Willsenton R8 Owners & Discussion Thread

[08Boss302]

30 minutes ago, Atmaj said:

 

Here is my observation.....

 

Tung Sol EL34 has very good base and excellent mids but highs are rolled off

KT77 has too much mid but I haven't broken them in to check further

Tung Sol 6SN7 is an excellent current production tube which is almost at par with NOS tubes.

There is nothing in current production for 6SL7 which can match NOS tubes (except . Don't even  bother to try Sovtek, it is same chinese tube what you have, just re-branded.

 

Stock KT88 are good tubes and suits to the taste what you mentioned, I think you will get the sound what you want by rolling pre-amp tubes. If you go to any EL34 family tube, mids will be pronounced one and you will loose base (except TS EL34B).

 

Cheers for this . So I am on the right track but maybe hold off on the power tubes and mess about a bit with the pre tubes first off.  The 6SN7 seems sorted but the 6SL7 which I'll roll the dice on TS or cough up for NOS.    My pocket says the TS will be the first step though.

 

29 minutes ago, echorec said:

@08Boss302 The nice thing, IMO, is that this amp can be tweaked to accommodate most preferences. First, what speakers do you use and what is/are your sources? I definitely recommend waiting a few weeks to make any moves. The character of the amp will change, I promise!

 

thank you!

yes, I certainly will wait a few weeks, I have a number or sources.  Speakers re KEF Q950 so probably on the slightly warmer side of neutral IMO (which I prefer) The stock tubes actually sound really nice with digital (CD or streaming) it seems they are bit more fussy with vinyl source, this could also be in part to the phono stage and carts I use, but with my other amp (Vincent SV237mk) vinyl sounds very nice.  I rolled the pre tubes in that but its a hybrid amp.  More than enjoying things at the moment and will give it time but if it still has that toppy almost distorted sound whilst playing vinyl i'll look to make some quick changes.

 

I will play some CD's on loop and then stream for a few hours back to back over the next few days and weekend. I'd say this time next week i'll well and truly have passed the 40hr mark, I should get a good impression then.

 

I've tried TR/UL mode too, I do prefer TR mode for most things i've played, UL seems to get quite grainy but again I have read this can be a characteristic of the KT88 and new tubes too. Some burn in will most certainly alter this imaging.

[echorec]

A little update on my R8 problem. Mr. Lee was very responsive (at first) and believes that the bias potentiometer for V1 is faulty (I also got the impression that I am not the first person to have this particular issue). He kindly offered to send the replacement part, however communication has stopped on his end, so I'm not sure if or when I will get the replacement part. My last email was simply asking how long I should expect the part to arrive, and I also offered to pay for express shipping to get it to me faster, but he hasn't replied (it's been about 1 week). So I don't know what to expect, but I wish there was better with communication...

Edited October 24, 2020 by echorec

[demoiree]

@Atmaj thanks for sharing your observations !

did you happen to try tungsol reissue 6sl7 gold pins they are 80 dollars each ? Or better to stick with NOS for 6sl7 ?

 

I think those stock tubes are actually Russian sovtek , I compared them side by side they are identical

[Atmaj]

1 hour ago, demoiree said:

@Atmaj thanks for sharing your observations !

did you happen to try tungsol reissue 6sl7 gold pins they are 80 dollars each ? Or better to stick with NOS for 6sl7 ?

 

I think those stock tubes are actually Russian sovtek , I compared them side by side they are identical

No, I did not bother to check those. When I compared those with normal TS 6SL7, they are same with construction. The only difference I saw was the golden pin. Also NOS Sylvania were cheaper.

 

Regarding stock tube, I mentioned about that in my observation post above. They are not Russian, Sovtek are Chinese tunes. 

