Tape Machine Thread
- Thread starter Greg
- Start date
Help Support GroupDIY Audio Forum:
Tascam makes a pretty heavy duty degausser. 50 bucks I believe!
The tape thing scares me. I want to stock up, but it has a certain shelf life.
ANd 60 bucks for 30 minutes!
Puts pressure on the artist!
Thel sell the Quantegy stuff at GitCenter over here at least.
How long does that half inch stuff last?
cj
The tape thing scares me. I want to stock up, but it has a certain shelf life.
ANd 60 bucks for 30 minutes!
Puts pressure on the artist!
Thel sell the Quantegy stuff at GitCenter over here at least.
How long does that half inch stuff last?
cj
Nat
Well-known member
I think the backing on the Quantegy stuff has been okay since the mid-90s. Emtec had so little shed, but they're gone now... damnit! I'm willing to bet shelf-life will be pretty long for modern tapes. I've got some Quantegy tapes from the late '90s that still play just fine - no more shed than normal.
Yeah, prices are getting rediculous. I pay around £50 - 60 per reel for 1" now...
Oh yeah, I noticed Protape in London still has some Emtec 1". Woohoo!!
Yeah, prices are getting rediculous. I pay around £50 - 60 per reel for 1" now...
Oh yeah, I noticed Protape in London still has some Emtec 1". Woohoo!!
Trade me a Studer for some T4's !
:wink:
:wink:
Greg
Well-known member
Soundguy -
Thanks for the advise. I've been doing some experimenting with my tape machine (i.e. overbias levels, REPRO/SYNC eq, and reference flux) over the weekend, and I've definitely learned a good bit about how the ATR60-16 responds to these changes. It seems that so far some of my personal preferences differ slightly from the Tascam specs in the manual. But I used the manual as a starting point.
Regarding tape, I get Quantegy 456 from American Musical Supply in quantities of 5 for about $62 a piece. I don't think that's a bad deal. Free shipping and since the order is $300 or over they divide the cost over three months.
Now on to my specific question. In one of my amp cards, a few of the ICs have been replaced. If I remember correctly, the NE5532ANs were replaced with an Analog Devices IC. When biasing this channel with a -10dB 10kHz signal, I noticed that the VU was oscillating back and forth 2-3dB at all bias levels. What does this indicate? Some type of high frequency instability?
Thanks for the advise. I've been doing some experimenting with my tape machine (i.e. overbias levels, REPRO/SYNC eq, and reference flux) over the weekend, and I've definitely learned a good bit about how the ATR60-16 responds to these changes. It seems that so far some of my personal preferences differ slightly from the Tascam specs in the manual. But I used the manual as a starting point.
Regarding tape, I get Quantegy 456 from American Musical Supply in quantities of 5 for about $62 a piece. I don't think that's a bad deal. Free shipping and since the order is $300 or over they divide the cost over three months.
Now on to my specific question. In one of my amp cards, a few of the ICs have been replaced. If I remember correctly, the NE5532ANs were replaced with an Analog Devices IC. When biasing this channel with a -10dB 10kHz signal, I noticed that the VU was oscillating back and forth 2-3dB at all bias levels. What does this indicate? Some type of high frequency instability?
are there plug in amplifier cards on that machine? If so, take those cards and plug them in a different channel and see if the same thing happens. As your heads wear, your high frequency response will get effected, usually first. Could be a sign of head wear but if you are just wavering 1/2 a dB I wouldnt worry too much. Have you done an azimuth alignment on the headstack and a tension calibration on the transport? Everything is all connected, so its really hard to say what a certain instability is for instance if your azimuth is totally out of wack or your transport doesnt have constant tension...
dave
dave
Greg
Well-known member
Soundguy -
The HF osc was happening on Track 1. I swapped it with a different card and the HF osc was still there on Track 1. So that rules out the card. I then did a quick amizuth check (summing method - no scope at the time) at 1k and 10k from tracks 2 and 15. At 1k, everything was ok, but at 10k we were bouncing all over the place. So it seems I need to do some azimuth adjusting. I did a tape tension measurement and that's on spec; however, I have not done a complete transport calibration (i.e. brakes, pinch pressure, table height, etc). I will start in on that tonight. Will post back with any questions... thanks for your advise and the help. It's definitely appreciated.
