# Apos Blog Discussions

**URL:** https://forum.apos.audio/c/apos-discussions/blog-discussions/6.md

[Latest](https://forum.apos.audio/latest.md) · [Categories](https://forum.apos.audio/categories.md) · [Tags](https://forum.apos.audio/tags.md)

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## [About the Apos Blog Discussions category](https://forum.apos.audio/t/about-the-apos-blog-discussions-category/16)

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**Author:** [@system](https://forum.apos.audio/u/system)\
**Replies:** 0\
**Last updated:** [January 13, 2026, 9:24pm UTC](https://forum.apos.audio/t/about-the-apos-blog-discussions-category/16 "2026-01-13T21:24:19Z")

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These are automatically generated posts for discussions of any Apos blog posts and link back to their respective page on Apos

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## [New: xduoo ta-68 balanced tube headphone amp](https://forum.apos.audio/t/new-xduoo-ta-68-balanced-tube-headphone-amp/2919)

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**Author:** [@AposAdmin](https://forum.apos.audio/u/AposAdmin)\
**Replies:** 1\
**Last updated:** [October 5, 2026, 9:21pm UTC](https://forum.apos.audio/t/new-xduoo-ta-68-balanced-tube-headphone-amp/2919 "2026-10-05T21:21:31Z")

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The xDuoo TA-68 is a fully balanced desktop tube headphone amplifier with independent volume controls for the left and right channels. Its signal path combines 5U4G tube rectification, 12AU7 voltage amplification, a four…

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## [FiiO K13 R2R vs TOPPING DX5 II](https://forum.apos.audio/t/fiio-k13-r2r-vs-topping-dx5-ii/230)

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**Author:** [@system](https://forum.apos.audio/u/system)\
**Replies:** 5\
**Last updated:** [August 4, 2026, 8:37pm UTC](https://forum.apos.audio/t/fiio-k13-r2r-vs-topping-dx5-ii/230 "2026-08-04T20:37:52Z")

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In this post, we’ll walk through how the FiiO K13 R2R and TOPPING DX5 II approach signal conversion, output behavior, and day-to-day usability—and where each might fit best in a desktop system. This is a companion disc…

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## [How to replace op-amps](https://forum.apos.audio/t/how-to-replace-op-amps/836)

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**Author:** [@system](https://forum.apos.audio/u/system)\
**Replies:** 18\
**Last updated:** [June 30, 2026, 3:17pm UTC](https://forum.apos.audio/t/how-to-replace-op-amps/836 "2026-06-30T15:17:48Z")

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Replacing op-amps is a precise but approachable process for anyone comfortable with component-level audio gear. It’s a way to alter the tonal character of a DAC, preamp, or headphone amplifier without changing the entire…

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## [What is Archive Vacuum Tubes?](https://forum.apos.audio/t/what-is-archive-vacuum-tubes/2400)

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**Author:** [@AposAdmin](https://forum.apos.audio/u/AposAdmin)\
**Replies:** 2\
**Last updated:** [March 4, 2026, 3:15am UTC](https://forum.apos.audio/t/what-is-archive-vacuum-tubes/2400 "2026-03-04T03:15:14Z")

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Since Ray Tubes launched, one topic has kept coming up: NOS. People love the sound of our current-production tubes so much that finding vintage tubes that measure up has become increasingly difficult. The community kept …