LANGEVIN AM5116B schematic errors? - Gearspace.com
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LANGEVIN AM5116B schematic errors?
Old 18th January 2013
Deleted e777837
LANGEVIN AM5116B schematic errors?

Hi, people

I am attempting to build a clone of the LANGEVIN AM5116B Tube pre-amp push-pull circuit.

I wanted to ask if anyone was aware if the schematic circulating on the web is accurate, IE: is there anything inaccurate or missing on that LANGEVIN schematic? There was errors apparently on the 5116 SCHEMATIC which is the single-ended version of the 5116b.


This is the one i am referring too:

Old 19th January 2013
Lives for gear
🎧 10 years
Well, I don't know about "missing" because that's only a partial schematic, but I can tell you what I don't see. I don't see a pad switch, I don't see a polarity switch, I don't see a "practical way" to adjust the gain, and I don't know what the Z is on the transformer output, nur do I see a peak OL indicator, nur do I know what the B+ is supposed to be. All these things are the very least that you would have to know before you can attempt to build this thing.
Old 10th February 2013
Here for the gear
berl's Avatar
🎧 5 years
B+ is the hi-voltage (300V).
The output 11 is written MTR so "meter" : for an indicator or voltmeter ?

Last edited by berl; 10th February 2013 at 05:37 PM.. Reason: precision
Old 10th February 2013
Lives for gear
🎧 15 years
It looks jolly fine to me.
The gains typically were 'pre set' so that the whole unit was treated as a 'plug in module' (which it would have been) so that 'untrained' operators could swap one out if it became faulty for any reason.
The 'table' suggests that usual setting would be for 40dB gain.
The 'manual' would have made reference to input and output transformer 'strapping' for different loads, which you may have to work out for yourself.
The MTR connection is for a DC milliameter which would have had a 'go/no go' marking and is used to check that the valves are drawing the correct range of current. Having the meter 'out of the module' meant that a common bus could be used so that one meter could 'service' the whole equipment ( many amplifier modules).
Matt S
Old 10th February 2013
Lives for gear
emrr's Avatar
24 Reviews written
🎧 10 years
Comparing that to some real modules I have only seen minimal/inconsequential differences. I think there's more input/output Z strapping choices on the boards, along with filament strapping options.
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