Setup: Turntable → Phono Preamp → PC Line-In
Turntable: Sony PS-LX56
Phono preamp: Behringer PP400
PC sound device: Realtek ALC898 (Intel HD)
OS: Gentoo Linux (kernel 3.17.8)
ALSA: 1.0.28
Audacity: 2.0.5
When recording a vinyl record, the right channel volume level is much higher than the left channel. The right channel is also being clipped, as can be seen in the screenshot below.
I have set the ALSA Line-In volume level at 31 (dB gain: -10.50, -10.50), and the Audacity input volume at 0.30. I’m using the default 44100 Hz sample rate and 32-bit float sample format.
The only way I’m able to get a “good” vinyl recording is to record in mono (left channel) and set the input volume to 0.43. However this is not ideal.
I suspect that the preamp or turntable is at fault. Is there anything else that could cause this issue?
I’d guess pre-amp, turntable, PC Line-in, interconnecting lead on connector.
Yes I know that it looks like the problem is on the right (lower) channel, but it could be that the left channel is at fault and the right channel is merely too loud.
Standard PC sound cards are manufactured for a couple of cents (or more likely, for a couple of Yuan) and rarely very good quality - It may be worth upgrading that to a USB device at some point even if it is not the immediate problem.
The one thing that you missed out from your otherwise excellent description (I wish everyone were so detailed ) is whether your PC is a laptop. The “line in” on a laptop is often intended for computer mic input only. Some will work for stereo line-level, but many don’t.
To narrow down the problem you need to do some cable juggling…
Is the lead from “Phono Preamp → PC Line-In” a “Y-lead” with stereo mini-jack on the PC end and 2 x RCA (phono) plugs on the other end?
If so, swap round the left and right RCA plugs so the left plug is in the right socket and the right plug is in the left socket, then make a test recording.
Which channel is clipped now?
If the right (lower) channel is loud and clipped (as now), then the problem is on the PC side. If the left (upper) channel is loud and clipped, then it is external to the PC.
Note that connectors are frequently the weak points, and the point at which a cable joins its plug are also weak points. Try swapping leads around until you isolate the problem.
The PC is not a laptop. The lead plugs into the blue “Line-In” port on the back of the PC.
It’s a “Y-lead” with a mini-jack and RCA plugs.
I swapped the left and right RCA plugs from the preamp output and now the left (upper) channel is loud and clipped while the right (lower) channel isn’t. When juggling the cables, I noticed that if I slightly pull the lead from the Line-In port so that it’s not pushed in all the way, then both right and left channels are loud and clipped.
To eliminate the PC sound device as the source of the issue, I recorded the output of a PS3 playing an MP3 via a RCA to mini-jack adaptor. Both left and right channels have the same volume levels and are not clipped. It seems the issue is external to the PC.
A standard stereo mini-jack has three contacts:
The “tip” has the signal for the right channel, the “ring” has the signal for the left channel, and the “sleeve” is the return path for both electrical circuits (“ground”).
The socket will have similar contacts to match the plug.
If the plug is only part way in, it is possible for the “tip” of the plug to touch both the left and right channel contacts inside the socket, giving you the right (loud) channel signal to both left and right inside the computer.
That shows that the problem is external to the computer.
and that confirms that the problem is external to the computer.
What you need to do now, is to put that Y-lead back in the right way round, and do the same test between the turntable and the pre-amp.
Looking on-line it appears that the cable between turntable and pre-amp is permanently attached to the turntable - is that correct?
If that’s correct, then all you can do is to swap round the plugs at the pre-amp end. If the loud channel moves from left to right, then the problem is with the turntable. If the loud channel stays on the right, then the problem is with the pre-amp.
I swapped the left and right RCA plugs from the preamp input and the loud (right) channel doesn’t move. So it seems the preamp is the issue, which is disappointing since it’s brand new.
That looks to be the case as this test probably rules out the turntable. Have you swapped over the output leads from the pre-amp, it could be one of those leads at fault?
If after further troubleshooting the finger remains pointing at the pre-amp then, if it were me I’d be asking for my money back (I hope you kept the receipt) - and then I’d recommend that you take a look instead at the ARTcessories USB Phono Plus: http://artproaudio.com/artcessories/turntable_preamps/product/usb_phono_plus-ps/
(I’m assuming your PC has USB input).
The big advantage that it has over the Behringer is that it has a gain control so you can manage the output level to avoid clipping. The other advantage is that as it is USB output then it will also work on any laptop you may acquire in the future. The ARTcessories box also has RCA outputs so just as with the Behringer it can also be used to connect your TT to a modern hi-fi rig (many of the amps/pre-amps on these now lack phono inputs with the necessary pre-amplification and RIAA EQ)
I have an ARTcessories DJ-Pre11 (which is just a pre-amp) that I run through an Edirol UA-1EX USB soundcard, this produced excellent results for my (many) vinyl conversions. The USB Phono Plus is basically my preamp bundled in with a USB soundcard - if that combined device had been available when I was purchasing I would have bought that.
The ART USB Phono Plus looks like a great device but it’s over my budget (from local suppliers). Would you recommend the Behringer UFO202? It doesn’t have gain control but it has RCA and USB outputs.
I think the most likely cause is that you have got a duff pre-amp.
These are “budget range” devices, so they probably don’t do much (any?) testing before they leave the factory. Normally I would expect these little preamps to work very well (for the price), so you may have just been unlucky. It may be worth asking the retailer to exchange the unit for a replacement rather than a refund.
I ended up exchanging the Behringer PP400 for a Behringer UFO202 since the store didn’t have any PP400’s in stock. I can report that the volume levels for both channels are now balanced with the occasional clipping with very loud tracks. Thanks again for the help.
) is whether your PC is a laptop. The “line in” on a laptop is often intended for computer mic input only. Some will work for stereo line-level, but many don’t.