[08Boss302]

5 hours ago, echorec said:

A little update on my R8 problem. Mr. Lee was very responsive (at first) and believes that the bias potentiometer for V1 is faulty (I also got the impression that I am not the first person to have this particular issue). He kindly offered to send the replacement part, however communication has stopped on his end, so I'm not sure if or when I will get the replacement part. My last email was simply asking how long I should expect the part to arrive, and I also offered to pay for express shipping to get it to me faster, but he hasn't replied (it's been about 1 week). So I don't know what to expect, but I wish there was better with communication...

I hope this improves for you.

Yong has been great with all comms I have had with him but that said, I have not had the issue you have had.  I think given the buzz about this amp, the Muzishare, Line Magnetic, JungSong  and some of the SoundArtist stuff available from him that he'd be all over making sure any issues are corrected swiftly.  With the audiophile world and also the reach of the internet any negativity will run rampant...not to mention there is arguably many folk out there that that are waiting to rant "I told you so" on ChiFi products, even though issues arise in products manufactured in all corners of the world.  The worst customer service I have ever experienced was with Sony, so I am certainly no believer that the bigger brand offers the better follow up, matter of fact, IME the bigger the brand the bigger bully and snub you are likely to receive.

 

Keep us upto date on this one, it is a good yard stick to gain perspective on after sales warranty.

 

I wonder if half the issue with the R8 is the demand and a few are slipping past QC to cater?

[2Dculture]

6 hours ago, echorec said:

but he hasn't replied (it's been about 1 week). So I don't know what to expect, but I wish there was better with communication...

 

I hear what you're saying. And have encountered the same thing. He is usually responsive to emails but there will be periods of silence esp if the diagnosis is already done. He might have already sent out the part. 

 

I'm guessing a lot of things are going through him and there's many of us. I sometimes get the feeling he's trying to catch up coz there were some confusion in his email reply to me. Sometimes he will email in the wee hours of the morning and weekends. I think he's doing what he can. Guessing everyone would appreciate the customer offering help but it might then mean an extra step or so in the process on his side when he's trying to standardise everything. 

 

 

[echorec]

I'm sure things will work out fine. I'm just anxious. It's only a testament to how much I love this amp though.

 

@Atmaj Do you happen to know the specs of the R8's bias trim pots? (I can't read schematics). I wonder if these are available through an online vendor or if they are proprietary to the Willsenton factory.

 

 

 

 

Edited October 24, 2020 by echorec

[echorec]

I was looking from the wrong angle. It's 22k. Does anyone recognize the company logo on the pot? It looks like planet Saturn.

 

 

Edited October 25, 2020 by echorec

[demoiree]

Thanks @Atmaj! 

 

Good to know about the stock tubes ,  I thought sovtek were Russian made . 

 

[muon*]

.................

 

Edited July 22, 2021 by muon*

[Atmaj]

21 hours ago, echorec said:

I was looking from the wrong angle. It's 22k. Does anyone recognize the company logo on the pot? It looks like planet Saturn.

 

 

 

Yes it is 22K but needs to open up that board to exactly find out the the type. They also come as Linear and Logarithmic. I will reckon to wait for Yong to send the replacement one or take to a tech close to you.

[echorec]

Quick update on my warranty through China Hifi - Yong emailed me today with tracking for my replacement part. The part is shipping from Los Angeles (I'm in the US) which is great because it should get here quickly. I believe he uses his US distributor for all US related issues, which is more efficient for everyone. Anyway, so far so good!

[echorec]

I received the replacement part from Yong yesterday! Instead of sending a potentiometer, he sent me the entire populated bias circuit board with leads attached, so I was quite pleased. I took the amp into my local HiFi shop yesterday and was able to pick it up this morning. Everything sounds good, so hopefully the problem doesn't come up again. I kept the old bias PCB in case I need any of those parts later. The labor cost to replace the bias circuit and bench test was $125 USD, so my R8's cost definitely went up. Still better than having to ship this beast to someone elsewhere and deal with that whole headache. A word of advice: if you have any issues with your amp, be patient with Yong. I think he is absolutely slammed with emails each day. He will get back to you and he will help you make things right, but sometimes he isn't as responsive as many of us are used to. I read somewhere else that he has apparently hired some people to help him, so that is good news if true.

