Willsenton R8 Owners & Discussion Thread

[Zed Zed]

Anyone got any views on my using the 4 ohm taps with my 8 ohm speakers?

[Wisker]

Looks sweet dude.......

[muon*]

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Edited July 22, 2021 by muon*

[xlr8or]

2 hours ago, Zed Zed said:

Anyone got any views on my using the 4 ohm taps with my 8 ohm speakers?

 

8 ohm nominal load speakers should typically be used with 8 ohm taps. If the 4 ohm taps are used instead, the load going back into the OPTs from the 8 ohm speakers will distort the power tube's output signal going into the primary of the OPTs.

[muon*]

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

Edited July 22, 2021 by muon*

[Lam Pham]

6 hours ago, Zed Zed said:

Here are the unboxing images I said I would post

Congrats

Thanks for the unboxing pictures as my earlier request, They have changed the way they packed the unit. Before all the tubed were preinstalled.

 

Happy listening!

[Zed Zed]

5 hours ago, muon* said:

Is there any good reason to use the incorrect taps?

 

Loads of good reasons, or so I read on what look like knowledgeable forums. This short thread, for example:

 

4 ohm taps on an 8 ohm speaker | Audiogon Discussion Forum

 

I know more or less nothing about tube amps at this stage (I am here to learn), which is why I posed the question here. Seems like some very knowledgeable members in this great thread.

 

That other thread implies there are significant benefits to running off the 4 ohm taps. Seems a little odd to me - why install 8 ohm taps if the 4 ohm taps are often/usually/always better?  Today I will swap over to the 8 ohm taps and see if I hear any difference. Thanks for all replies, as ever.

Edited January 30, 2021 by Zed Zed

[muon*]

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

Edited July 22, 2021 by muon*

[Zed Zed]

36 minutes ago, muon* said:

Lots of advice on forums, some are likely not as well informed as they may appear to be.

 

Includes yours truly

*shrug*

 

I'll continue to run my 8 ohm nominal ML-1's off my 8 ohm taps, they don't drop below 5.8 ohms across the frequency spectrum so using the 4 ohm taps would not be beneficial for myself

 

Do you know what the impedance of your speakers is like across the full frequency?

 

I have asked the manufacturer of my speakers if they will share an impedance curve with me (I can't find anywhere they publish one or any independent test where they do).

 

Agreed about forums, but that link I posted seems to have knowledgeable contributors, as does this forum of course. The one-eyed man and the kingdom of the blind comes to mind with regard to my current level of understanding of these things.

 

This is why I get confused when I read here that distortion may be increased when using the 4 ohm taps with nominal 8 ohm speakers, yet on the other forum I read the opposite. Here is what I read over there:

 

 

"More linear, reduces noise, raises damping factor, reduces distortion by 78% and 80$ more current", all sound to me like big benefits. No significant downsides are mentioned (other than be sure you don't allow the amp to run into clipping, which isn't likely here with the volume control never going beyond 11 o'clock and usually running nearer to 10 o'clock or lower, depending on content, mood etc.

 

If anyone can elaborate on this, I'd be extremely grateful. If this isn't the right thread for it, I'd be happy to open a new thread. I don't see it as off topic personally, since this will be of interest to all R8 owners, but, as always, I will respect the Mod's decision on this.

[xlr8or]

Here is some information taken from the web that may help explain what happens with impedance mismatch.

 

Impedance Mismatch Between the Power Tube and Speaker

As mentioned earlier to get the most power out of the amplifier the power tube and speaker should match their impedance. But what happens when they don't match?

 

Low Mismatch

 

If your output transformer is designed to match your power tubes to an 8 ohm speaker and you connect a 4 ohm speaker (4 ohm load and 50% decrease) then the impedance as seen by the power tube plate decreases by 50% too. Less impedance will cause plate current to increase. The power tubes are stressed by this increased plate current so the power tube lifespan can be shortened. This is especially true of Class A amps because they idle near max current flow. Since the plate current idles near maximum, the entire power supply also runs at maximum output so the rectifier tube and power transformer will run hotter. Power filtering effectiveness is reduced as current demand increases so hum and noise may increase, especially in Class A amps. Increased hum can cause ghost notes which are caused by hum interacting with musical notes to create false harmonic tones.

