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Old 31st January 2013 | Show parent
Lives for gear
Darth Preamp's Avatar
Originally Posted by nickvivid View Post
I just had some time to play around with my a77 last night and figured out the line input bypass mod, and since it doesn't seem to be publicly posted anywhere, I wanted to share it for any other a77 owners.

It's REALLY simple. And the end result is you're not even using those input amplifiers built into the a77 anymore! So more pure sound and no more clicking when you hit "0" on the tape, saturation is possible AND awesome on this machine!

On the back of the input level pots there's 4 pins each. a black wire goes to pins 1 and 4, pins 2 and 3 are red and orange (i forget which is which off the top of my head - doesnt matter). Solder the ground wire to either 1 or 4, and the hot lead to the same pin as the red wire (nothing needs to be disconnected from the pots - as a matter of fact everything should stay in case you do want to still use the regular inputs for any reason)

Now, with my board setup, the input was HOT! I was hitting 0 at almost no gain on the controls even with a -10db unbalanced output, and I did have a load happening on the board - lost most of my signal going to my master fader - my VUs dropped from 0 to around -20. A 10k resistor in line with the hot lead on each channel brought it back. I'm reading "0" on the VUs at around the 3 on the inputs of the tape machine now. At max gain the needle drops back a little on mine (almost looks what happens when you do bias adjustment). I don't think there's ever a situation when you would even begin to hit that threshold so it doesn't matter to me. Maybe a 22k would be a little more accurate, but no worries, i'm happy.

This machine can achieve BEAUTIFUL saturation - i just tested with 468 tape. Wow. I'm stunned how buttery and rich it is. Bypass those mic/line inputs pronto! You don't know what you're missing if you don't!

I want you to know that I just bought an A77, and used the above quote as a basis for the technician to modify the machine this way. He also went through and replaced all that needed to be replaced, put in a 15 ips motor, cleaned and calibrated it, and was all around an AWESOME person to work with.
Here's his website.

He calibrated it for ATR tape.

I am working on a mixdown for a client, and mixed simultaneously to Hard Drive, and the Revox.
All I can say is HOLY F$%^$# SH$#&^$^ it sounds good, and quiet too, barely any noise, negligible really.
As an alternative to the Ampex 102, this is it.
The Hard Drive mixdown sounded nice as well, but it really wasn't even close in terms of the deep accuracy, added depth and width, and believability, that the mix to tape has. I think the almost surreal accuracy of the mix to tape is what is really still blowing my mind.

It was funny actually, as the just about 40 year old machine worked flawlessly all day , several Hard Drives weren't cooperating, I had to reboot my converters and computer a bunch of times etc, it was poetic somehow.