My turntable hates subwoofers

[Dure16]

I upgraded from a Technics SL-Q200 to a Realistic LAB-420 and lost all subwoofer output. My speakers still play the content but my subwoofers sit there doing nothing.

I have done all the troubleshooting I can think of and hope someone here has more ideas I can try.

The problem

• No subwoofer output when listening to Realistic LAB-420 turntable as the source
• Entire system works perfectly with all other sources (Spotify Connect, 4K player, etc.)
• Denon settings for phono input are identical to other source inputs (speaker preset, crossovers, LFE handling, etc)
• Denon decoding set to "stereo" with Audyssey turned on

Troubleshooting completed

• Cleaned vinyls
• New stylus
• Verified headshell / cartridge wiring is correct
• Swapped back to Technics turntable (with no other changes) and the entire system works properly, including subwoofers
• Connected both TTs to external phono preamp and then to non-phono Denon input (Technics worked properly, Realistic still had no subwoofer output)

Equipment list

• Realistic TT cartridge: Shure R47XT
• Denon X3800H
• Parasound HCA-1000A
• MiniDSP 2x4HD (MSO & 20Hz HPF for TT rumble)
• KEF R7M & R6M
• SVS SB-2000 (dual)

 

[Chrispy]

Unlikely the issue is because you changed tt....still just the same analog inputs into the Denon, right? It worked fine before with same type of source, so much more likely in the Denon and associated gear settings. Might want to confirm what they are.

Have you tried a soft reset of the Denon (i.e. unplug it from power for a bit)? Maybe even consider a full microprocessor/factory reset.

 

[AaronJ]

I’m not sure what would cause this but I can think of a couple other things to troubleshoot.

The Realistic TT has built in RCA cables. Could be some issue with them or the tonearm wiring. Did you confirm operation with the previous owner?

Doesn’t seem to be a cartridge and tonearm mismatch. The Shure cartridge is high compliance and would prefer a low mass tonearm, lower than your TT’s tonearm. But if it works with the Technics it should not be an issue.

Could be some other mechanical issue with the tonearm though.

 

[Chrispy]

I’m not sure what would cause this but I can think of a couple other things to troubleshoot.

The Realistic TT has built in RCA cables. Could be some issue with them or the tonearm wiring. Did you confirm operation with the previous owner?

Doesn’t seem to be a cartridge and tonearm mismatch. The Shure cartridge is high compliance and would prefer a low mass tonearm, lower than your TT’s tonearm. But if it works with the Technics it should not be an issue.

Could be some other mechanical issue with the tonearm though.

How could it be the tt/cartridge/cabling if he still gets 2.0 audio (he's missing 2.1).

 

[kyuu]

Given the description, either something is changing that isn't being taken into account or there's an issue with the TT that is causing it not to play back low frequencies that would normally get routed to the subwoofer.

Is the OP absolutely sure that nothing else in the setup is changing? The exact same inputs are being connected to with the exact same cables? If not, what precisely is different when you are connecting the Technics versus the Realistic?

 

[Laika2]

Are you in Direct, you need to be in stereo? I have a 6800,6700 and a Marantz 8015. The only way for me to get 2.1 is stereo. If it does not show back up receiver settings to USB, full factory reset, install backup. Common sense would be don't back up when the receiver is not working properly but I have done this many times and the backup works, it does not seem to back up glitches.


MY BAD, I see you use stereo, back up, factory reset, restore backup.

 

[kyuu]

Are you in Direct, you need to be in stereo? I have a 6800,6700 and a Marantz 8015. The only way for me to get 2.1 is stereo. If it does not show back up receiver settings to USB, full factory reset, install backup. Common sense would be don't back up when the receiver is not working properly but I have done this many times and the backup works, it does not seem to back up glitches.

The OP specifically stated they are using the stereo setting with both setups. I would assume the OP is not changing settings between the two setups and then wondering why it's working differently, but it wouldn't hurt to triple check to make sure.

 

[Laika2]

The OP specifically stated they are using the stereo setting with both setups. I would assume the OP is not changing settings between the two setups and then wondering why it's working differently, but it wouldn't hurt to triple check to make sure.

Caught it before you corrected me. 99% factory reset and usb restore will work. I've lost sound fields on all 3 units a few times or they did not function properly. It always worked.

 

[Chrispy]

Caught it before you corrected me. 99% factory reset and usb restore will work. I've lost sound fields on all 3 units a few times or they did not function properly. It always worked.

I've cleared glitches with just the soft reset, too, which is easier to do and would start with that before going the full reset route.

