Great deal on a 6 channel amp

[sharp_1]

Marbles:

Do you think the gains are turned up too high? What would you suggest using to set gains? I don't have any testing equipment except for a multitester.

[scottw]

Glad to hear you like it. That's what I thought and for $30 shipped you can't beat it.


I am not using the AIP so maybe that is why I hear the thump.

[Marbles_00]

Do you think the gains are turned up too high?

Actually for me, it is the opposite. They may be set too low. But it's difficult to tell as I'm using the AIP which has a volume control, and I had to set both the master and winamp volume very low when I was using the car amp rig. I will have to turn up all the volumes, but it was too late last night to try that...I'd be sleeping on the couch for sure .

What would you suggest using to set gains?

Taken from earlier post:

There are two solid ways to set the gain controls on amplifiers.

1) the more proper way, though most people don't have the equipment is to set a signal generator up on the input of the amp. Use a typical sine wave at a frequency of 1kHz. Hook an oscilloscope up on the amps output so you can measure the 1kHz signal. Then turn the gain up until what was once a nice sine wave on the scope starts to turn into a square wave. That indicates that the amp is clipping. So turn back the gain so you see that nice sine wave again. Finally sweep the generator from 10Hz to 20kHz and verify that the signal looks fine through that range on the scope.

I forgot to say that the input signal should not exceed 2Vp-p (typical amplitude of low level audio).

2) the every-day Joe way. Turn your source to 3/4 volume (in this case Winamp). Turn the gain pot up on the amp until the music sounds like crap (amp clipping). Turn back until music is loud, but still sounds all together. You'll know what I mean if you experience it. That's all folks.

I would use the winamp volume and set the master volume at full, since the winamp volume will affect each individual zone, and for most people, the winamp volume will most likely be the one that is adjustable within Xlobby. I also say around 3/4 volume, that way you have some headroom for anomalies within the amp, speakers used, and soundcard.

Hope this helps.

[sharp_1]

Thanks for all your help!!!! Now I need to find a cheap scope

[Marbles_00]

All I know is that from now on, I'm going to make sure that I listen to some "normal" music after my kid's listen to theirs. My Nowplaying image makes me look like a FREAK

Seriously, of course I'm not going to say don't buy one, but unless you REALLY "need" an o-scope (I'd love to have one...so I don't have to borrow the one at work), just do option 2. In my car audio days, that's how we did it, and it works fine. And as an extra affect, I don't hear the wife so much (doh, I didn't say that out loud did I?).

[scottw]

All I know is that from now on, I'm going to make sure that I listen to some "normal" music after my kid's listen to theirs. My Nowplaying image makes me look like a FREAK

Nah alot of people have kids here, including me. My wife and I have some pretty embarassing music from back in the day but add in my 5 year old's

I also have this girly looking frame around my touchscreen:
http://www.xlobby.com/forum/viewtopic.php?t=5188&start=48
but my wife liked it and she DID let me cut a big hole in her new room. Actually it's not that bad and it does match the room.



Back to the topic....I have my input set to almost all the way down and it sounds great to me. I still have to do option 2 but have to wait till the house is empty

[jryan1776]

I think you missed the signal detection circuit (first one listed). It detects audio signals and if the signals exceed a pre-determined level, a relay closes...powering the amps. It is the sort of circuit used in a power subwoofer.

ya, i totally missed the first link!

Since looking over the circuit more, I'm not too sure if it is designed for stereo use as both left and right channels goto the same point. In my eyes that would allow the left channel to drift to the right and vise versa. Though for a powered amp, who cares, but for something like how you'd want to use it, then you would only want to hook up one channel...still requiring three seperate first stages.

i see that the left and right signals tie together, but they both have a 10k resistor in front of them. do you think that this is enough impedence to make the signal effects negligable, or do you think that i need some sort of isolation.

[Marbles_00]

According to Elliot's site:

A signal feed is taken from both Left and Right channels via R1 and R2 (leave out one input resistor for a mono source such as a sub-woofer).

