VR: L & R channels sound different

[Ben]

Hey Guys,

With the VR
Anyone had this before? My left side is more clear and my right side has more bass.... on Souri's main unit when I do a A-B... I still have low frequency content...

When I rip the cut I did ....when I put both channel in center... it becomes a little off phase and I lose a little clarity, I've checked the angle of the cutterhead... and also stylus but everythings looks alright.

Ever had to deal this before ?
Thanks
Ben

[tragwag]

seems like the issue is in your power amp, or the head itself. I would double check those connections, and the fuse holders.
one time I have a fuse shake a little loose, I reseated it and haven't had any issue since (years!)

[Ben]

The funny thing is I needed to adjust the balance of the RIAA a lot ... my right channel was a lot louder than the left .
I re-adjust the balance of L&R with a sine wave, after that the 2 channels seemed almost the same. so problem almost solved.

But Why the left channel would be that low compared to the right? It's really only in the main unit.... I tried to bypass the main unit and the cut was equal loudness on both channels.

There's always a new mystery with those machines.... lol

[tragwag]

it seems like you might have a bigger problem in your main unit unfortunately

[Ben]

Since I solved this problem I decided to post on it and warn people if they go through stuff like that.

When I bought the Vinyl recorder Souri gave me a little Rca in and out little pot... to put after the mixer to adjsut the level between both channel.. if ever the sound is not balanced going to the main unit.
I realized for """I don't know reason"" this changed the sound of a channel.... so instead of using this, I use the balance knob on the main unit and with a 0k tone I adjust it to be balanced.... and now the sound is back to normal

If ever you go through that stuff .... maybe trying to remove this can be a first step to find a solution
Cheers
Ben

[jtb]

Hi Ben,
reviving this old thread as I'm having the same issue here (louder volume on the right side), but when I use the balance/pan knob of the main unit all the way to the left to compensate I still cant get it balanced. Ive sent an audio signal loop in/out using pink noise to check this and while at it, I also checked the other racks and found the same problem on the "vinyl optimizer" rack, the strangest of all is, both racks were sent to Souri last year as I always had this problem and was using the RCA in/out pots you refer, but I also hate that and would like to solve this issue, does anyone have any tips? Will try to take the racks to an audio technician for further check up.

Also, how do you guys go directly from amp to the cutter head to bypass all racks I mean the plugs connected to the cutting head look like midi, is there any adapter to RCA or jack or straight cut and solder new plugs?

Thanks

[PMST]

Amp always goes direct to cutter head? It is the chain before the amp you wasn't to change. The cutter head has Speakon connectors that go to the amp,. The DIN plugs that you are talking about is for the motor and stylus heating, not audio.

It is advisable to change out Souri's cheap electrics. Keep the signal path as clean as possible. For example my set up is

Cutting Chain:

Computer/Interface
Cutter Amp
Cutterhead

Playback Chain:

Turntable
RIAA Preamp
Level Meter
Monitors

Nothing in between for the cleanest possible signal path. I do all my EQ in Reaper using Fab Filter ro Q and totally bypass the main unit and any other cheap electrics that Souri makes. The Vinyl Optimiser is purely to cut mid/side issues, which is done much much much more efficiently in a plug in.

Have you checked you cutter head driver coils ohm readings to see if one is blown? I would do this anyway just to run it out.

[Ben]

Hey Jtb,
Hope you're doing geat.

I'm gonna be honest with you, I've tried a lot of different stuff, from removing Sourri mixer, changing all the connections, removing the optomizert, removing Main Unit RIAA and doing it with plug ins.... basically going nuts to try to fix stuff.... in the end funny enough, I went back to the standard setup.

When you use all Souri equipement ... the way he "tuned" them, they all work together. It may not be the most clean path. But I feel it's the more pleasant sound to me.
I stopped going nuts trying to sound like Neumann Machine with the VR. The way that going through all those analog process before cutting sounds good to me, more than using a plugin. But that's personal to me, you may hear things differently.

Especially that if you do the RIAA in the plugin the wrong way.... you gonna end up with a short life diamond (been there, done that)

For your problem, there's not easy fix.... I suggest you use both the little resistor (rca to rca plug with the pot) and the main unit in conjunction... this is what I do now.
Never had a complain. You reduce your loud channel a little bit with the Rca plug (just a bit) and do the fine adjustment on your main unit.

If you have a too big difference, it could be another problem (I hope not). it could be Cutterhead, even the diamond play a role in this.

Let me know if it helps, don't hesitate to ask anything.
Ben

[jtb]

Hey Ben, thanks for your prompt reply. I get you, sometimes i start to overthink things but in any way I'm looking for it to sound like a VMS, just looking for the best sounding cuts this machine can achieve, I've already cut plenty of those using just the "stock equipment" plus minor adjustments as needed on the daw. There's a big difference between L and R but the cutterhead is good, its my rack units that have this balance problem, i easily tested this by sending a signal in to out and analyzing the return response of the units, if i use trim pots i get an acceptable balanced cut.

Do you also use the trim pot on the mixer for the phono preview? I remember Souri also told me to use it there.. my readings with the 0dB record that came with the machine also reads slightly more to the right but a lot less than the "main unit". I start to think, is it the cartridge, the test record, the mixer, or the deck that needs calibration.

There's also this Souri tip that in theory should align the balance for optimal cuts and that is, cutting a track with good bass, in mono, then while cutting selecting the horizontal/sides on the "monitor switcher" and adjusting the balance of the "main unit" till the bass disappears.

