Tascam atr 60/16 with ampex 407 & gp9

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zhou

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use tape machine is not easy,finally i get the tape compress...:)

set 0VU at 250 nWb/m and use AMPEX 407,and some good drum sound if you push more...

today i try GP9,set -6VU at 250 nWb/m.but i don't know how to bias it,in the manual TASCAM said:overbias 7db,but i don't know is just for AMPEX 456 or is for all the tape...so i just re-bias at over 7db.

in fact i don't like the sound of GP9,i feel seem lose some high frequency,sound is dispassionate(sorry my english)

i can get sound louder,clear...if i push it hard and still can get compress,but it's diffrent form AMPEX 407.

don't know if i did or think some thing wrong.
 
Probably too much bias. Too much bias will reduce the high frequency performance.
 
I use a software: Electroacoustics Toolbox,which can show the Third Harmonic Distortion when i adjust bias。
i found is almost the same when i over bias +3db,+5db,+7db.THD is about 0.05%。i play 10k sine wave at -10vu,i heard minimal THD is the best bias...maybe the software didn't show the THD well,or my soundcard....
and i see this
2012-05-18.webp

when i change tape,i adjust repro level and bias,do i need to re-adjust the frequency response?
 
You were using the overbias setting for 7.5ips. And have you confirmed that the record head gap on your machine is .25"?
 
GP9 is the cleanest sounding tape I've ever used. I still consider it the best +9/+10 class tape ever made. Something is wrong with your settings if GP9 sounds dull. Probably the bias as sweetbeats said. However I am a big fan of 407 for its character.

The chart looks ok. It is in agreement with Quantegy's chart for the same speed and Gap. Tascam decks have 0.25 Gap like most Studers and Revox. You might try 5 or 6 overbias at that speed and see if it helps. But I would use the ATR-60 only @ 15 ips, unless you can't get the heavy compression you want at that speed. You should not have to reset EQ for GP9, but you can if you want to optimize it for that tape. It's usually close enough, unless perhaps the machine is out of calibration. Maybe time for a full calibration.
 
thanks reply.
in the manual of ATR 60,it's just said adjust bias over 7db at low speed(7.5ips),i think the meaning is you adjust bias at low speed,you have set your bias done,you don't need adjust at high speed(15ips)。
and the 7db is for ampex 456,it's different than chart i post.
i do use at 15ips,but i adjust bias at 7.5ips,and i don't know why tascam do that way.
maybe i'm new on GP9,and i heard 407 a lot.i try over 5db today,sound is not bad.
__-1.webp
 
Hey, zhou...what kind of mixing console is that?
 
Hi:sweetbeats..AMEK M1000， it's not a ture recording console,and only 12 tracks working.:)but you can trust it.just sound good!
 
zhou,

GP9 or any +9 tape will not compress/saturate as well as 407 because with +9 the tape electronics has less headroom. When you use high recording levels the electronics will distort before the tape does and it sounds terrible. Better to stay with 407 or similar if you want tape distortion.
 
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