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3340 high sounds help

T

Tony el

New Member
Hi
Im putting this 3340 bavk to work, and everything is working so I am doing some testing.
For the moment i am testing on old tape that
Works for recording.
I noticed if I slow down the left reel with my hand, the tape gets more tension and I hear more high frequencies in the sound coming from the teac. Same if i lift the left lever and squeeze the tape before it enters the tape head box.
Is my left lever weak? It seems lower than on manual photos.
Am i exagerating highs by pressing with my hand ?
Or am i making the natural highs re-appear?
Any ideas?
Thanks
 
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Do the highs sound good when you are not touching the left tension arm? It is normal that increasing the tape tension yields more highs, what matters is whether or not the frequency response is flat in the normal conditions. If the sound is muffled, it could help to check the condition of the heads, give them a good clean with a cotton bud and isopropyl alcohol, and possibly to demagnetize them.
 
I am not sure because I am using old tapes, I have ordered new ones to compare, I hope when I hear the new ones the sounds comes out crispy clear.,
yes i have cleaned the heads with alcohol and have demagnetized also. by the way for the demagnetization does that include the record head the play head and the erase head,
or should some items by avoided?
 
If adding tension to the supply reel creates a noticeable change in high frequency response, then you likely have insufficient back tension. You will need a spring scale and adjust the dropping resistors (they are very large with a wiper arm secured by a screw). They typically get quite hot-btw.
Tony el said:
demagnetization does that include the record head the play head and the erase head,
or should some items by avoided?
Click to expand...
Any metal items in the tape path should get the demag treatment. I doubt this will improve performance much.
Loss of high end can be caused by poor calibration, but far more often, it's spacing loss (poor contact of the tape across the heads, from low back tension or dirty heads). The result of your creating drag on the supply reel supports spacing loss as the culprit.
 
Actually magnetized heads can be really nasty to the highs, cause noticeable noise and even permanently damage the recording too. I've seen such cases personally although only a couple of times, it depends on how the deck has been treated or stored. I'd still give the deck a good cleaning and demagging before considering a full ajustment which is a much more involved operation and requires equipment. Note that any trace of brown stuff on a head is a telltale sign that it needs cleaning, so make sure to clean the heads until the brown stuff is gone entirely.

BTW there are two important adjustments that you might not know about yet, and can cause loss of treble. One is the reel size selector, which must be set for the diameter of your tape reel as it adjusts the tape tension accordingly. The other one is the "record bias" switch in the "record" section on the lower left of the front pannel. It should be set depending on the tape you are using: "Normal" is for old tapes made until the early '70s, while "High" is suitable for the modern tapes. While recording, try both positions and see what works best for you, but don't expect a flat response (meaning that you can't hear a difference between the source and the recording) without a proper calibration, just concentrate on the trebles for the moment.

If still no trebles after all this, it would be a good idea to post a close-up of your record and play heads if you can. If worn out, the gap opens and becomes visible: at that point the head becomes increasingly unable to pick the trebles. In the early stage, adding more tension can improve things, but of course it won't last.
 
Ok thanks for the precise information.
On a recent recording on a old tape (compared to my precious test with old recordings on this old tape) I can’t hear any highs tightened or not.
This modern model of tape is said to be more warm, colored and grainy, this would be the 70’s mode bias?
https://www.thomann.de/gb/rtm_sm911_1_4_762m_nab_466314.htm?ref=mobile

I have ordered the sm900 that is said to be neutral (since i am used to digital sound, I think it will sound exotic to me..)
I hope it has a little warmth too

also, van you show me where the drop resistors are, you nd if i can make a diy tool or just add a little tension to these?
Thank you
 
Yes, the SM911 and SM900 would require the "High" bias setting. Note that in addition the precise bias adjustment (set by internal adjustments) matters more than the tape type to the sound, and different tapes all need a different bias, so you need to adjust the deck to the tape stock you are buying. You can expect a neutral sound with any good modern tape and a well adjusted recorder in good condition, so any difference between the source and the tape will be caused by bias and equalization misadjustment. Depending on how your A3340 is adjusted, the SM900 can very well give you a more "coloured" sound than the SM911 - since it depends so much on the adjustements - and both tapes may well sound more "coloured" than the old tape (if in good condition) with which the deck was factory-adjusted. Incidentally, it is a well-known procedure to voluntarily "twist" the bias and EQ adjustments as a sound effect, in order to obtain a "warm" and "coloured" sound - I don't know what "grainy" means in tape recording so I can't comment on this.

