I am busy with a single ended 12W amplifier design.
My question is how close to the output transformer power rating can one go.
If the transformer is rated at 12W output can one design to that as a maximum?
There should be a built-in margin in the transformer design before core saturation kicks in right or should one allow for a margin? If so, how much margin should be allowed for?
I am constrained by the availability of output transformer options available to me so need to either lower the amplfiier power or find another output ransformer which I cannot seem to get easily.
My question is how close to the output transformer power rating can one go.
If the transformer is rated at 12W output can one design to that as a maximum?
There should be a built-in margin in the transformer design before core saturation kicks in right or should one allow for a margin? If so, how much margin should be allowed for?
I am constrained by the availability of output transformer options available to me so need to either lower the amplfiier power or find another output ransformer which I cannot seem to get easily.
Last edited:
What output tube are you using?
What output transformer primary impedance will you use?
What quiescent current will you stand in the output tube (and therefore in the output transformer primary)?
What B+ voltage will you use on the output transformer primary?
(Primary DCR times the plate current will cause a lower voltage at the plate)
How low a frequency do you need full power, 40Hz, 20Hz, etc.?
Please post a schematic of your amplifier and power supply.
Otherwise, we are shooting arrows at the target while we are blindfolded.
These questions need to be answered first, and a schematic is required too.
What output transformer primary impedance will you use?
What quiescent current will you stand in the output tube (and therefore in the output transformer primary)?
What B+ voltage will you use on the output transformer primary?
(Primary DCR times the plate current will cause a lower voltage at the plate)
How low a frequency do you need full power, 40Hz, 20Hz, etc.?
Please post a schematic of your amplifier and power supply.
Otherwise, we are shooting arrows at the target while we are blindfolded.
These questions need to be answered first, and a schematic is required too.
Last edited:
With a 12W rms amp you will be well served with a 20W rms OPT (3 to 4kg)
With a 40-50W rms OPT (7kg) you will get more bass and a dense sound
A small OPT 2kg 10-15W rms will sound sweet and less dynamic.
"12W" *MUST* be qualified with a lowest useful frequency. (But never is. Do not confuse the customer.)
"12W @ 50Hz" can probably do 48W @ 100Hz.
In SE there will be other limits. Maximum current limits the DC power input.
You will almost never burn-up an audio transformer with "excess power". But you sure can have flabby bass.
"12W @ 50Hz" can probably do 48W @ 100Hz.
In SE there will be other limits. Maximum current limits the DC power input.
You will almost never burn-up an audio transformer with "excess power". But you sure can have flabby bass.
Thanks for the inputs guys.
The design is calculated correctly for primary DC, Max voltage and impedance.
It is all within limits and the transformer output power is rated at 30Hz.
I was just concerned that one must allow for margin to avoid saturation at obviously maximum drive.
Something I forgot to mention is.... In triode mode the power output is half the transformer spec.....but in Ultra Linear mode it will be running at maximum.
The design is calculated correctly for primary DC, Max voltage and impedance.
It is all within limits and the transformer output power is rated at 30Hz.
I was just concerned that one must allow for margin to avoid saturation at obviously maximum drive.
Something I forgot to mention is.... In triode mode the power output is half the transformer spec.....but in Ultra Linear mode it will be running at maximum.
Last edited:
valvesound,
It is most likely possible to design an amp around your 12 Watt transformer that goes up to 12 Watts at 1kHz (depending on whether the transformer manufacturer is telling the truth or not).
But to get 12 Watts at 40, 30, or 20 Hz, probably not.
We are back to wanting more details of your transformer, output tube, topology, single ended, push pull, etc.
No real answers with out details.
A 100 Horsepower gas engine can put out 120 Horse Power at RPM that is higher than maximum rating, but it will quit when either the piston hits a valve that does not have a strong enough spring, or when the heat causes the piston rings to melt and freeze up in the cylinder.
Details, please?
It is most likely possible to design an amp around your 12 Watt transformer that goes up to 12 Watts at 1kHz (depending on whether the transformer manufacturer is telling the truth or not).
But to get 12 Watts at 40, 30, or 20 Hz, probably not.
We are back to wanting more details of your transformer, output tube, topology, single ended, push pull, etc.
No real answers with out details.
A 100 Horsepower gas engine can put out 120 Horse Power at RPM that is higher than maximum rating, but it will quit when either the piston hits a valve that does not have a strong enough spring, or when the heat causes the piston rings to melt and freeze up in the cylinder.
Details, please?
Last edited: