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Sel-Sync/Bouncing issues with Ampex AG-440-8A Keyboard Synthesizers
Old 6th August 2018
  #1
Sel-Sync/Bouncing issues with Ampex AG-440-8A

Hi All,

I've been tracking my band with my Ampex AG-440-8A through my Soundcraft TS12. This is an all analogue setup. We've got all the drums, bass, guide vox and guide guitar down and are ready to start bouncing tracks. Tracks are as follows:

1: Kick
2: drum overhead L
3: drum overhead R
4: guide vocals (expendable)
5: guide guitar (expendable)
6: snare
7: (empty)
8: bass


Here's where the issues have begun.

I did little research and it seems that the problems I'm having may be "normal" for this deck, but I just want to get some feedback and see what my options are.

The problem is 2-fold.

Problem 1: From what I understand, you need to bounce using Sel-Sync, and not the repro heads (tracks 1,2,3, and 6 are are a stereo bounce going to 5 and 7: 1,2,3, and 6 would be set to Sel-Sync and 5,7 would be set to Ready/Record). The problem here is that there is a HUGE loss in level/quality of the Sel-Sync playback and hence the resulting bounced tracks. I understand that the Sel-Sync heads do not reproduce as high a quality as repro heads as a simple matter of fact, however, when I flip a nice strong signal between -3/+3 to Sel-Sync the level will drop to barely -10. Is this much of a drop normal? If it is, what is the "correct" way to make up the gain: The deck's per-track Repro levels, or the track faders on the desk? In general I'd really like to hear any "stories" etc about how bouncing was done "back in the day" on these machines. This was a complete non-issue on my Otari deck, but I understand that there's nearly 30 years technology difference between the two!

Problem 2: I think stems mainly from my ignorance of the inherent issues with this machine. Apparently you cannot bounce to an adjacent track or you will get feedback. Not knowing this beforehand, I did not leave adjacent tracks empty for this particular bounce and now we're stuck (as you can see by the track-listing, track 6/snare causes there to be no non-adjacent tracks for the bounce). My procedure is to assign my tracks to be bounced to a stereo group and that group to the tape sends to the target tracks... However, when I raise the gain on the group faders a high pitched squeal/feedback will result after a certain point. Being unable to raise the gain past that point, compounded with the issue of the significantly lower Sel-Sync playback results in bounced tracks that barely move the meters, even on a drum track they're barely between -20,-10. Even if Sel-Sync playback was "louder", it wouldn't help in this case: the feedback would just result at a lower group fader gain. Apart from not bouncing to adjacent tracks in the future, is there any sort of modification to the machine or otherwise that can be done to eliminate or minimize this feedback problem? The good news here is that we only tracked the snare separately for two songs (out of 8). So all of our other tracks are "ok" as there are non-adjacent tracks to bounce to.

All that being said, even with this feedback issue I can still get a decent sounding drum bounce to 2 tracks and I can bring it into the mix (with the bass and guide vox/guitar) to a decent level and don't hear "too much" added noise, but I'm worried that that final mix will have to be boosted too much to reach 0db when everything has to be mixed to the level of those bounced drums.

So I may have painted myself in a corner Re: problem 2 (though any advice or tips would be much appreciated!).
Old 6th August 2018
  #2
Lives for gear
 

Ampex AG-440-8

Quote:
Originally Posted by coniglius View Post
Problem 1: From what I understand, you need to bounce using Sel-Sync, and not the repro heads (tracks 1,2,3, and 6 are are a stereo bounce going to 5 and 7: 1,2,3, and 6 would be set to Sel-Sync and 5,7 would be set to Ready/Record). The problem here is that there is a HUGE loss in level/quality of the Sel-Sync playback and hence the resulting bounced tracks. I understand that the Sel-Sync heads do not reproduce as high a quality as repro heads as a simple matter of fact, however, when I flip a nice strong signal between -3/+3 to Sel-Sync the level will drop to barely -10. Is this much of a drop normal?
no.
re-align the machine and calibrate Sel-Sync gain by adjustment of R43 located on the rear of the electronics chassis.
playback from the larger gap record head has reduced top end,
but the midrange level can be the same as from the repro head (after alignment).
Old 6th August 2018
  #3
Quote:
Originally Posted by cathode View Post
no.
re-align the machine and calibrate Sel-Sync gain by adjustment of R43 located on the rear of the electronics chassis.
playback from the larger gap record head has reduced top end,
but the midrange level can be the same as from the repro head (after alignment).
Thanks for the reply cathode. I'm having my tech come by for a full re-alignment/setup as soon as he's available, but unfortunately in my neck of the woods it can be a bit of a wait. It's good to know that this isn't "normal" though!
Old 7th August 2018
  #4
Lives for gear
Hi!

