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Willsenton R8 Owners & Discussion Thread


Atmaj

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I am not an expert on tube amp like many on this forum however writing this blog to help those who are thinking of buying Willsenton R8 or those who owns it and want to know bit more about it. I am not good with ears as Audiophile guys but can provide some technical insight.

 

Initially I was thinking of building my own tube amp as I am a keen DIYer but then looked on the net and saw hype about R8. Pulled the trigger in the hope that it is Point to Point wired amp so if not good, I will enjoy modifying it rather than building from the scratch.

 

Received my amp 5 days ago and first thing I did is that I opened up back cover before even trying it out. I was curious to know the quality of soldering, and the internal voltage switch is correctly set to run on 240V. To my surprise, it was great. I did not have to re-solder any point, all the components used are of good quality, relays and electrolyte caps are of reputed Japanese brands. Coupling caps and Grid bypass cap in driver stage are own ‘Willsenton’ branded but looks good (and looking at the way it sounds, I don’t think there is a need of replacing those with better branded caps or PIO caps). All the components and cables are laid out properly and tied together. The only flaw I found was that the outside sticker displays 240V but the inside voltage selector switch shows 230V. Also, I could not see Capacitor discharge resistor on main filter caps.

 

After satisfied with the build quality, I connected the amp to my system and wow… it sounds amazing and better than my other tube and SS amps. It is dead quiet when no signal and the sound is just clean, open and excellent coverage at both bottom and upper end. While it was sounding great, I found that the outer casing of power transformer was warming up a bit. The casing felt like a thick sheet of metal hence was bit concerned about the actual temperature of the transformer itself. Also, the bias was bit on the higher side when I checked first time which created the doubt that they have actually used 230V trannie and just put the sticker of 240V.

 

However, with these concerns in the mind, I decided to partially tear down the amp over the weekend to check the Power transformer rating, measure all voltages, trace down Schematic and install a discharge resistor on the filter cap. Supplier sent me the Schematic but it was too basic and wanted to confirm that it is accurate.

 

Below are my findings.

 

  1. About 30% of resistor values in amp are different to actual schematic. The capacitance multiplier circuit is also different and there are some typo errors as well. I ended up drawing my own.
  2. Transformers are potted in the casing (which is a great thing) hence did not remove those  as it would require de-soldering of too many connections. However, when measured the heater voltage, it was precisely 6.33V at my home supply voltage of 245V which indicates that it is a 240V transformer and switch labelling is not correct. The potting of transformer also explains that the heat on the casing is a conduction from transformer and not the radiation (which would be in case of hollow casing), so nothing to worry about it. Potted transformers also explain why this unit is so heavy and outer casings feel like made of a thick metal sheet.
  3. KT88/EL34 switch changes the negative Grid voltage to power tubes and calibrates front Bias meter. I was expecting this switch to change the B+ voltage for different tubes but that’s ok, you can’t get everything at such a low price. B+ measures about 440V. This is optimum for EL34 but KT88 would have performed better with bit more voltage of about 500V or more.
  4. The soft start delay circuit does not delay B+ supply voltage to tubes but rather mutes input signals for 30 seconds after turning it on. At least something is better than nothing.
  5. I am not 100% sure about the Pre-IN input but I think it is not directly fed to driver stage bypassing pre-amp section. It still goes through pre-amp and volume control is bypassed to mimic the Power amp only condition. I do not use this input so didn’t bother going into further details.
  6. The designer has taken great efforts to minimise noise in the amp by adopting Capacitance Multiplier using tubes to remove ripples from the supply voltage before it is fed to Pre-amp tubes. An elevated heater supply using virtual ground is also used to heat preamp tubes to prevent humming. 6SL7 are great tubes for audio application but at the same time they are high gain tubes and hence prone to noise and humming. With implementation of these 2 measures, amp is extremely quiet and noise free.
  7. The elevated heater supply circuit also works as a capacitor discharge and no need to add additional resistor on the cap. I measured that after turning off the amp, there is hardly any voltage on power caps within 3 seconds, so it is very safe from that point of view.
  8. One drawback of this amp is that it uses digital circuit for input and TR/UL selection but there is no memory function. If you are using CD as an input source and TR mode, then you do not have to do anything. For anything else, each time you turn on amp, you will have to select the source and the mode. A simple rotary selector switch would have been a better option here.

 

In conclusion, this is a great amp as a value for money. I am not an audiophile and do not own too many amps so I would leave those reviews and comparison for Youtubers but from the technical point of view, you will not get anything better sounding and better-quality product in this price. Looking at how it performs in bottom and top end, I am sure that the output transformers are also of great quality which is heart and soul of any tube amplifier.

 

I don’t’ think spending thousands of $ and buying Prima Luna or something like that will give any kind of added benefits. Just roll few tubes on this and it will shine like those branded amps costing multi-folds. This is my personal opinion considering my own circumstances and others may have different opinion and I respect that as well.

 

As a summary, it is nicely designed for flexibility of tube rolling, manufactured with quality components, built with care and professionalism, very reasonably priced and most important, it also sounds great.

