DSE A2760 Amplifier (aka Koda-261)

[carlmart]

And here's the (edited) LTSpice library data file with SPICE models for all of the bipolar devices used in the LTSpice schematic for the modded amp that was posted a few days ago.

Unzip the attached "standard.zip" file, then rename "standard.txt" file to "standard.bjt". Overwrite the existing "standard.bjt" file in your LTSpice \lib\cmp folder with the renamed file.

You can then run simulations for the modded amp with LTSpice. Don't forget to turn off compression in LTSpice - click on Tools\Control Panel\Compression and uncheck "Only compress transient analyses", "Enable 1st Order Compression" and "Enable 2nd Order Compression". If this isn't done, the simulation results will be degraded.

Can you please upload the asc file for this amp's sim?

How will the compression degrade the simulation results? What will specifically be degraded?

 

[reszipsa]

reszipsa

Please see attached asc file.

Note that this version of the amplifier no longer uses two pole lag compensation, and that it is now a single nested differentiating feedback design.

There is no necessity to turn off compression in LTSpice for this version of the amplifier - it includes spice directives that render this otiose.

 

[carlmart]

Played a little on the sim and I think you can get better results in THD and output level.

To start with I changed all the LTP transistors to BC546B and BC556B, also Q5.

That results in 0.037% THD @ 20KHz. Much better @ 1KHz. Just before clipping, of course.

Changing the LTP transistors I think is a must, as the BC547 and BC547 are too close to their 45v limit from the supply. The news ones are for 65v, and should be on their sweet area with 45v.

Of course these are only sims.

Adding another output pair at the output might allow using more demanding speakers.

Didn't run square wave tests or Tian probe to see other results.