lovretta
10-10-2010, 05:36 AM
Hi everyone!
Everything started in this topic (http://www.tapeheads.net/showthread.php?t=9981).
To sum up whats been written there:
I'm recording my tapes only for listening in car, recording deck is Sony TC-KA1ES/K-561S.
So, i tried with Dolby B, but those sounded really bad in car.
Then for the last few days it's been on my desk.
I found out it plays bit slower, so i adjusted that (it's now adjusted to the Sony deck, but i don't really care if it's accurate as it is sort-of closed system, i suspect "outside" tapes will ever come in).
Then i found out that azimuth is totally wrong, while listening to it in mono mode switched on on my small mixer/sound card.
So i went on to adjust azimuth... No way to do it, as it's head is "fixed", and is some sort of "double-head", so it doesn't need to flip to read reverse side.
So i did painstaking and exhaustive process of matching the azimuth of the Sony to Pioneer's head alignment.
First i tried with the pre-recorded (original) Rubber Soul album by Beatles, it sounded great in car deck, so i adjusted to it.
Now i tried to record some tapes and every one of them performed differently in car deck (?). I saw it before, but didn't do anything about it - both capstan's were VERY dirty. I hesitated with cleaning, as i still haven't got any isopopyl. But last night decided
to go for it, and clean it with "ordinary" alcohol. It took me alot of time, since capstans are very hard to reach, not speaking of pinch rollers (which i haven't touched, waiting for isopropyl).
So now i got more consistent results, but only with C90 tapes - azimuth works well, normal and reverse mode, for the whole side.
But i'm having problems with C60 tapes. Every single on of the performs differently. One is "not quite off", other one is terribly off,
third is good only on the end, and also on every C60 tape "azimuth" changes over the lenght of the tape. Most of them function well on the end of the side, but begining of the tape appears to be random, sometimes it's subtly sometime it's huge.
What could be the cause of this? Belts? Cassette player was hardly used for maybe a year or two - i connected the 3.5 mm jack to the cd-changer input and listened to various portable devices, mini disc, mp3, mobile phone...
Also, Dolby seems to work pretty well now, eventough it still eats a little amount of what it should not.
And, left channel is significantly quiter then right one, ~1.5 - 2 dB overall lower volume, for normal side, and reverse side is bit better with 1 - 1.5 dB. (head problem?)
I've posted some pictures below, one of the device front side, just in case someone has some documents about it. (i have original printed owners manual and schematics in djvu file)
Cassette transport is built around Hitachi HA12192F IC, which features everything, including Dolby decoder.
I'm plannin on to "fixing" the channel PB volume difference - i found two "trimmers" on PCB next to the cassete transport, and reading the schematic diagram and Hitachi HA12192F datasheet these are PB level trimmers, separate for left/right channel.
Mabye it helps a bit with dolby tracking? And then again, i probably haven't aligned azimuth perfectly, as i was only using music tapes, not some precision meters + calibration tapes.
Picture of the deck:
http://www.pohrani.com/t/W/Wm/2SkNvYXz/1001603.jpg (http://www.pohrani.com/?W/Wm/2SkNvYXz/1001603.jpg)
Pictures of one of the trimmers:
http://www.pohrani.com/t/2C/Lo/3Em49ota/1001596.jpg (http://www.pohrani.com/?2C/Lo/3Em49ota/1001596.jpg)
http://www.pohrani.com/t/1V/fU/2ChBzMG1/1001597.jpg (http://www.pohrani.com/?1V/fU/2ChBzMG1/1001597.jpg)
Schematic diagram of the cassette player block - check "below" the HA12192F, VR301 and VR302, connected to pin 18 & 3.
http://www.pohrani.com/t/14/bo/1Bc6uQ9y/p0005.jpg (http://www.pohrani.com/?14/bo/1Bc6uQ9y/p0005.png)
Block diagram of the Hitachi HA12192F integrated circuit
http://www.pohrani.com/t/2W/aJ/30Dv7Gqs/hitachi-ha12192f.jpg (http://www.pohrani.com/?2W/aJ/30Dv7Gqs/hitachi-ha12192f.jpg)
Everything started in this topic (http://www.tapeheads.net/showthread.php?t=9981).
