I bought a set of mirrored 6550 push pull mono blocks yesterday.
The owner didn't have much info on them.
I paid a good price not knowing what the transformers are. Does anyone recognize the amplifiers or transformers?
They originally ran 4x 6550s with 5687 direct coupled cathode follower drivers, fixed bias, pentode mode, push pull parallel for something approaching 200w output power.
Any clues or info would be much appreciated.
Each amplifier weighs more than a 50 pound bag of chicken feed.
Chassis are 11" ×17" and the big caps are nearly the size of a can of beer.
What have I gotten myself into this time?
Thank you in advance.
The owner didn't have much info on them.
I paid a good price not knowing what the transformers are. Does anyone recognize the amplifiers or transformers?
They originally ran 4x 6550s with 5687 direct coupled cathode follower drivers, fixed bias, pentode mode, push pull parallel for something approaching 200w output power.
Any clues or info would be much appreciated.
Each amplifier weighs more than a 50 pound bag of chicken feed.
Chassis are 11" ×17" and the big caps are nearly the size of a can of beer.
What have I gotten myself into this time?
Thank you in advance.
I didn't cut anything.
I purchased them in that condition with the intent to rebuild them.
I'm more than capable of doing so, I'd just like to know more about them if at all possible...
I don't often post here on diy audio but I've designed and scratch built many tube amplifiers and preamps. I've never played with anything over about 60 watts. These amplifiers are certainly going to be way over 50 watts if they'll do what I think they'll do...
I purchased them in that condition with the intent to rebuild them.
I'm more than capable of doing so, I'd just like to know more about them if at all possible...
I don't often post here on diy audio but I've designed and scratch built many tube amplifiers and preamps. I've never played with anything over about 60 watts. These amplifiers are certainly going to be way over 50 watts if they'll do what I think they'll do...
If you measure the OPT and green wire cable stubs (5, 9) resistance is -almost- double than green (5 or 9)-red (7) resistance, it's the primary of PP ( 7 is the B++ pin).
The R-C (2-12) is between the secondary output.
Probably it's 0-4-8-16R transformer, so must to test, which (1, 2, 11, 12) is which. If you have good LCR measuring set, can be measured the secondary resistances (few tenth Ohm).
Connect 12V (or 24V, or if you experienced for high voltages 110V, 120V) AC to 5 and 9 pin and measure voltage on 2-12 (then between 1, 2, 11, 12) to decide output pins and ratio.
The R-C (2-12) is between the secondary output.
Probably it's 0-4-8-16R transformer, so must to test, which (1, 2, 11, 12) is which. If you have good LCR measuring set, can be measured the secondary resistances (few tenth Ohm).
Connect 12V (or 24V, or if you experienced for high voltages 110V, 120V) AC to 5 and 9 pin and measure voltage on 2-12 (then between 1, 2, 11, 12) to decide output pins and ratio.
One of them is still attached to the circuit.
I haven't analyzed the transformers yet but the one that's hooked up has the 4,8,and 16 ohm leads labeled and ground is obviously the black one
Plate windings are also hooked to the plate but that leaves several terminals disconnected, which is why I'd like to know more about what I've got, it's intended purpose and perhaps the winding diagram showing what's inside and the original circuit it's designed for.
A big ask, a tall order, possibly a quest for information that doesn't exist...
Thanks in advance for anything you can share
I haven't analyzed the transformers yet but the one that's hooked up has the 4,8,and 16 ohm leads labeled and ground is obviously the black one
Plate windings are also hooked to the plate but that leaves several terminals disconnected, which is why I'd like to know more about what I've got, it's intended purpose and perhaps the winding diagram showing what's inside and the original circuit it's designed for.
A big ask, a tall order, possibly a quest for information that doesn't exist...
Thanks in advance for anything you can share