Also wondering if all "main units" out there are like ours, i mean this unbalanced...

[jtb]

Hey @PMST i didnt see your post, thank you for the tips. Sorry it was my mistake, you're totally right!

Soon i will try to go directly from the daw to amp bypassing all units, one question, how do you measure the cutting volume inside the daw and how do you monitor the computer/phono signals at the same time?

I haven't checked the head coils as i don't have a multimeter, do you use one of these devices to measure the ohms?

[PMST]

Hey @PMST i didnt see your post, thank you for the tips. Sorry it was my mistake, you're totally right!

Soon i will try to go directly from the daw to amp bypassing all units, one question, how do you measure the cutting volume inside the daw and how do you monitor the computer/phono signals at the same time?

I haven't checked the head coils as i don't have a multimeter, do you use one of these devices to measure the ohms?

This is how i work, mastering and lathe cutting is my day job and i do about 600-800 discs a month and I think as simplified set up and clean signal flow is definitely preferential for this (in my opinion anyway).

Firstly you need to map your cutter heads frequency response and resonances. You would do this using EQ match software, i like Fab Filter Pro Q for this. Standard iRIAA will not work, so only do this is you are confident in understanding how to map your head correctly. If so, then this will work great.

I simply normalise all audio to -23lufs in Reaper with Fab Filter on the output with my EQ. I then send the audio to a volume knob (you can use your audio interface instead) and have a 0db reference point, all audio is always the same volume before sending to my amp, so its always reasonably calibrated once i found the 0db mark on the volume knob.

I only monitor volume from the playback, i find it fairly pointless trying to calibrate this in the DAW, it is the cutting volume that is important. I just do a short test cut before each run set volumes and go.

Here is an example of the kind of quality you can get from a VR, in here is a the original file, alongside a cut on my system at +6db.

https://www.dropbox.com/scl/fo/jdt2wdrk3ggblrbj4ckbx/h?rlkey=nlejue79f6y7w0ejpojb1l8yx&dl=0

[Ben]

Great sound @PMST !!
To answer your question @jtb, no I don't use it on playback. I have a test tone 0db that let me check if anything is wrong at playback and I'm really in the ballpark.
It's only on the cutting side.
But I would not be shy to use it on playback if my cartridge was the culprit. My turntable is plugged into a phono preamp and then a small mixer so I can if I want to, use the pan pot.


@PMST has some pretty great advices, it all goes down to how far you wanna go down the rabbit hole. Like he said, be careful cuz Souris RIAA is not a true one... if you listen to what's coming out of the main unit, you'll see there's still a lot of low end (on mine at least)... I already ask that question somewhere on this site years ago haha!

Every machine and cutterhead is different as well, I had my VR in 2014 and listen to a newer cutterhead from a friend (Hi Robyn!!) Mine had a lot more distortion for the same cut and same master.
But you look like someone understands the technicals of this... so give it a shot, try bypassing most of Souri's stuff.
Maybe it will be benificial for your setup.... definitely not mine.

Take care
Ben

[jtb]

Hey guys. today, once more dedicated several hours to sending test signals to the main unit, changing cables, and its weird sometimes the main unit has equal L and R signals then all of sudden get L and R differences on the sub/bass region below +-200hz, will try updating this post with a print screen that explains this better then words.

After sending pink noise and sine tones to the main unit's with all knobs set to center, there's an obvious smiling curve bossting bass and highs and dipping the mids, so the RIIA curve might be right before the cutterhead? Think i saw a post here by a member that also talks about this.

I bought the machine back in 2005, but I haven't used it for recording in the past decade, so I'm a bit out of practice. However, I have a lot of experience cutting records with this machine from before, and I'm starting up again. I've been busy cleaning, calibrating, gathering materials, and optimizing my workspace for the past couple of weeks, and everything is going well. However, I have to readjust because it's not 2005 anymore, there are better tools available now!

@Ben Maybe your friend has a feedback cutterhead, agree that all builds arent using the exact same components so sound different. The distortion can be angles, broken needle, phase issues on original recording but im sure you already know about this.

Hey @PMST sounds great even prefer your cut over the original, and well done, cutting that amount of records per month is insane!

[PMST]

As Ben mentioned, every head is different, I have three and all have a different frequency response, also inaccuracies in their dimensions affecting the sound. Souri implements his 'iRIAA' as a 3 band EQ in the main unit, usually a bass boost, slight mid dip and boost in the high end.

I have mapped maybe 30 heads over the years, and so far I have needed at least 10 bands of EQ to flatten their curve, so the 3 band EQ on the main unit just isn't enough generally to get it perfect. Also it totally depends on your needs, I cut loud 45s for reggae and dub sound systems, so the fidelity has to be as good as possible. Also mapping your head means you can account for the resonances meaning louder, clearer cuts. Again it just depends on your needs and expectations from the system.

I think before doing anything else you need to test the coil ohms, it is the only way to really tell if any coils are on their way out.

I would have the cutter head plugged in with the amp turned off. Unplug the speakon cables from the amp. Open the connectors, get a multimeter and place the testing cables onto the ends of the cutterhead audio cables from inside the speakon. Then you will see if both sides are equal and you can then rule out things as a process of elimination. Bare in mind the fuses will also affect this reading, but I am assuming they are checked and fine. Otherwise you can use a multimeter with small crocodile clips directly onto the cutter heads DIN plus, but I usually find this trickier