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    Building, troubleshooting and testing of these amplifiers should only be
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Antique Sound Lab Aq1003

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Joined 2004
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Try contacting ASL in Hong Kong by email, you may be able to get a replacement for a reasonable amount of money. Shipping it here will cost more, but it will be form, fit, and function compatible. IMHO you need to find out why it failed, it could be that the amplifier was incorrectly biased and the transformer overheated or it may be that the transformer was defective. They were an oem for my business and I never had one of their power transformers fail.
 
Thank you for your advice .

I also wonder why the transformer failed . Before this problem , everything was normal & the tranformer didnt show any overheated problem . May I know if any other possible factors that may cause this unit to malfunction ?
Only thing I remember was I on the amp for about 5 hrs before the whole amp blacked out .From then onwards , fuse always blow .

regards
 
AQ1003DT Manual or schematic

Hi guys,
I'm wondering if any of you guys might have a copy of the schematic for this amp or maybe a manual for the Antique Sound Lab AQ1003DT integrated amp.
I'm buying (my first entry into the audiophile world) a nice, mint, used one and there is no manual with it.
So I would like to see the schematic, of course, anyway.
Maybe someone can direct me to a site for a users manual too?
If you have the schematic print at least and are willing to help me out by emailing me a copy, I'd very much appreciate it.
I'm at:
pbpix AT optonline DOT net

Also... I know it sounds very noobie-dumb ....but I would like to know if anyone can recommend a pair of reasonably-priced (maybe book-shelf) speakers below $400 that I can hook up to it to begin to appreciate what I have here.

Thank you,
Peter
 
Here's a lousy low rez schem.

jeff
 

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You can get free replacement if it is under warranty. All transformers warranty for 5 years. Upcomming ASL products will be much more relaible than before.

1. It will have self recovr overheat protection.
2. Power tube over current protection. This new protection system can protect amplifiers even short circuit tubes.
3. Soft Startup/Off , Pre-heat system will also include.
 
I have a used ASL AQ1003 which does not have any serial number etc. So I can't say how old it is.
Can some one tell me how to set the bias for the output tubes and what the value should be. From what I have read so far I find that the measured voltage should be 0.4 Volts across the measurement terminals.
The terminals are on the side of the amp . Four holes appear to be access to the small pots and the single terminal at the rear appears to be the point for the meter with ground coming from the speaker ground terminal. Position 1 on the measurement switch appears to be off. Followed by tube ( EL34) 1, 2,3,4 from left to right.
How old is this amp ?
Cheers.
 

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For anyone who might be interested....

I got a message that this amp is 15 to 19 years old.
Would anyone have a circuit diagram for this. It's probably different from the versions that are numbered with a DT like AQ1003-DT . I see several film Bennic coupling caps inside. There are a couple of Samwah electrolytics. Must have been replaced by the owner ?

Can I get any service information at all ? Thanks.
 
ASL amp AQ1003

Look at the schematic on the previous page that someone posted for me.
I have that DT model which uses its own built-in meter.
Compare your circuit to that print to see if yours uses the same 10 ohm current sampling resistors in the cathode of each EL34.
The print shows a -37v grid bias.
In class AB1 the specs for EL34 show a plate current of 120ma.

If that's the same current your amp is operating at, and if the sample cathode resistor is 10 ohms, then you should be reading 1.2v across that resistor....I think.
 
Hi pbpix ,
My amp is running at about 30 mA. There is 0.3 V across that 10 ohm resistor. In fact one tube is set at 27.8 mA and I can't get it to go higher as the pot is at it's max setting.
Additionally I was informed by Divergent Technologies that the bias is 30 to 35 mA on this amp.

It does sound good as it is. Was wondering if the Bennic caps can be replaced by something audibly better ?
All those wire wound resistors appear too close to the electrolytic supply capacitors. Wouldn't it kill their life span ?
 
My unit had NOS 12BH7 input tubes. I changed them to new EH gold pin 12BH7's. Sounds very much better. I also tried new Sovtek 12AU7's. They sound good too but slightly brighter than the EH. Both types sound better than the NOS 12BH7's.
There is slight hum at the speaker but not audible from the listening position about 12 feet away.

Is there a Russian equivalent of the 12BH7 ? I guess the pin out will be different too .

I noticed the circuit diagram says 5 A for both heater windings. So using 12BH7's with double the heater current compared to the 12AU7 will not matter.
 
Hi pbpix ,
My amp is running at about 30 mA. There is 0.3 V across that 10 ohm resistor. In fact one tube is set at 27.8 mA and I can't get it to go higher as the pot is at it's max setting.
Additionally I was informed by Divergent Technologies that the bias is 30 to 35 mA on this amp.

It does sound good as it is. ?
If you move the EL34 tube w/27.8 ma to another socket does the current stay the same?
Will the pot be maxed out at a current of 27.8 there as well?
If so, it seems to indicate that tube is weak and should be replaced.
 
Hi pbpix ,
My amp is running at about 30 mA. There is 0.3 V across that 10 ohm resistor. In fact one tube is set at 27.8 mA and I can't get it to go higher as the pot is at it's max setting.
Additionally I was informed by Divergent Technologies that the bias is 30 to 35 mA on this amp.

It does sound good as it is. Was wondering if the Bennic caps can be replaced by something audibly better ?
All those wire wound resistors appear too close to the electrolytic supply capacitors. Wouldn't it kill their life span ?
BTW:
Are all the parts shown on that print the same for your unit except no on-board meter?
What is the grid#1 voltage on your unit? The print shows that is should be -37v.

As for other tubes:
I am using 12AU7A input tubes but I have also subbed in 5963 with good results.

I don't know anything about the Bennic caps. Where are they used?

As far as the WW-resistors being close to E-caps, I don't think it's a problem unless they get really hot.