I am new to this forum and was hoping you guys could answer some questions for me (please). I did use the search engine to try to get some answers but could not find much on the ADS PA-1's.
I am an ADS enthusiast and own quite a bit of their equipment including a pair of L1090's in walnut (that I recently refinished), a pair of M12/90's in black lacquer, and three pairs of L1290's, two are Series 1 (one pair in pristine condition and the other in good condition) and a pair of Series 2 (somewhat beat up but sound great), all in walnut. I also recently acquired a pair of ADS PA 1 Bi-amplifiers at what I thought was a good price ($500 for the pair). Both pair of the series 1 L1290's have the cavity in the rear for the amps, the series 2 does not. I have only tried them on one set of the L1290's and they sound really good. Now for the questions.
1) Although sounding really good, one of the amps cuts out after playing music at moderate levels for a few hours. It will play fine again after the amp is off for awhile, but will then cut off again after some length of time. I assume there is a thermal device somewhere in the power supply circuitry that is tripping at some level of internal heat but since I did not receive any documentation with the amps, I can not verify this. Can anyone help?
2) The set of L1290's I am using (the good condition pair) had their internal crossovers modified by Audio Proz in Massachusetts due to a forwardness of their midranges (a common series 1 issue). I was still not completely happy with the sound... has an overall megaphone sound but the midranges are no longer forward sounding. I also had the tweeters and midranges rebuilt by Richard So in Arizona (former ADS Technician). This improved the sound further but there was still a slight megaphone tint to the sound. Anyway, on to my question. Does anyone know if the crossovers internal to the speakers are completely eliminated when the Bi-amp switch on the rear of the speaker is activated or does some of the signal still pass through the internal crossovers? It sounds to me like maybe the signal is completely bypassed since I do not seem to hear the megaphone sound anymore. But without documentation, I really do not know for sure.
3) Does anyone know where I would be able to find the User's and Service Manuals for the ADS PA 1 Bi-amplifiers? I would definitely be willing to pay for them as long as the price somewhat reasonable. I know these Bi-amps are rare so I fully expect that the documentation would be hard to find also. BTW, I am currently using a Adcom GFP-565 as a preamp for these amps and a Philips/ Magnavox CDB 650 CD player (using the unfiltered outputs) along with my new addition, an echo dot playing Amazon Prime Ultimate collection (I know, I know, MP3 files vs lossless audio... not quite there yet on that decision).
The PA-1's are running on my second system that formerly employed an Adcom GFA-555 MK2 amp for power along with the preamp, cd player and the L1290's mentioned above.
My main system consists of an Adcom GFP-750 (in passive mode), an Adcom GFA-5500 amplifier, a Musical Concepts modified Philips/ Magnavox CDB 650 CD player and a Denon DP-15F entry level turntable. I also employ an REL Storm sub with this system for the extreme lows on some recordings. I mostly use the M12/90's with this set up but sometimes switch out to the pristine pair of L1290's. Both pair sound great but the M12/90's hold a slight edge in imaging. I would like to try the PA 1's in the L1290's on this system soon after fixing the cut out issue.
I am a mid-fi guy who loves the sound I get from ADS, Adcom and Philips equipment so I am not looking to change that, at least at this point anyway.
Any help you guys could give would be greatly appreciated.