[millercv]

ok I may be over thinking this but just wanted some help.

I've decided to gut my "learning" (read messy) CMOY and move it to a box with multiple switched sources and DC power. I was thinking it would be nice to have a line out also - for recording stuff to MD etc.

Is this as simple as just tapping the line before it hits the amp portion or would that mess with the signal too much?


Thanks!

-Chris

 

[tommyatkins]

All a traditional line out does is bypass the amp portion (or some part of the amp portion) of the source etc.

To do this, yes, you would just bypass the amp. The biggest problem I can see it additional components in the signal's path, which affects the sound. Depending on the quality of your design (not much creativity here though...) and components the result may or may not be to your liking. It shouldn't be that hard to build in and you can alway not use it, if you don't like the results.

TA

 

[tangent]

You can do it that way, millercv, but just realize that you're presenting two parallel paths for the signal from the perspective of the source, if the preamp output is hooked up to something. Parallel impedances result in a lower overall impedance, and the lower the impedance, the higher the load on the source. Therefore, you must make sure your amp has a relatively high-impedance front end, which means using a 50K or 100K pot and a large R2. Then you must also hope that whatever device you hook to the preamp output also has a relatively high input impedance. Look in its manual -- it might say. As long as the overall impedance is in the 20K to 50K range, you'll probably be okay.

The other way you could go is to put two output jacks on the amp, but this really works best in an amp with plenty of output current and low distortion. I.e., not a Cmoy. Again, it requires that the other device have a high input impedance to avoid changing the sound you get through the headphones. I do that sort of thing with my Corda HA-1: one output to my normal headphones, the other to a wireless headphone set so that I can move around and still listen if I want.

 

[Gino]

I don't get it. Why use an amp then reduce the signal to a lineout when you can hook your MD straight from the portable cd player's line out or headphone jacks? Your cleanest signal for lineout is whatever is going into your amp anyway.

 

[stereth]

By definition, doesn't a line out bypass the amp?

 

[rickcr42]

the cmoy is no different than an ordinary line amplifier so if you you have need for gain you could have a simple line/headphone switch (DPDT) on the "output" of the amp .

If the gain requirements differ you could also switch the gain simultaneously by using a 4PDT switch with two poles used as above and two switching in the different feedback loop resistors to set the gain (which could also be unity in the line mode so the cmoy would become and follower / buffer for cable driving)

if no buffering or gain increases are needed then a simple dpdt at the amp input will do with the center connections of the switch going to the input jack and each of the end pairs going to either the amp or the line out jacks

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