Shoutouts to my boy Tipo33 for sending me this CMOY to try out. I'm super stoked. I'll be writing a review on this later so please check it out when I put it up :D
/shameless plug :PShow Image(http://i.imgur.com/WOl0bOR.jpg)
I know this was on the previous page, but nice CMOY. What opamp did you use? I built a few of these and have tons of leftover opamps I wanted to try out but haven't had to time to test them all. It looks like PCB supports rechargeable circuitry, but you're just using non-rechargable batteries?
You'll have to get Tipo33 to answer all these questions. I honestly don't know. I think Tipo just sent me the battery because that's what he had but it seems to be rechargeable since there is a plugin on the side. What are opamps?
lol it's that black chip that looks like a spider, the main piece that the CMOY is built around. It's the actual amp, hence the name opAMP. There are many different types of opamps you can plug in there, and each one will change the color of the sound. All the other components more or less just convert or clean signals. It looks like that tiny switch below the opamp is the bass boost.
You'll have to get Tipo33 to answer all these questions. I honestly don't know. I think Tipo just sent me the battery because that's what he had but it seems to be rechargeable since there is a plugin on the side. What are opamps?
lol it's that black chip that looks like a spider, the main piece that the CMOY is built around. It's the actual amp, hence the name opAMP. There are many different types of opamps you can plug in there, and each one will change the color of the sound. All the other components more or less just convert or clean signals. It looks like that tiny switch below the opamp is the bass boost.
The opamp is a Texas Instruments OPA2227, but it fits into a PGA, so it is swappable. The little switch is indeed a bass boost. As far as the battery, I got one to try it out when I recieved it, and never needed to swap. I have only had to change the battery once since I got it, It doesn't really need that much current.
class A opas don't suck down nearly as much power as discrete fet-based circuits. it's definitely something you want to run on low noise wall power and not battery though.True.
Wait... You like vintage Sansui? Sorry for the potato, but this is mine.
i think i've posted elsewhere that i abandoned head-fi when jude became a money grubbing prick and turned the forum into a playground for snake oil salesmen (it happened pretty quickly, so shortly after the turn of the century i guess).
i think i've posted elsewhere that i abandoned head-fi when jude became a money grubbing prick and turned the forum into a playground for snake oil salesmen (it happened pretty quickly, so shortly after the turn of the century i guess).fair enough, what kind of amp do you own with OPA627's?
also, older big box integrated amplifiers like tipo's are typically class AB designs using discrete transistors (usually power mosfets. as this was all that existed before the age of everyman's VLSI) and high quality components (because that was literally all that was available at the time). their headphone ports are the amplifier output brought down to headphone voltages by a resistor network. they are exceptional values, and have a certain characteristic distortion that a lot of people love; it's the same distortion, coincidentally, that's present in most _recordings_ of that time. hence, to each his own.This is very true, look out for older amps next time you go to a thrift shop, lookout for old audio equipment and do a quick google on you smartphone for common issues and a general review. I got a Pioneer SX-580 for $15 like that :D A lot of vintage amps have the "sound" mkawa is talking about. Marantz is regarded as very warm. Sansuis sound kinda changed over the years.
if you want an inexpensive new integrated amplfiier with these same qualities, my favorite is the severely hidden and underrated onkyo a-5vl. it's cheap, has two beefy class AB channels, has a powered pentiometer that actually sounds good, a nice toroidal coming from mains, and if that weren't enough, they threw in a PCM1796 (one of my favorite dacs) with both toslink and spdif receivers. basically, it's a no-fuss way to power a couple of nicer-but-not-too-nice MTMs (i like the axiom m22 v3 -- ok ok it's a TMM -- but the sound is genuine). all of this together shouldn't cost you more than about 800 bucks, and it will sound fantastic (on-axis, of course) with nearly any source you pair it with at everything up to 20x20' room volumes.
at one point i had opa627s in a 2 to one brown dog in my meta42, but i think it has an ad8620 in it now. in theory i have a big bucket of parts that have been run through that and other topos, but at some point headphones became an "office-only" thing, and i settled on unamplified ety HFs for simplicity's sake. i still have my headphones, but now that i'm not an undergrad i just listen to speakers at home. i have an old hand-me-down-and-repaired pair of infinity ref1s powered by a chipamp in the home-office, and the aforementioned onkyo system in the living room.i think i've posted elsewhere that i abandoned head-fi when jude became a money grubbing prick and turned the forum into a playground for snake oil salesmen (it happened pretty quickly, so shortly after the turn of the century i guess).fair enough, what kind of amp do you own with OPA627's?
@ CPT there is AudioKarma which seems more for restoration of vintage gear, and a few other places I can't think of right now...
I allmost brought it to the meetup, but there wasn't that much intrest in it, so I didn't. ( it weighs the better part of 50 lbs. ) I want the upcoming meetup to be more Model M and soldering focused, but if you want to come over afterwards, we can definetly sit around and listen/discuss.