The HF osc was happening on Track 1. I swapped it with a different card and the HF osc was still there on Track 1. So that rules out the card. I then did a quick amizuth check (summing method - no scope at the time) at 1k and 10k from tracks 2 and 15. At 1k, everything was ok, but at 10k we were bouncing all over the place. So it seems I need to do some azimuth adjusting. I did a tape tension measurement and that's on spec; however, I have not done a complete transport calibration (i.e. brakes, pinch pressure, table height, etc). I will start in on that tonight. Will post back with any questions... thanks for your advise and the help. It's definitely appreciated.
greg-
how bad is the oscillation? If its like 1/2 dB or so, my outer tracks show that and I have no problem living with it. Ive put it off as a combo of head wear and wow. Just make sure that the oscillation is consistent at the head, middle and tail of the reels. If it changes, you know you have a tension problem that is playing into it.
dave
how bad is the oscillation? If its like 1/2 dB or so, my outer tracks show that and I have no problem living with it. Ive put it off as a combo of head wear and wow. Just make sure that the oscillation is consistent at the head, middle and tail of the reels. If it changes, you know you have a tension problem that is playing into it.
dave
Greg
Well-known member
Soundguy -
The oscillation is pretty bad. Anywhere from 2dB to 5dB. It just kind of jumps around at will. And the amount of oscillation isn't consistent either. I'll definitely check all tension alignments as well... in fact, I'll check all tensions before I adjust azimuth. I have a tentelometer and I just bought a couple new spring scales. This machine was shipped to me from around Sacramento (I'm in New Orleans), so I'm sure it was vibrating like hell in the back of some freight truck and will need some minor adjusting. I just powered it up a few days ago and was making sure all tracks passed audio. Then I saw the oscillation. So I haven't done a full mechanical alignment as of yet. After I do that I'll see where things stand. Also, the heads have no more than 500 hours on them, and have never been relapped... so at this point I don't expect head wear to be a factor.
Please keep an eye on this thread in case I run into anything unexpected. You've been very helpful so far.
The oscillation is pretty bad. Anywhere from 2dB to 5dB. It just kind of jumps around at will. And the amount of oscillation isn't consistent either. I'll definitely check all tension alignments as well... in fact, I'll check all tensions before I adjust azimuth. I have a tentelometer and I just bought a couple new spring scales. This machine was shipped to me from around Sacramento (I'm in New Orleans), so I'm sure it was vibrating like hell in the back of some freight truck and will need some minor adjusting. I just powered it up a few days ago and was making sure all tracks passed audio. Then I saw the oscillation. So I haven't done a full mechanical alignment as of yet. After I do that I'll see where things stand. Also, the heads have no more than 500 hours on them, and have never been relapped... so at this point I don't expect head wear to be a factor.
Please keep an eye on this thread in case I run into anything unexpected. You've been very helpful so far.
Winston OBoogie
Well-known member
...
unheardof
Active member
Cjenrick,
Which tascam 8 do you have?
I've got a 38 I've had for a couple of years. I've had only minor problems with mine, like those pesky output relays that stick sometimes. The only reason they are there is to prevent the "pop" when you power on. I just bypass them.
I fixed one for a friend of mine recently. His had lots of problems, but I managed to fix them all. Also replaced his capstan belt with an original from Tascam. I should have got one for myself, too, just didn't think about it.
Just wanted to shout out at another Tascam 8 user. What tape/operating level do you use? I've used a few different ones, 456, GP9 and some 3M tape that was supposedly a precursor to GP9. I think I'll keep buying GP9 for now, I run it at +6, but haven't had access to an MRL in a while. I'm about to buy one.
