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-   -   'nother noob Charlize question (http://www.diyaudio.com/forums/class-d/79572-nother-noob-charlize-question.html)

McRib 15th May 2006 01:09 AM

'nother noob Charlize question
 
Hi all,

First post! I think I was in a cave the last couple of years. I didn't find out about this Sonic Impact T-Amp phenomenon until a month ago. I had to try it out, so I bought the Super T-Amp. I really like it. Later on, I learned my Onkyo TX-LR552 digital receiver had a Tripath chip in it also.

Anyway, I'd like to build a Charlize amp, but I'm not an electrical engineer. I recently started soldering together interconnects, so I'm still a noobie. Because the Charlize is mostlly built, I thought it would be a good starting point. I think I've read every post regarding the Charlize on the forum, but I don't understand most of it.

I have a few of questions so far. I hope you guys can help explain.

1. I know you can either install a potentiometer or connect it directly to rca jacks. I would like to do the direct to RCA jacks way. I was planning on getting an iPod Universal Dock. The dock's line out is variable. It's controlled by the volume adjustment on the iPod. I would like to hook this up to the Charlize in lieu of a preamp. Would this work? It seems like a great option because I can control the volume and music using a remote.

2. I've been reading a lot about SMPS. I'd like to get one. There was one that someone linked to on a thread.
http://cgi.ebay.com/150W-12V-DC-Powe...QQcmdZViewItem
It looks nice, but I have no idea how to hook this up to the charlize. The wall plug hooks up to the screw terminals labeled L N? Then one wire goes from the +V terminal of the SMPC to the 12VDC hole on the Charlize and another wire goes from the -V terminal to the GND hole on the Charlize? I've read that the SMPS will create a high frequency switching noise and to remedy this you should add a capacitor somewhere? I'm not exactly sure where it would go. I've also read that removing the capacitor will make the amp sound better? Am I comparing the same thing?

3. I understand the Charlize makes a popping noise when you turn it on. Is it really loud or would you just consider it a bit annoying?

Thank you!

vt4c 15th May 2006 01:46 PM

Hi McRib,
The answers to your question....

1.) Yes it will work.
2.) Yes...The input a.c. supply to screw terminals labeled L N (since it is 'live', please be cautious!):att'n: The -Ve to the 'gnd' terminal. Don't remove anything.
3.) Follow the 'soft start' circuit to eliminate it.

:)

JohnnyBoy 15th May 2006 02:27 PM

My speakers are 96db sensitive. The pop isn't that big of a deal. I have heard far louder start up pops from SS gear. Try it without the soft start... you can always add it later if you want to.

McRib 16th May 2006 08:00 AM

Thank you so much for the responses.

vt4c,
What do you mean by 'live?' If you mean that I might blow myself up, I do want to be very cautious. Just so I don't hook it up wrong, do you know what the L and N stand for. I'm getting very nervous now, hah!

JohnnyBoy,
My current speakers are 91db, so I hope I won't hear it very much. I have an older rotel integrated amp that kind of made a pop when I turned that on.

theAnonymous1 16th May 2006 10:20 AM

Quote:

I've been reading a lot about SMPS. I'd like to get one. There was one that someone linked to on a thread..........
I've purchased 4 of those from emtel and they are nice quality supplies. I use all 4 of them in series to make a 28-0-28 12amp supply for 3 AMP-1B's.

They were only $15 each when I purchased them, looks like the price has almost doubled.

Also..... L = Live(white wire), N = Neutral(black wire)

http://i18.photobucket.com/albums/b1...us1/inside.jpg

RtV 16th May 2006 12:03 PM

McRib:

One of the hardest things for noobs is to prioritize. Without experience, it's hard to know what's worth your attention.

As in most things, it's important to get your feet wet, improve your soldering skills, and worry about details later. My advice is just to hook it up so it works. Don't worry about the pot or the hf noise--just get sound out of it. Make sure your R & L RCA's are wired correctly and the amp drives your speakers. If the power supply is beyond you, start with a wall wart. In any case you need to figure out how to hook up a power supply to the Charlize pcb. You must have a VOM to test your work.

Once it's working, and you're enjoying music through it, I'd consider the following tweaks in this order:

1) The biggest change to Charlize came when I replaced the cerafine input coupling capacitors. There's a good thread on this somewhere. You'd get excellent results for a reasonable price with the Jantzens from Parts Express. Lowering the capacitance a step or two will also soften the turn-on popping sound.

2) The connection for headphone out of the ipod really attenuates the bass. If you take the true line out signal from a docking station (or pocketdock) you will get far better sound. Of course, now you are back in the situation of needing a pot to control volume.

3) Only after the first two tweaks would I consider experimenting with the power supply. Personally, I just use a salvaged (= free) computer power supply with the fan disabled (Charlize doesn't use enough power to generate much heat). Try the SMPS straight first. If you hear the HF noise, then look to tweak it.

Randy

McRib 17th May 2006 01:01 AM

theanonymous1,
Thank you for the picture. That is an amazing looking amp! How long ago did you buy the power supply? I can't believe they've gone up so much!

RtV,
Thank you for the advice. I do feel a bit lost in all the details. I will just try to get it working before I start tweaking it. Regarding the iPod connection. I was going to hook up the iPod through the lineout port of Apple's Universal Dock. It just so happens the lineout's output level is variable, so you can control the volume level through the iPod itself. Do you think the bass will be attenuated still?

RtV 17th May 2006 01:33 AM

Quote:

Originally posted by McRib
[BRtV,
Thank you for the advice. I do feel a bit lost in all the details. I will just try to get it working before I start tweaking it. Regarding the iPod connection. I was going to hook up the iPod through the lineout port of Apple's Universal Dock. It just so happens the lineout's output level is variable, so you can control the volume level through the iPod itself. Do you think the bass will be attenuated still? [/B]
I don't know about the Apple Universal Dock. But I assume that the dock is getting the line out signal through the connector in the bottom, and then you attenuate it by using a knob on the dock--not though the ipod electronic interface. In that case it would be bypassing the headphone amplifiers and the bass problem.

Randy

theAnonymous1 17th May 2006 10:15 AM

Quote:

Thank you for the picture. That is an amazing looking amp! How long ago did you buy the power supply? I can't believe they've gone up so much!
Thank you. That was my very first DIY amp project and also my very first time putting together any sort of PCB, let alone one with SMD work involved. All three amps worked the very first time to my amazement. I didn't even do any of the low powered fused testing thats recommended, I just flipped the switch and had them playing full volume.

I am a complete novice and wanted something more than a transformer based supply. I don't have the knowledge for a complex SMPS solution so I just used my simpletons approach and used 4 off the self units in series. I originally had a weird stability issue because of the large capacitors but eventually got it worked out by adding very low value 0.1R homemade resistors in series with the caps.

I dug through my old emails and it looks like I bought the supplies last July for $16.95 each. I clicked on the old ebay link and it brought up the current listing and they are now $34.95 each!!!! Thats some serious inflation. I don't think I would have bought 4 of them at that price.

http://cgi.ebay.com/ws/eBayISAPI.dll..._BIN_Stores_IT

eVITAERC 17th May 2006 04:24 PM

Okay one important thing,

Do NOT hook up the GND on the Charlize to V-

Doing so might cause you to fry your Charlize. As far as I can tell, GND belongs to the FGND terminal on the SMPS. In any case, please measure with a multimeter first, the voltage difference btw V+ and FGND, and btw V+ and V-.


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