Hi all, new member from Sweden here, been reading a lot in the forum and posting now for first time, needing advice regarding an Alpage AL-300 cassette deck.
Many years back I bought this new, had it for a year or two then sold it to a friend. A few months ago I meet him and asked if he still had it, and yes he had it put away in the garage many years ago. He asked me if I wanted it, I said yes and he gave it to me for a nice bottle of whiskey in exchange.
Well, the deck was rater dirty from being stored in the garage whitout a box for a long time so I took it apart. Cleaned the entire deck, changed belts, idler tires and pinch rollers, lubed/oiled moving parts.Cleaned the tape head with aceton and polished with autosol, cleaned again with IPA.
Everything works fine, wow and flutter is ok.
When checking the playback frequency responese, the the response is falling from 1 KHz, reaching a minimum at -6dB around 10-12 KHz and then rising again towards 18KHz (se graph). Test was done using the tape from HPR, azimuth was adjusted (with analog oscilloscope) to match the response tape.
A -6dB high frequency loss does not look so good, so did another test with a flux loop to see if the loss was due to the playback eq or elsewhere. As it looks to me the flux loop curve nearly exactly follows the table from the Ampex flux loop paper, so if the flux loop curve looks right the playback response should be more or less a flat if the tape head is in good condition? If so, the HF loss much be due to the tape head?
Found a graph of the AL-300 playback response on LAB2104 Research Labratory homepage showing a -4dB loss at 10 KHz. Not as much loss as my deck but indicating that the loss could be expected.
After calibrating and doing a frequency sweep, I have no problem getting a flat record/playback response up to 20 KHz with low distortion and minimal channel imbalance. Used tapes was TDK SA (Chrome) and TDK D (Normal), both resulting in frequency response above 20 KHz.
This makes me a little confused rising some questions.
1. Is the IEC tape playback HF loss normal for this type of tape head/cassette deck?
2. Can the HF loss be due to wear of the head? As I understand, being a Ferrite head it sholud not be as sensitive to wear as other heads with softer alloys?
3. Have read some about Ferrite heads being sensetive to corrosion widening the gap, knowing that the deck has been stored in a garage (not in a box) for shurley more than ten years, exposed to humidity and temperature changes, could this have affected the head?
4. If cause is 2 or 3 above, could a relap of the tape head fix the HF loss?
The tape head is ALPS (41139, U02,A01F) as I read in the forums highly regarded. Picture of head below, not enough magnification to show if wear or not but maybe the general condition of the head.
Any advice or thoughts would be most welcome.
Many years back I bought this new, had it for a year or two then sold it to a friend. A few months ago I meet him and asked if he still had it, and yes he had it put away in the garage many years ago. He asked me if I wanted it, I said yes and he gave it to me for a nice bottle of whiskey in exchange.
Well, the deck was rater dirty from being stored in the garage whitout a box for a long time so I took it apart. Cleaned the entire deck, changed belts, idler tires and pinch rollers, lubed/oiled moving parts.Cleaned the tape head with aceton and polished with autosol, cleaned again with IPA.
Everything works fine, wow and flutter is ok.
When checking the playback frequency responese, the the response is falling from 1 KHz, reaching a minimum at -6dB around 10-12 KHz and then rising again towards 18KHz (se graph). Test was done using the tape from HPR, azimuth was adjusted (with analog oscilloscope) to match the response tape.
A -6dB high frequency loss does not look so good, so did another test with a flux loop to see if the loss was due to the playback eq or elsewhere. As it looks to me the flux loop curve nearly exactly follows the table from the Ampex flux loop paper, so if the flux loop curve looks right the playback response should be more or less a flat if the tape head is in good condition? If so, the HF loss much be due to the tape head?
Found a graph of the AL-300 playback response on LAB2104 Research Labratory homepage showing a -4dB loss at 10 KHz. Not as much loss as my deck but indicating that the loss could be expected.
After calibrating and doing a frequency sweep, I have no problem getting a flat record/playback response up to 20 KHz with low distortion and minimal channel imbalance. Used tapes was TDK SA (Chrome) and TDK D (Normal), both resulting in frequency response above 20 KHz.
This makes me a little confused rising some questions.
1. Is the IEC tape playback HF loss normal for this type of tape head/cassette deck?
2. Can the HF loss be due to wear of the head? As I understand, being a Ferrite head it sholud not be as sensitive to wear as other heads with softer alloys?
3. Have read some about Ferrite heads being sensetive to corrosion widening the gap, knowing that the deck has been stored in a garage (not in a box) for shurley more than ten years, exposed to humidity and temperature changes, could this have affected the head?
4. If cause is 2 or 3 above, could a relap of the tape head fix the HF loss?
The tape head is ALPS (41139, U02,A01F) as I read in the forums highly regarded. Picture of head below, not enough magnification to show if wear or not but maybe the general condition of the head.
Any advice or thoughts would be most welcome.
