Back to vinyl

[Bob Williams]

No way am I going to inflict our hard water on my precious vinyl Graham! Finger grease is avoided if you don’t handle the surfaces without a cloth.

When the Thought Police arrive at your door, think -
I'm out.

[D-Dan]

OK, Audio philes. I’m trying to lay my hands on a (free) analogue amp, but in the meantime, I hit on a fresh idea. Using pulseaudio on my desktop (5:1 audio) and USB out from the turntable, with some minor configuration, I can take the audio from the turntable through my PC to my desktop speakers (far superior to the Creative BT speakers I was using, and with the SUB, way better).

Now, I believe that USB audio is superior to other digital inputs, but is it as good as pure analogue (or to the point where I wouldn’t notice), or am I still looking at an analogue amp and some good analogue only speakers for the best (to my aging ears) sound.

Testing shows that the vinyl to PC via USB is superior to mp3, but will I get discernibly better?

Arch Linux, on a Ryzen 7 1800X, 32 GB, 5 (yes -5) HDs inc 5 SSDs, 4 RPi 3Bs + 1 RPi 4B - one as an NFS server with two more drives, PiHole (shut yours), Plex server, cloud server, and other random Pi stuff. Nice CoolerMaster case, 2 x NV GTX 1070 8GB, and a whopping 32" AOC 1440P monitor.

[D-Dan]

Oh, and to respond to the cleaning bit – 99.9% isopropyl alcohol all the way, but FFS, don’t drink it.

It is amazing at cleaning grease, and will not eat the plastic.

Arch Linux, on a Ryzen 7 1800X, 32 GB, 5 (yes -5) HDs inc 5 SSDs, 4 RPi 3Bs + 1 RPi 4B - one as an NFS server with two more drives, PiHole (shut yours), Plex server, cloud server, and other random Pi stuff. Nice CoolerMaster case, 2 x NV GTX 1070 8GB, and a whopping 32" AOC 1440P monitor.

[Wheels-Of-Fire]

It really depends on how good the ADC in your turntable is and if it does proper RIAA equalization. All records are cut with RIAA to reduce the maximum groove deflection, if you play them back without it then you loose the bass.

[Wheels-Of-Fire]

You can hear the effect by connecting an analogue turntable to the Mic input on your PC. The sound will be plenty loud enough but very “thin”.

[Wheels-Of-Fire]

I just noticed that Audacity has an RIAA filter preset and there is a VST plug in too. May be worth a look 😁

[D-Dan]

I had it going through audacity – which is how I knew it was possible, but too much effort for just playback. Now, I have it hooked up permanently via rear USB. Now, problem two was, after configuring pulse, there was an audible buzz through the speakers if the turntable wasn’t playing (not noticeable when it’s playing), so step two was to set up a toggle switch on my cairo dock to enable/disable the passthrough.

Anyone else on Linux with a similar setup (unlikely, I know) but here goes.

In /etc/pule/default.pa add:

load-module module-loopback

Then fire up pulse audio volume control (pavucontrol) and set the loopback input in the Recording tab to the turntable input, and set the loopback output in Playback to your speakers.

That gets it working.

The script to toggle (and so instantly mute, or just get rid of the silence buzz) is:

#!/bin/bash

if [ ! -f /tmp/turntable ]; then
    echo "1" > /tmp/turntable
    pacmd set-source-output-mute 0 1
fi

exec 3<> /tmp/turntable
read <&3 mute

exec 3>&-
echo $mute
if [ "$mute" == "1" ]; then
    pacmd set-source-output-mute 0 0
    echo "0" > /tmp/turntable

else
    pacmd set-source-output-mute 0 1
    echo "1" > /tmp/turntable
fi

You’ll need to verify the index of your loopback (in my case, 0)

Arch Linux, on a Ryzen 7 1800X, 32 GB, 5 (yes -5) HDs inc 5 SSDs, 4 RPi 3Bs + 1 RPi 4B - one as an NFS server with two more drives, PiHole (shut yours), Plex server, cloud server, and other random Pi stuff. Nice CoolerMaster case, 2 x NV GTX 1070 8GB, and a whopping 32" AOC 1440P monitor.

[D-Dan]

Damn – trying to format – where’s the damned preview?

/etc/pulse/default.pa

and echo $mute can be left out – debugging leftover.

