You have a major channel imbalance with both internal and external electronics which points to the head or the head switch as the source of the defect. Misadjusting the Tube Repro L/R gain to balance out the channels is not the proper fix as you may or may not know. Cleaning the head switch with Deoxit D5 may be worth a try and should be easy. Also examine the head surface with a strong magnifier.
Studer A810 with Tube Repro
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You have a major channel imbalance with both internal and external electronics which points to the head or the head switch as the source of the defect. Misadjusting the Tube Repro L/R gain to balance out the channels is not the proper fix as you may or may not know. Cleaning the head switch with Deoxit D5 may be worth a try and should be easy. Also examine the head surface with a strong magnifier.
Based on what's been reported so far, the best option for you is to:
1) take the machine to your local electronics repair shop to have the tape headblock removed (three long screws) and disconnect the direct wires at the end connection points (not knowing if DocB had installed a set of RCAs in the back or left them in long cables with RCA male connectors).
2) contact John French for him to test the repro head, ultrasonic cleaning, and optical realignment. If the repro head is worn, this will be an opportunity to upgrade to the Flux Mag repro head.
3) John can test the direct head output along with outputs from the Studer internal preamp when the switch is in internal mode.
4) have your local tech reinstall the headblock and reconnect the direct head outputs
It seems with your far location, above option maybe the only one.
Good luck
Ki
1) take the machine to your local electronics repair shop to have the tape headblock removed (three long screws) and disconnect the direct wires at the end connection points (not knowing if DocB had installed a set of RCAs in the back or left them in long cables with RCA male connectors).
2) contact John French for him to test the repro head, ultrasonic cleaning, and optical realignment. If the repro head is worn, this will be an opportunity to upgrade to the Flux Mag repro head.
3) John can test the direct head output along with outputs from the Studer internal preamp when the switch is in internal mode.
4) have your local tech reinstall the headblock and reconnect the direct head outputs
It seems with your far location, above option maybe the only one.
Good luck
Ki
I m confident it's not the tape head . Used it for less than 200 hrs & it was in pretty new condition when I bought it .
Probably got to do with the switch or direct wires modification.
Probably got to do with the switch or direct wires modification.
It never hurts to have a second machine... on the other hand, I am not one to speak too loudly...
You reported that the imbalance happens on both direct wired output as well as through Studer A810 internal electronics, one troubling shooting you can do to isolate the issue further is to measure the DCR with an ohmmeter at the direct wired connection for comparison of CH1 and CH2 of the repro head outputs. Both channels should be relatively same at ~100 ohm (@ 1khz).
If you see the difference, I would recommend you move up to the switch terminals and the twisted pair wires from the head to diagnose the source of the difference.
You won't hurt the head but would recommend demagnetizing the repro head after the test.
Ki
You reported that the imbalance happens on both direct wired output as well as through Studer A810 internal electronics, one troubling shooting you can do to isolate the issue further is to measure the DCR with an ohmmeter at the direct wired connection for comparison of CH1 and CH2 of the repro head outputs. Both channels should be relatively same at ~100 ohm (@ 1khz).
If you see the difference, I would recommend you move up to the switch terminals and the twisted pair wires from the head to diagnose the source of the difference.
You won't hurt the head but would recommend demagnetizing the repro head after the test.
Ki
Only head contamination (not head wear) was suggested as a possible defect: as in a piece of tape oxide the size of a pin head at the right spot could reduce a track's level by 5 dB.
He said the player was out of service for a few months during room renovation. I assume it was moved to another location. Since the output has changed without any good reason, has anyone thought to reseat the audio cards? It's an easy check. Dirt and vibration can cause a lot of squirley problems. He should be comfortable with just unseating and reseating the cards. He doesn't even have to remove them. It can't/shouldn't hurt.
The OP claims he has the same channel imbalance when by-passing the Studer playback amps (using instead an external head amp, a Tube Repro). That would tend to eliminate the Studer audio amps or amp connectors as the source of the problem.
Hmmm maybe time for me to get a Studer A80 RC MK 2 which is modified correctly to accept an external preamp . The tapes are costing me more than the playback .
Anyway it's playing fine with external preamp trim port - short cut for me to nice music
Anyway it's playing fine with external preamp trim port - short cut for me to nice music
If you have to imbalance the trim pots on your external head amp (the Tube Repro) by 5 db to get both channels to sound balanced, then your tape deck can't be "playing fine" or meeting manufacturers spec. Something is still quite wrong with it. Any competent repair professional could find the balance defect in 5 minutes and perhaps fix it in another 10 minutes. Rather than replacing the whole deck, why not just get it fixed???
Tape tech , you are probably right. However I don't have a technician in my country to help me to troubleshoot
Tony , how could I modified an A80 so that I won't have the same issue with my Studer A810 in which I can't use the VU meter to help me in adjusting alignment ?
I have 2 sets of outputs on my A80. One for internal (using the overhead vu meters) and external ( using either vu meters on outboard tape pre or just a voltage meter and O-scope for azimuth).
Got myself a Studer A80 R with 2812 hours on the meter from a seller in Austria . Modded for external preamp . So much better than A810.
No hum & no channel imbalance unlike the A810. So prime suspect is the direct head output modification
Oop correction . There is a channel imbalance to the left. When I played Hotel California , the vocal is veered 1/4 way to the left of centre . So possibly my tubes issue .
Anyway Hotel California on AFO + Axiom arm + Koetsu + Vitus Masterpiece phono costing more than 10x my reel to reel set up sounded like toy soldiers singing in my room compared to R2R playback. Imagine if its 1/2" 30 ips tape
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Good news , I sort out my channel inbalance . It's a bad input XLR connector. Nothing wrong with Tube Repro
I know my A80RC mkIi machines with Nick's tubed repro units are the best tape I've heard.
The A80 transport is in a whole 'nother league from the 810.
I have had the pleasure of listening with that combination. And I do mean pleasure.
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