Sounds like a great setup,
you do need to get a system going if you're going to bounce a lot in the future.
Personally I usually stay on 8trks (3M M56), but with more that 1 person around the mic/s on overdubs.

I have bounced stacked harmony vox a lot before, that was really fun,
but had to be planned for in advance.
Anything is possible on 8 irks with careful planning!

Enjoy...

Best/
Tom
Old 7th August 2018
  #5
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ruffrecords's Avatar
If you are going to discard all the other tracks after the bounce then you should do it from the replay heads. There should not be any problems with adjacent tracks doing it this way as you are recording on a different head.

Back in the day, a bounce down such as you are proposing would normally be done with two machines; one playing and the other recording.

Cheers

Ian
Old 7th August 2018
  #6
Quote:
Originally Posted by Mr. Tom View Post
Hi!

Sounds like a great setup,
you do need to get a system going if you're going to bounce a lot in the future.
Personally I usually stay on 8trks (3M M56), but with more that 1 person around the mic/s on overdubs.

I have bounced stacked harmony vox a lot before, that was really fun,
but had to be planned for in advance.
Anything is possible on 8 irks with careful planning!

Enjoy...

Best/
Tom
It's true, but the trick is "planning", heh. After this fiasco we've re-planned all of our bounces and even with leaving an extra "empty" track so that we don't bounce to an adjacent we'll end up with over 20 different "instruments" from just 8 tracks, none more than 2nd generation.
Old 7th August 2018
  #7
Quote:
Originally Posted by ruffrecords View Post
If you are going to discard all the other tracks after the bounce then you should do it from the replay heads. There should not be any problems with adjacent tracks doing it this way as you are recording on a different head.

Back in the day, a bounce down such as you are proposing would normally be done with two machines; one playing and the other recording.

Cheers

Ian
Thanks Ian, you answered my next question! (If it's ok to bounce to adjacent tracks from the repro heads if the only thing that will be kept is the result of the bounce). I was playing around with the machine last night and planning our tracks and basically there will be a point where we will bounce "everything" down to stereo and at that point I figured we should use the repro head since nothing will need to be synced. I did a test run bouncing from the repro to adjacent tracks and no issues!

When you say it was done back in the day with two machines, I assume you mean two sync'ed machines?
Old 7th August 2018
  #8
Quote:
Originally Posted by cathode View Post
no.
re-align the machine and calibrate Sel-Sync gain by adjustment of R43 located on the rear of the electronics chassis.
playback from the larger gap record head has reduced top end,
but the midrange level can be the same as from the repro head (after alignment).
My tech came by last night and realigned/recalibrated the machine. I watched him do it from the test tape and saw the meters read the same when flipping back between Sel-Sync and repro. After he left I threaded up one of our recordings and did the same. There was a huge drop between Sel-Sync and repro on the kick track and a huge drop on the bass guitar track. I freaked out as I had *seen* him fix this. I threaded up the test tape again and sure enough the levels were identical at 1kHz and more or less the same on the following high tones (even a slight bump on SS heads for some) but when the test tone went down to 50Hz you could see the Sel-Sync drop significantly. So basically what I'm seeing from the Sel-Sync heads is no loss in high end, none in mid range, but a huge drop in bass. I went back to the recording and flipped SS/repro between all the channels. They were all more or less the same except for the bass and kick which was a big drop. Since bass and kick are always on the outside tracks I just recalibrated Sel-Sync on 1 and 8 for better bass frequency response. I think I remember reading somewhere that people do this...
Old 8th August 2018
  #9
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ruffrecords's Avatar
Quote:
Originally Posted by coniglius View Post
T

When you say it was done back in the day with two machines, I assume you mean two sync'ed machines?
Syncing 4 track machines was rarely if ever done because you have to sacrifice a track on each machine for syncing so you only get 6 to play with.

