Noise at the heads. - UK Vintage Radio Repair and Restoration Discussion Forum

etrain · 9th Oct 2005, 11:42 am

hey there, was wondering if anyone could help me.I've got an AKAI 1721L and when I record or playback there is a horrible screeching noise coming from the heads. I know that old tape could do this, but i'm using fairly new AMPEX tape. funny thing is that when I put really old tape on to play, its totally fine.Could it be head alignment?.....still occurs after I thoroughly cleaned the heads.

ukcol · 9th Oct 2005, 11:57 am

I'm not experienced with reel-to-reel tape recorders, but I have come across this sort of thing when some makes of tape are used on a worn ACE head in a VCR. The solution being to use a different make of tape or replace the head. You may find that a small change in the back tension adjustment will cure it if this can be achieved without disturbing performance.

AndiiT · 9th Oct 2005, 4:44 pm

Quote:

Originally Posted by etrain

I know that old tape could do this, but i'm using fairly new AMPEX tape. funny thing is that when I put really old tape on to play, its totally fine.

Hi
I am not too sure on this but, contrary to what you say above about older tapes, believe that it is related to modern tapes using some kind of plasticiser for lubricant and older tapes being made with whale oil; The older tape not losing its "lubricant" properties (due to the whale oil), whilst the newer tape becoming "tacky" due to some kind of chemical reaction within the plasticiser. (I read something about this somewhere ages ago)
I am sure theres a chemist out there somewhere that will be able to enlighten us

Andrew

Nickthedentist · 9th Oct 2005, 4:49 pm

I think it's 1970s tapes that are worst affected, especially if they've been subjected to damp. The cure with these is to bake them in a temperature-controlled oven, and then immediately dub them onto a new tape, CD or whatever.

I suppose "1970s" tapes could seem new or old, depending on one's age

reel-to-reel-man · 9th Oct 2005, 4:50 pm

Hi,

I know what your talking about, you may find the heads get dirty very fast too when using the tape, its all to do with the glue which holds the oxide on, you may find that you will get like a black sticky substance on your heads if this is the case the glue has gone soft. The solution (Though sounds drastic) is to turn on your oven (Tested on an Electric oven on audio and video tape) must be on very low heat, leave the tape to more or less cook for half an hour, take the tape out and allow cooling before attempting to use. You will notice a huge difference, as the glue will reactivate, if the results are not perfect, repeat the above but not too often.

Hope that helps.

Sideband · 9th Oct 2005, 5:55 pm

I've also come across this with tape recorders that use pressure pads to hold the tape against the heads. The felt gets hard/clogged with gunge and a good clean or replacement cures. Some tapes squeak and others don't due to the base material the tape is made of.

Don't know if this Akai uses pads like this.

Rich.

etrain · 10th Oct 2005, 12:39 am

Cheers for the advice, will try the oven technique and see how it goes.

etrain · 10th Oct 2005, 12:42 am

Can the tape be left on the reel when doing this

reel-to-reel-man · 10th Oct 2005, 7:00 am

Yes, its best its on the reel anyway as the tape will not shrink, you may or may not see the end of the tape shrink, if so you know the oven is too hot, remember low heat for half an hour

Kentbloke · 11th Oct 2005, 9:32 pm

Hi, maybe stating the obvious - but dont bake on plastic reels!

reel-to-reel-man · 11th Oct 2005, 9:50 pm

Tried and tested, obviously you don't put them in the oven 200 decrees and leave to cook for 30 mins, they will burn

I first read about this technique once reading it on the internet, I had a Sony-O-Matic video recorder and the tape was dropping oxide like nobodies business, after leaving the reel in the oven for 30 mins (Oven barely on) the tape worked as new, no oxide drop and no screeching.

reel-to-reel-man · 15th Oct 2005, 3:26 pm

Juts a follow up, I got a reel to reel last week with a reel of Ampex tape, it would not play on anything because it screamed as it was played over the heads. I placed it in the oven on low heat and let it cool, just tried it now and its as good as new. The reel was left on the plastic spool and the spool did not melt, to give an idea on the type of heat we are talking about.

How did Etrain do?

Bob955i · 26th Nov 2005, 8:50 pm

The problem with tape depositing oxide on the heads is called "sticky shed" and if you do a search using those words you'll find a lot of information on this issue in addition to that previously given.

Also, back-coated tape will also squeal if used on machines with pressure pads.

reelguy · 26th Nov 2005, 9:53 pm

Hi, Once you have used the oven method to save the tape it is best to copy to some other medium as soon as possible. The bad tape will not last long and will go sticky and messy again.

Early tapes are usually OK {1950s to late 1960s} , Only tapes from 1970s seem to be affected. Newer tapes are supposed to be ok now especially the Quantegy tapes now being made. Good luck. Reelguy

DOFFERY · 2nd Dec 2005, 1:44 pm

Apart from bad tape the main cause of screech on the Akai 4000 range is the back tension on the feed spool, the felt pad in the clutch wears & needs to be replaced. Also tension from the rubber brake on the lower clutch part (L.hand) will increase the back tension(try holding it off when playing?

Doffery

9th Oct 2005, 11:42 am	#1
etrain Retired Dormant Member Join Date: Sep 2005 Posts: 5	Noise at the heads. hey there, was wondering if anyone could help me.I've got an AKAI 1721L and when I record or playback there is a horrible screeching noise coming from the heads. I know that old tape could do this, but i'm using fairly new AMPEX tape. funny thing is that when I put really old tape on to play, its totally fine.Could it be head alignment?.....still occurs after I thoroughly cleaned the heads.

