Hi,
does anyone know what the two wires in the Musical Fidelity A1, B200, and other amps from that perdiod are supposed to be for?
If I am not completely mistaken, the cut track is just reconnected with one of them, and the other wire is just in parallel to another (uncut) track.
This is the 2nd amp I see this "in person" on now and searching the net for pics of open A1s etc. shows this is "normal".
The tracks are both coming from the MM/MC switch.
Any reasonable explanation?
Thanks,
Mo
does anyone know what the two wires in the Musical Fidelity A1, B200, and other amps from that perdiod are supposed to be for?
If I am not completely mistaken, the cut track is just reconnected with one of them, and the other wire is just in parallel to another (uncut) track.
This is the 2nd amp I see this "in person" on now and searching the net for pics of open A1s etc. shows this is "normal".
The tracks are both coming from the MM/MC switch.
Any reasonable explanation?
Thanks,
Mo
Can you show us on a schematic where these are?
With current info: Could it be some weird-*** attempt at "humbucking"? How close is the power transformer? But I doubt it does even that, I think this does nothing at all.
And you say you've seen this seemingly pointless mod in multiple units? That's a head scratcher.
With current info: Could it be some weird-*** attempt at "humbucking"? How close is the power transformer? But I doubt it does even that, I think this does nothing at all.
And you say you've seen this seemingly pointless mod in multiple units? That's a head scratcher.
Once a convincing member somewhere on a forum heils it as a valuable mod, others follow.
Hugo
As I said, this seems to have been the typical way MF did it. I am completely puzzled why, though. If you search for MF A1 pics, you'll see this all over the place.
At one time I was a fan of English electronics and frankly, nothing surprises me anymore...
We must not forget that their production was very artisanal and that there were many versions of the A1.
What I can tell you is that I saw this oddity more than once and that they also had a spool of blue thread which was used from time to time (and which was used for lots of things like the green one) .
Leave that in place and everything will be fine.
The English are intelligent people and like the French, sometimes have "direct" and very "artisanal" methods to make changes in production, all without instruction notes or REV. , but every time I wanted to understand or do better, it ended in failure because, beneath this "messy" side, they know very well what they are doing...
We must not forget that their production was very artisanal and that there were many versions of the A1.
What I can tell you is that I saw this oddity more than once and that they also had a spool of blue thread which was used from time to time (and which was used for lots of things like the green one) .
Leave that in place and everything will be fine.
The English are intelligent people and like the French, sometimes have "direct" and very "artisanal" methods to make changes in production, all without instruction notes or REV. , but every time I wanted to understand or do better, it ended in failure because, beneath this "messy" side, they know very well what they are doing...
I still want to know proximity to the power transformer. A bad attempt at hum cancellation is all I can come up with.
OP, is this the correct circuit? https://www.markhennessy.co.uk/showpic.htm?mf_a1/a1_phono.jpg
OP, is this the correct circuit? https://www.markhennessy.co.uk/showpic.htm?mf_a1/a1_phono.jpg
I say this with all the love in the world, as one who had a Triumph TR4 in their mis-spent youth: this is British as hell ":^)
Anyway... OK maybe it's a really bad attempt at an RF filter for the FM band? The box appears to have zero RF protection otherwise.
(those were the days... late at night, when it was quiet, you could actually hear it rusting.)
Anyway... OK maybe it's a really bad attempt at an RF filter for the FM band? The box appears to have zero RF protection otherwise.
(those were the days... late at night, when it was quiet, you could actually hear it rusting.)
You mean like a "Forrest Gump" edition
?It definitely are lots of different amps. The first one I had this myself was an A1X (see https://www.diyaudio.com/community/threads/repairing-a-musical-fidelity-a1x.404761/post-7490057), wires were red in that one. I thought this was strange, fixed the track and removed the wires. Of course the phono amp worked after that.
This time, I have it on an MF B200X currently on the bench.
And the pics you can find on the net are from all over the word of diff devices.
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