The thought about low frequencies being so limited I'd think would show up in 2.0 playback somewhat as well, but it was mentioned the minidsp is using a high pass filter down low....did that change somehow?

 

[kyuu]

Caught it before you corrected me. 99% factory reset and usb restore will work. I've lost sound fields on all 3 units a few times or they did not function properly. It always worked.

Yes but if it's a simple glitch with the Denon, why does it work fine with the other TT? The fact that it's only an issue with one of the TTs seems to indicate the issue is with the TT itself or something that's changing between the two setups, and the Denon only having a glitch with one and not the other seems unlikely.

 

[Laika2]

Yes but if it's a simple glitch with the Denon, why does it work fine with the other TT? The fact that it's only an issue with one of the TTs seems to indicate the issue is with the TT itself or something that's changing between the two setups, and the Denon only having a glitch with one and not the other seems unlikely.

I agree. Everything seems unlikely here. Hard to see why 1 table works and the other does not, either direct or phono preamp, with just RCA hookups either way? I'm lost, I can't see the issue being the cartridge, even if damaged. It would be very odd for the cartridge only sending a signal above 80 or wherever the crossover is set. (Equally odd that it's the Denon since the same inputs are used.)

 

[Chrispy]

Yes but if it's a simple glitch with the Denon, why does it work fine with the other TT? The fact that it's only an issue with one of the TTs seems to indicate the issue is with the TT itself or something that's changing between the two setups, and the Denon only having a glitch with one and not the other seems unlikely.

How could a "glitch" (odd term for a simple analog device like a tt) work in 2.0 but interfere with the downstream gear converting it to 2.1?

 

[kyuu]

How could a "glitch" (odd term for a simple analog device like a tt) work in 2.0 but interfere with the downstream gear converting it to 2.1?

Huh? I think there's a misunderstanding. I'm using the word "glitch" only in reference to the Denon AVR, not the TT.

 

[Labhound]

Did you check the wiring from the headshell connectors on the tonearm to the end of the hardwired RCAs on the Realistic. Could it be out of phase?

 

[Laika2]

Huh? I think there's a misunderstanding. I'm using the word "glitch" only in reference to the Denon AVR, not the TT.

I understand, I'm looking at the trouble shooting here and process of elimination and it's hard to see the Denon at fault but also the TT, which elimination points to as the issue. Hard to see how the TT is not sending a full signal, the fact that it does not work with the denon phono input or a separate phono preamp both fail to trigger the sub but all else does makes me think cartridge but I can't think of a reason why. Hence the all encompassing glitch comment, referring to a repeatable unknown unidentified problem.

 

[Chrispy]

Huh? I think there's a misunderstanding. I'm using the word "glitch" only in reference to the Denon AVR, not the TT.

Yep took it the other direction.

 

[Chrispy]

I understand, I'm looking at the trouble shooting here and process of elimination and it's hard to see the Denon at fault but also the TT, which elimination points to as the issue. Hard to see how the TT is not sending a full signal, the fact that it does not work with the denon phono input or a separate phono preamp both fail to trigger the sub but all else does makes me think cartridge but I can't think of a reason why. Hence the all encompassing glitch comment, referring to a repeatable unknown unidentified problem.

All the Denon and downstream gear can do is take the 2.0 signal and convert to 2.1 (or more speakers). If the 2.0 signal is coming thru it makes no sense that it is the source of the issue. Am I missing something?

 

[Laika2]

All the Denon and downstream gear can do is take the 2.0 signal and convert to 2.1 (or more speakers). If the 2.0 signal is coming thru it makes no sense that it is the source of the issue. Am I missing something?

Likely not, all I can say is I lost a sub once (6700) and a reset and restore fixed it, that was on all analog inputs though, digital sources were fine. The only way I can see the source is the table is there is no signal below the crossover to trigger the sub which also makes little sense.

 

[Chrispy]

Likely not, all I can say is I lost a sub once (6700) and a reset and restore fixed it, that was on all analog inputs though, digital sources were fine. The only way I can see the source is the table is there is no signal below the crossover to trigger the sub which also makes little sense.

Yes, there are glitches with avrs, they're just another form of computer. I've fixed a few on a variety of Denon avrs with a simple soft reset, too. I didn't even think about a signal for triggering the sub, I don't use such.

 

[AaronJ]

How could it be the tt/cartridge/cabling if he still gets 2.0 audio (he's missing 2.1).

It’s an odd problem and seems the obvious tests have been done. Vintage turntables are not complicated I’d open it up and see what’s going on inside.