[LunaticPandora]

Hi.

I am using a CXA81. Through the headphone jack in the front of my CXA81 I've got a cable that splits into red/white that I am running into the back of my Schiit Valhalla 2 through the input jacks. Through the front of my Schiit Valhalla 2, I'm plugging in my HD-650s.

I must be doing something wrong because there is so much static and popping coming through my headphone speakers you would think it was Christmas and we had the Yule logs burning!

Please help.

Sincerely,

Ol' Sennhei' Nicholas

 

[jonathan c]

To @LunaticPandora , connect the CXA81 (Cambridge Audio, right?) to the Valhalla 2 as follows: pair of interconnect cables with RCA plugs at both ends; use ‘preamp out’ sockets in the back of CXA81 and ‘input’ sockets in the back of Valhalla 2. Keep red on right. Plug HD650 in front of Valhalla 2, as before.

 

[jonathan c]

I am assuming that you want to use the CXA81 as a preamp to Valhalla 2. If you want Valhalla 2 as the preamp to CXA81, you can still use the RCA interconnect cables: use ‘output’ sockets in the rear of Valhalla 2 and ‘input’ sockets in the rear of CXA81.

 

[ProtegeManiac]

Hi.

I am using a CXA81. Through the headphone jack in the front of my CXA81 I've got a cable that splits into red/white that I am running into the back of my Schiit Valhalla 2 through the input jacks. Through the front of my Schiit Valhalla 2, I'm plugging in my HD-650s.

I must be doing something wrong because there is so much static and popping coming through my headphone speakers you would think it was Christmas and we had the Yule logs burning!

Please help.

I wouldn't do that. Headphone amp output of the CXA81 is only "amplified." Not a good way to amplify the signal, but it's amplified. Unfortunately amplifiers don't work like Gundam beam weapons. You may have a pair of fictional energy weapons that can be connected in series so your mobile-suit busting twin rifles can become a battleship-eviscerating beam cannon by summing or squaring the output, but that's not how amplifiers work. When you amplify the signal you increase the voltage, which also amplifies every imperfection in that signal and then adds its own noise and distortion, and now it's a higher voltage signal that will overwhelm the input sensitivity of the input circuit it's hooked up to - which, by the way, is what amplifier #1 will see ie a 1,000ohm++++ load - and then the second amplifier will then amplify the already too loud signal but that does NOT change how much power there actually is in the output of the second signal. It's just louder at the same knob position...but with more distortion and noise than if you had just used a 2V line output.

I'm not too keen on using the "Preamp Out" on the back either since it might be a preamplifier output, ie, the CXA81's preamp still preamps the signal. It's not just a matter of avoiding setting unity gain because it's annoying to have to, but even preamp circuits can add their own noise and now you have to find where that preamp outputs a loud enough signal without adding noise.

What source are you using with the CXA81? If you're using a CDP or music server just get a different DAC and hook it up to a different SPDIF output on the source unit, and then you only flip on that DAC when using the headphone amp.

 

[gimmeheadroom]

This sounds like Deja Vu. I'm almost certain somebody posted a complaint about this combination a while back.

 

[tomb]

I don't know ... static and popping sound like bad connections to me. If any of these connections is a 3.5mm jack, I'd suspect that first. Twist the plug and see if the static/popping changes.

 

[LunaticPandora]

I wouldn't do that. Headphone amp output of the CXA81 is only "amplified." Not a good way to amplify the signal, but it's amplified. Unfortunately amplifiers don't work like Gundam beam weapons. You may have a pair of fictional energy weapons that can be connected in series so your mobile-suit busting twin rifles can become a battleship-eviscerating beam cannon by summing or squaring the output, but that's not how amplifiers work. When you amplify the signal you increase the voltage, which also amplifies every imperfection in that signal and then adds its own noise and distortion, and now it's a higher voltage signal that will overwhelm the input sensitivity of the input circuit it's hooked up to - which, by the way, is what amplifier #1 will see ie a 1,000ohm++++ load - and then the second amplifier will then amplify the already too loud signal but that does NOT change how much power there actually is in the output of the second signal. It's just louder at the same knob position...but with more distortion and noise than if you had just used a 2V line output.