I guess that's it. By the way, this is my first post here. I was registered at RO, but was usually too busy to read. I intend to get a little more active here. :musique:
Which tascam 8 do you have?
I've got a 38 I've had for a couple of years. I've had only minor problems with mine, like those pesky output relays that stick sometimes. The only reason they are there is to prevent the "pop" when you power on. I just bypass them.
I fixed one for a friend of mine recently. His had lots of problems, but I managed to fix them all. Also replaced his capstan belt with an original from Tascam. I should have got one for myself, too, just didn't think about it.
Just wanted to shout out at another Tascam 8 user. What tape/operating level do you use? I've used a few different ones, 456, GP9 and some 3M tape that was supposedly a precursor to GP9. I think I'll keep buying GP9 for now, I run it at +6, but haven't had access to an MRL in a while. I'm about to buy one.
I guess that's it. By the way, this is my first post here. I was registered at RO, but was usually too busy to read. I intend to get a little more active here. :musique:
hey greg-
I think my helpfulness is probably nearing the depth of my knowledge... 5 dB oscillation is quite a bit... Assuming the deck has VU meters, is the pattern of the oscillation consistent, meaning, does the VU meter rise and fall at a steady rate? If so, that could potentially be wow in your transport. If it is an erratic jerking needle movement then that is likely going to be a problem with your electronics. Is the problem repeatable in both repro and sel sync (if that deck has sel sync). If there are plug in relays, remove them, clean them, reseat them. Thats probably not the problem, but Ive had wierder shit get fixed by reseating a relay that had nothing to do with anything on my ampexes... Considering you swapped channel cards and got the same problem, its probably the transport, but maybe you swapped a bad card for a bad card, thats possible... Checking the voltage rails on a known good channel with the channel in question would be a good place to start if you cant isolate it to the transport and have to begin digging around with the electronics. Make sure you do your measurements with the transport running and it stopped.
I think Im out of ideas...
dave
I think my helpfulness is probably nearing the depth of my knowledge... 5 dB oscillation is quite a bit... Assuming the deck has VU meters, is the pattern of the oscillation consistent, meaning, does the VU meter rise and fall at a steady rate? If so, that could potentially be wow in your transport. If it is an erratic jerking needle movement then that is likely going to be a problem with your electronics. Is the problem repeatable in both repro and sel sync (if that deck has sel sync). If there are plug in relays, remove them, clean them, reseat them. Thats probably not the problem, but Ive had wierder shit get fixed by reseating a relay that had nothing to do with anything on my ampexes... Considering you swapped channel cards and got the same problem, its probably the transport, but maybe you swapped a bad card for a bad card, thats possible... Checking the voltage rails on a known good channel with the channel in question would be a good place to start if you cant isolate it to the transport and have to begin digging around with the electronics. Make sure you do your measurements with the transport running and it stopped.
I think Im out of ideas...
dave
apply a little friction to the supply reel to slow it down... see if the swing slows down with it....or if possibly is reduced.. I didnt read all of the thread but are you seeing this at different speeds? 15 ips verses 7.5 or 30? does it get worse or better at alternate speeds...
Do you know for fact that the heads have no more than 500 and havent been relapped? or is this based on the previous owners statement
Do you know for fact that the heads have no more than 500 and havent been relapped? or is this based on the previous owners statement
Greg
Well-known member
Scenaria -
I'll have a much better idea of what's going on after I do a complete mechanical alignment (this weekend) and get my MRL tape in for 30ips (I'll get it Friday). This is happening at 15ips. I haven't tried 30ips as of yet.
[quote author="Scenaria"]Do you know for fact that the heads have no more than 500 and havent been relapped? or is this based on the previous owners statement[/quote]
This is based on the previous owners statements; however, I bought this from John LaGrou at Millenia and I don't think he would've lied to me. Everything else he's told me about the deck, including a SYNC issue on one of tracks (which he'll repay me for), has been correct. He even said that if the heads needed relapping he'd repay me. So with a statement like that I'd believe him. According to John, he primary used this to record 2 track audio. He bought it in 1990 or 1991 and it's been in storage since the mid 90s. The condition, physically, is mint.