 

A couple of interesting comments from the service guy (This is one of the best guys in our State. He's been building and servicing tube amps for a very long time and works with a lot of high level and boutique HiFi equipment). His first comment was how he thought the design and layout was really good on this amp. He told me the solder job was "a bit sloppy" as he had to touch up several spots inside the amp that could have potentially turned into future problems. His final comment was that he thought the amp sounded "very beautiful and musical".

[Atmaj]

Good to know that you got the replacement and the issue is resolved.

 

$125 USD for replacing the bias board   Gosh, that is too much. I would have done it for free but we are at opposite end of world  

 

He is spot on with soldering but it is far far better than other Chinese product. I in-fact did not have to touch up any solder joints in my amp. Being manual soldering, it also depends upon which worker in production line soldered yours and who soldered mine.

[F_Fabio]

Channels unbalance.

Hello to everyone, I'm new to this nice forum, discovered looking for info about R8 tubes rolling and its quality improvement.  I’d like to share my experience about channels unbalance problem also reported from some of you.  My Willsenton too showed a little unbalance in favour of left channel. At first I was wrongly thinking about not symmetrical tubes gain or a poor quality volume potentiometer.  The root cause was instead an internal wrong connection of the left output transformer to the output plugs.  The left 8 ohm and 4 ohm connections  were exchanged,  The result was the right loudspeaker connected to the 4 ohm R8 output and the left loudspeaker connected to the 8 ohm R8 output,  the consequent bigger voltage output on the left channel was the unbalance root cause.  That is an easy assembling error cause the 2 wires connecting 8 & 4 ohm plugs are both brown color (at least in my unit).

How to check if your output transformers are wrongly  connected to the rear plugs?  easy, by a tester you can measure the resistance between the 8ohm plug / Black plug   and the 4ohm plug / Black plugs: the first resistance must be higher than the latter.   Now my  R8 is well channel balanced as confirmed also by oscilloscope acquisition.

[08Boss302]

25 minutes ago, F_Fabio said:

Channels unbalance.

Hello to everyone, I'm new to this nice forum, discovered looking for info about R8 tubes rolling and its quality improvement.  I’d like to share my experience about channels unbalance problem also reported from some of you.  My Willsenton too showed a little unbalance in favour of left channel. At first I was wrongly thinking about not symmetrical tubes gain or a poor quality volume potentiometer.  The root cause was instead an internal wrong connection of the left output transformer to the output plugs.  The left 8 ohm and 4 ohm connections  were exchanged,  The result was the right loudspeaker connected to the 4 ohm R8 output and the left loudspeaker connected to the 8 ohm R8 output,  the consequent bigger voltage output on the left channel was the unbalance root cause.  That is an easy assembling error cause the 2 wires connecting 8 & 4 ohm plugs are both brown color (at least in my unit).

How to check if your output transformers are wrongly  connected to the rear plugs?  easy, by a tester you can measure the resistance between the 8ohm plug / Black plug   and the 4ohm plug / Black plugs: the first resistance must be higher than the latter.   Now my  R8 is well channel balanced as confirmed also by oscilloscope acquisition.

Hi Fabio

Welcome to the forum and thank you for the information.  Thankfully mine seems fine with balance but it seems a few people have had some quirky issues.

Did you roll the tubes?

How are you enjoying it now and what tubes if you rolled did you go with?

 

 

 

[echorec]

40 minutes ago, F_Fabio said:

Channels unbalance.

