HF loss - general

ANT knows best, but I'm reasonably certain you would need to re-set bias and gain for sure with a head change. Behavior of one head to another would not be exactly the same...
 
Makymak said:
As I have replaced heads on an exactly same deck as yours, I can definitely confirm that you will need to recalibrate the deck after the replacement.
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OK, but question still remains, what is a reason my deck was so off?!
 
WOPL Sniffer said:
Azimuth too????
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To start with, test tape (ANT is a great choice), gauge for head adjustment and multimeter are ground. Without those 3 tools the one should absolutely not touch a head screws. If a head is not properly adjusted or dirty there is no need to check other things. To say, healthy tape path and mechanics first. So, no discussion about that.
What I'm wondering is, what can be a reason a deck become under-/overbiased, beside heads. Degradation of some components or ...
 
Alex SE said:
OK, but question still remains, what is a reason my deck was so off?!
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I truly don't know. Maybe some bad replacement parts? Some new caps are not on spec? Wrong calibration? Can't say. There are worse cases, though. When I bought my first RS-B965, the heads were so badly adjusted by the factory that over the years of use, there was an offset groove accumulated (half the left channel core of the pb head was out of the tape path)... Now consider how badly this deck was sounding...
 
Makymak said:
I truly don't know. Maybe some bad replacement parts? Some new caps are not on spec? Wrong calibration? Can't say. There are worse cases, though. When I bought my first RS-B965, the heads were so badly adjusted by the factory that over the years of use, there was an offset groove accumulated (half the left channel core of the pb head was out of the tape path)... Now consider how badly this deck was sounding...
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Don't believe caps are out of specs, I have used only Nichi and Pana from DigiKey. Soldered carefully and quickly, at 390 degree Celsius.
Now when you are saying, it can be a same problem with my heads thus mine doesn't look bad. There is signs of use but not groove. Planning to buy new one and will try to send those I have for re-lapp so that I have one in reserve.
 
You could easily see the wear pattern in my case. But at your case, it looks like something electronic and not mechanical (in my book, the wear of the heads is mechanical and not electronic issue). Since you switched the whole frond with another and the issue continues to exist, then it's not mechanical. It's something on the pcb. Alex was clearly identified the problem as overbiasing. In my opinion, you have to find out why. A deck should not behave like that.

Sorry I can't give you some serious help.
 
Alex just knows how equipment is breathing. If aliens would crash on the earth he would be able to fix their spaceship and to upgrade it with a cassette stereo :) So much about Alex. What Nikola Tesla was for electricity, Alex is for audio equipment. It is sad that he dont have some kind of youtube channel with explainings about how things works, but I understand that he is very busy and his time is extremely limited.
 
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Regular good Technicians can mount a head- it just takes an understanding of what is needed. Many decks do not have the hardware to move heads in a lot of directions and mostly only the Nakamichi decks do. The Tascam 122 Mk II and Mk III were much better. People have worn out heads and think they are still good by looking at them. I have one reel deck here that the owner said the heads were fine- they should have been replaced at least 600 hours ago. You can not get anything about heads from owners as they are evaluating the heads with their pocket book and do not have experience to know what a work head looks like- neither do some E bay sellers from the looks of things. Some Cassette heads will show no wear marks as Permalloy head show- they can still be worn out.
How did the deck get into the wrong bias? It might have been that way since Day 1. Assembly lines are only concerned with getting a deck to work not to make it perfect- if a deck has a problem in warranty that is the best thing as most factory service places I worked at did correct and precise calibration to a repaired deck. I was one of the guys doing it in the 80's till now. There are some Technicians at places that do not have a clue- these are not the high end or Lead Technicians they are just the workers. In my experience, some guys were more concerned with keeping a cigarrette going than doing the job. Now days I don't think smoking would even be allowed in the shop- it is not in mine.
 
I have every confidence in Alex's ability and advice. He is almost the only one I listen to myself. But let us not make him Pope. I don't think he wants the job anyway.
 
Skywavebe said:
Some Cassette heads will show no wear marks as Permalloy head show- they can still be worn out.
How did the deck get into the wrong bias? It might have been that way since Day 1.
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Can be both first and second. Fact is that I can't feel any "lines" under the nail, don't know, maybe there is some wear I can't see. Dont have microscope to see. Have checked by zooming a photo, couldn't see nothing special. Maybe it was so from a first "factory" day but I dont believe it would be so much. Maybe even previous owner have "adjusted" it. Thats why I say I'll make an pdf with all details and maybe even pictures of what I have done with a deck.

Regarding Alex and Pope, lets not involve religion and politics here in the House of Phoenix. Alex is a genius and Pope ... I don't know, never spoke to him.
 
Heads should be examined with a eye loop or some kind of magnification. Still you need to know what wear looks like on different heads. On ferrite it looks like a white abrasion that should not be there. Glass heads might look a bit the same. I thought on the graph that record EQ or bias would make the difference. Some designs are different in how they affect the recording. The fingernail test is a total waste of time because it really tells you nothing and I do not even do it.
 
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