.

Check out Tangent's website for more info on the meta42 and mint.

 

[BenW]

Quote:

Originally posted by eric343 Well, that's why he's a computer engineering major and not an EE... though he should know that kind of stuff regardless. It's rather sad; at my summer job I was talking to the graduate student in charge of the project we were working on, and he had mentioned that stuff like the differences between capacitor types wasn't really taught to them, it was something you "picked up by experience" or looking at the textbook (which was Art of Electronics, btw). Maybe that's why they were using a bipolar electrolytic cap in the feedback loop of an active low-pass filter...

He seemed pretty confident that we could make it sound just as good with Radio Shack parts, claiming that components are all the same and there cant possibly be much of a difference between different manufacturers.

As for the technical jargon you just ran by me, I'm sure there was a witty point in there somewhere but being that I am business major myself, I'll just chuckle and nod like I know what you're talking about, since thats what we like to do when speaking to technical geniuses like yourself.

I'll check out this mint and run some prices on the parts. Doesnt look like it would be incredibly expensive.

Any more tips?

 

[tangent]

Quote:

class project involving fabrication/design

Would I be correct in guessing that you will be making your own circuit boards for this project? In that case, you don't want a META42 or a MINT. These are both pre-made circuit boards. I also wouldn't copy the circuit layout even though it is available, because that would probably count as plagiarism if your prof caught you. You could start with the schematics and come up with your own layout, if you wanted. What you would have then is a "Jung multiloop amplifier", not a META42 or a MINT.

Quote:

project requires (2) IC's

Sounds like a buffered amplifier is the thing then. An op-amp in each channel wouldn't count as 2 ICs, I'm sure, since each channel is identical. Adding a buffer to each channel is legitimately a 2-IC circuit.

Quote:

it will be just as good to go to Radio Shack.

Build the amplifier to use a dual-channel op-amp, and then when you get it built, put a TL082 in it from Radio Shack. If your friend can't hear the difference between that and a good op-amp, advise him not to buy headphones more expensive than he has now. He won't get any value out of them.

 

[BenW]

I am not in the course myself, but from what my roommate has said, the requirements are very easy and the professor has cleared this as a project that will satisfy the requirements. The main things they are doing is:

designing the circuit on a proto board, then testing it, then sending the design off to be made into a wafer, then populating it.

I will ask him about the plagarism and be sure to ask the professor about it. If it is ok to build, from the pre-existing schematics, we will be sure to credit the creators of the META and the MINT. We arent trying to rip you guys off trust me on that!

Edit: just read what you said and it made sense. We will probably end up using the MINT schematic as a reference and build our own layout. Thanks for the info,

Ben

 

[tangent]

Quote:

If it is ok to build, from the pre-existing schematics, we will be sure to credit the creators of the META and the MINT. We arent trying to rip you guys off trust me on that!

My concern isn't being "ripped off". My concern is that if you just copy our existing circuit board layout, you will not get credit for the class. Since the circuit board layout is on the same page as the schematic, your friend's professor will be able to find our layout easily and compare it with your friend's layout.

It's perfectly fine to start with the MINT or META42 schematic and make your own layout. That is not ripping us off.

You should avoid looking at our layout before you start work on yours, though, so you don't inadvertently copy some of our ideas. You don't want someone who has seen our layout to see similar things in your layout.

 

[BenW]

tangent - that is definitely one of our main focal points we wish to avoid (simple schematic copying). I ran it by my friend and he says that he is going to design the appropriate circuits with his own ideas, enter it into a computer program, and it will automatically generate a layout from which he can modify and change.

When I mentioned "ripping you off," I just wanted to make it CLEAR that we respect your work and excellent dedication to the DIY community. We would never think of stealing that, and we have absolutely no intention of plagarism.

Thanks a million,
Ben

 

[picklgreen]

Quote:

Originally posted by BenW My roommate is a computer engineering major... but my roommate, who is going to be assembling it, says that the components are all the same and it will be just as good to go to Radio Shack....

dang i needed a good laugh.....

 

[Budgie]

How about building two of them, the same circuit board layout, same design, one with audio grade parts (for yourself) and one with Radio Shack generic crap, for your friend. Then a chance for a reasonably valid comparison can be part of the project.