Soundstream ref 414s Problem

[mrFrog]

Hello everyone, found plenty of useful information on SoundStream amplifier problems and thought I'd add mine to the mix

It's a reference 414s, and I have diagnosed two problems:

-RCA input grounds and signal show 10V difference with amplifier ground.
-3 of the 6 RCA grounds are common, the other 3 are open circuit from each other.

Any help much appreciated
Greg

[Perry Babin]

Have you checked with soundstream to see if a schematic is available?

If 2 of the RCAs that are common are outputs, that may be normal. One RCA input ground and the two outputs may be connected directly to the secondary ground. The other 3 inputs may be isolated with a 1K ohm resistor.

The 10v offset could be due to an open/missing resistor that connects the secondary ground to the chassis ground (if I'm not mistaken). It may connect the secondary ground to the signal ground. The schematic would be very helpful here.

[mrFrog]

Hi Perry,

thanks for your response.

I have emailed Soundstream tech-support and not got a response yet. I described the problem and asked if they knew what it could be.
If they respond, I'll ask for schematics.

On the subject of RCA grounds, there are four input terminals (2 channel left+right) and two line output terminals for daisy-chaining amps - so six sockets in total.

Three of the input socket grounds are common, the fourth appears "unconnected", it's an open circuit as far as I remember.

The remaining RCA input and two outputs don't appear to be connected either.
The two outputs don't even share a ground

Have you taken a soundstream amp apart ? I have only gone as far as the casing and not taken the PCB off the main heatsink.

There is a conductive material where the transistors touch the heatsink, I am worried that taking the whole amp apart will disturb this. Any thoughts on putting the amp back together properly would be appreciated

Thanks again
Greg

[1moreamp]

If you have 10 volts on your RCA shield you have some real issues in that amp. I am sure the 10 ohm secondary to primary ground resistor is burnt up. But still you should not be getting anything over 500 millivolts when referenced to ground of 12 volts.

I would say by your info that there is some damaged components in one or more of the channels causing this. And all the RCAs shield should read zero ohms between each other, so there maybe a issue there also.

These are symptoms of a more complicated issue inside the amp. You must find the main issue fix that, and also fix the symptoms that the original problem has caused.

SS should release the print to you , I have seen them do that before. If not contact jandrelectronics on e-bay. Jaime worked for them for years, he also has parts.

Good luck and cheers

[Perry Babin]

The outputs should definitely share a common shield ground. Recheck the connectors to be sure you have the correct readings. You need to check this on ohms, not diode check.

The kapton film is tough and difficult to damage. Try not to lift it. If you do and debris gets in the area under any of the heatsink mounted components, you'll have to remove it, remove all of the old heatsink compound and apply new compound.

When you remove the board from the sink, you need to screw all of the set screws down before lifting the board. When reassembling it, you need to make sure all of the LEDs are in their holes. It's annoying to find that one didn't fall into place AFTER you've reinstalled all of the screws.

You'll also need to check all of the switches for intermittant operation before reassembling it.

There may be one washer (holding the board to the sink) that has a rubber insert. If so, it needs to go back in the same location.

[mrFrog]

Thanks again for the input guys

No response from SS yet

I have disassembled the amp again for a closer inspection, and can't see anything obviously burnt/broken/etc...

Where would the 10ohm resistors you mention ? Close to the power supply ?

I'll try the chap you have mentionned on eBay

Thanks again.

[mrFrog]

Originally posted by Perry Babin
The outputs should definitely share a common shield ground. Recheck the connectors to be sure you have the correct readings. You need to check this on ohms, not diode check.

I used the ohm setting indeed

Also remembered, someone on another board mentionned fuse resistors, these can go and are synonymous with 10V on RCAs... Is this something you've heard of before ?

[mrFrog]

Well,

I've left a message on eBay for jandrelectronics and phoned soundstream tech support who are sending me diagrams

We may have some progress (fingers crossed).

[Perry Babin]

If your amp has the 10 ohm resistors (not all do), they could be anywhere on the board but are likely to be along the line where the power supply section meets the audio section. They are generally 1 watt resistors.

Did you re-check to see if you had the inputs and outputs conused? It's VERY strange not to have continuity (~0 ohms) between the shields of the output RCAs. Test continuity between the frames of the RCA connectors (the metal part that the threaded barrel is pressed into). Sometimes the threaded part has a poor connection to the frame.

Are they sending the schematics via snail mail or email?

[mrFrog]

Originally posted by Perry Babin
If your amp has the 10 ohm resistors (not all do), they could be anywhere on the board but are likely to be along the line where the power supply section meets the audio section. They are generally 1 watt resistors.

I'll have a look again tonight.

Did you re-check to see if you had the inputs and outputs conused? It's VERY strange not to have continuity (~0 ohms) between the shields of the output RCAs. Test continuity between the frames of the RCA connectors (the metal part that the threaded barrel is pressed into). Sometimes the threaded part has a poor connection to the frame.

The two RCA out are grounded together with one RCA in. The other three RCA in are not connected
I have tested continuity on the circuit board, as well as the barrels.

Are they sending the schematics via snail mail or email?

email, sent an email at 15:50 Californian time yesterday, kind of hoping for an immediate response since I spoke to the chap only minutes before, so far, no reply