 

The increase in primary current will cause the output transformer to run hotter.

 

High Mismatch

 

If you connect a 16 ohm speaker to your 8 ohm output transformer the impedance as seen by the power tube plate increases and plate current decreases which can lengthen the lifespan of your power tubes, especially in Class A amps. This decrease in plate current will decrease demands on the power transformer and it will run cooler. Power filtering effectiveness is increased as current demand decreases so hum and noise should decrease, especially in Class A amps. Decreased hum can help prevent ghost notes. Since the power tube and transformer are not coupled at maximum efficiency the amp's power output is reduced.

 

The main problem with a high impedance mismatch is flyback voltage generated in the output transformer which can damage the power tubes and the output transformer itself. The flyback voltage spikes can cause the power tube to arc between pins or burn through the thin lacquer wire insulation used in the transformer windings. This is normally not a concern when going "one step" away from a match such as running a 4 ohm output transformer with an 8 ohm speaker unless the output transformer is cheaply made or really old. But running the 4 ohm transformer with a 16 ohm speaker can generate very high flyback voltages when running the amp hard near max volume.

 

If your power and/or output transformers run hot with a matched output transformer and speaker load then mismatching them is more of a risk. The bottom line is the greater the low impedance mismatch the harder your amp works, and the greater the high impedance mismatch the more likely you are to burn out your output transformer and/or power tubes.

 

For tube amps a low mismatch is typically safer than a high mismatch. The opposite is generally true for solid state amps.

Edited January 30, 2021 by xlr8or

[Zed Zed]

I tried the 8 ohm taps, which I am listening to as I type. Differences seem to be subtle. The bass is a little looser, not so well controlled as with the 4 ohm taps, but not by much TBH. Transients seem to have a little less attack on the 8 ohm taps - noticeable on, say, acoustic guitar played with a bit of aggression (say, Friday Night in San Francisco with Al Dimeola, John McLoughlin and Paco de Lucia).

 

In truth, I think I am just as happy with either setting. I will keep it under review for a while. Until the amp has had a decent bun-in time, there may be little point in trying to evaluate subtleties. 

[Zed Zed]

2 hours ago, xlr8or said:

Here is some information taken from the web that may help explain what happens with impedance mismatch.

 

Impedance Mismatch Between the Power Tube and Speaker

As mentioned earlier to get the most power out of the amplifier the power tube and speaker should match their impedance. But what happens when they don't match?

 

Low Mismatch

 

If your output transformer is designed to match your power tubes to an 8 ohm speaker and you connect a 4 ohm speaker (4 ohm load and 50% decrease) then the impedance as seen by the power tube plate decreases by 50% too. Less impedance will cause plate current to increase. The power tubes are stressed by this increased plate current so the power tube lifespan can be shortened. This is especially true of Class A amps because they idle near max current flow. Since the plate current idles near maximum, the entire power supply also runs at maximum output so the rectifier tube and power transformer will run hotter. Power filtering effectiveness is reduced as current demand increases so hum and noise may increase, especially in Class A amps. Increased hum can cause ghost notes which are caused by hum interacting with musical notes to create false harmonic tones.

 

The increase in primary current will cause the output transformer to run hotter.

 

High Mismatch

 

If you connect a 16 ohm speaker to your 8 ohm output transformer the impedance as seen by the power tube plate increases and plate current decreases which can lengthen the lifespan of your power tubes, especially in Class A amps. This decrease in plate current will decrease demands on the power transformer and it will run cooler. Power filtering effectiveness is increased as current demand decreases so hum and noise should decrease, especially in Class A amps. Decreased hum can help prevent ghost notes. Since the power tube and transformer are not coupled at maximum efficiency the amp's power output is reduced.