The torque/back tension setting resistors are accessible on the back of the recorder after removing the lid. If you choose to adjust the back tension, the location and procedure are given in the "Reel torque adjustment locations" on pages 16-17 of the A3340S service manual (or "Torque measurement procedure" on pages 15-17 of the A3340 service manual). But I strongly advise to avoid it unless you have determined that this is indeed the cause of your loss of trebles AND you have the proper equipment, as this adjustment is very easy to mess up and almost impossible to recover without the proper tools. At the very least, do measure the current back tension before attempting an adjustment. There is no DIY alternative to a good spring scale.

PS- one last thought: have you made sure that the tape lifters are fully retracted when playing and recording? If not, the tape cannot make full contact with the heads and the trebles are lost. I had this problem on a 3340, it was a fairly easy fix.
 
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There are numerous reasons for poor high frequency response that have been mentioned in the thread. However, given the comment from the OP, where adding tension to the tape made an obvious change, I still believe this is something that will need to be corrected. The tape lifter should be observed for hindering good contact with the heads. Poor quality tape, mis-alignment, excessive head wear and BIAS\EQ mismatch will all affect highs. However, a relative change in high frequencies by temporarily adding tension, strongly suggests a tension issue. All the other factors mentioned will need to be reviewed after mechanical factors have been addressed.
 
Of course. There is a misunderstanding here: my comment about bias & EQ is a reply to Tony's question re. the different tapes he was considering, not a suggestion that it might be cause of his current problem - it can't be, according to the symptoms. I do agree too, that poor tape or azimuth misadjustment don't explain the fact that adding tension seems to solve the problem, so we can rule them out. Note that I don't say the same re. worn heads though, as experience taught me that adding tension can restore the highs somewhat when the gap is just starting to open - obviously it is not a fix though, let alone a permanent cure.

My point while saying this, is that all the mechanical factors should be checked first as you rightly say, but checking is not the same as changing adjustments in the blind, which is almost guaranteed to cause even more problems. I thought about this when I saw that Tony was considering just adding a little tension to the resistors with DIY measuring tools or no measuring tools at all. Hence my advice to Tony: check the easy things first (cleaning, demagging, checking the head gaps and all the parts of the transport that might cause insufficient head/tape contact), then check the things that require getting equipment (i.e. good quality spring scales to check the tape tension and torques), and start doing changes only once you have found what is wrong.
 
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Ok thank you for this information,
It sounds like this device is a musical device before being a mixer.
Thanks for the european voltage info,
That makes sense since I can’t find a 110/220 switch and it was purchased in europe and travelled to the usa and back.
Someone in the usa probably put the switch to 60hz.
The belt was already in 50hz position.
So now i think its in 220/50hz/belt in 50 ha position thanks to your help.
I will do some testing when i get the sm900 and come back here if I need some adjustments.
 
Ok thank you for this information,
It sounds like this device is a musical device before being a mixer.
Thanks for the european voltage info,
That makes sense since I can’t find a 110/220 switch and it was purchased in europe and travelled to the usa and back.
Someone in the usa probably put the switch to 60hz.
The belt was already in 50hz position.
So now i think its in 220/50hz/belt in 50 ha position thanks to your help.
I will do some testing when i get the sm900 and come back here if I need some adjustments.
 
Ok thank you for this information,
It sounds like this device is a musical device before being a mixer.
Thanks for the european voltage info,
That makes sense since I can’t find a 110/220 switch and it was purchased in europe and travelled to the usa and back.
Someone in the usa probably put the switch to 60hz.
The belt was already in 50hz position.
So now i think its in 220/50hz/belt in 50 ha position thanks to your help.
I will do some testing when i get the sm900 and come back here if I need some adjustments.
 
PS- one last thought: have you made sure that the tape lifters are fully retracted when playing and recording? If not, the tape cannot make full contact with the heads and the trebles are lost. I had this problem on a 3340, it was a fairly easy fix.
Click to expand...

can you describe that fix the left lifter seems very lazy, and all i see in the back is a tiny spring, is that tiny spring supposed to support heavy lifting?
 
I thought I had made photos while I fixed it, but I can't find them anywhere and now this deck is no longer with me, so I'll try to explain in words and links, from memory.

The tape lifters are actuated by the solenoid that presses the pinch roller against the capstan shaft. The arm that carries the pinch roller shaft applies a rotation movement to the arm that carries the right lifter, which in turn transmits the movement to a third arm that carries the left lifter. These ares are parts 5, 12 and 11 in section 13 "Lifter and pinch roller" of the service manual of the A3300S service manual - strangely, there is next to no mechanical schematics in the A3340-A3340S manuals, but fortunately the A3300 and A3300S have essentially the same mechanics. You can find the correct service manual as file "teac_a-2300_2300s_3300_3300s_service.pdf" on Hifiengine (if the website does not block your country) or on Elektrotanya.

