I am hoping someone will be able to offer some opinion / advice on an issue I am experiencing with my early(ish) 8000A - serial no 8711454 - PCB No 10257.32.
I have owned this from new in the mid 80s and it's like one of the family so I am loathe to part with it (even though I know there are many better amps out there). Originally I used it as an integrated, and then as a preamp into a Meridian 557 which has recently replaced an Audiolab 8000SX.
When I switch it on I get a very loud thump through the speakers almost immediately after the switch is pressed. After around 10 seconds I can hear the click from the speaker protection circuit. On switching off I get a similar thump together with a squeal.
I can get around this by turning the 8000A on and then after 10-15 seconds I turn the power amp on (and then do the reverse when switching off), but this is a faff as the power button for the 557 is at the back and not easy to get to.
I would like to know what might be causing this issue and if there is a simple / low cost fix for it, or do I need to face up to the fact that I've had my money's worth out of it and look for a new preamp? Ideally I'd prefer to squeeze a bit more life from it before trying to decide on a replacement.
Any thoughts gratefully received. I am very much not an electrical engineer but can just about tell the difference between a capacitor and a resistor! I have had the cover off the unit and cannot see any obviously leaking capacitors but the main part of the PCB has browned from heat.
Thanks.
I have owned this from new in the mid 80s and it's like one of the family so I am loathe to part with it (even though I know there are many better amps out there). Originally I used it as an integrated, and then as a preamp into a Meridian 557 which has recently replaced an Audiolab 8000SX.
When I switch it on I get a very loud thump through the speakers almost immediately after the switch is pressed. After around 10 seconds I can hear the click from the speaker protection circuit. On switching off I get a similar thump together with a squeal.
I can get around this by turning the 8000A on and then after 10-15 seconds I turn the power amp on (and then do the reverse when switching off), but this is a faff as the power button for the 557 is at the back and not easy to get to.
I would like to know what might be causing this issue and if there is a simple / low cost fix for it, or do I need to face up to the fact that I've had my money's worth out of it and look for a new preamp? Ideally I'd prefer to squeeze a bit more life from it before trying to decide on a replacement.
Any thoughts gratefully received. I am very much not an electrical engineer but can just about tell the difference between a capacitor and a resistor! I have had the cover off the unit and cannot see any obviously leaking capacitors but the main part of the PCB has browned from heat.
Thanks.
Are you saying you have used the 8000A as a preamp and not had this problem because the preamp output does not have muting . On boards with ser. no 89... a preamp muting relay could be added . A note in the service manual for ser no 87... (downloadable from Hifiengine ) suggests you do exactly what you are doing to overcome the issue .
Hi and thanks for your reply. When last I used the A as an integrated I didn't have the thump. When running the 8000A as a preamp into my 8000SX I was getting it and used to get around it in the same way by switching on the A first and the SX after the A's relay had clicked (and then off in reverse order). Since changing from the SX to the Meridian the thump is way louder (attributable to it being a more powerful amp I presume?).
Doing this wasn't a problem on the A/SX combo because power switches are at the front of the units, however it's a pain with the 557 due to the switch being at the back.
So from what you have told me it seems I am stuck with having to use the same switching on/ off sequence because my board is the earlier 87... type. Maybe it's time to choose a new preamp after all and retire the 8000A.
It's reassuring to know that the 8000A is behaving as it was designed to at least, so thanks for the info.
Doing this wasn't a problem on the A/SX combo because power switches are at the front of the units, however it's a pain with the 557 due to the switch being at the back.
So from what you have told me it seems I am stuck with having to use the same switching on/ off sequence because my board is the earlier 87... type. Maybe it's time to choose a new preamp after all and retire the 8000A.
It's reassuring to know that the 8000A is behaving as it was designed to at least, so thanks for the info.