DS DAC Sr -> RCA -> BHK 250 - very noisy/hum

Anyone with this setup experience hum/noise feeding Saga into BHK 250? Mine is experiencing loud hum coming out of the speakers, even with the DAC off, saga volume at zero.

Looks like the saga isn’t compatible with BHK 250 some how?

You might want to browse through this so that other more experienced people on this forum than me can help you troubleshoot :slight_smile:

I isolated the problem to the DS DAC. The hum comes from the DAC even when it’s powered off (rear switch), using single ended connection to the amp, I get the hum, disconnect them remove the hum. Using ground lifter plug on the DAC removes the hum.

What should I do next?

Use the ground lift plug on the DAC, and enjoy the music.
Actually there is one other thing, is the DAC plugged in to a different wall socket?
If so, get a good power strip or a Dectet, even better would be a power regenerator.
If the DAC is on a different circuit you have a ground problem with one of the two.
Even with my whole front end plugged in to a Dectet, I still have to use a ground lift on my phono preamp’s separate power supply, which is a battery charger.
Does the humming stop when you bypass the Saga? It is unusual for two PSA components to have a ground issue. If it is still there when you run the DAC straight to the amp, and they are on the same circuit, I would call PSA’s customer service.

Both the DAC and Amp are plugged into the P15. No saga in the loop, just DAC -> Amp direct. Even with the DAC hard power off, I get hum from the amp. Nothing else is connected to the DAC except the two RCA cables.

I’m updating the title to not place the blame on Schiit.

From experience your only real options are to either use balanced cables between the DS and the BHK or lift the ground on one of them and the DS is the best option. I found that to be the case with three different preamps even before I owned the DS and Fremer found the same when he tried to use the SE Dartzeel preamp with the BHK amps in his review. He had to lift the ground. The BHK amps just don’'t like SE cables in some home enviroments. He was using the Niagra 5000 at the time of the review.

So it’s the amp issue? I guess I should contact PSA to find out. I just wanted to make sure they’re OK or get replacement if not.

Any recommendation on cable with removable ground pin?

Do you mean power cable with removable pin? I think the PS cables do, don’t know any others. The cheater plug does the same thing for less than a dollar.

I found this statement from Michael Fremer BHK 300 review:

Setup Note
Though the BHK Signature 300s are fully balanced, I ran them single-ended, from my single-ended reference preamp, the darTZeel NHB-18NS. Everything was plugged in to my single, dedicated AC circuit, but I ran into a hum problem—which, in my system, happens only with some balanced amps that are being operated in single-ended mode: Keep that in mind if you run single-ended and are considering the BHKs. Cheater plugs took care of the hum, and I was subjected to only occasional lethal shocks (kidding).

Got me wondering why PSA design it like this? a flaw within the design, why even bother with SE inputs if they’re no good. Even more perplexed, this happens with their own DAC. Sorry for the rant, but even fanboy get get annoyed/dissapointed sometimes too.

The products were designed by two different people, and even though it should have been discovered, it may not have happened in their testing.
I wouldn’t consider an amp that didn’t have single ended inputs, as my Conrad Johnson CT5 has only single ended outputs.
Some of the PSA power cords had ground posts that could be unscrewed.
Just call PSA if it concerns you, otherwise lift the ground on the DAC and don’t worry about it.

Pretty disheartening for me, I was excited of getting a turntable, but going single ended into BHK250 produces hum from my Schiit Saga preamp (not schiit fault as I’ve demostrated even with DS Sr DAC direct, I get hum). I got my turntable setup, but can’t listen to it, I have no other preamp or amp to try… I already emailed PSA, if I need to send in my BHK, this would be the 3rd time. Granted, the other times are due to cosmetic issues, I never tested the other amp with single ended, I should have.

Not sure why putting a cheater plug on the amp prevents you from using your TT. At this point from my experience the options are pretty simple. Either a new preamp with XLR outputs or the cheater plug unless Jensen makes a device that will resolve the issue.

You are using a pair of $7.5k amp, a $6k DAC, and a $350 preamp. If I was you, I would look for a used Audio Research preamp. They are balanced, and even if the Schiit is great for the money, it isn’t 10x better.
But in the meantime, use the cheater plugs on the front end gear. If you are concerned, use the remotes.


From my experience the preamp doesn’t even need to be fully balanced but only have a pair of “convenience” XLR outputs to stop the hum. When I first received the 250 I was using the Modwright LS-100 with SE inputs to the Odyssey Kismet so I just put one amp in for the other with the SE cables and got the hum. I had to use the cheater plug until I could borrow a pair of balanced cables and found out that the “convenience” XLR output on the LS-100 was enough to stop the hum. I then ordered an XLR cable to match the others in the system.

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Was this with single ended RCA? If it was I would defintiely try some balanced cables before sending your amp back to PS Audio. For the cost of shipping you could easily buy a set of Mogami balanced cables (Guitar Center used to carry them) or get a used set of Kimber Hero or similar lower end name brand cables. As for the Saga (had to look that up since it lost context when the thread title was changed), you do realize Schiit makes a balanced preamp, the Freya for $649, don’t you? I can’t attest to it’s performance, but given the rest of your system a balanced preamp is highly recommended.

Thanks for the recommendation guys. I’m waiting for PSA to response to my email. I wanted to make sure PSA official position is to use cheater plug before using it.

I know Schiit offer Freya, but to my ears, Saga is so much better, much cleaner.

Hi Jeffstarr,

One thing nobody has mentioned is to short pins 1 to 3 in the XLR inputs of the power amps and preamp inputs when using the unbalanced RCA inputs. This may or may not stop hum but is good practice to ground the unused phase input of the amp and preamp when using the unbalanced inputs. Make a U shaped piece of #12 or 14 bare house wire with the legs of the U so formed to be about 3/8" long. One has to futz with the distance between the legs and their being parallel to get it such that it just pushes into the female sockets of the connectors.

Now the other thing that has been talked about is to use a cheater plug on one or more of the components. I never worry about the safety issue as long as one piece of gear in the setup is third wire grounded.

When I was experimenting with the prototype of the upcoming BHK Phono Preamp that has XLR balanced and unbalanced inputs, I was using the unbalanced inputs with the unused input not grounded. The hiss noise level at playing volume was pretty low but when I grounded pin 1 to 3 in the XLR inputs, the hiss noise vanished to very low levels. So ground the unused phase of XLR inputs with the above mentioned shorting links.


BHK, all of my preamps have been single ended only. I do recall seeing something about shorting plugs on the back of amps I was looking at online.
I appreciate you giving the OP some expert advice, as I am not knowledgeable enough to give that advice.
I do know the risks of using cheater plugs on front end components is usually nothing to worry about.

falling_leaves, you have now heard from the man who designed your amp. That should put your mind at ease. I would certainly try his recommendation on shorting the XLR socket. Just be sure you know which pins are 1 and 3.

The competition from Auburn, CA mentions the use of RCA vs XLR inputs in all of their user manuals. They even supply each amp with two gold (plated) jumpers to short XLR pins 1 & 3, that they replace for free in case you loose them.