AVS Forum banner

1 - 13 of 13 Posts

·
Registered
Joined
·
103 Posts
Discussion Starter #1
I'd like to ask a question that may sound crazy, but we're trying to solve a problem and this might solve it.

So we have a pair of tower speakers that are currently connected to a receiver. I think the amp on the receiver is not powerful enough to drive the towers. This is a 7.1 receiver with no preamp output.

And we also have a stereo receiver that is currently unused. It has only 1 rca input and 2 speaker connections for speakers.

Here is (the potentially crazy part) what we're thinking:
1. DIY a cable that connects the front left and front right from the receivers'output to the amps' rca input
2. Connect the speakers to the amps' output.

My question is:
1. Can this be done?

2a. If yes, then how should we go about making the cable ?

2b. If not, is there a way to add the power to the speakers ? It seems like a waste to get a new receiver while we already have an amp laying around

The aim is to be able to play 7 channel while providing enough power to the speaker.

Thank you for your advise.
 

·
Registered
Joined
·
3,500 Posts
What makes you think your 7.1 receiver is insufficient to drive your speakers?

Perhaps someone can clarify if I’m wrong on this, but here’s how I see it.

The problem is that the amp needs to see an 8-ohm load. In lieu of a speaker, you need an 8-ohm resistor with a suitable power rating, say 50 watts (if your receiver is rated for more than that, it’s fine, 50 watts should be plenty for this application).

The resistor will connect to the first receiver’s speaker connections. That will make the amp happy. A second (parallel) connection from the receiver’s speaker connection will have to go to an “L” pad, which is like a passive volume control. From the “L” pad, a cable with RCA connector that you can plug into the second amp’s inputs.

The “L” pad is necessary because the second amp’s inputs are expecting a small signal of maybe a few millivolts. The volume knob on the receiver will generate that much at the speaker outputs in maybe the first 1/4” – 1/2" of travel of the knob. So, you’d have to live with a hair-trigger volume control from then on. The “L” pad would dial back the signal to the second amp so that you could have regular volume control operation from the main receiver.

All in all, probably not worth the trouble.

Regards,
Wayne A. Pflughaupt
 

·
Registered
Joined
·
1,746 Posts
Short story: you will gain nothing and damage your gear if you do weird stuff.
Long story: well, ain't nobody got time for that.

Would be better to tell us which AVR and speakers you have so someone will tell you if you are clipping and when.
 

·
Registered
Joined
·
103 Posts
Discussion Starter #4
Thanks for the reply Wayne.

We think the speaker is not getting enough power because previously using the unused stereo amp, it sounded fine.
But using the receiver, it sounded as if it is muffled.

I think we need to digest the rest of your post. It sounds more complicated than we thought it would be.

Regards
Hugh
 

·
Registered
Joined
·
1,502 Posts
What Device are you using? Bluray player? Or do you have a whole slew of things going into the receiver?

My thinking is that you could possibly use a second output from the device and run that to your second receiver.

I'd like to know more about your setup as well. What speakers, what receiver.

In my early days I think I fried something learning the hard way.
 

·
Registered
Joined
·
3,500 Posts
We think the speaker is not getting enough power because previously using the unused stereo amp, it sounded fine.
But using the receiver, it sounded as if it is muffled.
Does your current receiver have a room calibration (auto EQ) system? If so, try bypassing it – it could very well be the problem.

Regards,
Wayne A. Pflughaupt
 

·
Registered
Joined
·
103 Posts
Discussion Starter #7
@trilkb
"In my early days I think I fried something learning the hard way." Is exactly what I wanted to avoid :D
@donktard @trilkb
The amp is Carver TFM15
The receiver is yamaha RX-V565
Speaker is an old one from infinity systems. Cant figure out the model number.
@wayne
The receiver has a basic EQ but is not in use.
When I say muffled sound, I was standing in front of the speakers.
 

·
Registered
Joined
·
3,500 Posts
Have you checked the tone controls? Maybe the treble has been turned down. Unfortunately, these days basic tone controls are buried in menus.

Alternately, if you have manual EQ, you could use it to boost the high end.

If none of that helps, I’m with Auger on the blown tweeters.

Regards,
Wayne A. Pflughaupt
 

·
Registered
Joined
·
1,564 Posts
Thanks for the reply Wayne.



We think the speaker is not getting enough power because previously using the unused stereo amp, it sounded fine.

But using the receiver, it sounded as if it is muffled.



I think we need to digest the rest of your post. It sounds more complicated than we thought it would be.



Regards

Hugh

Not sure you really need to do this but if you do the easiest way is to stop at a car audio place and buy a $20 converter from speaker level to rca. Not the best plan for hifi but just throwing it out there. These probably can’t handle many watts but I did this many years ago to hack together a sub amp from an old receiver, a car crossover, and a large sealed cylindrical sub made from a vinegar drum from my local bbq sauce plant. Before I knew about avs back in college. Had an 18” Rockford driver and was actually pretty legit per dollar invested.


Sent from my iPhone using Tapatalk
 

·
Registered
Joined
·
3,500 Posts
Not sure you really need to do this but if you do the easiest way is to stop at a car audio place and buy a $20 converter from speaker level to rca.
That option worries me. Car head units don’t put out more than what, 10 watts or so? I’d be concerned that a typical 100-watt AVR would fry the thing.

Regards,
Wayne A. Pflughaupt
 

·
Registered
Joined
·
1,564 Posts
That option worries me. Car head units don’t put out more than what, 10 watts or so? I’d be concerned that a typical 100-watt AVR would fry the thing.



Regards,

Wayne A. Pflughaupt

Yes but in reality I doubt it’s fed more than 20 Watts. The metra says it can handle 50w, idk it worked okay for me at reasonable loud levels (not avs, I need my better meter than can measure jet turbine levels) and probably in real usage it would be able to handle some peaks above etc.

https://www.bestbuy.com/site/metra-two-channel-line-output-converter-black/1265702.p?skuId=1265702&cmp=RMX&extStoreId=547&ref=212&loc=1&ksid=96a82a8e-6029-487d-82fa-93617906c90d&ksprof_id=18&ksaffcode=pg196730&ksdevice=m&lsft=ref:212,loc:2

But op as others have mentioned you might have a damaged speaker But please test and rule things out. If it worked with the amp put the speaker and amp back together and confirm working or not before proceeding. You could have amp channel blown or too much eq or who knows what.


Sent from my iPhone using Tapatalk
 

·
Registered
Joined
·
103 Posts
Discussion Starter #13
Ok. Good advice @All. Thank you.
We will try to figure out first if the tweeter is blown.
Didnt consider this previously since both Left and Right sounded underpowered.
Thank you @All
 
1 - 13 of 13 Posts
Top