I plugged the amp in with Dim light bulb and it wasn't dim. One of the transistors is the cause of the short circuit. There were also a couple of leads disconnected. It didn't appear thatthey were intentionally disconnected.
With the shorted transistor disconnected and everything else strapped down, I plugged in to the dim light bulb and it remained dim. I plugged it in directly to the mains, flipped the switch and no sparks. I then checked DC offset at speaker connectors. I don't know what it should be but at half a volt I felt safe that it wasn't going to kill me or burn the house down.
I connected the assumed functional channel and heard nothing. But wait.... What's that? Sound was coming frome one ok the choke or caps. That's a first for me. From what I can see, The smaller pair of transformers do not have primary and secondary leads, the larger two may be the same. But beyond doubt the smaller pair has only two leads each. Does that mean they are are chokes? Somebody wanna buy this thing? My brain Capacity allows me only enough space to bulld and maintain my studio at best and this is a distracton albeit quite interesting
With the shorted transistor disconnected and everything else strapped down, I plugged in to the dim light bulb and it remained dim. I plugged it in directly to the mains, flipped the switch and no sparks. I then checked DC offset at speaker connectors. I don't know what it should be but at half a volt I felt safe that it wasn't going to kill me or burn the house down.
I connected the assumed functional channel and heard nothing. But wait.... What's that? Sound was coming frome one ok the choke or caps. That's a first for me. From what I can see, The smaller pair of transformers do not have primary and secondary leads, the larger two may be the same. But beyond doubt the smaller pair has only two leads each. Does that mean they are are chokes? Somebody wanna buy this thing? My brain Capacity allows me only enough space to bulld and maintain my studio at best and this is a distracton albeit quite interesting
Attachments
Can you post some well-lit, in-focus photos of the circuit board near the front? That would be incredibly helpful.
The pair of open-frame chokes you photographed are chokes. The bigger ones are chokes IF the only leads they have are the black and yellow attached to the PCB.
I'd like to see a photo of the back panel also.
The pair of open-frame chokes you photographed are chokes. The bigger ones are chokes IF the only leads they have are the black and yellow attached to the PCB.
I'd like to see a photo of the back panel also.
In post#1 we can see that the negative terminals of all four electrolytic capacitors are connected together. So this is not a bipolar power supply providing ±X volts. Instead it is two single ended power supplies, each providing +X volts. One supply for the left channel and the other for the right channel.
The output stage appears to consist of a single transistor in TO-3 package, mounted to the enormous heatsink on the side of the cabinet. This makes me think the output stage is a single ended class-A affair, with a transistor driving the primary of an output transformer, whose secondary drives a loudspeaker.
The amplifier PCB seems to contain 3 transistors per channel. One is a metal can TO-18, one is a plastic TO-92, and one is a power transistor in a TO-220 package with its own 1.5 inch PCB mounted heatsink. Then there's a DIP8 (opamp?) and a TO-220 device shared between the channels -- voltage regulation?
It smells like one of those John Linsley Hood or Rob Elliott "minmal transistor count" low wattage class A amps. With a huge amount of money spent on transformers and chokes.
The output stage appears to consist of a single transistor in TO-3 package, mounted to the enormous heatsink on the side of the cabinet. This makes me think the output stage is a single ended class-A affair, with a transistor driving the primary of an output transformer, whose secondary drives a loudspeaker.
The amplifier PCB seems to contain 3 transistors per channel. One is a metal can TO-18, one is a plastic TO-92, and one is a power transistor in a TO-220 package with its own 1.5 inch PCB mounted heatsink. Then there's a DIP8 (opamp?) and a TO-220 device shared between the channels -- voltage regulation?
It smells like one of those John Linsley Hood or Rob Elliott "minmal transistor count" low wattage class A amps. With a huge amount of money spent on transformers and chokes.
This brand was mentioned 2003 in context with a review of two power conditioner devices - go to
https://web.archive.org/web/20031206111711/http://cgi.audiogon.com/cgi-bin/cl.pl?accspowr&1074732135
maybe this distributor telephone numbers, email address and post address are still up to date:
https://web.archive.org/web/20031014061243/http://www.musicfirstdistribution.com/
but I don't think, the currently web address is the same distributor:
https://musicfirstdistribution.ca
Are there anywhere a model naming on your amplifier envelope like on the last image under
https://www.whatsbestforum.com/thre...0-line-conditioner-among-the-very-best.20350/
more URLs:
https://www.audiocircle.com/index.php?topic=6253.0
https://corbysaudio.com/used/demo-for-sale/f/foundation-research-lc100-line-conditioner-1850
https://www.canuckaudiomart.com/details/649334969-foundation-research-v6-preamp/images/1460896/
https://www.aussieaudiomart.com/details/649334969-foundation-research-v6-preamp/images/1460892/
https://www.canuckaudiomart.com/det...research-nl1-noise-load-pairs/images/1464754/
what means this term?
Copland CTA 501 Stereo Amplifier c/w Foundation Research Upgrades - go to
https://www.aussieaudiomart.com/det...-foundation-research-upgrades/images/1734555/
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