So technically you only should really need to connect one input. He also indicated further down:

The 10k input resistors may introduce some crosstalk if the drive amp has high output impedance, but this is unlikely to cause a problem with the majority of preamps.

Not too sure what the output impedence is of a typical soundcard (my "preamp").

I was going to experiment with this circuit, but I'm pretty much decided to go with X10 automation control to power up/down the rest of the equipment. So I won't be of much help. I've built some circuits based on Elliot's stuff, and I can say first hand, his circuits have been excellent. One of my current projects is the MayBALD - based on his Line Driver/Receiver circuit.

Good luck, and have fun...DIY is just so rewarding.

[scottw]

Which X10 are you going for???

[joebob2006]

im sure somebody said this already, but im too lazy to read everything to check.

i wouldnt recomend a 6chanell amp unless you have cheap speakers, because an amp with that many channels has too little power per chanel to power quality speakers properly

i have a set of vandersteens, and i have a 2chanel NAD that i bought 15 years ago. if you know that name then you know what i mean when i say that they are really good speakers.

you cant find good quality amps anymore because everyone just wants 7.1 surround sound, and the sacrifice for quantity is always in quality.

if you actually care about the quality of sound you are producing, and if you have speakers that are even half-way decent, i wouldnt get this amp. i would go to a pawn shop or a really good audio store in a major city and tell them what speakers you have to get something that will do them justice.

[Marbles_00]

i would go to a pawn shop

Oh ya, I would trust a guy at a pawn shop and take his word on a good quality speaker and audio equipment. Dude, most of us are not using these amp to drive surround sound systems, nor are we using them in a dedicated listening room. We're using them for simple zoning amps...nothing more than to get some music around the house. Do they compare well with mid-stream components like NAD and Rotel...no...no where close. I can agree with you there as I also have a NAD and love it. I've built my home theater around it because I don't want to give it up. But hey, for as cheap as they are, they do the job, and from what I can tell, they do it well, not audiophile class, but sure better than a ghetto blaster.

i wouldnt recomend a 6chanell amp unless you have cheap speakers, because an amp with that many channels has too little power per chanel to power quality speakers properly

So what your saying is that the NAD 906 or 916 six channel amps are no good? Right there I take what you say with a grain of salt. I'm sure those simple 30 watt amps would make your vandersteens sound sweet. Hell, I bet a simple Gainclone would drive those speakers fine, and it's only 9 components (well 18 for 2 channel), and only 50W max. Next your going to say that the Rotel RMB-1048 is a crap amp as well. I suppose your one of these believers in snake-oil speaker wire and interconnects or better known as Monster Cable. I take it your one of these guys that figure you need a 1000Watts to have something that sounds good, only to drive a fraction of that..."but hey...I have a 1000Watt system built around Monster Cable. So it doesn't matter that I can't turn the dial past 1 or your ears will bleed"

Again, can't say for everyone, but I'm not willing to spend $1000/room to get full zoning audio, nor is it worth putting in 100W/ch amps for a bedroom or better yet...bathroom, just to get some music to it. Though it would be neat to see the bathtub water ripple . If I wanted to spend that much, then I would have bought a Russound system or something dedicated to music distribution.

you cant find good quality amps anymore because everyone just wants 7.1 surround sound, and the sacrifice for quantity is always in quality.

Again, you don't know what your talking about and haven't done your homework. Since we're on the topic of mid-systems like NAD and Rotel, they make lot's of good quality amps. Anything that has a THX logo on it is good. Read the datasheets man before your post a statement like that. What your saying is that the RMB series amps by Rotel are crap? I'd pair one of them up with a Rotel RSP-1068 anyday. Let's look at NAD, since you seem to like them so much having owned one for 15 years. Your saying that the new NAD M25 is no good? I'd love to get my hands on a T955 for T973. Or if you want to go high-end, your really going to say that multi-channel amps made by companies like Sunfire (owned by legendary Bob Carver, a guy who strives for excellence in all his products) are "not good quality"? You know nothing.

