N0bb building CMoy Amplifier

[tetrakarbon]

Hi. I'm interested in improving the bass performance of my HD280's, so I figured building an amp wouldn't hurt. I've looked at Cmoy's in the past, and I think I'm ready to finally build one.

But I want to do it right. I am interested in building one that uses alternate high quality components. I was wondering what modifications are popular to cmoys to get the highest quality sound out of them possible. Larger caps (is there a real trade-off here)? What opamps are considered the best, etc.

Any ideas are reall welcome...

-- Ned

 

[mustang]

I'm a DIY newbie myself so please...anyone correct me...

Quote:

I am interested in building one that uses alternate high quality components.

I'd recommend Visay-Dale caps from mouser and Yageo or BC components resistors. I'd also include the TLE2426 voltage splitter. The standard power supply for the cmoy is a dual one, meaning it splits the 9V (or whatever you use) to 4.5 and 4.5 for each rail. However, the disadvantage with this setup is that an imbalance can occur where one rail is 3.8V and the other is 5.2V. The TLE2426 insures that each rail will recieve an equal voltage.

Quote:

Larger caps (is there a real trade-off here)?

A larger cap can handle more voltage and as I far as I know, I don't think there's any advantage to buying a cap that goes well over your power source.

Quote:

What opamps are considered the best, etc.

From what I hear, OPA2227s are best for the cmoy.

Hope it helps

 

[chillysalsa]

Those HD280 are 64 Ohms.

You may want to try the new OPA2614, it would be perfect for use because of the high current output, and the +/- 4.5V supply with a rail splitter would be in the recommended range.

I've found capacitor in the 470 to 1000uF range will give you the best bass and clearest highs, larger than that and the bass starts to get muddy.

 

[Nisbeth]

My recommendation would be to build a cmoy using whatever components you can find. Use a good opamp such as the OPA2134 or OPA2227, but use whatever caps and resistors you can get. When you've completed the CMoy and found out if it improves the sound, build a MINT/Pimeta/Szekeres/SDS/PPA or another amp using what ever quality components your heart and wallet can agree on. Outfitting a cmoy with expensive caps and exotic resistors is a waste of effort in my opinion, especially if it is your first project.

Either way, if you haven't already, start you DIY-adventures with a look here: http://www.tangentsoft.net/audio/


/U.

 

[tetrakarbon]

Thanks for your advice so far guys.

Thank you for the link. I was not aware the same site had information on how to build other types of amplifiers. I will definitely check those out.

This would be my first project, so it may well be foolish to think about building something that's beyond my experience. However, I do want something portable and relatively high quality. The Cmoy will sound better if I use quality parts, no?

Are there portable alternatives to the cmoy?

-- Ned

 

[Nisbeth]

Quote:

Originally Posted by tetrakarbon The Cmoy will sound better if I use quality parts, no?

Sure. But the question is how much. In the end the limiting factor for quality will be the simple circuit and not the quality of the parts.


/U.

 

[tetrakarbon]

Quote:

Originally Posted by Nisbeth Sure. But the question is how much. In the end the limiting factor for quality will be the simple circuit and not the quality of the parts. /U.

That's something I'll keep in mind. Do I have any portable alternative?

-- Ned

 

[einolu]

If you have never built anything, do the cmoy first, since its cheap and you can see how to solder and all that. It seemed easy to me, but its a lot harder when you actually do it. Also, having a friend help you is great when your starting out, since they can hold things for you while you solder and so on...

 

[tangent]

Quote:

I am interested in building one that uses alternate high quality components

Laudable, but don't go too far overboard. A $300 CMoy probably won't outperform a $200 PIMETA, to most ears.

I'm not telling you to start with the PIMETA. By all means, build a CMoy...it'll teach you a lot that you can't learn from a PCB-based amplifier.

Quote:

What opamps are considered the best, etc.

As long as you use sockets, op-amps are a good place to go overboard, because you can always move them to another project if you decide to upgrade.

To that end, go for the big guns: OPA627/637, AD8610/20, AD843. Also popular for audio, and cheaper than the above, are the AD825, AD8065, and the OPA2227.

Quote:

Visay-Dale caps from mouser

Vishay is a conglomerate made of many formerly-independent companies. Dale made resistors, not caps. The caps are offered under the Vishay-Roederstein and Vishay-Sprague lines, at Mouser. Also, I think there are some marked simply "Vishay".

While you're there, you might as well use the Vishay-Dale RN55D resistors. They're not much more expensive than average resistors, and a lot of people like them better than the generics.

 

[tetrakarbon]

Thanks a lot for the advice! I've been using your website tons

What's the MINT like in terms of sound quality? I'd really like something portable...

-- Ned

 

[tangent]

Quote:

What's the MINT like in terms of sound quality?

That's for the independent reviewers to answer. Do a search in the Amplification forum.

 

[sunfowerggs]

Many thanks to ur post. I love it.

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