 

The main problem with a high impedance mismatch is flyback voltage generated in the output transformer which can damage the power tubes and the output transformer itself. The flyback voltage spikes can cause the power tube to arc between pins or burn through the thin lacquer wire insulation used in the transformer windings. This is normally not a concern when going "one step" away from a match such as running a 4 ohm output transformer with an 8 ohm speaker unless the output transformer is cheaply made or really old. But running the 4 ohm transformer with a 16 ohm speaker can generate very high flyback voltages when running the amp hard near max volume.

 

If your power and/or output transformers run hot with a matched output transformer and speaker load then mismatching them is more of a risk. The bottom line is the greater the low impedance mismatch the harder your amp works, and the greater the high impedance mismatch the more likely you are to burn out your output transformer and/or power tubes.

 

For tube amps a low mismatch is typically safer than a high mismatch. The opposite is generally true for solid state amps.

 

Great info - thanks Kirk. You can see why a toobnoob like me can get confused. One site says 'no problem, just do it', another says 'be careful, you could break stuff'.  Normally in these circs I play safe until I know what I am doing (maybe never!) so I think I will stick with the 8 ohm taps, for now at least. Thanks for taking the time to post that info.

Edited January 30, 2021 by Zed Zed

[Candan]

17 hours ago, Zed Zed said:

This is one tube, in its protective 'sock'.

Interesting how your tubes were individually wrapped.  Mine were all installed and a block of EVA foam placed over the whole thing.  Also stock tubes with KT88s.

[Zed Zed]

20 hours ago, Candan said:

Interesting how your tubes were individually wrapped.  Mine were all installed and a block of EVA foam placed over the whole thing.  Also stock tubes with KT88s.

 

I wonder why they changed it?  The way yours was delivered looks better to me, and easier for the user. Not that it was any sort of problem as the instructions were clear enough and all the tubes are marked with their relevant number, also printed on the amp itself, so the possibility of getting it wrong is slim.

 

I have 25 hours on mine now...

 

Can you (anyone?) tell me what to expect after it has been burned in for, say, 100 hours?  What am I looking for after this time?  What changes will occur? Sorry for these very basic questions, but I am a total tube virgin and trying to get myself up to speed as fast as I can. Thanks.

[xlr8or]

23 minutes ago, Zed Zed said:

Can you (anyone?) tell me what to expect after it has been burned in for, say, 100 hours?  What am I looking for after this time?  What changes will occur? Sorry for these very basic questions, but I am a total tube virgin and trying to get myself up to speed as fast as I can. Thanks.

 

The sound will mellow out nicely and captivate/immerse you in a balanced presentation that has everything going for it. You'll feel like you're part of the action and presentation. The depth and spread of the sound field will also fill up the listening environment. The tonal character will be there: top end, mids and bass notes will sound correct, open up and shine, and portray a realism factor that will excite. You'll get addicted to this sound and will keep coming back for more.

Edited January 31, 2021 by xlr8or

[Zed Zed]

7 minutes ago, xlr8or said:

 

The sound will mellow out nicely and captivate/immerse you in a balanced presentation that has everything going for it. You'll feel like you're part of the action and presentation. The depth and spread of the sound field will also fill up the listening environment. The tonal character will be there: top end, mids and bass notes will be correct and shine, and portray a realism factor that will excite. You'll get addicted to this sound and will keep coming back for more.

 

Wow. Thanks! Something to really look forward to then. I am already loving the sound, so if it is going to get even better, well, what can I say!

 

Am I right in thinking this will happen after 100 hours or so, or will it be quicker/slower than that?

 

Sorry for the endless questions, guys, but I really appreciate all the help from everyone. One day I might actually be able to contribute something to the discussion instead of asking question after question. It's great that I can reach out to the other side of the world for help and to receive it so graciously.

[xlr8or]

6 hours ago, Zed Zed said:

Am I right in thinking this will happen after 100 hours or so, or will it be quicker/slower than that?

 

I received some glowing feedback today from a fellow SNA member about the 80 hour mark they had reached for some early 1950's 12BH7's I had recommended to replace the 12AU7's on his preamp. I said wait till you hit the 200 hour mark.