 

Waiting for lock down in Melbourne to open so that I can try some tube rolling :-).

 

Cheers,

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Thanks for writing this. It has given R8 owners like myself more info on the amp that we can appreciate. It was a risk that we took buying an amp that is not from a dealer but my experience with Yong at China Hi Fi has been wonderful. I recently upgraded the preamp tubes and after a week or so, there was a humming sound coming from one of the speakers. Yong helped me diagnose the issue and now the faulty preamp tubes are being exchanged. 

 

Back to the R8. Its comforting to know that its well built. I wasn't expecting the R8 to be punching well above its weight but rather hoping it wasn't a unit that just reeks of people cutting corners. Well.. maybe a bit, like you pointed out in the warm up delay.  Nevertheless, its value for money. Love the sound, love the package and its versatility. Pairs really well with my sonus fabers. 

 

I'm keen on your point 5 coz I ran the signal from my bluesound 2i (streamer) to cxa81 (DAC) to R8 (pre-in). Yes, the volume knob was not working but I felt there was difference in the sound and sensitivity. Now I'm running direct from the bluesound to R8 for the time being. 

 

Hope this thread can be a useful source of info on the R8. 

 

Maybe we can have our own discussion here after Thomas Stereo does his review of the R8? 

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@Atmaj 

 

Thanks for the detailed review of the technical side , I took delivery of the R8 yesterday and concur with your findings on the built quality and how silent the background is out of the box !

 

Not to mention the weight , almost broke my back carrying it upstairs .

 

 

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4 minutes ago, demoiree said:

@Atmaj 

 

Thanks for the detailed review of the technical side , I took delivery of the R8 yesterday and concur with your findings on the built quality and how silent the background is out of the box !

 

Not to mention the weight , almost broke my back carrying it upstairs .

 

 

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Nice setup .... outside. You need to move the tree on the right to be more in line with the one on the left or the centre balance will be out. ???

Edited by xlr8or
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Just now, xlr8or said:

Nice setup .... outside. You need to move the tree on the right to be more in line with the one on the right or the centre balance will be out. ???

Thank you ! Haha to combat that I just roll the blinds down haha ?

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Yes, very nicely made. I too have pictures but my write up was so big that I pushed myself back from posting pictures. ?

 

Just plug it in and enjoy. Rolling 6SL7 and 2 of 6SN7 will improve the sound a lot. You don't need to replace the 6SN7 in the middle as it is used as power supply filter and won't have any impact on the sound.

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3 minutes ago, Atmaj said:

Yes, very nicely made. I too have pictures but my write up was so big that I pushed myself back from posting pictures. ?

 

Just plug it in and enjoy. Rolling 6SL7 and 2 of 6SN7 will improve the sound a lot. You don't need to replace the 6SN7 in the middle as it is used as power supply filter and won't have any impact on the sound.

Good tip thank you  ! I bought 3x tungsol 6sn7 reissue as they pretty affordable . But I'm leave them stock at the moment , so I get to feel the sound diff when I roll in the tungsols . 

 

I bought a set of el34  electro harmonics , will see that make any major diff compared to the stock ! 

 

Tube rolling is hurting my wallet !

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1 minute ago, demoiree said:

Good tip thank you  ! I bought 3x tungsol 6sn7 reissue as they pretty affordable . But I'm leave them stock at the moment , so I get to feel the sound diff when I roll in the tungsols . 

 

I bought a set of el34  electro harmonics , will see that make any major diff compared to the stock ! 

 

Tube rolling is hurting my wallet !

They will definitely make a difference however the biggest difference will come from 6SL7 as those are main pre-amp tubes. I too had Tung sol 6SN7 and it has improved mids and overall sound than stock. Haven't rolled other tubes but will do soon.

 

Please post here your experience with it.

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24 minutes ago, demoiree said:

@Atmaj definately ! One thing is the smell , it is just funku, hopefully not toxic ... 

Yeah, 2DCulture also mentioned the same thing. However, I did not get any smell (or shall I need to see doc? ?)

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3 hours ago, demoiree said:

@Atmaj definately ! One thing is the smell , it is just funky, hopefully not toxic ... 

OH... you got the smell too!!! hahahaha! It does have quite a smell. I quickly moved the box and all its packaging out of the room on the first day and the smell stayed on for 3 days!! After that, you don't smell anything unless you put your face near the tubes when its hot... which is always a good idea for an accident waiting to happening. 

 

I have upgraded the tubes but foresee very limited tube rolling. Too heavy on my wallet. But I noticed those from local shops are usually a few suspects. A kind forum fellow shared with me a link to an overseas site with more variety but I'm hesitant. Anyway, still enjoying the music.

 

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I have had one for a few months now and got the paint smell too! I noticed that with the stock tubes (KT88 version) it sounded much cleaner and better as a power amp. 
As an integrated it was very warm sounding with good  bass and treble. However the mids with vocals (the benchmark) and acoustic instruments sounded grainy and I did not like the sound of the amp at that stage.

