Willsenton R8: Fixing the Shielded Volume Control Wiring
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- Опубліковано 13 бер 2023
- In this part, I dive into the shielded volume control wiring in search of the last of the noise. There was a little noise left, even on the pre-in and it made sense it must be in the volume control to RCA jack wires. I found more bad grounding design and cleaned it up!
This is a video series about the popular Willsenton R8 KT88 EL34 Push Pull tube audio amplifier. We will go through the repair this amp needs, testing and reviews of the amp as delivered, and then work on modifications to improve the sound quality and durability.
This is the cable I used:
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A great book for DIY amp building info!
Morgan Jones: Building Valve Amplifiers.
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You can buy this amplifier here
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Hi! Two weeks ago I received my Willsenton R8 in order to go some of the changes you propose. I was surprised to notice that most of them were in! I think that the manufacturers watch your clips! It’s great!
I've been in contact with the manufacturer, yes they are watching my videos and are sending me one of the "updated" models. You may have gotten one too :)
Thank you! I also have this humming/buzzing noise in my R8. Now I understand what is causing it.
This seems like an easy fix and should have been by the manufacturer.
I just watched your entire Willsenton R8 series, kinda just like watching some informative and entertaining thing on Disney+. Great stuff. On your comments about the headphone jack and good separate headphone amplifier alternatives. How about doing a series on good headphone amplifier DIY options?! I'm sure it would be great.
Yeah, I have that on my list, maybe one powered by a pair of 6SN7 tubes.
Great video 👍
Thanks 😁
Just wanted to say thanks for giving me the courage to take on this project. Went through the mods one at a time. Not an electronics engineer by any means but managed to complete the amp upgrades just fine. Plugged it in and BEHOLD! No SMOKE:) Sounds amazing!! One thing I noticed is the transformers run totally cool now. I used to be able to cook an egg on those puppies. Now they're barely warm. Thanks again for this series.
thank you. great educational video!
Glad it was helpful!
Nice job. That amp looks very clean!
Thanks!
Thank you for all your work, the information on the projects you do are both instructive and inspirational. I have an R8 and have been following this series with great attention. So far I have made to the point of doing your dual rail mod next. As opportunity and time allows I would love to see how much further you can take the R8. Maybe tackling an output transformer upgrade. I believe you mentioned in one of the earlier videos that it might be a weak link. Thank you again!
AWESOME!!!! Thanks for a great how to on this!!! I just replaced the two main power caps yesterday with some 330uf 550v that you sent me the link for!! Also replaced the .33 phase splitter caps with some Jentzen .33uf 1200v cpas and hoping to use the same for the four .22uf caps on either side, rooms a bit tight tho…. I will move to make this grounding mod next tho as I do have that humm in mine. Thanks Skunkie. 😁😁🤘🏼🤘🏼
So many issues to correct on this amp .........In many cases but not all you get what you pay for !
The ground loop indeed ! .....the ground should stay as a shield on the signal wires but should only be connected to one end ....your diagnosis and advice for correcting this error is correct !
I suspect that most of these amplifiers are not designed by people from old school knowledge .......good thing there are people like you and experienced audiophiles wgho know how to build modify or repair tube amplifiers .
In this case I would now even go and check/measure if the operation points of all the tubes are within the window of their correct operation conditions or if thssi amplifier is a tuber eater....as seen on some other designs.
Nice job and good information for all people who love music ( as good as tube technology can bring them the joy of listening and closer to good music )
Have a nice day
That was all done in earlier videos.
If you add a cap to the positive side of the coils on the on the relay's it will take any signal on the coils to ground if the relay coils are de-energized. Relay coils and relays are nosey.
Hi all, I have done following modifications on my Willsenton R8 MKI amplifier:
1.) Power supply mods, remove 115V/230 switch - Sonic (no hiss or hum), SQ
2.) Voltage Regulator Mod - Sonic, SQ (removes crosstalk, lesser noise floor, darker background)
3.) Bias Boards Mod - Sonic, SQ (smooths the sound)
4.) Grounding Mods (headphones output wires removal and input relay board grounding)- Sonic (no hiss or hum), SQ
5.) Grid stopper resistors 1kx4 on output tubes - Reliability, Safety, SQ (smooths the sound)
6.) Choke replacement - Reliability, Safety
7.) Power supply caps replacement with min. 500V ones - Reliability, Safety
Optional
8.) Replace capacitors with higher grade electrolytic or polypropylene capacitors (Nichicon, Mundorf). - Reliability
9.) Replace all resistors with Vishay PRO metal film resistors - Reliability
10.) KT88 heaters wires rerouting and removing grounding jumper from heaters - Reliability, Safety
11.) Global Negative Feedback - GLNFB - Ongoing...
After all job done I'm pleased to confirm everything that Stephe said or demonstrated in Willsenton R8 series.