I would use the "line out". Some sound cards (Asus Xonar essence comes to mind) have a built in amp, in that case I wouldn't run an amp into an amp, it would sound too distorted.I allmost brought it to the meetup, but there wasn't that much intrest in it, so I didn't. ( it weighs the better part of 50 lbs. ) I want the upcoming meetup to be more Model M and soldering focused, but if you want to come over afterwards, we can definetly sit around and listen/discuss.
That would be awesome. I'd really enjoy that. I can bring my Grados again. And maybe I'll bring something else. I'm planning on visiting that Headphone shop we talked about.
On another note, Smallfry pitched a question last night to me. I think I know the answer but I wanted more opinions. I just popped in a sound card into my rig and then I wanted to run the CMOY as well. Smallfry asked why I would use both and I wasn't sure how to answer other than it's gonna sound super good.
And yes mkawa, I know that people mix for earbuds and crap now. :(
Line out from the sound card into the amp?Yup.
unless your cmoy is set up for unity gain (ie, a buffer), your input should be line-level.Given that line outs are usually 1V+ if you have low impedance headphones, a buffer may be all you need. For example, 1V into 30 Ohms of impedance (or Z) flows about 30mA, and therefore about 30 mW
http://en.wikipedia.org/wiki/Amplifier#Power_amplifier_classesNice Marantz man. I tried to pick one of those up but ended up going with a NAD 3130 instead. I thought the Marantz was beautfiul but it had a few features not working 100% and I thought the NAD would fit better with my general desk theme.
Crash course.
This thread needs picks of stuff. :DShow Image(http://i1112.photobucket.com/albums/k494/tipo33/IMG_0561_zpsc8ca6a42.jpg)
Marantz 2245, Grado SR-60i, Sony MDR-7506, and my HTPC.
Sound is very objective. What sounds good to me, might sound terrible to someone else. That being said, I think dual OPA627's sound awesome for the price. It is also widely regarded that Class A amps sound better than anything, despite sucking down power like it's free, and making quite a bit of heat in the process. I personaly like vintage Marantz and Sansui amps, but they are NOT portable by any stretch of the imagination. We discussed this at the meetup a bit, If you think of geekhack as wallethack, don't even think about getting into audio equipment. This is a long, yet very rewarding road: http://www.head-fi.org/ - I'm tipo33 on those forums as well.
Nice Marantz man. I tried to pick one of those up but ended up going with a NAD 3130 instead. I thought the Marantz was beautfiul but it had a few features not working 100% and I thought the NAD would fit better with my general desk theme.Thanks, I got a pretty good deal on it and it matched the Antec Fusion HTPC. Living closer to mainland europe you have a better chance of scoring one of the "blackface" vintage amps. God what I would pay...Show Image(http://i.imgur.com/57RFkoM.jpg)
I use my Sennheiser PC 350s with it and it works great.
Subjective is the word you mean.That is what I mean.
So I realized that the CMOY doesn't turn on until the Line In and Headphones are plugged in. Can someone educate me as to why this is? Do those 2 lines complete the circuit?Yeah, sorta. They don't complete the circuit by conducting, but rather by a switch that's activated in the jack I think. Either way, its to save battery.
Just wanted to chime in and say how funny/surreal it is you guys are discussing cmoy's....my first addiction was to headphones and amps...courtesy of head-fi forums....its basically to headphones/amps/sources/cables etc what geekhack is to mechanical keyboards....
I was into it when the penguin mint tin amps were just beginning to be a thing....
But all good things must come to an end and I got out of the craze long ago (its a long story).....now I'm quickly forming a new addictions here.....
tl;dr: i had at one point easily a couple thousand in headphone equipment and it started with the cmoy....
cmoys are great first-step soldering projects. it's a textbook negative feedback opamp (opa) circuit, and perfect for high quality audio opamps. in the past, this really meant the ti/burr brown 627/637 series. you can get these binned up to like 30-40$ for each channel. they are very nice audio opas and have a very smooth sound when used in a simple feedback circuit due to their high slew rate, low rise and fall times and lack of ringing, even at high (audio) frequencies. however, it's been many years since the 627 was designed, and the new high end from burr-brown is actually the opa827, which, conveniently, is a lot cheaper.
one tweak you'll want to make to a cmoy using two of these chips is to bias them into class A. http://tangentsoft.net/audio/opamp-bias.html
you'll also want to toss a unity-gain buffer in front of the circuit to insulate the opa from high output impedance and to increase drive current, as explained in the above link. buf634 used to be the preferred buffer, but the LME49610 seems like it's a better chip these days.
but the great thing is that these can be easily hand-wired on brown (paper phenolic) perfboard and tossed into a mint tin for EMI. great circuit. you really don't need more than this and a pack of NIMH batteries with a rail splitter to max out a good pair of headphones. you can go crazy with a dynahi, but unless you have AKG k1000s, that super high power topology is pretty much being wasted. diminishing returns kicks in very quickly.