Hello All,
I recently acquired a 600LX for $129 shipped. I could not pass it up.
It is in fair condition cosmetically, it looks like it may have been in a stadium or such at one time.
It had one bad power supply capacitor. I happen to have a stash of misc amp parts and shoe-horned in two 20,000uF/100VDC caps just for a test... that's all it needed.
Attached are some AP graphs of its performance. A little shy of the published specs, but it has plenty of power for my needs.
I recently acquired a 600LX for $129 shipped. I could not pass it up.
It is in fair condition cosmetically, it looks like it may have been in a stadium or such at one time.
It had one bad power supply capacitor. I happen to have a stash of misc amp parts and shoe-horned in two 20,000uF/100VDC caps just for a test... that's all it needed.
Attached are some AP graphs of its performance. A little shy of the published specs, but it has plenty of power for my needs.
Attachments
Older thread but wanted to chime in. Yes...the 600LX is a beast and imo the measurements you ended up with are nothing to sneeze at. AB International made some amazing amps through the years.
AB International amplifiers
Hello to all,
Just to say that I can confirm the quality of those amps.
I own some (Ex Imax) 713A,421A and 821A all with built-In active crossovers (Sub and three way).
Mid and high pcb's of the 713A look like the pcb of the 600LX,never found a good resource for the bias values..
Greetings-Jorre
Hello to all,
Just to say that I can confirm the quality of those amps.
I own some (Ex Imax) 713A,421A and 821A all with built-In active crossovers (Sub and three way).
Mid and high pcb's of the 713A look like the pcb of the 600LX,never found a good resource for the bias values..
Greetings-Jorre
Jorre,
I found a thread where a guy that was involved with the company, AB International in the early to mid 90's had this to say.
As far as I remember, the 600 offered letters behind the last zero, as they (AB) made changes.
600
600A
600LX
I own the 600A (Toroidal Transformer) and, the 600 (Black Cast Iron Transformer) Possibly, the modification of the LX was to go back to the Black Cast Iron Transformer, due to heating issues, and still offer the bridging capability, in which, the 600 did not offer.
By heating issues, I mean the 600A's heatsink would be
warm just idling, whereas, the 600 would be cold.
agedhorse
Posted May 24, 2006
The A was 1/4" only and the LX was XLR balanced. Both were square frame transformers except possibly some very early production. From my service info, 1991 an on was definately square frames. They also idled pretty cool when biased properly.
The 900A/1100A going back to 1988 were toroidal. I do not have good info on early 600's but the predecessor to the 600 used square frames.
This is the problem with so many versions of a product and my off & on involvement.
Bias voltage should be about 10-12mV across each emitter resistor on the 600's output stage. It's not uncommon to see them biased up to 50mV which is where the idle heat comes from.
The date of manufacture is coded in the serial number... date code.
I found a thread where a guy that was involved with the company, AB International in the early to mid 90's had this to say.
As far as I remember, the 600 offered letters behind the last zero, as they (AB) made changes.
600
600A
600LX
I own the 600A (Toroidal Transformer) and, the 600 (Black Cast Iron Transformer) Possibly, the modification of the LX was to go back to the Black Cast Iron Transformer, due to heating issues, and still offer the bridging capability, in which, the 600 did not offer.
By heating issues, I mean the 600A's heatsink would be
warm just idling, whereas, the 600 would be cold.
agedhorse
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Posted May 24, 2006
The A was 1/4" only and the LX was XLR balanced. Both were square frame transformers except possibly some very early production. From my service info, 1991 an on was definately square frames. They also idled pretty cool when biased properly.
The 900A/1100A going back to 1988 were toroidal. I do not have good info on early 600's but the predecessor to the 600 used square frames.
This is the problem with so many versions of a product and my off & on involvement.
Bias voltage should be about 10-12mV across each emitter resistor on the 600's output stage. It's not uncommon to see them biased up to 50mV which is where the idle heat comes from.
The date of manufacture is coded in the serial number... date code.
Nice Work! How many channels was the 713 originally? Hard to believe you could get a +7 or +8 tilt (boost) on the EQ switches...that's a lot. I wonder where the low, mid, and high frequencies were set to add or reduce the tilt there....?
100, 1000, 10,000 maybe?