What I meant was back in the day it was common to record a rhythm section on all four tracks. These would be bounced down to one track on the second machine. You then record three more tracks on the second machine. These four tracks might then be bounced to stereo on the first machine. Two more tracks would be added then those four mixed down to stereo or mono.

Of course many versions of this technique are possible. It was done with two track machines in the early days of the Beatles. They would record 2 tracks on a 2 track machine and bounce it to one track on another two track machine. They would then record the other track and bounce those two down to mono.

In both cases some of the tracks are second or third generation and lose top end so you needed to pick your instruments carefully. This is why sometimes extra percussion was added to the final tracks to regain some top end in the rhythm section.

It is also worth remembering it was common to record several instruments at a time to one track.

Cheers

Ian
Old 8th August 2018
  #10
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Ampex AG-440-8 Sel-Sync

Quote:
Originally Posted by coniglius View Post
the levels were identical at 1kHz and more or less the same on the following high tones (even a slight bump on SS heads for some) but when the test tone went down to 50Hz you could see the Sel-Sync drop significantly. So basically what I'm seeing from the Sel-Sync heads is no loss in high end, none in mid range, but a huge drop in bass.
there is no mention of Sel-Sync frequency response in the specification pages of AG-440 and AG-440b manuals.
however, the AG-440c manual does list Sel-Sync response as
+/- 2 dB 30 Hz to 12,000 Hz
and overall frequency response as +/- 2 dB 30 Hz to 15,000 Hz.

it does not appear right that you are losing low end in sync.
top end should be less per theory of the wider gap record head.
am thinking the alignment procedure should be re-visited.

lets hear from other "tape-heads" about loss of low end in sync.

for those more familiar with Studer than Ampex,
there is no separate eq adjustment for Sel-Sync.
Old 22nd August 2018
  #11
Quote:
Originally Posted by cathode View Post
there is no mention of Sel-Sync frequency response in the specification pages of AG-440 and AG-440b manuals.
however, the AG-440c manual does list Sel-Sync response as
+/- 2 dB 30 Hz to 12,000 Hz
and overall frequency response as +/- 2 dB 30 Hz to 15,000 Hz.

it does not appear right that you are losing low end in sync.
top end should be less per theory of the wider gap record head.
am thinking the alignment procedure should be re-visited.

lets hear from other "tape-heads" about loss of low end in sync.

for those more familiar with Studer than Ampex,
there is no separate eq adjustment for Sel-Sync.
Thanks for all of the responses. In the end, bouncing from the Sel-Sync heads was just not going to work (even with the adjacent tracks left empty). There was just too much loss in quality even in the first bounce, and we'd have needed 2 bounces in some cases. It would have been ok for certain instruments (guitars would have been ok, or even "good") but not for drums and bass. So that would have been the end of story and no way for us to move forward... but out of sheer luck I was able to borrow a second 1" 8 track machine: a Scully 280b.

Now, our process is to record 7 or 8 tracks (drums, bass, and rhythm guitars mainly) bounce everything down to 2 or 4 tracks on the Scully, put the tape back on the Ampex and now we've got 4 or 6 first gen tracks for vocals etc that can stay 1st generation.

This was a pretty big lesson for me as to how recording "used to be done" on 8 track machines like the Ampex. I've only worked on newer machines before, such as an Otari MTR-90 (16 track). I've been using tape for "awhile" (about 10 years) and never knew that bouncing between machines for 8 tracks was the "standard". Sure, I've heard about bands like the Beatles bouncing between 4 track machines, but I always just assumed that 8 track recordings were done on 1 machine as it's not so unreasonable: if you assume repro-head quality bounces without the adjacent track problem, then you can fit quite a bit on an 8 track machine without going beyond 1st generation (assuming you're recording music in the style of the era of 8 track recording).

So now I just need to find a second 8 track AG-440
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