Great deal on a 6 channel amp

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Great deal on a 6 channel amp

Postby rembetis on Wed Oct 25, 2006 5:39 pm

Just a heads up on a 6 channel amp (30 watts per) that somebody is selling hundreds of on ebay for $19.95 plus $10 shipping.

I ordered 2. Lots of applications for these, including a nice multizone amp and a super cheap 5.1 amp. One caveat is you would have to make your own RCA > 6CH Din adapter (it comes with the 6 CH din and pinout info).

ebay item # 220040886797
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Postby Marbles_00 on Wed Oct 25, 2006 8:04 pm

BIG problem...according to the ebay ad, they will only deal with US bidders.

Rem, I suppose you aren't into taking a couple of orders then shipping them to the Great White North (Canada that is) are ya :?: :wink:

We can deal through paypal and USPS if you want?

If your interested, drop me an email to mayhemDOTprodATgmailDOTcom.
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Postby scottw on Thu Oct 26, 2006 1:56 pm

Just want to understand properly, since I have delayed setting up multizone audio because of finances.
So with this amp you could power 3 different zones with 2 speakers in each zone with 30watts in each zone or 6 zones with one speaker if you wanted, right???

So, you would have one output of your sound card into 2 channels of the amp (the cable you would have to make), right?


Thanks,
Scott
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Postby rembetis on Thu Oct 26, 2006 3:08 pm

Please don't take what I say as gospel, as I am anything but an expert on these matters, but from the images and manual captures displayed in the auction, it looks like *each* channel is 30W, so your 3 zones w/2 speakers would have 60w a piece.

Using it as a zoning amp would be both simpler and more complicated than you suggest. If you are only using a L/R output from your soundcard, you would not need to make a cable as the amp input head already has 1 set of stereo RCA inputs. However, separately controlling the volume (and on/off, for that matter) in those individual zones would be require an additional component. There are input gain controls for each channel on the back of the amp, but they are not user friendly and would need some kind of tweaking to use as volume knobs. I haven't looked into it yet, but I am guessing you could use some sort of volume attenuator (like this) in each room, wired between the amp and the speakers.

Hope that helps
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Postby Marbles_00 on Thu Oct 26, 2006 3:49 pm

If your intentions were to use one source to drive the same signals to all the zones, whether it be 3 stereo pairs or 6 individual, then the included head unit and cabling would suffice.

If your intentions are to have seperate signals to each stereo pair, or each channel for 6 mono zones, then the included head unit is of little value.

Rembetis mentioned that having two channels would be 60W. Well it is not really termed that way, each channel would be 30W and it is usually termed 30W/Ch...keeping the channels as seperate entities. When you combine or bridge channels together to double the output power is when you combine the wattage value (60W bridged for three channels then).

I do have some concerns with this amp though...I'm hoping that Rembetis, though I'm sorry to term you as a guinea pig, will be able to validate the amp's stability. The thing that struck me after looking over the limited specifications provided is the low damping factor value (>50). Damping factor is the ability for an amplifier to control the speakers attached to it. Basically it is the speaker impedence/output impedence of the amp. The higher the value, the more stable the amplifier. Two problems with this value:

1) It is low. If you look at the specs of most other amplifier companies, you will find values of 200, or even greater, though above 200 is not really noticable.

2) They did not put a speaker impedence value to that number. Say >50 with 8ohm speakers. If >50 is with a speaker impedence of 2ohms (they say they can drive 2 ohm loads), then I will feel a little more at ease. This being that 2/50=0.04ohm output impedence (ideally you would want a 0 ohm output impedence...so the lower value the better). This would mean that 8/0.04=200 (pretty good amp then for basic requirements).

But regardless, ~$40 (after shipping) for a 6ch amp...it is worth trying it out. If it works then you have yourself a steal. If it doesn't, then you haven't forked out a dish load of money, and you can still walk away knowing that.
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Postby scottw on Thu Oct 26, 2006 4:37 pm

Ok maybe I am looking at it the wrong way but it did not seem that complicated to me, but I am no expert by any means.
I was thinking of using this as a multizone amp, lets just say 3 zones with 2 speakers in each. Say you have 3 sound cards in your Xlobby machine and each output of a card would goto 2 channels and the volume would be controlled by the winamp volume slider on the computer. You would have a seperate sound card and a seperate copy of winamp for each "zone" so you would not need any additional components, right?

Now thats the concept, if it's right :?: ) but how to hook it up is where I am a little lost.
Am I thinking of this the wrong way???

And isn't it $30 after shipping Marbles??
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Postby rembetis on Thu Oct 26, 2006 4:50 pm

scottw wrote:Now thats the concept, if it's right :?: ) but how to hook it up is where I am a little lost.
Am I thinking of this the wrong way???


In that case, you would need to make the cable I mentioned in my first post. I am basing this notion on something someone said about these amps on another forum, but based on the pinout diagram in the manual, I don't see why you couldn't splice 3 separate RCA L/R cables with the 6 CH DIN input cable provided with the amp.

And isn't it $30 after shipping Marbles??

Yes
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Postby scottw on Thu Oct 26, 2006 4:57 pm

rembetis wrote:
scottw wrote:Now thats the concept, if it's right :?: ) but how to hook it up is where I am a little lost.
Am I thinking of this the wrong way???


In that case, you would need to make the cable I mentioned in my first post. I am basing this notion on something someone said about these amps on another forum, but based on the pinout diagram in the manual, I don't see why you couldn't splice 3 separate RCA L/R cables with the 6 CH DIN input cable provided with the amp.

And isn't it $30 after shipping Marbles??

Yes


Can you post a link to the other forum, I was trying to find more info about this amp but came up dry.