Thank You Stephe for posting all these valuebale videos and documentation!!!
Thanks for the feedback.
@@SkunkieDesignsElectronics You are welcome. I can share a feedback on Skunkie Designs Forum, too. I wonder if there is a way to replace that irritating automatic volume control pot? Is it logarithmic 50K or 100K pot?
Another good video. I’m running Klipsch Heresy ii’s with new Crites diaphragms on the tweeter, mid horn, and new crossovers, (parts 5 years old or so) Supposed to be 99 db efficient. I’m just not hearing any hum from them. The only hum I’ve ever heard from the amp was when I had a cheap Pyle phono preamp go bad. I know the heresy’s are very efficient my unaltered A10 which I’m not a fan of even drives the heresy’s to respectable levels. Like I said, just don’t understand the lack of hum in my R8 playing through what I’d consider very efficient speakers. Still liking your videos, keep them coming. Also pushed PA speakers, Klipsch RP-160M, RP-280F, RF-7iii and Wharfedale LINTON with the R8 and it’s been a quiet amp. Not sure the reason. House is newer, I wired it, over built everything, maybe just clean power and the way I set up equipment. Maybe just got lucky.
I am wondering if this would achieve the same result. Replace that long ground cable with a single shielded cable with the shield grounded only at the volume control end. Then cut the L/R shield connection at the RCA end?
Might be worth trying!
Great videos, really enjoyed them. Just wondering how much would it cost, labor plus parts to have my R8 upgraded to this level.
$500-650 depending on who does it and what level of caps you choose.
@@SkunkieDesignsElectronics Thank you so much! Not a huge amount, though.
Your videos are awesome. I setup my preamp and R8 exactly as you described near the end. Using a Freya+ and R8 volume set to about 3:00 o’clock. I honestly put my ear up to the mid range tweeter and listen for the quietest region of the volume dial. Then use the Freya to control volume and out the signal to the subwoofer. This way I get a 128 step relay attenuator and a super easy subwoofer integration. I suspect when I put this grounding edit to work in addition to the other mods I’ve done, I may be able to run the R8 at a more linear region of its gain spectrum. How would one bypass the entire input relay board and wire the signal directly to the volume?
If I was gonna to that and you don't care about the remote volume, replace the pot with a "normal" one, ditch the boards and install a pair of jacks on the side near the volume control.
@@SkunkieDesignsElectronics my spouse might be touchy about the extra wires coming from the side. What’s the best option in terms of value for a shielded signal wire from the back up to the front?
@@UptownReef You can always just use shielded wire from the back if aesthetics is more of a concern. The shorter the signal path inside the amp the better IMHO.
Have you had a Decware zkit1 on the bench?
Nope
Interestingly, my amp did not come with the extra earth wire from the volume control to the relay region
Some have them, some don't. It's why I have said I believe people when they say theirs is dead quiet. But that doesn't mean they all are, because clearly some are wired differently than others!
Hi all. Whats the best wire guage for this? Thanks
This is low level signal wire so it doesn't really matter, just know the really small sizes are a little more difficult to work with but also you don't want fat insulation like a microphone cable would have.
@@SkunkieDesignsElectronicsSo 22 AWG should work? I looked at getting some Alpha shielded 2-conductor 22 AWG communications/control wire thinking the 22 AWG would be easier to work with on the smaller pads.
yes, will be fine!
Why is it that theres a lot of modification on this integrated amp? Is it really bad amp???
I dont see on other tube amp like rogue audio. Primaluna. Audio research, mcintosh and so forth .
For a made in china amp, the basic design is good. Where they screwed up was a) using cheap resistors and b) grounding. Never looked at these others and a McIntosh it 5X the money at least!
Interesting that the Chinese can design and build reference level DACs but can’t build a tube amp with technology that’s been around for over a hundred years! Thanks for the video
Good point!
The Willsenton R300B must be made and designed at a different factory. I have a write up at AudioKarma and this Amp is so good I purchased two and with be doing a complete Parts Upgrade to the 2nd one just to see how far I can take this.
@@joenovak6393 i've just checked your post at audiokarma. Great job you're doing there!!
8k I will also need a lot more 8888u
i dont have a hum or any noise at all, why is this
No idea. Others have reported theirs are silent, some say theirs have some noise like the one I worked on did.
Yeah, it becomes more and more obvious why these Chinese amps are a lot of hardware for the money...they need a lot of attention to finesse them and ensure reliability... which is fine if you like DIY....It's a shame in a way, because most of the important mods are fairly cheap and easy to implement and could be done by the manufacturer within the same budget....But then they need you to do the trouble shooting!.....
Most of what I find wrong is basic engineering and would add no cost.
During the Great Recession, a lot of companies were having a lot of workshops/instructional sessions. One of the things mentioned about all the off-shoring that was going on was that if they needed reliable and/or efficient engineering done, they would use U.S. engineers.