Broken AMP or Wrong Cabling Solution....need help, no sound

jwl

Hello,

This was supposed to be simple. My goal is to use the Polk speakers I have and control the sound from the computer. It is not working and I need some help to figure out why. I have done some tests (see below) and I think it is one of several things.

1. Bad AMP
2. Bad Speakers
3. Problem with the configuration
4. Missing component or substandard component


Here is the equipment I am using (I pasted links to manuals below)

Polk Monitor 40 Series II
Polk PSW10
Adcom GFA-535--UPA-200 would replace this amp
HT Omega eClaro (PC sound card)

I also have a Klipsch Promedia dd 5.1 (pre-amp decoder) and a DVD/CD player I use to test with.

Here is how everything is connected (Would the same connections would hold true for the UPA-200?)

3.5mm-to-stereo RCA cable connects L/R output from sound card to RCA inputs on Adcom
Speaker cable (12 AWG) from the GFA-535's outputs to the speaker-level inputs on the PSW-10
Speaker cable from the speaker-level outputs on the PSW-10 to the Monitor 40s



Tests I ran

1. I know the sound card works because I can hear sound through computer speakers.
2. Tried connecting Adcom directly to monitor 40s - no sound
3. Connected DVD player (and played CD) to Adcom - no sound
4. I placed a Klipsch Promedia DD 5.1 between the sound card and the AMP (connected with different RCA cables) - nothing.
5. Then connected the DVD/CD player to the Klipsch (which was connected to the AMP) - again, no sound.
6. The last test, I kept the DVD/CD connected, but then connected the AMP to the speakers (skipping the sub). Still nothing


I have never used the Polks or the Adcom before, so I do not actually know if they work. I know the Klipsch works fine ? had it connected to something else. I am not sure if it is sufficient to supply the AMP (I have no idea how to match requirements between an amp and pre-amp). The sound card works (test 1).

Thanks,

J

Manuals

Polk Monitor 40s: http://ec1.images-amazon.com/media/i3d/01/A/man-migrate/MANUAL000074437.pdf
Polk Sub: http://www.polkaudio.com/downloads/manual/PSW10_12_MN.pdf
Adcom GFA-535: http://www.adcom-usa.com/userguides/gfa-535-ug.pdf
HT Omega eClaro: http://www.htomega.com/filedown/eclaro.pdf

klipsch dd5.1:
http://www.klipsch.com/promedia-dd-5-1
http://www.themusichelpers.com/z/248061100000001

tonyb

My guess is one of 2 things. Either the amp itself is not working or the computer doesn't have enough line voltage to drive the amp. If you have a cheapo receiver with preouts laying around, take the computer and the sub out of the equation to test the amp. Connect a cd player to the receiver, preouts to the amp and speaker cables from the amp to the speakers. I understand you tried just the cd player to the amp, which should have worked at a very loud volume considering in that configuration you have no volume control.

Also, what rca cables are you using for these connections ? It seems to me if your goal is to just play audio from the computer to the Polk speakers, you can get by with a cheapo receiver instead of an amp. Return the amp while you still can, if you can, and hit your local craigslist for a 50 buck receiver.

jwl

The problem with a reciever is that I lose control of the volume and muting from the computer.

I put a pre-amp (the Klipsch ProMedia dd5.1) between the CD and AMP which does have a volume control - still no sound (also tried putting pre-amp between computer and AMP - no sound. I am not 100% sure the pre-amp is adequate for this task (I have no idea how to match pre-amps with amps or even if this is a consideration).

The RCA cable between the computer and AMP (or preamp) is a monoprice 3.5mm to L/R RCA. The cable from CD to AMP, was a Radio Shack L/R RCA to L/R RCA - bought it the other day for testing. All the other cables are 12 AWG CL2 monoprice speaker wire with the appropriate connectors for the device (bare wire, pin and banana).

F1nut

You should test all the monoprice, known to be DOA.

jwl

I eliminated the pre-made cable from being the issue in the CD test. The other cables were made by me from wire. I tried both with ends and bare wire. Unless the wire within the entire length of the cable is bad, I thinking I should have heard something. I am not sure how I would test the bare wire (I do not have any more equipment than what I listed). Is there such a thing as a wire tester?

Syndil

A multi-meter can test continuity in wire. Should have a setting for it. Usually the lowest measurement in Ohms (200) will beep if there is continuity.

This might help:

http://repair2000.com/resistance.htm

nwohlford

Is the Adcom GFA-535 the original version with the twist speaker connections? If so, 12 AWG may not fit that well in it. I assume that none of the yellow lights on the front of the Adcom are on. (If this is the original 535, also check the A/B speaker settings on the front.)

I would check hooking the sub directly up to the computer out (or your other sources) with rca cables. You should at least get some sound this way.

jwl

It is an original Adcom GFA-535 with the twist connections. 12 AWG seems to fit fine - goes in all the way and locks fine. I will have to try the RCA cable from the card to the sub. I was not sure if that was a good idea or not because the manual suggests that it is either/or type decision (between input/output and RCA connection). I am assuming there is no risk to trying?

nwohlford

jwl wrote: »

It is an original Adcom GFA-535 with the twist connections. 12 AWG seems to fit fine - goes in all the way and locks fine. I will have to try the RCA cable from the card to the sub. I was not sure if that was a good idea or not because the manual suggests that it is either/or type decision (between input/output and RCA connection). I am assuming there is no risk to trying?

I am saying just hooking up the sub directly to the sound card with nothing else hooked up just to confirm you can at least get audio out of the sound card and that the sub works. I would turn the volume all the way down on the sub and slowly turn it up until you hear sound.

Have you tried both the a and b speaker connections on the Adcom? Make that the corresponding button is pushed in on the front.

Syndil

Doh I forgot about the A/B on the 535.

jwl

Got a hold of a receiver and proved speakers, sub, setup and cables work...the AMP is the only thing left and must be the problem. Thanks for your help

tonyb

So just use the receiver then, you can still adjust volume by the computer. I don't see the problem here.

Syndil

Buying an amp from eBay that arrives DOA is a problem.

Hope you are able to get it resolved without too much headache, jwl.