[CrawlingEye]

I'm considering purchasing either Beyer DT831's or DT250-250's. Regardless, both should require an amp.

I need an amp that is capable of being used as a portable, yet doesn't need to run strictly on battery power (can utilize a wall adapter).

My technical skills in soldering and so forth are decent but my electrical knowledge isn't very high.

Ideally, I'd like to have the amp be able to produce a natural (flat) sound (no tubes, no added warmth).

Any suggestions... under $300 USD?

 

[Sol_Zhen]

Quote:

Originally posted by CrawlingEye My technical skills in soldering and so forth are decent but my electrical knowledge isn't very high. Ideally, I'd like to have the amp be able to produce a natural (flat) sound (no tubes, no added warmth). Any suggestions... under $300 USD?

Build yourself a meta42. My electrical skills are low, but I can solder and work with tools. I built myself a nice meta with a crossfeed.

 

[CrawlingEye]

Thanks, I'm looking at his DIY intro section and OpAmp section, at the moment.

I'm debating on op-amps. Tangent's comment about the 2228P slightly confuses me but also interests me.

Quote:

The 2228P is faster (33 MHz vs. 8 MHz) but is only stable in gains of 5 and over. In some of the amps I tested with (not just my official test amp), it seemed not to perform quite as well, probably due to minor circuit layout problems. I got it to oscillate occasionally, and other times I got a kind of "grunge" in the sound. This suggests that this is a cranky chip, requiring special handling. But when I did get good results, it sounded a bit more analytical than the OPA132. By comparison, the 132 sounded more "alive". This difference is purely subjective, so some people may prefer the difference. It has the same supply voltage behavior as the 227: it works fine on my toughest test down to 8V.

It seems 'analytical' would be what I'm looking for. However, with it being difficult to get positive results from, it may not be the best option. I'll keep reading on. Any suggestions would be appreciated though.

 

[jaskin]

For me I would rather buy. I'm terrible with the soldering iron. I believe are soldering skills. There are many step by step instructions on the web on how to built an amp.

 

[AIM9x]

buy if you're not confident in your soldering skills or for pure convenience.

build if you want to have fun with it.


i personally don't have very good soldering skills, so i bought.

 

[Lando]

I'm looking into building a cmoy right now, and if I do it it'll be my first real electronics project. Do you guys think it would be a good idea to buy a breadboard and test everything out before I break out the soldering iron?

 

[Sol_Zhen]

Quote:

Originally posted by Lando Do you guys think it would be a good idea to buy a breadboard and test everything out before I break out the soldering iron?

The protoboards are cheap enough at Rat Shack (about $1.40 ea) for you to just solder away and re-do it if you mess up. After all, each board will yield 2 Cmoy and the parts can be de-soldered easily enough as long as you socket the Opamp.

I say, just go for it.

 

[CrawlingEye]

I think I may try the CMoy first and see how it goes. I'm buying the 2228 OpAmp as well as their suggested OpAmp, so if I run into complications with the 2228, I can just pop the other in.

 

[Sol_Zhen]

My first build, I ordered enough parts for two Cmoys just in case I screwed up. I ended up with 2 good working models. So, I sold one to another user at just above parts cost to cover for the extra parts.

Unloading an extra is never an issue. So long as it works just fine – both of mine were identical in parts and build.

So, I have an extra protoboard lying around for future use in something.

 

[CrawlingEye]

Some of the parts I have to double up with, just because Digi-key won't let me buy under 5 of them. (resistors and so forth).

Tangent mentioned that the 2228 doesn't like anything under a gain of 5, so I intend to have it set to 6. This should work well, hopefully.

I'll post my results.

 

[Lando]

I was reading Tangent's cmoy tutorials and his comparisons of different op-amps and got to thinking: with a larger enclosure and slightly more complicated layout, wouldn't it be possible to fit two op-amps in? You could have one with a warmer, smoother sound and another with a more revealing, analytical sound. Then you just toggle between them with a switch for different music types.

So am I crazy, or just off my rocker?

 

[AIM9x]

too much work...