I have a project in mind.
The soekris 1941 dam in parallel mode comes out at 2.6 volts and zout of 313ohm.
At the output there is no dc offset but still there is high frequency noise from the r-2r switching process.
For this reason I would like to make a transformer output stage.
A transformer thanks to its bandwith can filter out high frequency noise without using a harmful low pass filter, right?
My concern is, is technically possible to build a 1:1 transformer that will accept its 2.6volt SE and 313 output impedance? With a bandwitdh of 20-25.000 khz.
Thank you.
The soekris 1941 dam in parallel mode comes out at 2.6 volts and zout of 313ohm.
At the output there is no dc offset but still there is high frequency noise from the r-2r switching process.
For this reason I would like to make a transformer output stage.
A transformer thanks to its bandwith can filter out high frequency noise without using a harmful low pass filter, right?
My concern is, is technically possible to build a 1:1 transformer that will accept its 2.6volt SE and 313 output impedance? With a bandwitdh of 20-25.000 khz.
Thank you.
A 1:1 transformer fed from a low impedance and without any dc is about the easiest transformer to design. Don't know how you can limit the bandwidth to 25kHz though. Or why. Do you plan to use the NOS filter with redbook?
Great, I mean at least a bandwith of 20-25khz.
I suppose a wider bandwidth is even better.
There are no measurable high frequency noise.
That (using transformers) was my idea too, but years ago working well without its.
1941 output fed to directly my #801a preamp tubes.
If you still using transformers, choose Jensen JT-11P1 or Cinemag CMLI 15-15B.
Both of them measured -3dB point are over 70kHz.
I’ve a question, since the output impedance of the dam1941 in parallel mode is 313ohm, is better to use a transformer with the same primary impedance or higher? For example an 1:1 trafo with 315ohm impedance?
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So your plan is to remove one parallel capacitor and replace it with 2 inductors? Or will you keep the capacitors as you add the trafo?
What noise have you measured? Or seen in measurements - ref?
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Rule of the thumb using transformers: if you want lower distortion, the transformer impedance must be at least 4-5 times grater, than source impedance.
Listed 1:1 transformers are "high" primary voltage, high impedance line input ones.
Listed 1:1 transformers are "high" primary voltage, high impedance line input ones.
The DAM DACs has a capacitor on its output forming a LP filter.
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No, they are not. Whatever they cannot amplify they just filter. Whatever they do amplify, the output transformer filters. Either way, no prob. A solid state, high NFB circuit may indeed get upset with a lot of out of band noise but a tube amp working open loop, no way.
In my case the dam1941 was followed by a balanced tube preamp with a transformer coupled output into solid state power amps. Removal of the dam low pass filter brought only benefits.