[loac]

First of all, I want to say that the amount of information out there on building headphone amps is staggering. I have spent about 4 hours reading about them today, and I still don't know what direction to go.

I want to build an amp for my Senn HD201's. They will be used with a Chaintech AV-710, and a 4G Ipod. I want to build an amp as opposed to buying one because I have some time, and it sounds like a lot of fun. I have some experience with soldering and electronics too. I want to try to keep the price for parts under $50.

I would like to make one that complements the HD201s, perhaps bumping the bass up a notch. Since I will be using this a lot at my desk at school, it would be nice if I could plug it in to the wall to save batteries. Also, I think using the Altoids tin as a case looks really cool

so it would be nice if it fit in there.

It seems the CMoy is the most popular choice, are there any adjustments to the basic layout that you guys would suggest? Or perhaps a different amp altogether?

Thanks for any advice you can give. I have read a lot of stuff, but have no idea which way to go.

 

[Porksoda]

I will start off this greeting as we do all forum greetings: Sorry about your wallet

I am a fan of the CMoy with a TLE2426 in place of the resistor divider for ground. It saves a bit on batteries and improves the quality of the virtual ground. Making a CMoy that runs off of a wall wart shouldn't be too hard, depending on how fancy you want to get. A standard rat shack unit of ~15V-20V should do the trick, though the quality of the supply is not good and might result in hum. You could put one of tangent's TREAD regulators in there, but that would take up the space for the batteries, so it would be wall wart only. Also, that is another level of complexity that will require some more troubleshooting and testing on your part.

Alternatively, you could make a CMoy that runs on one 9 volt battery, and with the space you save you could probably squeeze the TREAD in aswell, so you could get a good wall supply and still have battery power. A lot of people tend to knock the CMoy with only 1 9-volt, but mine worked fine for low impedence headphones.

If you use the right barrel connector for the wall wart, you can make it so that the amp runs on battery when the wall wart is unplugged, and when you plug it in, it disconnects the batteries. I forget the name for that kind of jack...

 

[ATAT]

A vote for the CMoy as well.. and yes, the TLE is a very very good upgrade to do =)

 

[diablo9]

vote for MINT or PINT

 

[diredesire]

Quote:

Originally Posted by diablo9 vote for MINT or PINT

Parts for those are slightly more expensive.

Edit: Although i think they would be a worthy step up..

I think the A47 is also a good choice, it's very similar, just slap in another opAmp

 

[mono]

Hmmm. One of these days I'm going to have to offend all the audiophiles and see just how cheaply I can build a Pimeta. I think it can be done under $50, with power supply and still sound better than a anything else tweaked out to same construction cost. Maybe not though, all those odds and ends add up if you have no parts at all yet, unless you start cannibalizing something you have lying around. Some of you might be surprised how many useful (yet not audiophile-grade) parts you'd find in something like an old computer monitor, especially a fairly good make from the late '90s opposed to a cheaper but more recent model. Don't think I'd use the 'lytic caps of one though... been sitting around in the elevated temp environment for too long.


Anyway, HD201 have fairly good efficiency but 24 Ohm. CMOY isn't going to have enough current for very loud listening without early distortion, IMO. An A47 with separate L/R opamps is a start, will tolerate a little noisier supply than CMOY too, but is still a bit raw sounding, IMO. Mint is a harder first project to do due to surface mount but I would try to fit that into the budget for the higher current alone. However, I'd still think hard about trying to do a budget Pimeta, I like Pimeeta very much for low-cost amps and would easily go from a Mint to a Pimeta with a cheaper (but still linear) power supply than a Mint with a better PSU, but again this is only IMO.

 

[loac]

Thanks guys, alot of very good info. However, I am reconsidering taking on building an amp with a wall wart power supply on my first attempt. I think I will just go with a small, simple battery-powered design.

I like the Mint, due to the small size and simplicity. I think I will look into making one of those.

One dumb question though. On http://tangentsoft.net/audio/mint/ (Cmoy's site I guess), the picture of the amp doesn't have input or output connectors. What am I missing?

Thanks again for the help!

 

[ericj]

Quote:

Originally Posted by Porksoda = You could put one of tangent's TREAD regulators in there, but that would take up the space for the batteries, so it would be wall wart only.

No need for a whole TREAD, there's plenty of room on tangent's cmoy layout for a 78Lxx fixed to92 regulator and required input & output caps. You'd just need that and a switched DC jack.