Edited January 31, 2021 by xlr8or

[Zed Zed]

27 minutes ago, xlr8or said:

 

I received some glowing feedback today from a fellow SNA member about the 80 hour mark they had reached for some early 1950's 12BH7's I recommended to replace the 12AU7's on his preamp and said wait till you hit the 200 hour mark.

 

I've a way to go then

[Lam Pham]

1 hour ago, xlr8or said:

2 hours ago, Zed Zed said:

Am I right in thinking this will happen after 100 hours or so, or will it be quicker/slower than that?

 

Prepare for 200 hours running r8. It s a surprise for you (good things)

[Wisker]

R8 made it to the states, Estimated TOA is Wednesday ,  that would be 4 weeks to the day....

[Zed Zed]

Following on from my earlier posts about using the 4 ohm taps with my 8 ohm speakers . . .

 

I have checked about 15 different 'audiophile' websites now for information on this and in every case the advice can be summarised as "it will do no harm to the tube amplifier or speakers so use whichever sounds best to you". There is usually a caveat that the user needs to be sure they are not running the amp into clipping by using it this way. This isn't an issue for me as I have plenty of power from the R8, with my speakers in my room at my preferred listening levels.

 

I have consequently switched back to the 4 ohm taps and I can hear an immediate improvement. The bass is fuller and tighter and the mids and highs smoother and more 'inviting'. (This is in Triode mode. I am not using Ultralinear mode extensively - just on certain types of music where the extra dynamism of this mode complements the content well). Used in this way, here at least, there is a beautiful 'liquid' quality, especially on female voice, which is astonishingly realistic in its presentation. I can hear no downsides at this time.

 

I now have about 60 hours on the amp and am looking forward to reaching 100 this weekend.

 

 

 

 

On 31/01/2021 at 4:23 PM, Wisker said:

R8 made it to the states, Estimated TOA is Wednesday ,  that would be 4 weeks to the day....

 

Today's the day dude!!! Is it on schedule?

Edited February 3, 2021 by Zed Zed

[Ihearmusic]

1 hour ago, Zed Zed said:

Following on from my earlier posts about using the 4 ohm taps with my 8 ohm speakers . . .

 

I have checked about 15 different 'audiophile' websites now for information on this and in every case the advice can be summarised as "it will do no harm to the tube amplifier or speakers so use whichever sounds best to you". There is usually a caveat that the user needs to be sure they are not running the amp into clipping by using it this way. This isn't an issue for me as I have plenty of power from the R8, with my speakers in my room at my preferred listening levels.

 

I have consequently switched back to the 4 ohm taps and I can hear an immediate improvement. The bass is fuller and tighter and the mids and highs smoother and more 'inviting'. (This is in Triode mode. I am not using Ultralinear mode extensively - just on certain types of music where the extra dynamism of this mode complements the content well). Used in this way, here at least, there is a beautiful 'liquid' quality, especially on female voice, which is astonishingly realistic in its presentation. I can hear no downsides at this time.

 

I now have about 60 hours on the amp and am looking forward to reaching 100 this weekend.

 

 

 

 

 

Today's the day dude!!! Is it on schedule?

All you do when you use a different impedance tap (4 Ohm) is changing the operating point of the tube. This will result in a change of tone. Whether good or bad is up to the listener.

The operating point was however chosen to operate the tube in the most linear region with the least amount of distortion.

But this is just another example of why you can never judge a hifi component from just reading a review. It is just to subjective.

 

[Zed Zed]

21 hours ago, Ihearmusic said:

All you do when you use a different impedance tap (4 Ohm) is changing the operating point of the tube. This will result in a change of tone. Whether good or bad is up to the listener.

The operating point was however chosen to operate the tube in the most linear region with the least amount of distortion.

But this is just another example of why you can never judge a hifi component from just reading a review. It is just to subjective.