What erks me about your post the most is that you criticize but you don't give any substance to back you up, only just to brag that you have some vandersteens and a NAD...WOW...good for you. If you decided to read the former post and weren't so lazy, you'd see that I've been critical of this amp, but for the money it's worth it. What would you recommend for zoning audio? How much wattage do you think you need to fill a bedroom or bathroom? What's your budget your looking at? You don't share any of your excellent wisdom in a constructive way.

Anyways...

Scott,

I think I'm going for a CM11a and 3-prong appliance module. Something simple is all I need, and I've read some posts on setting up a CM11a. I think it should be fine for this use. How bout you? It sounds as though we may be working on this together.

[scottw]

First I agree with you Marbles, I was not looking for anything audiophile grade and when this thread was started by Rem it was stated numerious times that this was a "cheap" amp. You get what you pay for and I have gotten WAY WAY more that $30 out of this thing, I probably would have spent $100 on this amp since it perfect for a person like me and the setup I am going for.


On to the X10 I just bought this last night:
http://www.x10.com/promotions/cm15a_ed_freesuite_onalert_0103.html
which has the CM15a and a bunch of other stuff and additionally I bought the a 3 prong appliance module. What I was afraid of with the CM11a was that I was going to get so into the X10 stuff ($$$) that the cm11a would limit me, although I may be wrong.
Before yesterday it was going to cost me $50 for the CM15a with the PC software and another $20 or so for the appliance module.
Last night, the deal I bought, cost me $70 as well but I got a few extra's to play around with:

1 2-Way Appliance Module (2-pin) (AM14A)
1 ActiveHome Professional Computer Interface and USB Cable (CM15A)
1 Door/Window Sensor (DS10A)
1 ActiveHome Professional Software (SW31A)
1 Smart Macro Software Module for ActiveHome Pro (SW32A)
1 iWatchOut Software Module for ActiveHome Pro (SW33A)
1 myHouse Online Software Module for ActiveHome Pro (SW34A)
1 ActiveHome Pro - Home Security Solution (SW39A)

This package is $50, go figure, and I bought the appliance module for $19. Pretty good deal for me as a starter package and I can buy other components little by little to addon.

I did spend some time in the X10 forums and read that the RF range of the CM15a can be pretty crappy although some have gotten great results with no modifications to the unit. There are some tips on how to get better range out of it. Additionally you can buy the tm751 tranceiver:
http://www.x10.com/automation/tm751_s.html
for $13 which will take over the RF past where the cm15a reaches and is supposed to have good range.
I thought X10 was all RF but I read somewhere that it uses your existing house wiring as well so I am a little confused on that, maybe we should start another thread for this X10 stuff

If I am wrong on any of this please let me know, I am trying to figure out exactly how all this works.

[Marbles_00]

I am trying to figure out exactly how all this works

I hear ya. I'm in the same boat, that's one reason why I decided to start small with just a serial controller and 3 prong appliance switch. I only want to use it to shut down the AC to the rest of the components when the computer goes to sleep. I don't have a great need for alot of home automation stuff, but I see a reason to learn how to use it. Most likely I will dive more into it once I get a HTPC setup, where I will want to control the lights in the room.

Gotta admit, Damage's "Doghouse" setup is pretty sweet.

[scottw]

Wow that is cool. The cool thing about X10 is you can have it as small or as big as you want. You also don't have to buy an expensive package to get one light automated.

I'll let you know how it goes.

[Marbles_00]

Upon further playing around and experimenting, this little amp is really good for filling small and mid-size rooms with music (for 2 channels), in my eyes. I'm currently still using the AIP, turned the volume all the way up, turned the Bass and Treble all the way down (so that is affecting the audio at a minimum). I adjusted my KX settings for the EQ, and made sure my Winamp EQ is off. Got some good sound coming out of some R10 Polk Audio speakers.

To further describe my settings, I've got the system Master all the way up, and the Winamp volume at like 20% and the rest of my family is complaining that it is too loud. I haven't adjusted any gains on the amp itself. I hope the family will go out soon so then I can hear how loud it will get before it starts to clip.

On a side note, I like how little room these amps take up.

I'm pretty satisfied as to what this critter can do. Thanks to Rem for posting this in the beginning.