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A question about playback

boonie

boonie

Active Member
Hey there, folks. I am running 2 decks currently - a Denon DR-M33HX and an Akai GXC-730D. I've noticed that on a couple of tapes I have when I play them in the Denon the volume fluctuates (goes soft for a few seconds then normal level for a few seconds then soft again for a few seconds and so forth). If I switch the same tape over and play it in the Akai it plays fine. This has only happened on 3 tapes so far (have only had both decks for a few weeks) and on one of the tapes the Denon chewed the tape a little.
Any ideas what's going on here? Is it a sign of a potential issue? Or just a matter of a tape not suiting the deck?
Any info would be appreciated.
Cheers,
Luke
 
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Did you open the Denon up and have a look at the pinch roller? I would start suspecting that it needs replacement.
 
are the rollers soft? sticky? or just real dirty. Start by using a real tape head cleaner. I only use American Recorder. Use q-tips and clean the rollers til the q-tip stays white. Personally, I never recommend alcohol. Never!! No matter what some think, alcohol softens rubber.

Before you used them the first time, you should have given the heads/tape path a good cleaning. Especially if you have no idea how the previous owner treated his gear.
 
The rollers aren't soft or sticky at all and no cracking. I cleaned the rollers and whilst some dirt came off they weren't overly dirty. And the tape player came in good condition from a collector of 3 head tape decks.
I just can't understand how if the the pinch rollers were faulty why it wouldn't be affecting all the tapes played on it. But apart from the 3 tapes (none dubbed on this deck) that it plays funny it plays everything else fine. And it records tapes perfectly.
Could it be just an alignment issue with those tapes?
 
It might be a tape issue.
I have a Suzanne Vega tape that on the WM-D6C, during "Luka", a very specific portion of the left channel sometimes cuts off. I rewind, pop the tape, put it back in and it plays fine. Then pop again and the same parts cut off again.
This never happens with any other of my tapes. I can't see how the pinch roller is at fault here as what will happen is speed variations, not volume. If the volume changes are somewhat constant and regular, it might be print-through or something. Some of my tapes during the first minute or so did something similar; I erased the tapes and re-recorded and the problems disappeared.
 
As others have said, pinch rollers. Also back tension and take up tension. To really check thos, you need a torque tape. Where the volume drops on your tape, take the tape out and look at the tape. Is it creased?
 
Yeah, it's definitely volume variation not speed. And the tape gets chewed a bit along the top of the tape.
But when I put that same tape in the akai it plays through just fine.
It's a mystery.
 
Hey Boonie, Is that Body Count in your avatar?? If so, cool. I saw them once at the Omni in Oakland CA. The Omni was a club owned by John Nady of Nady wireless systems fame. I saw their tour when cop killerwas making a big bruhaha.

So, for stable tape motion in play, the pinch roller pinches the tape to the metal capstan. This determines the speed that the tape will roll. The supply reel (left side if the open part of the cassette is down) adds a little bit of drap called back tension. It's usually about 7~10gr/cm of drap. This allows the tape to be "streched" across the had. This is important for tape/head contact pressure AND so the pinch roller doesn't start eating tape. The supply reel( right side when the opened part of the cassette is down), supplies take up torque. This is to wind the tape AND to prevent the pinch roller from eating tape. Ideally the take up torque should be around 40~50 gr/cm. There really is no mystery, these are the things to fix when tape eating occurs. Also, try to stay away from tapes longer than C-90 (45 minutes per side). Longr tapes are thinner and more troublesome in getting accross the pinch roller safely.
 
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Hey mate. My avatar is John Cale from the cover of his album Guts. But the funny thing is I saw Bodycount on the Cop Killer tour in Australia. :D

I'm afraid the bulk of your post went way over my head as I'm technically challenged. But raising the thinness point could it just be that these particular tapes have tape that is too thin for this unit?
 
boonie said:
Hey mate. My avatar is John Cale from the cover of his album Guts. But the funny thing is I saw Bodycount on the Cop Killer tour in Australia. :D


I'm afraid the bulk of your post went way over my head as I'm technically challenged. But raising the thinness point could it just be that these particular tapes have tape that is too thin for this unit?
Click to expand...

Wow!! John Cale is sporting a flying V and a hockey mask?!?! For reliable tape operation, stay away from tapes longer than C-90. Yes, it does make a difference in reliablity. Some decks seem to handle them, some don't. At the first sign of any trouble, the thinner tapes get chewed. Not so much for C-90 and shorter.
 
Thanks, mate. None of the tapes were longer than c-90. Most of the tapes I listen to however are experimental artists produced now in small runs of 100 and less using modern tape (like that offered by National Audio Company) and then dubbed either on home decks or professionally dubbed. The tapes that had trouble were type 1's. Maybe they were stretched thin when put together? Or maybe the dubbing process did something?
 
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