 

 

Bear in mind that, despite having decades of experience with high end and ultra high end audio, I am a newb when it comes to tube amps.  So please don't think I am in any way contradicting your comments above - and I note and entirely agree with your last two sentences. That said, from my recent research, this is what I have learned so far. When using the 4 ohm taps to drive (some) 8 ohm speakers:

 

• The 4 ohm taps will drive more current, whereas the 8 ohm taps will drive more voltage.
• For a given speaker impedance the damping factor will be twice as high for the 4 ohm tap as for the 8 ohm tap. (Damping factor is inversely proportional to output impedance). This may explain why I am hearing a noticeably tighter bass - the amp has more grip on the woofers.
• As we know, the impedance of most nominal 8 ohm speakers varies significantly as a function of frequency - so the 4 ohm tap may be a better match at some frequencies than the 8 ohm tap. This will result in a less linear output, but possibly a more pleasing or satisfying one.
• Tonal balance is affected by the interaction of the amp's output impedance with the speaker's frequency-induced impedance variations. Now it is very likely that most modern speakers have been voiced with the expectation that they will be used with SS amps. Since SS have have vanishingly small output impedances (a fraction of an ohm), it may be that the impact on FR by using the 4 ohm taps comes closer to the interaction intended by the designer - this may noticeably impact the 'sound'.
• Distortion introduced by the amplifier will depend to some extent on how well matched (or mismatched) the tap and the speaker impedance are at various frequencies.
• Using the 4 ohm taps with (nominal) 8 ohm speakers reduces the output current demand on the output tubes, which may allow them (the tubes). to be more linear.
• An obvious potential downside is that the power output will be reduced (possibly by as much as 3dB) - whether this is a real downside or not will depend, among other things, on the sensitivity of the speakers, size of room, preferred SPLs etc.
• I should also say that the amp runs warmer. So far, this doesn't seem to be a major issue, but it is worth noting.
   

Now all of the above are just summaries of what I have read. As I say, my experience with tube amps is very limited. Nonetheless, I do understand the issues involved and all of the above seems to make sense to me, based on what I (think) I know.

 

I'll post some listening impressions later, based on a dozen or more female vocalist tracks which I think are particularly revealing. 

 

Since I  am hearing a significantly superior sound using the 4 ohm taps with my 8 ohm speakers, I would recommend people give this a try, experimentally, to see if they also hear any sonic improvements. It will depend on the speakers used and their interaction with the amp, and this will be different for pretty much everyone so it has to be a 'suck it and see' basis I think.

 

My speakers are not a difficult load and they do not dip below 5 ohms at any point in their frequency range. Below is the manufacturer's impedance curve, for reference. Clearly, what anyone else hears if they try this experiment will greatly depend on the characteristics of their own speakers.

 

 

 

 

May I take this opportunity to thank everyone for their contributions to my understanding of this issue. It is a learning process for me, which is ongoing.

 

 

Edited February 4, 2021 by Zed Zed

[Zed Zed]

Here are my listening impressions as referred to in the post above (the tracks used are listed at the end). All tracks played in Triode mode at moderate to high volume levels.

 

I am new to tube amps, but have decades of listening experince with high-end and ultra-high-end systems. It is difficult to describe what one hears without descending into 'audiophile BS', but I will try to give as objective a report as I can.

 

If I had to summarise in a few words the difference I hear when using MY 8 ohm speakers with the R8's 4 ohm taps, I would say this: a significantly deeper emotional connection with the music.

 

Why is this?

 

1. The bass is clearly much better defined. Pretty much anyone would be able to hear the difference, more or less immediately. The bass is also (subjectively since I have taken no REW measurements at this time, but may do later) deeper. It may be that the greater sense of control (tightness) is giving an illusion of greater depth of FR, but whatever it is, this is how I am hearing it. This in turn adds to the rhythmic drive of the music (the 'foot tapping effect') and enhances one's pleasure.
    
2. Mid-range is where the biggest benefits come. Music lives in the mid-range and if this region of the FR improves, then the entire listening experience improves with it. I am finding that, with the 4 ohm taps in use, the mid-range is more 'liquid', more 'fluid' - smoother and more pleasant to listen to. It is an 'inviting' sound which seduces you and draws you into the music (hence the greater emotional connection I mentioned above). The female voices I used for the listening test have 'body' as well as soul. I feel that I can open my eyes and reach out and embrace Alison Krauss, who is performing, just for me, right in front of me. It sounds like a real human being singing. There is a palpable tactility to the sound. Again, this adds to the emotional connection. Bear in mind that some of these impressions are there when using the 8 ohm taps, but they are *enhanced* when using the 4 ohm taps (in my system I need to stress - YMMV).
    
