Background hiss on my BSG 6champ

[smata67]

Looks like no one has mentioned this one. I get a noticeably hiss sound out of the speakers even when I don't have a source hooked up. Is this common?

[Marbles_00]

Though you shouldn't hear a hiss (unless it's part of a soundtrack), regardless if the source is connected or not. The fact that a source is not connected there could be a fault with the amp. Though it shouldn't make a differece, are the gains for that channel set too high (even if the gains were set to max, under good conditions, it should be silent if a source was not connected)?

It could be high frequency interference, which may indicate that a small filter cap is either missing, blown, or just not performing to spec (which would be very difficult to determine...which cap?). If it is only happening in one channel at least your then isolated to looking at that specific circuitry. Though very tedious without schematics, you could trace the signal path back from the terminals and inspect all the components by comparing to one of the adjacent channels.

If the hiss appears as the amp warms up, then it could indicate a cold solder joint. That would require looking over the whole solder job on the circuit board...another tedious task.

You may be better off getting in touch with etom and see if you can just replace the amp. Or, this sucks even more, just not use that channel.

Man, I feel for ya. Wish I could be more helpful. Times like this I'd would much rather see a puff of smoke and that great odour of electronics burning smell...then at least the troubleshooting is easy...just look for the blown up part.

[smata67]

Yeah, its disappointing, I really like the feel of the unit, got it yesterday. I have a single speaker connected and it is bridged over to the second channel for 60W. Sounds good. Gains are turned all the way up. At normal listening level and 3/4 bass and full treble setup, I can hear the hiss between tracks, not just a little, too, but like the background hiss on a cassette tape. I have an email into Etom to see what he says. Will post his reply.

[Marbles_00]

Well, you got me thinking. Currently I'm just using the AIP and one stereo pair. I guess my weekend will be to try the other channels and the other amp I have to verify that both amps are working correctly.

[smata67]

I moved the speaker connections to Channel 1 only with no change, still hissing. Disconnected the pre-amp, hiss is gone. Turned down gain to 1/2 way, reconnected preamp hiss is back. Looks like the pre-amp is causing it. Also, my red light does not come on when powered up (on the preamp). It does blink though, when the amp is switched off. Is the red light coming on when your amp is switched on? RJ-45 power cable and contacts look fine.

[scottw]

I don't think the red light works on any of them but the preamp still works.

[sharp_1]

Scottw is right, none of the preamp lights work.

I do have a hum in my amp too and have been trying (with Marbles help) to find a ground loop somewhere. Maybe thats what you're hearing too?

[smata67]

No, it is a definite hiss sound, like when TV stations used to be off the air (if you are old enough to know that sound). Etom was not very helpful, I emailed him again, I might want to try or even purchase another pre-amp, I like the case anyway. I do have some other preamps to try, but I'd have to modify the plug and they are a bit more pricey than I would want to hook up to something like this.

[scottw]

I am not using and don't plan to use my pre-amp, maybe we can work something out

[smata67]

I can't seem to PM. That sounds good to me, Scott, though I would like to hear back from Etom before I commit (is he skipping town now that they're all sold????) I'm in Alexandria, VA by the way and work in DC, so this could be easy or shipping pretty cheap. I am using my setup to power two all weather JBL N26AW speakers in the corners of my bathroom, the small footprint of this setup is working well. I'm feeding it with a portable CD player sitting on top of the preamp.

[scottw]

NP. I don't want anything for the preamp, just pay for shipping or whatever.

My email is swindmiller at gmail dot com

[Marbles_00]

If you don't want to hack the mini-DIN harness, then use one of these:

http://www.cui.com/pdffiles/MD-60PL100.pdf

They are readily available at Digi-key...dirt cheap (shipping and handling will cost you more, if these are all you buy). The wires are about 4" in length and can easily be terminated to RCA connectors. There are two tabs coming off the side of the housing for soldering returns to, which will connect to the mini-DIN shield. Then you could drill some more holes into the AIP casing for mounting this and the RCA's and have a nice little harness converter.

I bought two of them for mounting in my Maylume project enclosure.

This way, the wires are nice and short, with a good solid guage wire for return, it should be a good signal path.

[etom56]

thanks again for all of your help.you have help in selling over 260 of these amps.i do not know much about electronics so it was very helpful to read responses to understand problems that occurred with some of the sales.the real problem that i had was fraud 15 amps were reported not recieved out of one shipment of 50 in the begining. i sent out replacements.sence i am new fool to this shipping stuff i replace them at a cost of $600.00 to me.when i ask the po they told me that either they recieved or i did.i did not recieve any back.when i added ins and tracking the losses stoped.this made me a little leary of claims.i only had 5 real waranty claims to replace a couple gain adjustments broken and 2 had damage on control nobs and 1 hiss on pre amp.for this many amps this low amount was great none of us needed bad amps.when i bought these amps at the magnavox zenith tv auction i was not sure what to do with them.i wanted a couple but did not need 280 of them.so thanks to all for finding them homes.i ended up 1 pallet with over 500 of the aid or preamps extra.they would make great little project enclosures.i am not sure what to do withthem.i guess i will try them on ebay.or sell for scrap metal.i did keep back some amp kits in case of waranty.i will sell that last of them after all current shipping clears. thanks again etom56..never forget the thought of honesty..

[smata67]

For the record, Etom has kindly offered to send me another pre-amp, but I don't think that will be necessary. The hiss is perfectly acceptable given my application. Scott, I have sent you an email, would like to purchase that baby for a potential project, I only have some 500 I haven't gotten to yet.

I opened up the unit to take a look, but don't see how to add pics here. Construction looks very solid, nichicon caps. Wish I new the first thing about troubleshooting. I do have an esr meter and of course all the caps checked out A-OK.

I think those little pre-amps might make good cases for an amp project, perhaps the CMoy or maybe moving the Sonic-T into it?