I'm not too keen on using the "Preamp Out" on the back either since it might be a preamplifier output, ie, the CXA81's preamp still preamps the signal. It's not just a matter of avoiding setting unity gain because it's annoying to have to, but even preamp circuits can add their own noise and now you have to find where that preamp outputs a loud enough signal without adding noise.

What source are you using with the CXA81? If you're using a CDP or music server just get a different DAC and hook it up to a different SPDIF output on the source unit, and then you only flip on that DAC when using the headphone amp.

Thank you Protege. Unfortunately, to decipher all of this I would need to watch a 30-part video series by Bill Nye. I had no idea what kind of Schiit I was getting myself into here. My source is my sound card: Sound Blaster AE-7 which has a pre-amp of its own. Probably I didn't need the pre-amp upgrade.

 

[silentraindrop]

Don't complicate yourself too much. You need to simplify things.
If I understand you correctly, your current setup is:
1 PC sound card (SoundBlaster) 3.5mm out to
2 RCA input(red/white) on back of CXA81(A1,2,or3)
3 CXA81 front headphone jack to Schitt, then you are amplifying the sound waaaaaaaaay too much.
This really is not ideal way to chain these devices together.

My suggestion:
1. Bypass your sound card all together. Use your PC usb to CXA81 "USB Audio" input. Then buy a RCA cable(red/white to red/white). You want to connect one side to "Pre-Out" of CXA81 and the other side to Schitt's input. Try with "Low Gain" on Schitt first, there should be no noise. If the volume is too low, set it to "High Gain".
1a. If everything works, sell the sound card.
2. If you want to include the sound card in the above chain, instead of using the usb cable, use a s/pdif cable. You will need to connect the cable to "Optical Out" on Sound Blaster and either one of the "Toslink" (D1 or D2).
Either Case, start with low volume on both CXA81 and Schitt then work your way up. (Both should control the volume unless CXA81 runs in fixed mode for pre-out), don't worry if CXA81 volume does affect headphone volume.

Alternatively to above, if you are running speakers with CXA81, you can go Sound Blaster -> Schitt -> CXA81. With this method, tube sound signature of Schitt will affect everything coming out of CXA81.

*Cables in above links are for your reference only. It will work, but may not be high(enough) standards or correct length for your application.

Hope this all makes sense. I am pretty bad at writing instructions. Good luck with your journey ahead!

 

[ProtegeManiac]

Thank you Protege. Unfortunately, to decipher all of this I would need to watch a 30-part video series by Bill Nye. I had no idea what kind of Schiit I was getting myself into here. My source is my sound card: Sound Blaster AE-7 which has a pre-amp of its own. Probably I didn't need the pre-amp upgrade.

Actually my point is eliminating multiple preamps and headphone amps in the signal chain, not upgrading any one of them but just replacing all of them for a simpler circuit.

Try a Modi3 and an SPDIF splitter. Hook up the SPDIF output of the AE-7 (or your motherboard if it has one if you're not using the processing on the AE-7) to the splitter. Connect the splitter to the CXA81 and to the Modi3, then the Modi3's fixed voltage analogue output to the Valhalla2. Now you only have one preamp and one amplifier circuit on the speaker as well as the headphone signal chain.

"But why do I have a big speaker amp and not use the ports?" Because it has the wrong ports. Just because old amps like that would have a Tape Out that can go to another amp doesn't mean the Preamp Out on the new amp is the same as the old amps' Tape Out as opposed to being like...ya know...the Preamp Out on old amps. And just because it's called "Tape" doesn't mean it only works on recording tape decks - it just means it will just reroute the input signal that would otherwise have to pass through the amp's preamp first. Which is what the Preamp Out usually does, which is why it's called a Preamp Out. Because it's coming out of the Preamp.