And yes, the script could be simplified by setting the mute to abs(mute-1)

Arch Linux, on a Ryzen 7 1800X, 32 GB, 5 (yes -5) HDs inc 5 SSDs, 4 RPi 3Bs + 1 RPi 4B - one as an NFS server with two more drives, PiHole (shut yours), Plex server, cloud server, and other random Pi stuff. Nice CoolerMaster case, 2 x NV GTX 1070 8GB, and a whopping 32" AOC 1440P monitor.

[D-Dan]

OK, simplified script.

#!/bin/bash

if [ ! -f /tmp/turntable ]; then
echo "1" > /tmp/turntable
pacmd set-source-output-mute 0 1
fi

exec 3<> /tmp/turntable
read <&3 mute
exec 3>&-

let "mute=$mute-1"
mute=$(echo "$mute*$mute" | bc)
pacmd set-source-output-mute 0 $mute
echo $mute > /tmp/turntable

Arch Linux, on a Ryzen 7 1800X, 32 GB, 5 (yes -5) HDs inc 5 SSDs, 4 RPi 3Bs + 1 RPi 4B - one as an NFS server with two more drives, PiHole (shut yours), Plex server, cloud server, and other random Pi stuff. Nice CoolerMaster case, 2 x NV GTX 1070 8GB, and a whopping 32" AOC 1440P monitor.

[Wheels-Of-Fire]

It would be nice to get rid of the buzz in the first place but I doubt you can do it because I will bet your USB turntable is not connected to earth in any way. In my setup the analogue turntable is connected to the earth post on the Amp and the Amp is earthed through the 3 pin plug, that avoids an earth loop problem. The PC and the Amp are both plugged into the same power strip so they share a common earth but you don’t usually get a buzz on line level inputs anyway.

[Ed P]

Wheels-Of-Fire wrote:

avoids an earth loop problem. The PC and the Amp are both plugged into the same power strip so they share a common earth but you don’t usually get a buzz on line level inputs anyway.

+1

[Wheels-Of-Fire]

I was just reading the Audacity online manual (only just found out there was one) and it says there is a special case for connecting your turntable to the Mic input.

78’s and other records recorded before the late 50’s do not use RIAA equalization so you do not want it in your playback system.

[keith with the teef]

{AMP} Onkyo A9010B is good the B is for black.

[D-Dan]

keith with the teef wrote:

Onkyo A9010B

For £199 new it does look rather nice. As it happens, I have an audiophile friend who’s promised to have a look at what he has, and I may be able to get an analogue amp FOR FREE 🙂

If not, I’ll re-visit this.

Oh, and there’s no ground lead on the turntable, so I’m going to do some searching to see if it can be modded. If not, well, I guess I’ll spend more money on a new one with a ground and full calibration (rather than the rather static deck that this is).

Arch Linux, on a Ryzen 7 1800X, 32 GB, 5 (yes -5) HDs inc 5 SSDs, 4 RPi 3Bs + 1 RPi 4B - one as an NFS server with two more drives, PiHole (shut yours), Plex server, cloud server, and other random Pi stuff. Nice CoolerMaster case, 2 x NV GTX 1070 8GB, and a whopping 32" AOC 1440P monitor.

[Wheels-Of-Fire]

There are 3 important settings on a turntable, tracking weight, antiskate and azimuth. Tracking weight im sure you can guess and you get the figure from the cartridge manufacturer. Skate is a tendency for the record grove to pull the arm towards the center of the  the record, antiskate corrects it. Azimuth is the angle you mount the cartridge in the head shell, you would need a protector to measure that. Audio technica sell a good cheap one 😁

[Wheels-Of-Fire]

Oh yes, to set the tracking weight you set the small weight to zero, screw the big weight until the arm ballances and then dial in the number of grams you want.

[Wheels-Of-Fire]

On the small weight 😁

[Wheels-Of-Fire]

Oops forgot to mention the 4th setting. It is important that your turntable is level.

[keith with the teef]

One thing that bugs me is connection corrosion as with the copper cable.

OOOH Oygen fee cable.

But end to end connection will oxydize. Fuuny thing is though some people complain that the sound is too bright when the connection is new. As in no copper rust.

[Wheels-Of-Fire]

That is a bit of a nonsense  that keeps getting spread Kieth. Use hard gold plated contacts if you can and also a good quality contact cleaner if things get dirty. Apart from that a conductor is a conductor 😁

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