Also pardon my major lack of knowledge on this, but on the diagram it shows what looks like one wire coming off if each pin or is it 2 wires, hard to tell. If it's 2 wire which is what it should be, it would just be a positive and negative which would connect to the positive and negative on the rca's you would splice in, right?? Sorry for such a basic and maybe stupid question, but it looks like it may work for me but I want to make sure I have everything covered before I order.

Thanks,
Scott
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Postby rembetis on Thu Oct 26, 2006 5:44 pm

scottw wrote:Can you post a link to the other forum, I was trying to find more info about this amp but came up dry.


Well, it's not really a forum per se, just a message board (for PartsExpress), but here's the thread: http://www.pesupport.com/cgi-bin/config.pl?read=312003


Also pardon my major lack of knowledge on this, but on the diagram it shows what looks like one wire coming off if each pin or is it 2 wires, hard to tell. If it's 2 wire which is what it should be, it would just be a positive and negative which would connect to the positive and negative on the rca's you would splice in, right??


You're right, it's hard to tell and I can't say anything for certain until mine arrives and I try it myself, but in theory it would be 6 wires coming out of the 6 CH Din connector (and maybe a ground, or whatever "shield" means in the picture, in which case, I'm a little lost as to what to do with that). So for Zone One L/R, or Front L/R in a 5.1 setup, you would splice the right RCA channel to red wire, and the left to the yellow, and so on.

Image
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Postby scottw on Thu Oct 26, 2006 5:47 pm

Cool thanks,

I always thought there were 2 wires coming out of each RCA plug, 1 + and 1-, but I could be wrong.

Thanks for the help!!!!
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Postby rembetis on Thu Oct 26, 2006 6:03 pm

scottw wrote:I always thought there were 2 wires coming out of each RCA plug, 1 + and 1-, but I could be wrong.


Hmmm... I think you're right. I just stripped a spare RCA cable I had lying around and there is an outer wire and an inner (sleeved) wire. Well, I'm kinda stumped if there are indeed only 6 wires coming out of the DIN. Perhaps all six of the inner or outer wires get wired to the "shield"?

EDIT: Upon further research, it looks like all RCA's have an "earth braid" as an outer sleeve. I'm guessing these would all get wired together with the "shield" but I'll have to look into it further.
Last edited by rembetis on Thu Oct 26, 2006 6:08 pm, edited 1 time in total.
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Postby scottw on Thu Oct 26, 2006 6:07 pm

rembetis wrote:
scottw wrote:I always thought there were 2 wires coming out of each RCA plug, 1 + and 1-, but I could be wrong.


Hmmm... I think you're right. I just stripped a spare RCA cable I had lying around and there is an outer wire and an inner (sleeved) wire. Well, I'm kinda stumped if there are indeed only 6 wires coming out of the DIN. Perhaps all six of the inner or outer wires get wired to the "shield"?


Yeah that makes sense, there has got to be a way. Hopefully someone will chime in here and help us out. :D
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Postby Marbles_00 on Thu Oct 26, 2006 6:10 pm

Sorry, I was thinking Canadian funds...eh?

As for connecting, rembetis is right for hooking up the low level audio. Pin1 and 2 would go back to one audio card stereo output, 3&4 to another, 5&6 to another. Shield will be used for the return for all 6 channels.

Using the shield as a return is pretty typical for unbalanced low level audio.

If your wondering how one shield could be a return for all 6 channels? Plug an RCA-3.5mm stereo plug adapter into your soundcard. Measure the continuity (resistance) between the RCA ring, to the soundcard faceplate. You should measure 0 ohms (I did this just last night with an CL Live 5.1 card). Plug all the cards your going to use into the PCI slots then measure the resistance from one faceplate of one card to the ring of the RCA adapter plugged into another. If you measure around 0 ohms, then the returns are all tied together in the computer and the shield can be used.

Or an even better test is to plug two adapters into two different cards and measure the resistance on the ring of both adapters. If you measure around 0 ohms then the returns are again tied together in the computer and you can use the shield for a return.

Hope this helps.
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Postby scottw on Thu Oct 26, 2006 6:19 pm

Marbles_00 wrote:Sorry, I was thinking Canadian funds...eh?

As for connecting, rembetis is right for hooking up the low level audio. Pin1 and 2 would go back to one audio card stereo output, 3&4 to another, 5&6 to another. Shield will be used for the return for all 6 channels.

Using the shield as a return is pretty typical for unbalanced low level audio.

If your wondering how one shield could be a return for all 6 channels? Plug an RCA-3.5mm stereo plug adapter into your soundcard. Measure the continuity (resistance) between the RCA ring, to the soundcard faceplate. You should measure 0 ohms (I did this just last night with an CL Live 5.1 card). Plug all the cards your going to use into the PCI slots then measure the resistance from one faceplate of one card to the ring of the RCA adapter plugged into another. If you measure around 0 ohms, then the returns are all tied together in the computer and the shield can be used.

Hope this helps.


Thanks Marbles but you lost me at EH......just kidding :D

So if I have you correct you take the "inner (sleeved) wire", as rembetis called it, and connect to pin 1 then take the outer wire and hook it to the "Shield - Bare" wire named in the pic above. You then repeat connecting the inner wire from each RCA plug to 2, 3, 4, 5, 6 and connecting each of the outer wires to the common "Shield - Bare" wire, right??

Thanks for your input!!!!
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Postby Marbles_00 on Thu Oct 26, 2006 6:36 pm

That is correct. The inner pin of the RCA is the positive connection. Pins 1 through 6 would go to each center pin. If the returns are all tied together in the computer then you would only need to tie one return then to the shield as opposed to 6 (makes life a little easier). If they aren't then yes you would have to splice all the outer rings of the RCA cable to the shield.
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