[Mitch318i]

Hey, I've been reading up on this site for about the past 7 months, I think its time I actually built something.

I'm aware there are chips available that are able to control volume in a solid state circuit.

My plan is to build a high end Cmoy with such a chip. and having the ability to put the amp in my backpack and adjust volume from some sort of remote.

Can anyone create a circuit that includes a rail spiltter ic and include provisions for a volume control chip like the PGA2310 (I'm not sure how to quite impliment this chip, or even if its possible)

I am aware of forum member "Guzzler" and his board, I plan to use this if I am unable to go with a volume chip.

I will be using porta pro headphones, so if anyone is able to give a resistor gain value it would be great. Also, I plan on using middle-high range components, and required battery life for 2 -9V batterys are ~7 hours

I want an OK sounding amp, with the ability to drive my pros with ease, and with great bass response, highs aren't as important as a few years with high powered car amps have left my hearing for high tones very weak

parts will be ordered through digi-key so suggestions on favorable parts would help

Thanks from a newbie

...Mitch

 

[Wyloch]

Can't help you with the volume control.

Check out here for advice on what parts to buy:

http://tangentsoft.net/audio/cmoy-tutorial/parts.html

For enclosure, Serpac H-67 AC. It can hold two 9V and IMO is perfect for the CMOY.

Also, battery life on a CMOY with two 9V batts is beyond 40 hours. I've been timing how long they last in my current 2-9V cmoy and it passed the 40 hour continuous play benchmark just an hour ago. LED still bright and shows no sign of stopping.

 

[Mitch318i]

I'm willing to sarcifice battery time for a better amp.
I'm just been reading about the Basic Szekeres type of amp, it seems to be simple, has anyone had experence with this type?

The volume control was just a thought, but my mp3 player is able to have a remote (any basic sony mini-disc type)

I've been reading about the Szekeres layout, and this combined with a bass boost seems to be enough, I can go with 3*9V as the amp will only be used once every 2-3 weeks ( bus ride home

) I just need something that is somewhat inexpensive, and has the ability to go for loudness compaired to battery life.

Sorry if I'm being the typical noob. But I dont mind buying $12 of batterys if they can last the trip home.

 

[silmaauki]

If I remember correctly the volume control chip PGA2310 has been found to create some hum - it is not a good choice. I might remember this wrongly - I did not check this up. Some others might have better information available - maybe search would reveal it.

 

[Jazper]

I had a thought that may or may not be relevant. You could try using an old fashioned log pot and hook it up to a 3v stepper motor on it's own circuit, using a very small logic gate controller for it. Provided you had it on a seperate power supply (say a 1.5v AA with a voltage doubler circuit) it could be made to work, and I daresay work well.

If you were real game you could use a shaft extension type thing with a mating device and shield the secondary circuit, with a connector so you could have it as necessary or alternatively run the amp without it.

*shrugs* I'm just throwing around ideas.

 

[Mitch318i]

The stepper motor idea is just too complex for a portable amp. I could just go with a normal pot, its really not worth the extra effort.

As for the type of amp, the mint seems to involved to build for the quality over a Cmoy, as does the higher amps (when accounting for cost vs what I plan to use it for),
The Szekeres amp seems relatively simple, though heat is a consern, it can be delt with.

I'm screwing around in eagle to make a board, if you have one already created, post away.

Right now, I have very limited info on the Basic Szekeres amp and its sound quality. Also, if anyone happens to have a "higher end" Cmoy setup, post what you've used.

Thanks.

 

[till]

The DS1802 from Maxim seems to be the only option if you want to keep it simple - what you need is only a 5 V regulator in addition to the IC itself. Other ICs need a microcontroller, for which in turn you need a program and a programming device and some knowledge. Or you could wait for the digital attenuator by Tangent (scroll down some posts) which will be released soon, I think.