To sum up whats been written there:
I'm recording my tapes only for listening in car, recording deck is Sony TC-KA1ES/K-561S.
So, i tried with Dolby B, but those sounded really bad in car.
Then for the last few days it's been on my desk.
I found out it plays bit slower, so i adjusted that (it's now adjusted to the Sony deck, but i don't really care if it's accurate as it is sort-of closed system, i suspect "outside" tapes will ever come in).
Then i found out that azimuth is totally wrong, while listening to it in mono mode switched on on my small mixer/sound card.
So i went on to adjust azimuth... No way to do it, as it's head is "fixed", and is some sort of "double-head", so it doesn't need to flip to read reverse side.
So i did painstaking and exhaustive process of matching the azimuth of the Sony to Pioneer's head alignment.
First i tried with the pre-recorded (original) Rubber Soul album by Beatles, it sounded great in car deck, so i adjusted to it.
Now i tried to record some tapes and every one of them performed differently in car deck (?). I saw it before, but didn't do anything about it - both capstan's were VERY dirty. I hesitated with cleaning, as i still haven't got any isopopyl. But last night decided
to go for it, and clean it with "ordinary" alcohol. It took me alot of time, since capstans are very hard to reach, not speaking of pinch rollers (which i haven't touched, waiting for isopropyl).
So now i got more consistent results, but only with C90 tapes - azimuth works well, normal and reverse mode, for the whole side.
But i'm having problems with C60 tapes. Every single on of the performs differently. One is "not quite off", other one is terribly off,
third is good only on the end, and also on every C60 tape "azimuth" changes over the lenght of the tape. Most of them function well on the end of the side, but begining of the tape appears to be random, sometimes it's subtly sometime it's huge.
What could be the cause of this? Belts? Cassette player was hardly used for maybe a year or two - i connected the 3.5 mm jack to the cd-changer input and listened to various portable devices, mini disc, mp3, mobile phone...
Also, Dolby seems to work pretty well now, eventough it still eats a little amount of what it should not.
And, left channel is significantly quiter then right one, ~1.5 - 2 dB overall lower volume, for normal side, and reverse side is bit better with 1 - 1.5 dB. (head problem?)
I've posted some pictures below, one of the device front side, just in case someone has some documents about it. (i have original printed owners manual and schematics in djvu file)
Cassette transport is built around Hitachi HA12192F IC, which features everything, including Dolby decoder.
I'm plannin on to "fixing" the channel PB volume difference - i found two "trimmers" on PCB next to the cassete transport, and reading the schematic diagram and Hitachi HA12192F datasheet these are PB level trimmers, separate for left/right channel.
Mabye it helps a bit with dolby tracking? And then again, i probably haven't aligned azimuth perfectly, as i was only using music tapes, not some precision meters + calibration tapes.
Picture of the deck:
http://www.pohrani.com/t/W/Wm/2SkNvYXz/1001603.jpg (http://www.pohrani.com/?W/Wm/2SkNvYXz/1001603.jpg)
Pictures of one of the trimmers:
http://www.pohrani.com/t/2C/Lo/3Em49ota/1001596.jpg (http://www.pohrani.com/?2C/Lo/3Em49ota/1001596.jpg)
http://www.pohrani.com/t/1V/fU/2ChBzMG1/1001597.jpg (http://www.pohrani.com/?1V/fU/2ChBzMG1/1001597.jpg)
Schematic diagram of the cassette player block - check "below" the HA12192F, VR301 and VR302, connected to pin 18 & 3.
http://www.pohrani.com/t/14/bo/1Bc6uQ9y/p0005.jpg (http://www.pohrani.com/?14/bo/1Bc6uQ9y/p0005.png)
Block diagram of the Hitachi HA12192F integrated circuit
http://www.pohrani.com/t/2W/aJ/30Dv7Gqs/hitachi-ha12192f.jpg (http://www.pohrani.com/?2W/aJ/30Dv7Gqs/hitachi-ha12192f.jpg)