9th Oct 2005, 11:57 am	#2
ukcol Rest in Peace Join Date: May 2003 Location: Harlaxton, Lincolnshire, UK. Posts: 3,944	Re: Noise at the heads. I'm not experienced with reel-to-reel tape recorders, but I have come across this sort of thing when some makes of tape are used on a worn ACE head in a VCR. The solution being to use a different make of tape or replace the head. You may find that a small change in the back tension adjustment will cure it if this can be achieved without disturbing performance.

9th Oct 2005, 4:49 pm	#4
Nickthedentist Dekatron Join Date: Jan 2005 Location: Oxford, UK. Posts: 17,865	Re: Noise at the heads. I think it's 1970s tapes that are worst affected, especially if they've been subjected to damp. The cure with these is to bake them in a temperature-controlled oven, and then immediately dub them onto a new tape, CD or whatever. I suppose "1970s" tapes could seem new or old, depending on one's age

9th Oct 2005, 4:50 pm	#5
reel-to-reel-man Heptode Join Date: Jan 2005 Location: Paignton, Devon, UK. Posts: 805	Re: Noise at the heads. Hi, I know what your talking about, you may find the heads get dirty very fast too when using the tape, its all to do with the glue which holds the oxide on, you may find that you will get like a black sticky substance on your heads if this is the case the glue has gone soft. The solution (Though sounds drastic) is to turn on your oven (Tested on an Electric oven on audio and video tape) must be on very low heat, leave the tape to more or less cook for half an hour, take the tape out and allow cooling before attempting to use. You will notice a huge difference, as the glue will reactivate, if the results are not perfect, repeat the above but not too often. Hope that helps. __________________ Vintage recorder collector www.vintagerecorders.co.uk

9th Oct 2005, 5:55 pm	#6
Sideband Dekatron Join Date: Oct 2003 Location: Croydon, Surrey, UK. Posts: 7,580	Re: Noise at the heads. I've also come across this with tape recorders that use pressure pads to hold the tape against the heads. The felt gets hard/clogged with gunge and a good clean or replacement cures. Some tapes squeak and others don't due to the base material the tape is made of. Don't know if this Akai uses pads like this. Rich. __________________ There are lots of brilliant keyboard players and then there is Rick Wakeman.....

10th Oct 2005, 12:39 am	#7
etrain Retired Dormant Member Join Date: Sep 2005 Posts: 5	Re: Noise at the heads. Cheers for the advice, will try the oven technique and see how it goes.

10th Oct 2005, 12:42 am	#8
etrain Retired Dormant Member Join Date: Sep 2005 Posts: 5	Re: Noise at the heads. Can the tape be left on the reel when doing this

10th Oct 2005, 7:00 am	#9
reel-to-reel-man Heptode Join Date: Jan 2005 Location: Paignton, Devon, UK. Posts: 805	Re: Noise at the heads. Yes, its best its on the reel anyway as the tape will not shrink, you may or may not see the end of the tape shrink, if so you know the oven is too hot, remember low heat for half an hour __________________ Vintage recorder collector www.vintagerecorders.co.uk

11th Oct 2005, 9:32 pm	#10
Kentbloke Retired Dormant Member Join Date: Oct 2005 Location: Folkestone Posts: 2	Re: Noise at the heads. Hi, maybe stating the obvious - but dont bake on plastic reels!

11th Oct 2005, 9:50 pm	#11
reel-to-reel-man Heptode Join Date: Jan 2005 Location: Paignton, Devon, UK. Posts: 805	Re: Noise at the heads. Tried and tested, obviously you don't put them in the oven 200 decrees and leave to cook for 30 mins, they will burn I first read about this technique once reading it on the internet, I had a Sony-O-Matic video recorder and the tape was dropping oxide like nobodies business, after leaving the reel in the oven for 30 mins (Oven barely on) the tape worked as new, no oxide drop and no screeching. __________________ Vintage recorder collector www.vintagerecorders.co.uk

15th Oct 2005, 3:26 pm	#12
reel-to-reel-man Heptode Join Date: Jan 2005 Location: Paignton, Devon, UK. Posts: 805	Re: Noise at the heads. Juts a follow up, I got a reel to reel last week with a reel of Ampex tape, it would not play on anything because it screamed as it was played over the heads. I placed it in the oven on low heat and let it cool, just tried it now and its as good as new. The reel was left on the plastic spool and the spool did not melt, to give an idea on the type of heat we are talking about. How did Etrain do? __________________ Vintage recorder collector www.vintagerecorders.co.uk

26th Nov 2005, 8:50 pm	#13
Bob955i Retired Dormant Member Join Date: Nov 2005 Location: Leven Posts: 38	Re: Noise at the heads. The problem with tape depositing oxide on the heads is called "sticky shed" and if you do a search using those words you'll find a lot of information on this issue in addition to that previously given. Also, back-coated tape will also squeal if used on machines with pressure pads.

26th Nov 2005, 9:53 pm	#14
reelguy Heptode Join Date: May 2003 Location: Bexhill on Sea, East Sussex, UK. Posts: 746	Re: Noise at the heads. Hi, Once you have used the oven method to save the tape it is best to copy to some other medium as soon as possible. The bad tape will not last long and will go sticky and messy again. Early tapes are usually OK {1950s to late 1960s} , Only tapes from 1970s seem to be affected. Newer tapes are supposed to be ok now especially the Quantegy tapes now being made. Good luck. Reelguy

2nd Dec 2005, 1:44 pm	#15
DOFFERY Retired Dormant Member Join Date: Aug 2004 Location: Blackpool, Lancashire, UK. Posts: 1,488	Re: Noise at the heads. Apart from bad tape the main cause of screech on the Akai 4000 range is the back tension on the feed spool, the felt pad in the clutch wears & needs to be replaced. Also tension from the rubber brake on the lower clutch part (L.hand) will increase the back tension(try holding it off when playing? Doffery