To access these parts, you have to remove the back lid and the capstan flywheel (see section 12 of the manual). You will need to remove the belt, the thrust plate 10, the flywheel 13 (unscrew the two setscrews that hold it) to gain access. I am not 100% sure, but if my memory serves you don't need to unmount the capstan motor.

The problem I solved was twofold:
  • The shafts of the lifter arms (13, section 13) are mounted with grease to avoid rotation. With time, the grease hardens and the rotation becomes difficult, which is probably the problem you have. You need to remove the two arms, clean the old grease with IPA and remount with fresh grease. No need for a specific grease there, although Teac recommended DAW DC33L or Molycoat (I don't know what these are, personally I use SKF LGMT2 with good success). Also clean the grease on the spring 10. While you are at it, you may want to change the grease on the capstan shaft as well.

  • The arms 5, 11 and 12 were not flat any more for some reason and, since the contact surface in between is so thin, the left arm had forced it way and was on the wrong side of the right arm. Needless to say, the lifters were in an odd position and the system did not work as it should. The relative position of the two arms must be as shown on section 13 of the manual, otherwise you will need to check that the arms are flat and that the M3x8 screws that hold they are tight. Before reassembling the flywheel, make sure that the movement is well transmitted from the solenoid to the right and left lifters. Check this by actuating the solenoid with the Play button, as moving it by hand causes a different movement and less force on the arms, so it can work ok when testing by hand but not in actual operation (guess how I know...).

As for the small spring, it is only there to ensure that the left lifter arm makes contact with the right lifter arm when they are not actuated (lifters deployed), so it does not apply heavy lifting and does not need to be more powerful than it is.
 
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Thanks for the details to get the lifter working again like it should.
I will download the manual and take a look.
Do you know where I can find parts like now I am thinking of replacing the black rubber ring around the latger roller that is under the tape in the pinch and turn process.
And I have the feeling the driving belt of the capstan could hit the list.
Thank you
 
Greetings from RojoLand!

By "the black rubber ring aroung the [larger] roller…under the tape in the pinch and turn process" I believe you mean the pinch roller itself. Don't try to replace just the rubber on that; you need to replace the entire roller, or have the old one re-rubbered properly (by someone like Terry's Rubber Rollers). Simply slapping a new tire on it (such as you might find on the Dock-o'-the-'Bay for cheap) won't last long and will give inferior results. It's no bargain.

Take care,
—
J. E. Knox "The Victor Freak"
 
Ok perfect i will contact him, on the eebay the rubber is much thicker and looks like a complete different beast. Smaller metal part and much thicker rubber, i expect it to be a very different diameter once installed with all these changes.
 
Terry does not only do a great job, he is also a very nice person to deal with. The only problem I see is that, since he is in Michigan and you are in Europe, the shipping and taxes will be costly, especially at the moment. I can also recommend you the "Italian Terry": https://www.sofh.it/category-product/teac/a-3340-series/. I can say from experience that he is very good at making and fixing idler rollers too. The website shows the new rollers he sells, but he can also re-rubber your old one, so feel free to leave him a message on the contact page.

Another option is one of the serious ebay sellers (yes, there are a few ones), who can provide you not only with a pinch roller for your Teac, but also with belts and lubricants: https://www.ebay.fr/sch/i.html?_dkr...=0&store_name=blackreelshop&_oac=1&_nkw=a3340. I bought the spares from them for my A3340, they worked very well.
 
Thanks for the info, that’s good to know there’s availability from italy and sources from ebay.
Before I invest in the repairs,
Can you tell me how you can tell if the pinch roller has a worn rubber, uneven surface, or bearing issues from the sound quality heard from the teac or another source?
 
Tru using a straight edge. Place it perpendicular to the roller. The roller should show no gaps between the straight edge and the rubber. If gaps are present, it will not pull tape evenly. Place the deck in play mode, and place the straight edge on the face plate, so it’s rubbing slightly. Does it rub consistently, or are there parts of the roller where it loses contact? If so, it’s out of round. The surface should not be shiny-and the rubber should give ever so slightly, if you pinch it firmly-you will not see it squish-it’s all by feel.

The bearing should not make any noise when spinning. When you spin it by hand, it should feel totally smooth. You should be able to spin it and it continue to turn for a moment, perhaps spinning for a revolution or so. If you grasp the roller, it should not have any play on the shaft axis. There should be a tiny amount of play if you pull and push it-you will not see it, but you should be able to feel a tiny movement.

When you replace the belt, you should be removing the flywheel, cleaning and reapplying lubricant to the bearing and shaft. You should clean and relubricate the roller bearing and shaft.

I have done a few Teac decks, and so far, none have needed new pinch rollers-they hold up well on Teac machines. They have all needed the disassembly, cleaning, applying fresh lubricant, and reassembly.
 
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