I replaced the 6SN7 (the stock tubes seem to be of Russian origin) by some RCA smoked glass 6SN7 and it was a large difference for the mids, then I inserted some RCA 6SL7GT and again much more delineated soundstage with beautiful vocals now. The sound is less warm now but more true.

Because of its affordable price, the stock tubes are poor. Upgrading the preamp tubes cost me just over $100 and is mandatory for the amp to become very good sounding.

I wonder if the YouTube reviewer used the stock tubes...

Edited by pretender
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13 minutes ago, pretender said:

I have had one for a few months now and got the paint smell too! I noticed that with the stock tubes (KT88 version) it sounded much cleaner and better as a power amp. 
As an integrated it was very warm sounding with bass and treble. However the mids with vocals (the benchmark) and acoustic instruments sounded very grainy and just unacceptable; I did not like the sound of the amp at that stage.

I replaced the 6SN7 (the stock tubes seem to be of Russian origin) by some RCA smoked glass 6SN7 and it was a large difference for the mids, then I inserted some RCA 6SL7GT and again much more delineated soundstage with beautiful vocals now. The sound is less warm now but more true.

Because of its affordable price, the stock tubes are really poor. Upgrading the preamp tubes cost me just over $100 and is mandatory for the amp to become very good sounding.

I wonder if the YouTube reviewer used the stock tubes...

Very true. You must roll the tubes on these amps as they are not that good.

 

However I am wondering the cost you mentioned. From where did you get those NOS at such a low price?

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On 19/09/2020 at 6:02 PM, Atmaj said:

Very true. You must roll the tubes on these amps as they are not that good.

 

However I am wondering the cost you mentioned. From where did you get those NOS at such a low price?

From Stereo.net! I bought a pair of very high mileage RCA 6SN7 for $35 and $70 for the RCA JAN 6 SL7 GT. 
So they are definitively not NOS and they will probably not last for years but it was great to test. 

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Looks really good! Was there a blue tinge on the power tubes or it was reflecting off something? Anyway, looks real classy. 

 

The missus came into my listening session yesterday evening and without asking, took my phone and keyed in her songs through spotify. Then stood in front of me and complained: why does the singer sound so far away? I stood up, walked to the amp and hit ultralinear. She was happy. 

 

Love the amp. So versatile. ?

 

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@Atmaj @2Dculturedid you notice any hissing/buzzing/humming when nothing is connected to the pre out terminals on the R8? I tried with or without preamp connected the hiss and hum is evident when I'm about  1meter away from the speaker , not overly loud but enough to make me want to trouble shoot what's going on. 

 

 

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I noticed indeed a slight hiss/hum from the Willsenton amplifier when connected to my Doge 8 tube preamp. The hiss is not there when I use a solid state power amp so it is due to the Willsenton. The spurious noise is obvious in front of my speaker which are 93db efficient but not a worry at the listening position.

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2 hours ago, demoiree said:

@Atmaj @2Dculturedid you notice any hissing/buzzing/humming when nothing is connected to the pre out terminals on the R8? I tried with or without preamp connected the hiss and hum is evident when I'm about  1meter away from the speaker , not overly loud but enough to make me want to trouble shoot what's going on. 

 

 

 

If you can hear 1m from the speaker, its quite bad. I didn't get any unusual noise from the R8 when I first got it. Sometimes I get some type of feedback noise when I switch the RCAs between the terminals. But after turning the amp off and on (I need to bear in mind the 5 mins delay as advised by Atmaj), the sound goes away. 

 

There's a pre-out on the R8? There's a pre-in, which I connect from an external amp's pre-out. But no noise.

 

However, after I upgraded my preamp tubes, there was a humming sound coming out from my right speaker after some time.  Its quite faint and you need to put your ear near the speaker to hear it. Coz I do nearfield when working, I can hear it. Back then, the R8 was on my desk and sometimes the humming noise gets louder like when my laptop goes close to the amp. 

 

I contacted Yong and troubleshooted. Found out it was one of the upgraded preamp tubes. I never noticed before but when I moved my hand near the 'faulty' tube, the speaker will hum louder, like when my laptop was the near the amp 

 

I'm back on stock 6SL7 tubes and the humming is gone. As of now, I don't get any buzz, hiss, or hum. Once I detected a crackle or buzz? But only when I put my ear real close to the mid woofer cone and had to strain to hear the buzz. 

 

I previously get speaker pops a few seconds after turning on the amp. But Atmaj advise me to turn off the amp when music playing and let the music died out (usually 1 or 2 secs).. like gas BBQ =). No more pops since *knock on wood*.

 

Have you tried troubleshooting? Is it from one speaker like me or both? 

Edited by 2Dculture
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@2Dculture

 

Thanks for sharing ! 

 

Sorry I meant pre-in , if you have nothing attached to pre in , are you getting any hiss or hum from the speakers ? It comes out from both speaker so I think is something to do with the amp itself . As I do not have any other sources connected . Might just be the pre in has too much gain , so amplified all the noise from the tube ? 

 

 

 

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