I'll do a mech calibration and then I'll post back... and I'll slow things down a bit as you suggested and see what that does to the problem track.
I'll have a much better idea of what's going on after I do a complete mechanical alignment (this weekend) and get my MRL tape in for 30ips (I'll get it Friday). This is happening at 15ips. I haven't tried 30ips as of yet.
[quote author="Scenaria"]Do you know for fact that the heads have no more than 500 and havent been relapped? or is this based on the previous owners statement[/quote]
This is based on the previous owners statements; however, I bought this from John LaGrou at Millenia and I don't think he would've lied to me. Everything else he's told me about the deck, including a SYNC issue on one of tracks (which he'll repay me for), has been correct. He even said that if the heads needed relapping he'd repay me. So with a statement like that I'd believe him. According to John, he primary used this to record 2 track audio. He bought it in 1990 or 1991 and it's been in storage since the mid 90s. The condition, physically, is mint.
I'll do a mech calibration and then I'll post back... and I'll slow things down a bit as you suggested and see what that does to the problem track.
Mark Burnley
Well-known member
There are some good tape-machine articles here:
MRL Tapes
...in particular this one:
Demagging PDF
:thumb:
Mark
MRL Tapes
...in particular this one:
Demagging PDF
:thumb:
Mark
DrFrankencopter
Well-known member
How's the pinch roller? If it slips even the slightest bit (as can happen when pinch rollers get old and harden), then you can get transport instability.
Mechanical alignment is also a big suspect in oscilations...if the tape is moving up and down along the head, then the level will vary. If you have a scope hook it up and see if the oscilations are at varying frequency and amplitude, or if it's just amplitude. This may give you a clue.
Cheers,
Kris
Mechanical alignment is also a big suspect in oscilations...if the tape is moving up and down along the head, then the level will vary. If you have a scope hook it up and see if the oscilations are at varying frequency and amplitude, or if it's just amplitude. This may give you a clue.
Cheers,
Kris
Greg
Well-known member
My old tape machine was unbalanced, this one is balanced. When measuring azimuth, using the scope method, should I measure across tip and ring or tip and gnd?
I did a check (measuring across tip and ring of tracks 2 and 15), and the azimuth is way off... but I did notice that the phase relation was changing, meaning it fluctuated between 90 and 120 degrees out-of-phase, so maybe there is something unstable about the transport. I didn't have an allen set with me so I didn't adjust. I still need to do that mech alignment, but I don't think I'll get to it today.
I found a "brand new" pinch on e-bay for $75. Is that a good price, or at least fair? My pinch does have some glazing, but it only seems to be that way towards the bottom.
I did a check (measuring across tip and ring of tracks 2 and 15), and the azimuth is way off... but I did notice that the phase relation was changing, meaning it fluctuated between 90 and 120 degrees out-of-phase, so maybe there is something unstable about the transport. I didn't have an allen set with me so I didn't adjust. I still need to do that mech alignment, but I don't think I'll get to it today.
I found a "brand new" pinch on e-bay for $75. Is that a good price, or at least fair? My pinch does have some glazing, but it only seems to be that way towards the bottom.
T-Dogg
Well-known member
hi --
Have any of you guys come across computer software suitable for calibrating a tape machine? I guess something that would compare to a 100mhz dual trace scope (I think the bias frequency on my machine is around 100mhz...)? If so -- I suppose my audio interface would have to support a 192Mhz sampling rate to accurately gauge such high frequencies, right?
Have any of you guys come across computer software suitable for calibrating a tape machine? I guess something that would compare to a 100mhz dual trace scope (I think the bias frequency on my machine is around 100mhz...)? If so -- I suppose my audio interface would have to support a 192Mhz sampling rate to accurately gauge such high frequencies, right?
DrFrankencopter
Well-known member
T-dogg, most machines have a bias frequency between 100-200 kHz, not MHz.
Cheers,
Kris
Cheers,
Kris
