Boyuurange / Reisong A50 300B Tube Amp Advanced Mods Part Two

Тәжірибелік нұсқаулар және стиль

In this multi part video, we complete one channel doing the advanced modification of this amp. This is rewiring the front end 6SN7 driver to a cascode design to drive the 300B correctly.
The tubing I use in the video is: 1mm ID 2mm OD PTFE Tubing
The next video we will test these modifications and report back how this mod sounds vs the original design. I have plan for further mods to increase the reliability and some cooling issues I see.
After what I learned from mods to my personal DIY 300B build, this A50 should turn out sweet! I'm going to use a LED/resistor combo for bias on the cascode + add gridstopper resistors etc.
Please subscribe to stay tuned!

Пікірлер: 20

  • @frankfrank9711
    @frankfrank971127 күн бұрын

    Truly enjoy your wealth of knowledge. Keep the modifications coming 👍

  • @greghardy2676
    @greghardy26762 жыл бұрын

    This A50 video has been my favorite to date, so much good info and DETAIL...one of the BEST!

  • @davidnguyen5028
    @davidnguyen50285 ай бұрын

    Pretty cool to see you’re showing your soldering work.

  • @user-uq3wt8dc8z
    @user-uq3wt8dc8z10 ай бұрын

    First, I'm genuinely impressed by your wealth of knowledge. I truly wish more people were as generous with their expertise. I come from an IT background, so some specifics fly over my head. Just a quick one - I've got this stock amp, and I'm considering replacing the original tubes to enhance its sound. Got a budget of around $1500. Suggestions? One of these days, I'll muster the courage to DIY this mod! Thank you!

  • @greghardy2676
    @greghardy26762 жыл бұрын

    Love ur tips and tricks...

  • @christiantudor-williams1184
    @christiantudor-williams11849 ай бұрын

    I've completed all the mods and have the Mundorf paper in oil and Audio Note caps on order. 2 questions. I've used a small red led for bias, where can i get one like you've used. Also, with cascode there is a lot less gain. Is there a way round increasing the gain. Great work BTW, love your channel and excellent explanation.

  • @SkunkieDesignsElectronics

    @SkunkieDesignsElectronics

    9 ай бұрын

    Yes the gain is lower but before, the amp would go into clipping/distortion at less than 1/3 volume with normal sources. Yes, you will have to turn the knob more to get the same SPL, but the whole range is usable. You can get that LED at mouser HLMP-Q150

  • @brycejeannotte7699
    @brycejeannotte76992 жыл бұрын

    I noticed that you changed the B+ resistors, now using 8.2K ohm units. Unless there was a problem with your camera, you had 100 ohm resistors in place before.

  • @SkunkieDesignsElectronics

    @SkunkieDesignsElectronics

    2 жыл бұрын

    Unfortunately some of the video was shot out of order, the schematic is correct.

  • @douwebakker3707
    @douwebakker37072 жыл бұрын

    Hello, it seems to me better to connect the grid leak resistance just as close to the tube base than the stop resistance.

  • @SkunkieDesignsElectronics

    @SkunkieDesignsElectronics

    2 жыл бұрын

    Interesting, I've always heard that since the grid stopper is there to halt oscillations, it was the one that needs to be close to the pin. I do slip up a couple of times in the video and call the grid stopper "Grid leak" but I corrected it with a speech bubble. The grid stopper is the resistor in the signal path to create a low pass filter, the grid leak is there to reference the grid to ground for biasing. Hope this helps! www.aikenamps.com/index.php/grid-resistors-why-are-they-used

  • @douwebakker3707

    @douwebakker3707

    2 жыл бұрын

    @@SkunkieDesignsElectronics I generally mount the leakage resistor on the other side of the stop resistor

  • @danielemorgani7459

    @danielemorgani7459

    2 жыл бұрын

    @@SkunkieDesignsElectronics in the final schematic posted on your website it shows the grid leak resistor tapped off the input before the grid stop resistor, in the video you wire it directly from the tube pin to ground, effectively putting it after the grid stop resistor? Is there a difference between your schematic and the way you actually wired it? Would it matter which comes first?

  • @SkunkieDesignsElectronics

    @SkunkieDesignsElectronics

    2 жыл бұрын

    @@danielemorgani7459 It really doesn't matter. The grid stopper is there to stop oscillations that might be in the input signal. You are not going to have any oscillation from the ground, where the grid leak resistor is located.

  • @ericlane5949
    @ericlane59492 жыл бұрын

    Is there no risk of the resistor overheating under the shrink tubing?

  • @SkunkieDesignsElectronics

    @SkunkieDesignsElectronics

    2 жыл бұрын

    This resistor has almost no current running through it, only the AC/music signal.

  • @ammej768
    @ammej768 Жыл бұрын

    Is there room for a motorised volume control?

  • @SkunkieDesignsElectronics

    @SkunkieDesignsElectronics

    Жыл бұрын

    not sure, I no longer have the amp here to check/measure.

  • @roroseppel2077
    @roroseppel20772 жыл бұрын

    you have plenty of cathodes on your finger nails !

  • @hl2dus1
    @hl2dus1 Жыл бұрын

    중국산 앰프는 조잡합니다. PCB기판을 제작하는 비용이 전체 비용으로 추가되므로, 잇점이 적습니다. 이해하기 어렵군요. PCB기판을 쓰레기통에 버리고, 처음부터 새롭게 내부 배선을 다시 해야 옳습니다.

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