I have a Studer A812 in my main listening room which doesn't get much play time since I prefer to use my Doshi Audio EVO tape preamp. Currently I have 2 Technics RS-1500s with wired out Flux Magnetic heads feeding the Doshi.
So, I purchased a Studer A810 head block for the purpose of making it usable with the Doshi. The A810 and A812 head blocks are identical except for the rear D-sub connector which is a 3 row 50 pin on the A812 and a 2 row 25 pin on the A810. My other consideration is doing this was that I wanted to be able to go back to the stock head block on the A812 if I needed to.
My plan was to use the wires coming from the repro head and wire it to the existing 25 pin d-sub connector on the back of the head block. I didn't feel comfortable at this point wiring directly to the head. Of course, I can do this in the future. What I learned in the process of doing this is that there is a small preamp on the head block which is fed by the repro head before connecting to the d-sub connector. I disconnected the preamp since I didn't want it in the signal path.
The head block wires, surrounded by shielding springs, were not long enough to reach the d-sub connector so I soldered on some extensions for that. Not ideal but I didn't have a choice.
I soldered the 4 leads from the head to the d-sub connector. I reused the existing ground wires from the internal preamp.
Next I needed to build a 5 foot interconnect with a female d-sub connector on one end and XLRs on the other.
I may have over done it with the heat shrink but I was nervous about the small wires shorting out. There isn't much space to work with on the d-sub connector.
I wrapped the first 2 feet of the interconnect with 2 layers of shielding tape of try to prevent any interference and hum with the wire running through some of the internal electronics.
Lo and behold it works and it is dead quiet.
Version 2 may replace the Studer head with a Flux Magnetic head and wire out directly without the d-sub connector but for now this is good enough.
Thanks to Nick Doshi for providing me with a blue print for the project.
So, I purchased a Studer A810 head block for the purpose of making it usable with the Doshi. The A810 and A812 head blocks are identical except for the rear D-sub connector which is a 3 row 50 pin on the A812 and a 2 row 25 pin on the A810. My other consideration is doing this was that I wanted to be able to go back to the stock head block on the A812 if I needed to.
My plan was to use the wires coming from the repro head and wire it to the existing 25 pin d-sub connector on the back of the head block. I didn't feel comfortable at this point wiring directly to the head. Of course, I can do this in the future. What I learned in the process of doing this is that there is a small preamp on the head block which is fed by the repro head before connecting to the d-sub connector. I disconnected the preamp since I didn't want it in the signal path.
The head block wires, surrounded by shielding springs, were not long enough to reach the d-sub connector so I soldered on some extensions for that. Not ideal but I didn't have a choice.
I soldered the 4 leads from the head to the d-sub connector. I reused the existing ground wires from the internal preamp.
Next I needed to build a 5 foot interconnect with a female d-sub connector on one end and XLRs on the other.
I may have over done it with the heat shrink but I was nervous about the small wires shorting out. There isn't much space to work with on the d-sub connector.
I wrapped the first 2 feet of the interconnect with 2 layers of shielding tape of try to prevent any interference and hum with the wire running through some of the internal electronics.
Lo and behold it works and it is dead quiet.
Version 2 may replace the Studer head with a Flux Magnetic head and wire out directly without the d-sub connector but for now this is good enough.
Thanks to Nick Doshi for providing me with a blue print for the project.
