SB3 volume output lower on left than right channel

[fieldwolf]

thanks Ralphy.

Just to confirm - I went ahead and bought a cheap DAC off Ebay (£10) which came with Toslink optical cable. That has fixed my L/R balance problems.

I don't believe the sound quality is as rich as it was before which is probably due to the budget DAC I purchased.

I'm going to give the soldering the caps solution a go and will report back.

[lemmy999]

I know some have talked about it being difficult working with surface mount devices, but to be honest, I find it much easier than through hole parts. If you can obtain two soldering irons, just put one on each side and the capacitor will come off very easily. Good luck.

[mgraves]

Three of my five SB3s now have this problem. I've responded thus far by adding a cheap ($20) outboard DAC in one case. In another case I purchased an SMSL amplifier with digital inputs to power some speakers on our front porch. Nether are truly HiFi solutions, but adequate for the situations they address.

I'm considering an external DAC from Shiit Audio, or just getting inside to make the repairs on the third SB3.

With five SB3s still running converting to any other system is prohibitively expensive. I'd like to keep these going as long as I can.

[DonnLaurent]

Can you please share the specifications of your SB3?
What are the components for its hardware and what interface it uses for its channel?
What is its capacity to drive the channel in terms of devices and the Output current?

pcb manufacturer

[klotz]

SB3, Willy 230050630, right channel is very low. Jumpering C16 alleviated the problem, at least for one channel in the headphones. But I get no output now. Ordered some replacement electrolytics.

Also, all the though-hole pins had white bloom from the flux. I touched up the pins and scraped away the flux in most places, but I think it's not a high-impedance path anywhere anyway.

-- update --

Replaced the caps with similar ones, factory polarity. No longer crashes, but I have low audio in the right channel of my tube amp still, clearly unrelated.

[mgraves]

Over the holidays I came to own a Shiit Modi 2 Uber DAC. This overcomes the trouble with the analog outputs of one of my SB3s quite nicely.

I do think that I'll eventually go inside my remaining SB3s and replace the output capacitors.

[TP96]

Over the holidays I came to own a Shiit Modi 2 Uber DAC. This overcomes the trouble with the analog outputs of one of my SB3s quite nicely.

I do think that I'll eventually go inside my remaining SB3s and replace the output capacitors.

I wanted to thank everyone for helping me fix my SB3. I ended up using some non-polarized surface mount caps that fit perfectly. Here is a pic of the parts which cost $1.80 each when you buy 10.

[ralphy]

I just replaced the capacitors in my SB3 as well.

See the SB3 common faults over time thread for details and pictures.

[raichea]

I tried to switch on my SB3 a couple of days ago and the display didn't show anything. From the server, it looked as though everything was working as expected, but there was no sound even though the player was playing according to the web interface.

A quick google threw up the power supply as a possible candidate for the display issue. I took some measurements and the voltage held up reasonably well, even under load, so I was dubious. A known good supply brought the display back to life, however.

Assuming I was now up and running again, I then realised my SB3 had another fault. The left channel was much quieter than the right. I've no idea whether the power problem precipitated this other fault, but I hadn't noticed it before so it's a possibility.

Thanks to this thread, I was able to home in on the probable cause quickly. Measurements indicated that C20 had failed. Having tried a quick fix with a regular electrolytic and determined that was the problem, it also highlighted that the right channel was quiet compared to the now fixed left channel so C16 needed replacing too. I decided that as C21 and C23 are subject to similar waveforms, they may be on their way out as well so I decided to replace all four. I removed the headphone socket to make accessing C21 and C23 less difficult.

The hardest part is getting the old capacitors off the board without damaging the tracks. I managed to lift one track but, fortunately, it didn't break... certainly a potential weak spot now though. Someone recommended having two soldering irons to release both sides of the capacitor at once and this would definitely be less risky to the tracks, if it bit tricky with only two hands. Getting the headphone socket off was a bit fiddly, but easy enough with judicious use of a solder sucker.

I selected these capacitors as replacements - http://bit.ly/2ehag7K - as their endurance rating was better than most.

Thanks to those who came before me - it made fixing this a whole lot easier than it might have been.

I've attached the existing schematic updated with the SB3 component numbers. Note that the dual opamp has had each opamp reassigned to the opposite channel compared to the SB2 schematic.

Raichea

[vinnielo]

I've attached the existing schematic updated with the SB3 component numbers. Note that the dual opamp has had each opamp reassigned to the opposite channel compared to the SB2 schematic.

Raichea

Thanks for this amended schematic.
It made life easier when a bit of soldering work didn't quite go to plan.