Hello to everyone, I'm new to this nice forum, discovered looking for info about R8 tubes rolling and its quality improvement.  I’d like to share my experience about channels unbalance problem also reported from some of you.  My Willsenton too showed a little unbalance in favour of left channel. At first I was wrongly thinking about not symmetrical tubes gain or a poor quality volume potentiometer.  The root cause was instead an internal wrong connection of the left output transformer to the output plugs.  The left 8 ohm and 4 ohm connections  were exchanged,  The result was the right loudspeaker connected to the 4 ohm R8 output and the left loudspeaker connected to the 8 ohm R8 output,  the consequent bigger voltage output on the left channel was the unbalance root cause.  That is an easy assembling error cause the 2 wires connecting 8 & 4 ohm plugs are both brown color (at least in my unit).

How to check if your output transformers are wrongly  connected to the rear plugs?  easy, by a tester you can measure the resistance between the 8ohm plug / Black plug   and the 4ohm plug / Black plugs: the first resistance must be higher than the latter.   Now my  R8 is well channel balanced as confirmed also by oscilloscope acquisition.

 

Welcome @F_Fabio ! This is excellent information! Can you give a little more detail on how to test this? I have a multimeter, and I'm assuming I can test it on the back terminals, correct? Does the amplifier need to be on? And do I need to remove the speaker wire? etc.. Thank you!

Edited November 14, 2020 by echorec

[F_Fabio]

Hi,  here more details.

R8 must switched OFF  !!

Disconnect both the loudspeakers

Test ohm values directly connecting the tester to the back terminals

Verify both channels,  8 ohm terminals resistance must be higher than 4 ohm resistance,  values must be very similar on both channels.

[echorec]

@F_Fabio I just tried it and I don't think my multimeter is sensitive enough. The lowest resistance setting is 2K and I get "0" reading. It has the following settings: 2M, 200K, 20K, 2K, and a symbol that looks like this:   ->|-

 

I am currently using the 8ohm taps for my speakers. I guess I could simply change the one speaker (the perceived quieter one) to the 4ohm and see if I can hear a difference in balance. Is there any harm to the amplifier if I do this temporarily? Thanks!

[F_Fabio]

You are right. You have to utilize tester able to measure  values  around or below  1 ohm

Yes, try to connect the single speaker to the 4 ohm terminal  and check the balance,  no harm at all for the R8.

[echorec]

@F_Fabio I was able to borrow my neighbors multimeter, which has better sensitivity. The 8ohm taps both tests at 8ohm and both 4 ohm taps both tests at 6ohm.

 

I also don't notice any channel imbalance since I had the new bias circuit installed this week, so I think everything is good now.

 

Thanks again for the information!

[F_Fabio]

Quite strange and high resistance value..   my R8  output transformer resistance is about 0, 48 ohm  measured   @ 4ohm rear terminals.   Could be nice to have data from other R8 owner..

[2Dculture]

2 minutes ago, F_Fabio said:

Quite strange and high resistance value..   my R8  output transformer resistance is about 0, 48 ohm  measured   @ 4ohm rear terminals.   Could be nice to have data from other R8 owner..

Thanks @F_Fabio and welcome. Interesting to hear about the issue with the wiring. Can't say I have a problem with the imbalance but I had to experiment coz my speakers are 6 ohms.

 

Folks say to play around the 4 and 8 ohm outputs and see which sounded better. I'm now on the 4 ohm output and I recalled the 8ohm output sounded softer and the soundstage was smaller. 

Hopefully your advice can help solve the imbalance others are facing. 

 

 

[F_Fabio]

Hi,  Connecting  the speakers to the R8  4 ohm output terminals  will increase the  sound quality ,    that is due to the lower output impedance of the 4 ohm output.  Low output  resistance means better control of the speakers and double output current  (although  you won't reach the nominal R8 output power if you have 8 ohm speakers).  I'm on the 4 ohm output too.

[echorec]

Interesting. I have been using the 8ohm tap with my 6ohm speakers. For me, the 8ohm sounded better (slightly bigger soundstage and slightly more punch), so perhaps it will vary from speaker to speaker.

 

Btw, Thomas and Stereo just published his video on the R8: