I recently purchased a set of these mono blocks second hand and have had difficulty finding information about them. I'm particularly looking for a schematic so I can pass onto the tech who is checking them out for me. Can anyone help out on this? Schematic now located and added to the post.
Due to the lack of information around about these, I thought I'd start a thread to collect it in one place in the hope I help someone in the future.
So far I've found the following:
Designer seems to be Joseph Lau
ASL home page (looks old and half the email addresses don't seem to work) - http://www.tubehifi.com/main_page.htm - no longer in production
Looks to be currently distributed by Divergent Technologies - http://www.divertech.com/antiquesl.html
Schematic for Northern American built amps located and added below.
Biasing information - https://www.audioasylum.com/cgi/t.mpl?f=tubes&m=113626 - extract from the information provided by Joseph below for future reference, in case it disappears..
Antique Sound Lab AQ 1009 DT mono power amplifiers
Bias instructions: Output tubes (845)
(A small slot-tip screwdriver required)
- Install al the tubes as shown and marked on the manual.
- Connect amplifier to loudspeakers and turn them on.
- Select an out put tube (VB-1 or VB-2) by the small round switch, located in between the two out tubes.
- Adjust the set screw next to selected tube (VR-1 or VR 2) until the digital meter ready 800 ¨C 850 (milivolt).
- Repeat this procedure with both 845-output tubes.
- Allow amplifier to warm up for 15 minutes and try again.
Bias instructions: Driver Tubes (KT66, 6L6 or EL34), (not always necessary).
(A voltmeter and a small slot-head screw driver required).
- Install al the tubes as shown and marked in the manual.
- Connect amplifier to a loudspeaker and turn it on.
- Set voltmeter to milivolt DC setting.
- Connect the (-) ground probe of the meter to anywhere on the chassis.
- Connect (+) positive probe of the meter to TP, located next to the one of KT66 tube.
- Adjust the setscrew (VR-4 or VR-3) next to the tube to 300-350 milivolt DC .
- Repeat this procedure for the other driver tube.
Some internal shots of my amps and a shot of the front with the 845 tubes removed, showing biasing controls and hum pots (I believe these have changed design over time)
I'll update this post with more information as it comes to light. In the meantime, I'd welcome any assistance on located schematics.