3. The highs are smoother - more 'velvety' and 'liquid'. No sense of strain at all. Relaxed and seductive.
    
4. Overall, transients are also better defined. This may just be a by-product of the enhanced mid-range, but I am hearing the leading edges of notes more clearly with a definition which then morphs into the harmonics seamlessly. I can hear this on all instruments but especially so on plucked instruments, piano and drums, where it is almost possible to determine exactly where on the skin the stick is making contact - more centrally or more to the edge. The decay of notes, cymbals especially, is also clearer.

 

I am fairly certain that I have nothing like a 'flat' frequency response here right now. Nor do I care one bit. I am seeking pure aural pleasure (note spelling ). I listen to music to have a good time, to have fun. At some stage I will probably break out my mic and run REW and take some in-room measurements of what is actually happening. It will be instructive to do a 4 ohm vs 8 ohm tap and to measure the differences totally objectively.

 

Following my listening test today, I am leaving the amp in the 4 ohm setting. I do believe this is something that is well worth experimenting with. Obviously, results will depend to a very great extent on the partnering speakers and I can only speak for my own.

 

Here is the content I used for evaluation. It is more or less all female vocalists. I believe that if I can get this right, then everything else I play will also sound right (based on years of similar evaluations of amp/speaker/turntable/cartridge combinations).

 

All the tracks were, for convenience, streamed via Tidal, using their highest level (some tracks in MQA, all others in their 'CD quality' 'HiFi' level). I use an SMSL DAC which is fairly neutral in its presentation. I would expect content played via my TT to sound even better, but that is a different can of worms

 

How Can I Be Sure - Shelby Lynne
When The Love Breaks - Vanessa Fernandez
Cry Me A River - Lyn Stanley
You Don't Know Me - Alison Krauss
Marisa - Dave's True Story
I Don't Want To Hear It Any More - Shelby Lynne
Immigrant Song - Vanessa Fernandez
Lullaby Of Birdland - Lyn Stanley
September In Montreal - Anne Bisson
Gentle On My Mind - Alison Krauss
Like A Rock - Dave's True Story
Concrete Love - Julia Fordham
Pretend - Shelby Lynne
Still Life - Sarah Jarosz
Use Me - Vanessa Fernandez
I'm Walkin' - Lyn Stanley
Soothing Your Sould - Anne Bisson
Tattoo - Janis Ian
Ghost In The House - Alison Krauss

 

On several of those tracks, I had a shiver run down my spine, which is what I mean by 'emotional connection'.

 

Thanks for reading my ramblings

 

EDIT: I didn't mention the apparent increase in dynamics. It may not have been too noticeable on most of the tracks above, but I have since played some of my favourite Muddy Waters tracks and wow! At one point, when he went from quiet picking to a full-on assault on the strings of his Fender Telecaster I literally jumped in my seat - the sort of jump you make if someone crept up behind you and shouted 'Gotcha; right in your ear. The sound just exploded from the speakers! Now I happened to play this track when I was on the 8 ohm taps, at similar volume level, and I did not jump the way I just did. I was totally taken by surprise by the sheer dynamics. Is this because I am supplying more current now? High current and sensitive speakers is, in my experience, a potent combination. I am loving this amp!
 

Edited February 3, 2021 by Zed Zed

[echorec]

Great write-up @ZedZed Great test tracks as well, especially for "emotion".

 

Interestingly, my 6ohm speakers sound better on the 8ohm taps. I feel like I get more space between sounds/instruments, but it is very subtle. I also get a bit more output volume relative to volume position. I'll have to switch back to 4ohm taps now that I have a completely different tube configuration than when I first experimented with the taps. Maybe my preference will change. It's good to experiment with these things and choose whatever sounds best to your ears.